CN115160089B - Spray-coated film-forming type slow-release urea fertilizer and preparation method thereof - Google Patents
Spray-coated film-forming type slow-release urea fertilizer and preparation method thereof Download PDFInfo
- Publication number
- CN115160089B CN115160089B CN202210950870.XA CN202210950870A CN115160089B CN 115160089 B CN115160089 B CN 115160089B CN 202210950870 A CN202210950870 A CN 202210950870A CN 115160089 B CN115160089 B CN 115160089B
- Authority
- CN
- China
- Prior art keywords
- kitchen waste
- urea
- water
- maleic anhydride
- oxidized
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000004202 carbamide Substances 0.000 title claims abstract description 189
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 title claims abstract description 148
- 239000003337 fertilizer Substances 0.000 title claims abstract description 63
- 238000002360 preparation method Methods 0.000 title claims description 29
- 239000007921 spray Substances 0.000 title description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 115
- 239000000839 emulsion Substances 0.000 claims abstract description 95
- 239000007788 liquid Substances 0.000 claims abstract description 67
- 239000002362 mulch Substances 0.000 claims abstract description 27
- 239000010806 kitchen waste Substances 0.000 claims description 125
- FPYJFEHAWHCUMM-UHFFFAOYSA-N maleic anhydride Chemical compound O=C1OC(=O)C=C1 FPYJFEHAWHCUMM-UHFFFAOYSA-N 0.000 claims description 95
- 239000002002 slurry Substances 0.000 claims description 95
- 238000003756 stirring Methods 0.000 claims description 72
- 239000007864 aqueous solution Substances 0.000 claims description 70
- 239000000203 mixture Substances 0.000 claims description 59
- 229920005610 lignin Polymers 0.000 claims description 53
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 47
- 239000000178 monomer Substances 0.000 claims description 47
- 239000003995 emulsifying agent Substances 0.000 claims description 46
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 claims description 42
- 238000006243 chemical reaction Methods 0.000 claims description 40
- 239000000243 solution Substances 0.000 claims description 40
- 229920001732 Lignosulfonate Polymers 0.000 claims description 36
- 239000003999 initiator Substances 0.000 claims description 36
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims description 31
- 239000007800 oxidant agent Substances 0.000 claims description 28
- USHAGKDGDHPEEY-UHFFFAOYSA-L potassium persulfate Chemical compound [K+].[K+].[O-]S(=O)(=O)OOS([O-])(=O)=O USHAGKDGDHPEEY-UHFFFAOYSA-L 0.000 claims description 25
- 238000002156 mixing Methods 0.000 claims description 24
- 230000001590 oxidative effect Effects 0.000 claims description 23
- 230000001105 regulatory effect Effects 0.000 claims description 22
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 21
- 229910001870 ammonium persulfate Inorganic materials 0.000 claims description 21
- 239000011259 mixed solution Substances 0.000 claims description 21
- 239000002244 precipitate Substances 0.000 claims description 21
- 239000002245 particle Substances 0.000 claims description 19
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 16
- 238000001816 cooling Methods 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 15
- 229920002678 cellulose Polymers 0.000 claims description 12
- 239000001913 cellulose Substances 0.000 claims description 12
- 239000008367 deionised water Substances 0.000 claims description 11
- 229910021641 deionized water Inorganic materials 0.000 claims description 11
- 102000004169 proteins and genes Human genes 0.000 claims description 11
- 108090000623 proteins and genes Proteins 0.000 claims description 11
- 229920002472 Starch Polymers 0.000 claims description 10
- 229940051841 polyoxyethylene ether Drugs 0.000 claims description 10
- 229920000056 polyoxyethylene ether Polymers 0.000 claims description 10
- 235000019698 starch Nutrition 0.000 claims description 10
- 239000008107 starch Substances 0.000 claims description 10
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 claims description 9
- CQEYYJKEWSMYFG-UHFFFAOYSA-N butyl acrylate Chemical compound CCCCOC(=O)C=C CQEYYJKEWSMYFG-UHFFFAOYSA-N 0.000 claims description 9
- 239000004519 grease Substances 0.000 claims description 9
- DUIOKRXOKLLURE-UHFFFAOYSA-N 2-octylphenol Chemical compound CCCCCCCCC1=CC=CC=C1O DUIOKRXOKLLURE-UHFFFAOYSA-N 0.000 claims description 8
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 8
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 8
- 238000001035 drying Methods 0.000 claims description 8
- 239000000706 filtrate Substances 0.000 claims description 7
- 238000001914 filtration Methods 0.000 claims description 7
- 230000007935 neutral effect Effects 0.000 claims description 7
- 238000007873 sieving Methods 0.000 claims description 7
- 229920005552 sodium lignosulfonate Polymers 0.000 claims description 7
- 238000005406 washing Methods 0.000 claims description 7
- RYAGRZNBULDMBW-UHFFFAOYSA-L calcium;3-(2-hydroxy-3-methoxyphenyl)-2-[2-methoxy-4-(3-sulfonatopropyl)phenoxy]propane-1-sulfonate Chemical compound [Ca+2].COC1=CC=CC(CC(CS([O-])(=O)=O)OC=2C(=CC(CCCS([O-])(=O)=O)=CC=2)OC)=C1O RYAGRZNBULDMBW-UHFFFAOYSA-L 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 5
- 229920005551 calcium lignosulfonate Polymers 0.000 claims description 4
- 150000001875 compounds Chemical class 0.000 claims 1
- 239000002689 soil Substances 0.000 abstract description 59
- 230000000694 effects Effects 0.000 abstract description 22
- 238000005507 spraying Methods 0.000 abstract description 18
- 238000012271 agricultural production Methods 0.000 abstract description 7
- 240000007124 Brassica oleracea Species 0.000 abstract description 6
- 235000003899 Brassica oleracea var acephala Nutrition 0.000 abstract description 6
- 235000011301 Brassica oleracea var capitata Nutrition 0.000 abstract description 6
- 235000001169 Brassica oleracea var oleracea Nutrition 0.000 abstract description 6
- 238000010276 construction Methods 0.000 abstract description 6
- 235000016709 nutrition Nutrition 0.000 abstract description 4
- 230000035764 nutrition Effects 0.000 abstract description 3
- 230000000052 comparative effect Effects 0.000 description 60
- 238000012360 testing method Methods 0.000 description 19
- 239000000047 product Substances 0.000 description 17
- 229920000642 polymer Polymers 0.000 description 15
- 229920000058 polyacrylate Polymers 0.000 description 13
- 239000002699 waste material Substances 0.000 description 13
- 230000001186 cumulative effect Effects 0.000 description 12
- 239000003153 chemical reaction reagent Substances 0.000 description 11
- 244000221633 Brassica rapa subsp chinensis Species 0.000 description 9
- 235000010149 Brassica rapa subsp chinensis Nutrition 0.000 description 9
- 230000032798 delamination Effects 0.000 description 9
- 238000004321 preservation Methods 0.000 description 9
- 235000000536 Brassica rapa subsp pekinensis Nutrition 0.000 description 8
- 238000002835 absorbance Methods 0.000 description 8
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 8
- 238000006116 polymerization reaction Methods 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- 238000006065 biodegradation reaction Methods 0.000 description 6
- 238000007720 emulsion polymerization reaction Methods 0.000 description 6
- -1 feed Substances 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 6
- 229920005615 natural polymer Polymers 0.000 description 6
- 230000009471 action Effects 0.000 description 5
- 239000012153 distilled water Substances 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000002028 Biomass Substances 0.000 description 4
- 238000007654 immersion Methods 0.000 description 4
- 238000005070 sampling Methods 0.000 description 4
- BGNGWHSBYQYVRX-UHFFFAOYSA-N 4-(dimethylamino)benzaldehyde Chemical compound CN(C)C1=CC=C(C=O)C=C1 BGNGWHSBYQYVRX-UHFFFAOYSA-N 0.000 description 3
- 239000011203 carbon fibre reinforced carbon Substances 0.000 description 3
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000011056 performance test Methods 0.000 description 3
- 238000004537 pulping Methods 0.000 description 3
- 239000012086 standard solution Substances 0.000 description 3
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 229920001131 Pulp (paper) Polymers 0.000 description 2
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 2
- 238000007605 air drying Methods 0.000 description 2
- 125000003277 amino group Chemical group 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000002354 daily effect Effects 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- 230000001965 increasing effect Effects 0.000 description 2
- 229920002521 macromolecule Polymers 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000000618 nitrogen fertilizer Substances 0.000 description 2
- 238000005191 phase separation Methods 0.000 description 2
- 235000013311 vegetables Nutrition 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 241000219000 Populus Species 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 231100000209 biodegradability test Toxicity 0.000 description 1
- 239000002551 biofuel Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- YDEXUEFDPVHGHE-GGMCWBHBSA-L disodium;(2r)-3-(2-hydroxy-3-methoxyphenyl)-2-[2-methoxy-4-(3-sulfonatopropyl)phenoxy]propane-1-sulfonate Chemical compound [Na+].[Na+].COC1=CC=CC(C[C@H](CS([O-])(=O)=O)OC=2C(=CC(CCCS([O-])(=O)=O)=CC=2)OC)=C1O YDEXUEFDPVHGHE-GGMCWBHBSA-L 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000003203 everyday effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000003979 granulating agent Substances 0.000 description 1
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000010985 leather Substances 0.000 description 1
- 235000021190 leftovers Nutrition 0.000 description 1
- 229920001684 low density polyethylene Polymers 0.000 description 1
- 239000004702 low-density polyethylene Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 238000000643 oven drying Methods 0.000 description 1
- 239000010893 paper waste Substances 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000012088 reference solution Substances 0.000 description 1
- 238000007142 ring opening reaction Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 150000003384 small molecules Chemical class 0.000 description 1
- 238000009331 sowing Methods 0.000 description 1
- 238000013112 stability test Methods 0.000 description 1
- 239000011550 stock solution Substances 0.000 description 1
- 125000000542 sulfonic acid group Chemical group 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
- 239000000375 suspending agent Substances 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000000870 ultraviolet spectroscopy Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05C—NITROGENOUS FERTILISERS
- C05C3/00—Fertilisers containing other salts of ammonia or ammonia itself, e.g. gas liquor
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G3/00—Mixtures of one or more fertilisers with additives not having a specially fertilising activity
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G3/00—Mixtures of one or more fertilisers with additives not having a specially fertilising activity
- C05G3/40—Mixtures of one or more fertilisers with additives not having a specially fertilising activity for affecting fertiliser dosage or release rate; for affecting solubility
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G3/00—Mixtures of one or more fertilisers with additives not having a specially fertilising activity
- C05G3/50—Surfactants; Emulsifiers
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G3/00—Mixtures of one or more fertilisers with additives not having a specially fertilising activity
- C05G3/80—Soil conditioners
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G5/00—Fertilisers characterised by their form
- C05G5/10—Solid or semi-solid fertilisers, e.g. powders
- C05G5/16—Films or sheets; Webs; Fibres
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G5/00—Fertilisers characterised by their form
- C05G5/20—Liquid fertilisers
- C05G5/27—Dispersions, e.g. suspensions or emulsions
Abstract
Compared with common urea, the slow-release urea fertilizer with the spray-coating film-forming function has the advantages that the release rate of urea in water is reduced, and nutrition can be continuously provided for crops. The sprayable film-forming slow-release urea fertilizer prepared by the invention also has the function of spraying a liquid mulch film, is emulsion before use, can be sprayed on the surface of soil to form a liquid film layer, and then the liquid film layer is self-air-dried to form a film, so that the air-dried film layer can play a role in preventing moisture and heat in the soil from being dissipated outwards; the sprayable film-forming slow-release urea fertilizer prepared by the invention simultaneously meets three important basic factors required by efficient agricultural production, so that the effect of improving the yield of the cabbages is achieved; in addition, the slow-release urea fertilizer provided by the invention has the sprayability, so that the construction is simple, the operation is easy, and the popularization and the application of the product are facilitated.
Description
Technical field:
the invention provides a sprayable film-forming slow-release urea fertilizer and a preparation method thereof, belonging to the field of agricultural fertilizers and liquid mulching films.
The background technology is as follows:
although the continuously innovated agricultural science and technology has greatly alleviated the grain crisis problem faced by human society, people in some countries are still threatened by grain shortage and famine. Therefore, the agricultural production efficiency is continuously improved, the high standard requirements of people on the yield and quality of crops are met, and the important scientific and technical problems related to folk life are still urgently needed to be solved in all countries of the world. It is well known that three important basic factors are required to achieve efficient agricultural production: (1) Can continuously provide fertilizer nutrition for the whole growth stage of crops (including seeds to seedlings and seedlings to mature crops); (2) Suitable soil temperature and (3) soil moisture, these three basic factors being interdependent, indispensable.
Lignin and kitchen waste are waste and are biomass materials with important application value. Lignin is a natural high polymer with the second largest yield, in the paper industry, about 400kg of lignin is dissolved in paper waste liquid every 1t of paper pulp is produced, and the lignin is still not fully utilized until now, and most lignin is used as waste, so that not only is a great deal of resource waste caused, but also serious ecological environment pollution is caused. Kitchen waste generally refers to waste generated in activities such as daily living and eating services of residents, and comprises discarded unused vegetable leaves, leftovers and the like, and the kitchen waste is easy to spoil, so that malodorous smell polluting the environment, acid liquor polluting underground water and the like are generated. The lignin and kitchen waste after proper treatment and processing can be converted into fertilizer, feed, biofuel and the like. Lignin and kitchen waste have been used for preparing urea-containing fertilizers to meet the demands of crops for nitrogen elements, and for example, literature (1) CN104068206A) introduces lignin raw materials and pulped kitchen waste to be mixed, urea and other nutritional ingredients are added, and the mixture is extruded and puffed by an extruder to obtain the fertilizer. The fertilizer described in document 1 has effects of releasing urea and providing nitrogen fertilizer to crops, but has no effect of heat preservation and water preservation to soil, i.e., the fertilizer of document 1 lacks two of three important basic factors required for the aforementioned efficient agricultural production, and thus the fertilizer described in document 1 has limited effect of improving crop growth. A large amount of lignin and kitchen waste are continuously manufactured every day in the world, and if the lignin and kitchen waste can be jointly converted into products meeting three important basic factors required by efficient agricultural production, namely the products can be fertilizers and have the functions of heat preservation and water preservation of soil, and the products have important significance for promoting agricultural production and environmental protection.
The invention comprises the following steps:
in order to solve the problems in the prior art, the invention provides a preparation method of a sprayable film-forming slow-release urea fertilizer, which uses two common wastes as raw materials, has low cost and simple preparation method, and is easy to popularize and apply in the market.
The invention also provides a sprayable film-forming slow-release urea fertilizer, which can be used as a liquid mulching film, namely has the effects of preserving heat and moisture of soil, and can be used as a slow-release urea fertilizer, so as to achieve the effects of reducing the release rate of urea and continuously providing nitrogen fertilizer for crops.
The invention also provides application of the sprayable film-forming slow-release urea fertilizer in agricultural slow-release fertilizer and agricultural liquid mulching film.
The specific scheme of the invention is as follows:
a preparation method of a sprayable film-forming slow-release urea fertilizer comprises the following preparation steps:
(1) Mixing lignin sulfonate, maleic anhydride and water to obtain a solution, regulating the pH value of the obtained mixed solution to 10-11 by using a NaOH solution with the concentration of 1mol/L, stirring at 50-75 ℃ for reaction, cooling the mixed solution to room temperature after the reaction is carried out for 5-10h, regulating the pH value of the mixed solution to 1-2 by using a sulfuric acid solution with the concentration of 1.8mol/L, filtering the precipitate in the solution, repeatedly washing the precipitate by using water until the pH value of the filtrate is neutral, and drying the washed precipitate at 55-80 ℃ for 24-72h to obtain maleic anhydride modified lignin, wherein the mass ratio of lignin sulfonate, maleic anhydride and water is 1 (0.8-2): (5-15);
(2) Mixing kitchen waste with water, and crushing the obtained mixture into kitchen waste slurry by using a crusher, wherein the mass ratio of the kitchen waste to the water is 1: (1-2.5), sieving the kitchen waste slurry to ensure that the particle size of the kitchen waste slurry is less than 2mm, adding the sieved kitchen waste slurry into a reaction vessel provided with a stirrer, a thermometer and a condenser pipe, then adding an oxidant aqueous solution into the reaction vessel while stirring at 80-90 ℃, wherein the stirring speed is 500-1200r/min, and the stirring time is 1-3h, so as to obtain the pre-oxidized kitchen waste slurry, and the mass ratio of the sieved kitchen waste slurry to the oxidant aqueous solution is (3-5.3): 1, the oxidant aqueous solution in the step (2) is potassium persulfate or ammonium persulfate aqueous solution, and the mass percentage concentration of the potassium persulfate or ammonium persulfate is 6-12%;
(3) Stirring the maleic anhydride modified lignin obtained in the step (1), the pre-oxidized kitchen waste slurry obtained in the step (2) and urea at room temperature at a stirring speed of 800-2000r/min for 1.5-3.5h to obtain a slurry containing a maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound, wherein the mass ratio of the maleic anhydride modified lignin to the pre-oxidized kitchen waste to the urea is 1: (2.1-4.5): (4.4-9);
(4) Mixing the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3) with an acrylic acid monomer mixture, an emulsifier and water, and stirring the obtained mixture at 55-65 ℃ for 50-150min to obtain a pre-emulsion, wherein the stirring speed is 500-3000r/min, and the mass ratio of the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3), the acrylic acid monomer mixture, the emulsifier and the water is (32-44): (15-21): 1: (36-56), wherein the acrylic monomer mixture in the step (4) comprises the components in a mass ratio of (5.8-6.8): (2.1-3.2): butyl acrylate, methyl methacrylate and acrylic acid of 1;
(5) Raising the temperature of the pre-emulsion obtained in the step (4) to 75-90 ℃, dropwise adding an initiator aqueous solution into the pre-emulsion at a dropping speed of 0.04-0.2mL/min while stirring, continuing to react for 2-8h after the initiator aqueous solution is added dropwise, cooling the reaction system to room temperature, and then regulating the pH value of the system to 6.8-7.3 by using ammonia water with a mass percentage concentration of 25%, thereby obtaining the emulsion which is used as the sprayable film-forming slow-release urea fertilizer, wherein the mass ratio of the pre-emulsion obtained in the step (4) to the initiator aqueous solution is (67-97): 1.
The invention is further designed in that:
the lignosulfonate in the step (1) is sodium lignosulfonate or calcium lignosulfonate.
The kitchen waste in the step (2) contains 7.2-9.5wt% of starch, 10.0-12.2wt% of cellulose, 2.1-4.3wt% of protein, 1.1-2.1wt% of grease and 40-64wt% of water.
The mass ratio of the emulsifier in the step (4) is 1: (1.5-4.5) a mixture of a reactive emulsifier and octyl phenol polyoxyethylene ether (10), the type of the reactive emulsifier being LRS-10.
The initiator aqueous solution in the step (5) is potassium persulfate or ammonium persulfate aqueous solution, wherein the mass percentage concentration of the potassium persulfate or ammonium persulfate is 2.2-3.1%.
The water used in steps (1) - (5) is deionized water.
The invention also provides a sprayable film-forming slow-release urea fertilizer product which takes lignin and kitchen waste as raw materials and is prepared by the preparation method, and the dual-functional application of the product in the aspects of agricultural slow-release fertilizer and agricultural liquid mulching film.
Compared with the prior art, the invention has the following advantages:
the invention prepares the material with the urea slow-release function and the liquid mulching film spraying function by utilizing lignosulfonate extracted from the waste liquid in the paper industry and kitchen waste produced by daily life of residents, and the preparation technology realizes the simultaneous recycling of two waste biomass resources and achieves the effect of changing waste into valuables. Compared with the defect that the dissolution rate of common urea in water is too high, the slow-release urea fertilizer capable of being sprayed and formed has the urea slow-release function, and the urea release rate of the product in water is reduced, so that the product can realize high-efficiency urea utilization and can provide nutrition for crops continuously. The sprayable film-forming slow-release urea fertilizer prepared by the invention also has the function of spraying a liquid mulching film, wherein the liquid mulching film is liquid before use, has sprayability, can be sprayed on the surface of soil to form a liquid film layer, can be automatically air-dried to form a film, and can play a role in preventing moisture and heat in the soil from being dissipated outwards. The test results of the effect embodiment show that the sprayable film-forming slow-release urea fertilizer product prepared by the invention has sprayability, is convenient and quick to use, and reduces the construction cost; the product also has the function of forming a film on the surface of the soil, thereby playing a role in preserving water and heat of the soil; the product also has the urea slow-release function, and the sprayable film-forming slow-release urea fertilizer product prepared by the invention simultaneously meets three important basic factors required by efficient agricultural production, so that the slow-release fertilizer product has the effect of better improving the yield of the cabbages.
The working principle of the invention is analyzed as follows:
1. the step (1) of the invention is to prepare maleic anhydride modified lignin by taking lignosulfonate and maleic anhydride as raw materials. The lignosulfonate is a byproduct extracted from sulfite pulping waste liquid in the paper industry, has a plurality of applications, such as cement water reducing agent, pesticide suspending agent, ceramic or refractory plasticizer, coal water slurry dispersing agent, mineral separation dispersing agent, leather tanning agent, carbon black granulating agent and the like, but the amount of the lignosulfonate consumed by the applications is still small compared with the total content of the lignosulfonate in the paper pulp waste liquid, namely most of the lignosulfonate in the paper making waste liquid is not effectively utilized, and the discarded lignosulfonate is not only a resource waste, but also causes harm to ecological environment. Maleic anhydride is a molecule with a cyclic structure, also called maleic anhydride, and can react with hydroxyl in lignin sulfonate through structural ring opening, so that the lignin sulfonate is connected with a group with carbon-carbon double bond, and the maleic anhydride modified lignin is obtained. The maleic anhydride modified lignin with carbon-carbon double bonds can be subjected to polymerization reaction with acrylic ester monomers under the action of a catalyst, so that the maleic anhydride modified lignin can be uniformly fused with polyacrylate generated after polymerization to form a copolymer with good compatibility of each component and stable performance.
2. The step (2) of the invention is to pulp and screen the kitchen waste, and the screened kitchen waste slurry is pre-oxidized by potassium persulfate or ammonium persulfate aqueous solution as oxidant. Kitchen waste is also an important biomass raw material, has good biodegradability, contains natural polymers rich in hydroxyl groups such as cellulose, protein and sugar, and the natural polymers rich in hydroxyl groups can be mutually associated through hydrogen bonding action among the hydroxyl groups, so that kitchen waste slurry becomes sticky, the sticky kitchen waste slurry also can cause a subsequent reaction system to become sticky, a sticky liquid mulch emulsion product is obtained, and the spraying property of the too sticky mulch emulsion is poor, so that the spraying operation is not facilitated. After the potassium persulfate or ammonium persulfate aqueous solution in the step (2) preoxidizes the kitchen waste, part of hydroxyl groups in the kitchen waste are oxidized into carboxyl groups, so that the hydrogen bond association between natural polymers in the kitchen waste is reduced, the viscosity of kitchen waste slurry is correspondingly reduced, and the viscosity of a finally obtained liquid mulch emulsion product is further reduced, so that the liquid mulch emulsion has better sprayability, the spraying construction of the product in the field is facilitated, and the mulch construction difficulty is reduced.
3. The step (3) is to stir the maleic anhydride modified lignin obtained in the step (1), the pre-oxidized kitchen waste slurry obtained in the step (2) and urea at room temperature to obtain a maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound. The maleic anhydride modified lignin is a polymer, the pre-oxidized kitchen waste slurry is also rich in natural polymers, the two polymers are not easy to be compatible and uniformly mixed together, and if the two polymers are not well compatible, emulsion layering phenomenon caused by phase separation is easy to occur in the emulsion prepared subsequently. Urea is a small molecule containing two amino groups and a carbonyl group, the amino groups of the urea molecule can easily obtain a hydrogen ion with positive charges, so that the urea is combined with a sulfonic acid group with negative charges on maleic anhydride modified lignin through electrostatic action; meanwhile, urea molecules can be associated with carboxyl groups in the pre-oxidized kitchen waste and the maleic anhydride modified lignin through hydrogen bonding and the like, namely, the urea molecules are taken as bridges, so that the maleic anhydride modified lignin and the pre-oxidized kitchen waste can be well combined together to form a maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound, and the maleic anhydride modified lignin and macromolecules in the pre-oxidized kitchen waste are compatible and uniformly fused together at a molecular level; the urea molecules also reduce the hydrogen bond association between macromolecules, further reduce the viscosity of kitchen waste slurry and liquid mulch emulsion products prepared later, ensure that the liquid mulch emulsion has better sprayability, facilitate field spraying construction and reduce construction difficulty.
4. The step (4) of the invention is to obtain a pre-emulsion by using maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound, acrylic acid monomer mixture and water under the action of an emulsifier. In emulsion polymerization systems, especially in multiple emulsion polymerization systems, if conventional monomer dropping methods are employed, the formation of emulsion particles and the depth of polymerization are not synchronized, which tends to be difficult to control with respect to the particle size distribution of the emulsion, the elimination of residual monomers, and the stability of the system. The emulsion polymerization stability can be greatly improved, the amount of aggregates can be reduced, and the generation of wall forming substances can be reduced by preparing the pre-emulsion. In the preparation of the pre-emulsion, the stability of the pre-emulsion is good, demulsification and layering cannot be carried out, the viscosity of the pre-emulsion is moderate, and the proper proportion of the emulsifier solution, the proper temperature and the proper stirring condition are the precondition of forming the stable pre-emulsion.
5. In the step (5), the pre-emulsion obtained in the step (4) is subjected to emulsion polymerization under the action of an initiator. After the emulsion polymerization reaction, the polymerization reaction is carried out between the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound and the acrylic ester monomer, and between the acrylic ester monomer and the acrylic ester monomer. The polyacrylate part is obtained after the polymerization reaction between acrylate monomers, the polyacrylate has good film forming property, the emulsion of the obtained sprayable film forming type slow release urea fertilizer can form a film on the surface of soil, and the film forming can block gaps among soil particles, so that the heat and moisture in the soil are prevented from being lost, and the effects of heat preservation and moisture preservation on the soil are achieved. After grafting polymerization reaction of the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound and the acrylic ester monomer, the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound and the polyacrylate are uniformly compatible and fused together, and urea is wrapped in a two-layer polymer network: one is in the polymer network of maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound, the other is that the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound is embedded in the polyacrylate network, and under the continuous encapsulation of the two polymer networks, the release rate of urea molecules is greatly reduced, so that the slow release effect of urea is realized.
Drawings
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate the invention and together with the description serve to explain, without limitation, the invention.
FIG. 1 is a process flow diagram of the invention for preparing a sprayable film-forming slow release urea fertilizer.
FIG. 2 is a process flow diagram of a slurry containing a maleic anhydride modified lignin-pre-oxidized kitchen waste-urea complex prepared in accordance with the present invention.
FIG. 3 is a graph of the cumulative urea release curves of the film samples prepared in examples 1-5 and pure urea in a urea release performance test according to the invention, wherein the error bars represent the standard deviation of the mean of the results obtained from three parallel experiments, numbered: a is the example 1 sample, B is the example 2 sample, C is the example 3 sample, D is the example 4 sample, E is the example 5 sample, F is pure urea.
Detailed Description
The above and further technical features and advantages of the present invention will be described in more detail below with reference to the examples. The chemical raw materials used in the following examples are all commercially available, chemically pure reagents;
lignosulfonate (sodium lignin sulfonate and calcium lignin sulfonate) is extracted from poplar sulfite pulping waste liquid and is provided by Jiangsu province pulping and papermaking science and technology key laboratory (Nanjing).
Kitchen waste is taken from students canteen at university of Nanjing forestry.
Butyl acrylate, methyl methacrylate and acrylic acid, as well as ammonia, all having a purity of 99% were purchased from metallocene chemical reagent limited (Tianjin, china).
Reactive emulsifier with purity of 99% (model LRS-10) and octyl phenol polyoxyethylene ether (10) (OP-10) with purity of 99% are purchased from Nanjing chess, new Material Co., ltd (Jiangsu China).
Potassium persulfate and ammonium persulfate having a purity of 99.5% were purchased from Lingfeng chemical reagent Co., ltd (Shanghai, china).
Urea is purchased from Jinan winning chemical technology Co., ltd, total nitrogen is more than 46.0%, and particle size is 0.85-2.8mm.
Example 1
(1) Mixing lignosulfonate, maleic anhydride and water to form a solution, regulating the pH value of the obtained mixed solution to 10 by using a NaOH solution with the concentration of 1mol/L, stirring at the temperature of 75 ℃ for reaction, cooling the mixed solution to room temperature after the reaction is carried out for 10 hours, regulating the pH value of the mixed solution to be between 1 by using a sulfuric acid solution with the concentration of 1.8mol/L, filtering the precipitate in the solution, repeatedly washing the precipitate by using water until the pH value of the filtrate is neutral, and drying the washed precipitate at the temperature of 55 ℃ for 72 hours to obtain maleic anhydride modified lignin, wherein the mass ratio of the lignosulfonate, the maleic anhydride and the water is 1:0.8:5;
(2) Mixing kitchen waste with water, and crushing the obtained mixture into kitchen waste slurry by using a crusher, wherein the mass ratio of the kitchen waste to the water is 1:1, sieving kitchen waste slurry to ensure that the particle size of the kitchen waste slurry is less than 2mm, adding the sieved kitchen waste slurry into a reaction container provided with a stirrer, a thermometer and a condenser pipe, then adding an oxidant aqueous solution into the reaction container while stirring at 80 ℃, wherein the stirring speed is 500r/min, and the stirring time is 1h to obtain pre-oxidized kitchen waste slurry, and the mass ratio of the sieved kitchen waste slurry to the oxidant aqueous solution is 3:1, the oxidant aqueous solution in the step (2) is ammonium persulfate aqueous solution, and the mass percentage concentration of ammonium persulfate is 6%;
(3) Stirring the maleic anhydride modified lignin obtained in the step (1), the pre-oxidized kitchen waste slurry obtained in the step (2) and urea at room temperature at a stirring speed of 800r/min for 1.5h to obtain a slurry containing a maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound, wherein the mass ratio among the maleic anhydride modified lignin, the pre-oxidized kitchen waste and the urea is 1:2.1:4.4;
(4) Mixing the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3) with an acrylic acid monomer mixture, an emulsifier and water, and stirring the obtained mixture at 55 ℃ for 150min to obtain a pre-emulsion with a stirring speed of 500r/min, wherein the mass ratio of the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3) to the acrylic acid monomer mixture, the emulsifier and the water is 32:15:1: the acrylic monomer mixture in the step (4) comprises the components with the mass ratio of 5.8:2.1: butyl acrylate, methyl methacrylate and acrylic acid of 1;
(5) Raising the temperature of the pre-emulsion obtained in the step (4) to 75 ℃, dropwise adding an initiator aqueous solution into the pre-emulsion at a dropping speed of 0.04mL/min while stirring, wherein the stirring speed is 200r/min, continuing to react for 2 hours after the initiator aqueous solution is added dropwise, cooling the reaction system to room temperature, and then regulating the pH value of the system to 6.8 by using ammonia water with a mass percentage concentration of 25%, thereby obtaining the emulsion which is used as the sprayable film-forming slow-release urea fertilizer, wherein the mass ratio between the pre-emulsion obtained in the step (4) and the initiator aqueous solution is 67:1.
Wherein the lignosulfonate in the step (1) is sodium lignosulfonate. The kitchen waste in the step (2) contains 7.2wt% of starch, 12.2wt% of cellulose, 2.1wt% of protein, 2.1wt% of grease and 40wt% of water. The mass ratio of the emulsifier in the step (4) is 1:1.5 and octylphenol polyoxyethylene ether (10), the type of the reactive emulsifier being LRS-10. The initiator aqueous solution in the step (5) is potassium persulfate aqueous solution, wherein the mass percentage concentration of the potassium persulfate is 2.2%. The water used in steps (1) - (5) is deionized water.
The spray-coating film-forming slow-release urea fertilizer of the embodiment 1 can be obtained through the steps (1) - (5), has uniform and stable emulsion appearance, and has no layering phenomenon after standing for 30 days.
Example 2
(1) Mixing lignin sulfonate, maleic anhydride and water to obtain a solution, regulating the pH value of the obtained mixed solution to 10.2 by using a NaOH solution with the concentration of 1mol/L, stirring at 69 ℃ for reaction, cooling the mixed solution to room temperature after the reaction is carried out for 9 hours, regulating the pH value of the mixed solution to be between 1.2 by using a sulfuric acid solution with the concentration of 1.8mol/L, filtering the precipitate in the solution, repeatedly washing the precipitate by using water until the pH value of the filtrate is neutral, and drying the washed precipitate at 61 ℃ for 60 hours to obtain maleic anhydride modified lignin, wherein the mass ratio of lignin sulfonate, maleic anhydride and water is 1:1.1:7.5;
(2) Mixing kitchen waste with water, and crushing the obtained mixture into kitchen waste slurry by using a crusher, wherein the mass ratio of the kitchen waste to the water is 1:1.4, sieving the kitchen waste slurry to ensure that the particle size of the kitchen waste slurry is less than 2mm, adding the sieved kitchen waste slurry into a reaction container provided with a stirrer, a thermometer and a condenser pipe, adding an oxidant aqueous solution into the reaction container while stirring at 83 ℃, wherein the stirring speed is 700r/min, and the stirring time is 1.5h, so as to obtain the pre-oxidized kitchen waste slurry, and the mass ratio of the sieved kitchen waste slurry to the oxidant aqueous solution is 3.6:1, the oxidant aqueous solution in the step (2) is potassium persulfate aqueous solution, and the mass percentage concentration of the potassium persulfate is 7.5%;
(3) Stirring the maleic anhydride modified lignin obtained in the step (1), the pre-oxidized kitchen waste slurry obtained in the step (2) and urea at room temperature at the stirring speed of 1100r/min for 2 hours to obtain a slurry containing a maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound, wherein the mass ratio of the maleic anhydride modified lignin to the pre-oxidized kitchen waste to the urea is 1:2.7:5.6;
(4) Mixing the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3) with an acrylic acid monomer mixture, an emulsifier and water, and stirring the obtained mixture at 58 ℃ for 125min to obtain a pre-emulsion with a stirring speed of 1100r/min, wherein the mass ratio of the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3) to the acrylic acid monomer mixture, the emulsifier and the water is 35:16.5:1:41, the acrylic monomer mixture in step (4) comprises a mass ratio of 6.05:2.4: butyl acrylate, methyl methacrylate and acrylic acid of 1;
(5) Raising the temperature of the pre-emulsion obtained in the step (4) to 79 ℃, dropwise adding an initiator aqueous solution into the pre-emulsion at a dropping speed of 0.08mL/min while stirring, wherein the stirring speed is 300r/min, continuing to react for 3.25h after the initiator aqueous solution is added dropwise, cooling the reaction system to room temperature, and then regulating the pH value of the system to 6.9 by using ammonia water with a mass percentage concentration of 25%, thereby obtaining the emulsion serving as the sprayable film-forming slow-release urea fertilizer, wherein the mass ratio between the pre-emulsion obtained in the step (4) and the initiator aqueous solution is 75:1.
Wherein the lignosulfonate in the step (1) is calcium lignosulfonate. The kitchen waste in the step (2) contains 7.8wt% of starch, 11.6wt% of cellulose, 2.6wt% of protein, 1.9wt% of grease and 46wt% of water. The mass ratio of the emulsifier in the step (4) is 1:2.5 and octylphenol polyoxyethylene ether (10), the type of the reactive emulsifier being LRS-10. The initiator aqueous solution in the step (5) is ammonium persulfate aqueous solution, wherein the mass percentage concentration of the ammonium persulfate is 2.4%. The water used in steps (1) - (5) is deionized water.
The spray-coating film-forming slow-release urea fertilizer of the embodiment 2 can be obtained through the steps (1) - (5), the appearance of the slow-release urea fertilizer is in a uniform and stable emulsion, and layering phenomenon does not exist within 30 days after standing.
Example 3
(1) Mixing lignin sulfonate, maleic anhydride and water to obtain a solution, regulating the pH value of the obtained mixed solution to 10.5 by using a NaOH solution with the concentration of 1mol/L, stirring at 63 ℃ for reaction, cooling the mixed solution to room temperature after the reaction is carried out for 8 hours, regulating the pH value of the mixed solution to be between 1.5 by using a sulfuric acid solution with the concentration of 1.8mol/L, filtering the precipitate in the solution, repeatedly washing the precipitate by using water until the pH value of the filtrate is neutral, and drying the washed precipitate at 67 ℃ for 48 hours to obtain maleic anhydride modified lignin, wherein the mass ratio of lignin sulfonate, maleic anhydride and water is 1:1.4:10;
(2) Mixing kitchen waste with water, and crushing the obtained mixture into kitchen waste slurry by using a crusher, wherein the mass ratio of the kitchen waste to the water is 1:1.8, sieving the kitchen waste slurry to ensure that the particle size of the kitchen waste slurry is less than 2mm, adding the sieved kitchen waste slurry into a reaction container provided with a stirrer, a thermometer and a condenser pipe, then adding an oxidant aqueous solution into the reaction container while stirring at 85 ℃, wherein the stirring speed is 800r/min, and the stirring time is 2h, so as to obtain the pre-oxidized kitchen waste slurry, and the mass ratio of the sieved kitchen waste slurry to the oxidant aqueous solution is 4.1:1, the oxidant aqueous solution in the step (2) is ammonium persulfate aqueous solution, and the mass percentage concentration of ammonium persulfate is 9%;
(3) Stirring the maleic anhydride modified lignin obtained in the step (1), the pre-oxidized kitchen waste slurry obtained in the step (2) and urea at room temperature at a stirring speed of 1400r/min for 2.5h to obtain a slurry containing a maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound, wherein the mass ratio among the maleic anhydride modified lignin, the pre-oxidized kitchen waste and the urea is 1:3.3:6.8;
(4) Mixing the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3) with an acrylic acid monomer mixture, an emulsifier and water, and stirring the obtained mixture at 60 ℃ for 100min to obtain a pre-emulsion with a stirring speed of 1800r/min, wherein the mass ratio of the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3) to the acrylic acid monomer mixture, the emulsifier and the water is 38:18:1:46, the acrylic monomer mixture in step (4) comprises a mass ratio of 6.3:2.7: butyl acrylate, methyl methacrylate and acrylic acid of 1;
(5) Raising the temperature of the pre-emulsion obtained in the step (4) to 83 ℃, dropwise adding an initiator aqueous solution into the pre-emulsion at a dropping speed of 0.12mL/min while stirring, wherein the stirring speed is 400r/min, continuing to react for 4.5h after the initiator aqueous solution is added dropwise, cooling the reaction system to room temperature, and then regulating the pH value of the system to 7 by using ammonia water with a mass percentage concentration of 25%, thereby obtaining the emulsion which is used as the sprayable film-forming slow-release urea fertilizer, wherein the mass ratio between the pre-emulsion obtained in the step (4) and the initiator aqueous solution is 82:1.
Wherein the lignosulfonate in the step (1) is sodium lignosulfonate. The kitchen waste in the step (2) contains 8.4wt% of starch, 11wt% of cellulose, 3.1wt% of protein, 1.7wt% of grease and 52wt% of water. The mass ratio of the emulsifier in the step (4) is 1:3 and octyl phenol polyoxyethylene ether (10), the model of the reactive emulsifier is LRS-10. The initiator aqueous solution in the step (5) is potassium persulfate aqueous solution, wherein the mass percentage concentration of the potassium persulfate is 2.6%. The water used in steps (1) - (5) is deionized water.
The spray-coating film-forming slow-release urea fertilizer of the embodiment 3 can be obtained through the steps (1) - (5), the appearance of the slow-release urea fertilizer is in a uniform and stable emulsion, and layering phenomenon does not exist within 30 days after standing.
Example 4
(1) Mixing lignin sulfonate, maleic anhydride and water to obtain a solution, regulating the pH value of the obtained mixed solution to 10.8 by using a NaOH solution with the concentration of 1mol/L, stirring at 56 ℃ for reaction, cooling the mixed solution to room temperature after the reaction is carried out for 7 hours, regulating the pH value of the mixed solution to be between 1.8 by using a sulfuric acid solution with the concentration of 1.8mol/L, filtering the precipitate in the solution, repeatedly washing the precipitate by using water until the pH value of the filtrate is neutral, and drying the washed precipitate at 74 ℃ for 36 hours to obtain maleic anhydride modified lignin, wherein the mass ratio of lignin sulfonate, maleic anhydride and water is 1:1.7:12.5;
(2) Mixing kitchen waste with water, and crushing the obtained mixture into kitchen waste slurry by using a crusher, wherein the mass ratio of the kitchen waste to the water is 1:2.1, sieving the kitchen waste slurry to ensure that the particle size of the kitchen waste slurry is less than 2mm, adding the sieved kitchen waste slurry into a reaction container provided with a stirrer, a thermometer and a condenser pipe, adding an oxidant aqueous solution into the reaction container while stirring at 88 ℃, wherein the stirring speed is 1000r/min, and the stirring time is 2.5h, so as to obtain the pre-oxidized kitchen waste slurry, and the mass ratio of the sieved kitchen waste slurry to the oxidant aqueous solution is 4.7:1, the oxidant aqueous solution in the step (2) is potassium persulfate aqueous solution, and the mass percentage concentration of the potassium persulfate is 10.5%;
(3) Stirring the maleic anhydride modified lignin obtained in the step (1), the pre-oxidized kitchen waste slurry obtained in the step (2) and urea at room temperature at 1700r/min for 3h to obtain a slurry containing a maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound, wherein the mass ratio of the maleic anhydride modified lignin to the pre-oxidized kitchen waste to the urea is 1:3.9:7.9;
(4) Mixing the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3) with an acrylic acid monomer mixture, an emulsifier and water, and stirring the obtained mixture at 62 ℃ for 75min to obtain a pre-emulsion with a stirring speed of 2400r/min, wherein the mass ratio among the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3), the acrylic acid monomer mixture, the emulsifier and the water is 41:19.5:1:51, the acrylic monomer mixture of step (4) comprises a mass ratio of 6.55:3: butyl acrylate, methyl methacrylate and acrylic acid of 1;
(5) Raising the temperature of the pre-emulsion obtained in the step (4) to 87 ℃, dropwise adding an initiator aqueous solution into the pre-emulsion at a dropping speed of 0.16mL/min while stirring, wherein the stirring speed is 500r/min, continuing to react for 6.75 hours after the initiator aqueous solution is added dropwise, cooling the reaction system to room temperature, and then regulating the pH value of the system to 7.1 by using ammonia water with a mass percentage concentration of 25%, thereby obtaining the emulsion serving as the sprayable film-forming slow-release urea fertilizer, wherein the mass ratio between the pre-emulsion obtained in the step (4) and the initiator aqueous solution is 90:1.
Wherein the lignosulfonate in the step (1) is sodium lignosulfonate. The kitchen waste in the step (2) contains 9wt% of starch, 10.6wt% of cellulose, 3.7wt% of protein, 1.4wt% of grease and 58wt% of water. The mass ratio of the emulsifier in the step (4) is 1:3.8 and octyl phenol polyoxyethylene ether (10), the model of the reactive emulsifier is LRS-10. The initiator aqueous solution in the step (5) is ammonium persulfate aqueous solution, wherein the mass percentage concentration of the ammonium persulfate is 2.8%. The water used in steps (1) - (5) is deionized water.
The spray-coating film-forming slow-release urea fertilizer of the embodiment 4 can be obtained through the steps (1) - (5), the appearance of the slow-release urea fertilizer is in a uniform and stable emulsion, and layering phenomenon does not exist within 30 days after standing.
Example 5
(1) Mixing lignosulfonate, maleic anhydride and water to obtain a solution, regulating the pH value of the obtained mixed solution to 11 by using a NaOH solution with the concentration of 1mol/L, stirring at 50 ℃ for reaction, cooling the mixed solution to room temperature after the reaction is carried out for 5 hours, regulating the pH value of the mixed solution to be between 2 by using a sulfuric acid solution with the concentration of 1.8mol/L, filtering the precipitate in the solution, repeatedly washing the precipitate by using water until the pH value of the filtrate is neutral, and drying the washed precipitate at 80 ℃ for 24 hours to obtain maleic anhydride modified lignin, wherein the mass ratio of the lignosulfonate, the maleic anhydride and the water is 1:2:15;
(2) Mixing kitchen waste with water, and crushing the obtained mixture into kitchen waste slurry by using a crusher, wherein the mass ratio of the kitchen waste to the water is 1:2.5, sieving the kitchen waste slurry to ensure that the particle size of the kitchen waste slurry is less than 2mm, adding the sieved kitchen waste slurry into a reaction container provided with a stirrer, a thermometer and a condenser pipe, adding an oxidant aqueous solution into the reaction container while stirring at 90 ℃, wherein the stirring speed is 1200r/min, and the stirring time is 3h, so as to obtain the pre-oxidized kitchen waste slurry, and the mass ratio of the sieved kitchen waste slurry to the oxidant aqueous solution is 5.3:1, the oxidant aqueous solution in the step (2) is ammonium persulfate aqueous solution, and the mass percentage concentration of ammonium persulfate is 12%;
(3) Stirring the maleic anhydride modified lignin obtained in the step (1), the pre-oxidized kitchen waste slurry obtained in the step (2) and urea at room temperature at a stirring speed of 2000r/min for 3.5h to obtain a slurry containing a maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound, wherein the mass ratio among the maleic anhydride modified lignin, the pre-oxidized kitchen waste and the urea is 1:4.5:9, a step of performing the process;
(4) Mixing the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3) with an acrylic acid monomer mixture, an emulsifier and water, and stirring the obtained mixture at 65 ℃ for 50min to obtain a pre-emulsion with a stirring speed of 3000r/min, wherein the mass ratio of the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3) to the acrylic acid monomer mixture, the emulsifier and the water is 44:21:1:56, the acrylic monomer mixture of step (4) comprises a mass ratio of 6.8:3.2: butyl acrylate, methyl methacrylate and acrylic acid of 1;
(5) Raising the temperature of the pre-emulsion obtained in the step (4) to 90 ℃, dropwise adding an initiator aqueous solution into the pre-emulsion at a dropping speed of 0.2mL/min while stirring, wherein the stirring speed is 600r/min, continuing to react for 8 hours after the initiator aqueous solution is added dropwise, cooling the reaction system to room temperature, and then regulating the pH value of the system to 7.3 by using ammonia water with a mass percentage concentration of 25%, thereby obtaining the emulsion which is used as the sprayable film-forming slow-release urea fertilizer, wherein the mass ratio between the pre-emulsion obtained in the step (4) and the initiator aqueous solution is 97:1.
Wherein the lignosulfonate in the step (1) is calcium lignosulfonate. The kitchen waste in the step (2) contains 9.5wt% of starch, 10.0wt% of cellulose, 4.3wt% of protein, 1.1wt% of grease and 64wt% of water. The mass ratio of the emulsifier in the step (4) is 1:4.5 and octyl phenol polyoxyethylene ether (10), wherein the model of the reactive emulsifier is LRS-10. The initiator aqueous solution in the step (5) is potassium persulfate aqueous solution, wherein the mass percentage concentration of the potassium persulfate is 3.1%. The water used in steps (1) - (5) is deionized water.
The spray-coating film-forming slow-release urea fertilizer of the embodiment 5 can be obtained through the steps (1) - (5), the appearance of the slow-release urea fertilizer is in a uniform and stable emulsion, and layering phenomenon does not exist within 30 days after standing.
Comparative example 6
The difference between the preparation of the sprayable film-forming slow-release urea fertilizer according to the step of example 3 and the preparation of the sprayable film-forming slow-release urea fertilizer according to the step of example 3 is that the particle size of the kitchen waste slurry in the step (2) of the embodiment is 2.5-3.5mm, and the particle size is larger than 2mm of the kitchen waste slurry in the claims of the invention, namely the particle size of the kitchen waste slurry in the comparative example 6 is larger. Other preparation steps and reagent amounts were the same as in example 3.
Comparative example 7
In this example, a sprayable film-forming slow release urea fertilizer was prepared according to the procedure described in example 3, which differs from example 3 in that the mass ratio of lignosulfonate, maleic anhydride and water in step (1) of this example was 1:0.6:10, and the amount of maleic anhydride used in this mass ratio was less than the range (0.8-2) of the claims of the present invention, i.e., the amount of maleic anhydride used in comparative example 7 was small. Other preparation steps and reagent amounts were the same as in example 3.
Comparative example 8
The difference between the preparation of the sprayable film-forming slow-release urea fertilizer according to the step described in example 3 and the preparation of the sprayable film-forming slow-release urea fertilizer according to the step (2) of the embodiment is that the mass ratio between the sieved kitchen waste slurry and the oxidant aqueous solution is 2.8:1, the amount of the oxidizing agent used in the mass ratio is smaller than the range (3-5.3) of the present invention claimed, i.e., the amount of the oxidizing agent used in comparative example 8 is smaller. Other preparation steps and reagent amounts were the same as in example 3.
Comparative example 9
The difference between the preparation of the sprayable film-forming slow-release urea fertilizer according to the step described in the example 3 and the example 3 is that the mass ratio of maleic anhydride modified lignin, pre-oxidized kitchen waste and urea in the step (3) of the example is 1:1.9:6.8, the mass ratio of the kitchen waste is smaller than the range (2.1-4.5) of the invention in the claims, namely the kitchen waste in the comparative example 9 is smaller. Other preparation steps and reagent amounts were the same as in example 3.
Comparative example 10
This example was a liquid mulch prepared according to the procedure described in example 3, which differs from example 3 in that instead of preparing a slurry containing a maleic anhydride modified lignin-pre-oxidized kitchen waste-urea complex, maleic anhydride modified lignin, pre-oxidized kitchen waste and urea were directly mixed with an acrylic acid monomer mixture, an emulsifier and water. Other preparation steps and reagent amounts were the same as in example 3. The specific test steps are as follows:
steps (1) and (2) of this embodiment are the same as steps (1) and (2) of embodiment (3).
(3) Mixing the maleic anhydride modified lignin obtained in the step (1), the pre-oxidized kitchen waste slurry obtained in the step (2), urea, an acrylic acid monomer mixture, an emulsifier and water, and stirring the obtained mixture at 60 ℃ for 100min to obtain a pre-emulsion, wherein the stirring speed is 1800r/min, and the mass ratio of the maleic anhydride modified lignin, the pre-oxidized kitchen waste slurry and the urea is 1:3.3:6.8, the mass ratio between the total mass of maleic anhydride modified lignin, pre-oxidized kitchen waste pulp and urea and the acrylic acid monomer mixture, emulsifier and water is 38:18:1:46, the acrylic monomer mixture in step (3) comprises a mass ratio of 6.3:2.7: butyl acrylate, methyl methacrylate and acrylic acid of 1;
Step (4) of this embodiment is the same as step (5) of embodiment (3).
Wherein the lignosulfonate in the step (1) is sodium lignosulfonate. The kitchen waste in the step (2) contains 8.4wt% of starch, 11wt% of cellulose, 3.1wt% of protein, 1.7wt% of grease and 52wt% of water. The mass ratio of the emulsifier in the step (3) is 1:3 and octyl phenol polyoxyethylene ether (10), the model of the reactive emulsifier is LRS-10. The initiator aqueous solution in the step (4) is potassium persulfate aqueous solution, wherein the mass percentage concentration of the potassium persulfate is 2.6%. The water used in the steps (1) - (4) is deionized water.
Comparative example 11
This example is a liquid mulch film prepared according to the procedure described in example 3, which differs from example 3 in that in step (4) of this example, the mass ratio between the slurry containing the maleic anhydride-modified lignin-pre-oxidized kitchen waste-urea complex, the acrylic monomer mixture, the emulsifier and the water is 38:13:1:46, the amount of the acrylic monomer mixture in the mass ratio is smaller than the range (15-21) of the present invention, i.e., the amount of the acrylic monomer mixture is smaller. Other preparation steps and reagent amounts were the same as in example 3.
Comparative example 12
This example was a liquid mulch prepared according to the procedure described in example 3, which differs from example 3 in that the pre-emulsion was not prepared, but rather the aqueous initiator solution was added directly to the slurry containing the maleic anhydride-modified lignin-pre-oxidized kitchen waste-urea complex, the acrylic monomer mixture, the emulsifier and the water mixture. Other preparation steps and reagent amounts were the same as in example 3.
The specific test steps are as follows:
steps (1) - (3) of this example are the same as steps (1) - (3) of example (3).
(4) Physically mixing the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3) with an acrylic acid monomer mixture, an emulsifier and water, immediately raising the temperature of the obtained mixture to 83 ℃, dropwise adding an initiator aqueous solution into the mixture at a dropping speed of 0.12mL/min while stirring, continuously carrying out reaction for 4.5h after the dropwise addition of the initiator solution is completed, cooling the reaction system to room temperature, and then regulating the pH value of the system to 7 by using ammonia water with a mass percentage concentration of 25%, thereby obtaining the liquid sample for implementation, wherein the mass ratio of the total mass of the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound to the acrylic acid monomer mixture, the emulsifier and the water to the initiator aqueous solution is 82:1;
Wherein the lignosulfonate in the step (1) is sodium lignosulfonate. The kitchen waste in the step (2) contains 8.4wt% of starch, 11wt% of cellulose, 3.1wt% of protein, 1.7wt% of grease and 52wt% of water. The mass ratio of the emulsifier in the step (4) is 1:3 and octyl phenol polyoxyethylene ether (10), the model of the reactive emulsifier is LRS-10. The initiator aqueous solution in the step (4) is potassium persulfate aqueous solution, wherein the mass percentage concentration of the potassium persulfate is 2.6%. The water used in the steps (1) - (4) is deionized water.
Application example 13
In the embodiment, the emulsion of the sprayable film-forming slow-release urea fertilizer obtained in the embodiment 1-5 and a part of the liquid sample of the comparative embodiment are sprayed on the soil surface to be used as an agricultural slow-release urea fertilizer and an agricultural liquid mulch film respectively, and the specific test steps are as follows:
(1) Selecting a vegetable planting field, wherein the place is east longitude: 118.98385532736967 ° and north latitude: 32.06034538505579, planting Chinese cabbage in the field;
(2) In 2021, 9 months, dividing the field into several fields with the size of 0.5m×0.5m, wherein each field is spaced by 0.1m; uniformly sowing 30 seeds of the Chinese cabbage in each field; then the soil is applied to 5 fields of the soil at a rate of 0.58kg/m 2 The emulsion of the sprayable film-forming slow-release urea fertilizer obtained in examples 1 to 5 was uniformly sprayed, respectively; alternatively, a field is a bare field without any emulsion sprayed as a control group; other plots were sprayed with the liquid samples of the corresponding comparative examples, respectively, at a dosage of 0.58kg/m, respectively 2 。
Effect examples
This example the following performance tests were performed on the emulsions of sprayable film-forming slow release urea fertilizers obtained in examples 1-5 and the liquid samples prepared in comparative examples 6-12.
1. Emulsion stability test
Observing whether the sample is layered within 30 days, if the sample is not layered, indicating that the emulsion has stability, and performing the following test; if layering occurs, the sample is unstable and is not suitable for being used as liquid mulch emulsion, and the sample does not enter a later testing link.
2. Viscosity test
The viscosity of the liquid was measured using an NDJ-1 rotary viscometer (Shanghai, intelligent technologies, ltd, china). The temperature of each sample was maintained at 30℃and the rotational speed was controlled at 60r/min during the test. Viscosity values are recorded in mPas.
3. Sprayability test
The sprayability of the liquid samples was tested using a hand-held spray gun. The inner diameter of the spray gun is 2.5mm, the air pressure is 0.3MPa when the spray gun is used for spraying liquid, if the spraying distance of the emulsion can be more than 200mm under the condition, the emulsion is considered to have sprayability, otherwise, the emulsion does not have sprayability.
4. Soil temperature and humidity test
Testing of soil temperature: the temperature at 5cm depth per field soil in application example 13 was measured using a curved pipe geothermal meter (Beijing Dingsheng and technology Co., ltd., china) for a test period of 14:00-16:00 per day for 30 days, and the average temperature during this test period was used as a report value.
Testing the water content of soil: and 5g of soil at the position of 5cm in depth of each soil layer of the field is taken while the soil temperature is measured, and the water content of the soil is measured by adopting a drying method, namely, the taken 5g of soil is dried at 80 ℃, and then the water content is calculated according to a formula: soil moisture = [ (5-soil mass after oven drying)/5 ] ×100%, once every 2 days, for 30 days, with the average moisture content of the soil during this test period as the report value.
5. Biodegradability of the material
The biodegradability test was carried out in the experimental field of application example 13. Naturally air-drying the emulsion or liquid in a culture dish to obtain round film sample (diameter 50mm, mass W 0 ) Buried in soil at a depth of 20cm, and then a sample is taken from the soil on day 100, repeatedly washed with deionized water, dried to constant weight at 55deg.C after no obvious impurities are present on the sample, and weighed, with the mass recorded as W d . The biodegradation rate of the sample was calculated according to the following formula:
biodegradation rate = [ (W) 0 －W d )/W 0 ]×100％
6. The urea slow release performance test method comprises the following steps:
firstly, preparing a p-dimethylaminobenzaldehyde color-developing agent solution: 20.00g of p-dimethylaminobenzaldehyde was accurately weighed and dissolved in 1000mL of absolute ethanol.
Urea standard solution (1000 μg/mL) was prepared: accurately weighing 1.00g of urea standard substance, dissolving the urea standard substance with deionized water, transferring the dissolved urea standard substance to a 1000mL volumetric flask, and fixing the volume to obtain stock solution.
Drawing a urea standard absorbance curve: taking 6 25mL colorimetric tubes, respectively adding 1000 mug/mL of urea standard solution 0, 0.50, 1.00, 2.00, 3.00 and 4.00mL, and then respectively supplementing distilled water 10.00, 9.50, 9.00, 8.00, 7.00 and 6.00mL to a scale of 10 mL. Then, adding 10mL of a color reagent and 4mL of 2mol/L sulfuric acid solution into each colorimetric tube, adding distilled water to a volume of 25mL, mixing, shaking uniformly, and standing for 10min. Then, the absorbance of the reaction solution of the first cuvette was measured at 422nm (absorbance was performed on the ultraviolet-visible spectrophotometer 752 Pro) by using the reaction solution of the first cuvette as a reference solution. And drawing a urea standard absorbance curve graph by taking an absorbance value as an ordinate and the concentration of the urea standard solution as an abscissa.
The emulsion or liquid obtained in the example was first placed in a petri dish, then the emulsion or liquid was naturally air-dried to a film 1mm thick, 2g of a round sample was cut out from the air-dried film, and the sample was placed in a tube 60mm long and 10mm in inner diameter, and one end of the tube was sealed. The catheter was immersed horizontally in a beaker containing 500mL of distilled water with the center of the catheter coincident with the center of the beaker horizontal plane, keeping the catheter parallel to the water surface and 1cm below the water surface. Then placing the stirrer into a beaker, placing the beaker on a magnetic stirrer, and controlling the rotating speed to be 10s -1 The solution temperature was 25 ℃, and the catheter was rotated 90 ° horizontally every 2 hours in order to reduce the effect of fluid flow rate irregularities in the beaker on the diffusion rate of urea molecules released by the sample at the port of the catheter. And 3, simultaneously sampling from 3 different positions in a beaker at regular intervals, accurately transferring 5mL of sample liquid from each position, respectively adding the sample liquid into 3 25mL of colorimetric tubes, accurately adding 3mL of the prepared p-dimethylaminobenzaldehyde color reagent solution into each colorimetric tube, diluting to a scale with distilled water, standing for 30min, and measuring the absorbance value at the wavelength of 422 nm. The absorbance measured for each sample can be used to find the corresponding urea concentration from the urea standard absorbance curve. The average value of the urea concentration at 3 different positions is taken as the urea concentration corresponding to the sampling time point. After sampling at three positions at each time point, 15mL of distilled water needs to be timely supplemented into the beaker, so that the liquid in the beaker is always 500mL. And collecting the urea concentration corresponding to different sampling time points, and calculating the urea accumulation release rate. The cumulative release rate of urea refers to the mass percent of the cumulative release mass of urea released from a sample over a period of time to the mass of urea contained in the sample prior to release of the sample, calculated as follows: urea cumulative release rate= (mass of urea cumulative release mass in a certain release period/mass of urea contained in sample before release) ×100%
7. Yield test of pakchoi
When the chinese cabbage of each field of application example 13 was at the end of one growing period (2 months), the chinese cabbage together with their roots was taken out of the field, and the soil attached to the roots was gently swept off with a brush. And then, weighing all the cabbages produced in each field, and evaluating the influence of the sprayable film-forming slow-release urea fertilizer on the yield of the cabbages according to the yield of the cabbages in each field.
8. As can be seen from Table 1, the emulsions prepared in examples 1 to 5 all showed no delamination for 30 days, which indicates that the emulsions prepared in examples 1 to 5 were stable. In addition, the emulsions prepared in comparative examples 8, 9, 10 and 11 also showed no emulsion delamination, indicating that the emulsions prepared in these examples were stable. The liquid sample prepared in comparative example 6 shows delamination at day 3, which means that the sample is unstable because the kitchen waste slurry in step (2) of comparative example 6 has a particle size of 2.5 to 3.5mm, which is larger than 2mm as claimed in the present invention, i.e., the kitchen waste slurry in comparative example 6 has a larger particle size, and it is difficult for these particles having excessive mass and volume to remain suspended in the emulsion, and thus to be precipitated at the bottom of the liquid, i.e., delamination occurs. The liquid sample prepared in comparative example 7 shows delamination at day 1, which means that the sample is very unstable because the amount of maleic anhydride used in step (1) of comparative example 7 is small, which results in less maleic anhydride reacting with hydroxyl groups in lignosulfonate and thus less carbon-carbon double bond groups attached to lignosulfonate, and such maleic anhydride-modified lignin is difficult to copolymerize with acrylic monomers, and maleic anhydride-modified lignin is also difficult to fuse with polyacrylate moieties uniformly, resulting in difficulty in compatibility of two polymers (lignin and polyacrylate), and delamination due to phase separation. The liquid sample prepared in comparative example 12 was subject to delamination on day 1, which indicates that the sample was also very unstable because comparative example 12 did not prepare a pre-emulsion, but rather, the aqueous initiator solution was directly added to the slurry of the lignin-pre-oxidized kitchen waste-urea complex containing maleic anhydride, the acrylic acid monomer mixture, the emulsifier and the water mixture, because the absence of preparation of a pre-emulsion resulted in a decrease in the stability of the emulsion polymerization, and an excessive amount of aggregates and wall build-up in the emulsion, so that comparative example 12 exhibited a more pronounced delamination. In summary, the liquid samples prepared in comparative examples 6, 7 and 12 were all prone to demulsification and delamination, and the uneven liquid, if used in spraying operation, was blocking the nozzle and also failing to form a liquid film layer with uniformly distributed components on the soil surface, so that the samples prepared in comparative examples 6, 7 and 12 could not be used as liquid mulch film products, and they did not need to enter the following test procedures.
As can be seen from the results of Table 2, the samples of examples 1-5 and comparative examples 9-11 all had sprayability. Whereas the samples of comparative example 8 did not have sprayability because the viscosity of comparative example 8 was much higher than the samples of examples 1-5 and comparative examples 9-11, and too much of the viscosity of the liquid was difficult to meet the spraying requirements. The reason why the viscosity of the liquid sample of comparative example 8 is high is that the amount of the oxidizing agent used in the preparation step (2) is smaller than the range (3-5.3) as claimed in the present invention, i.e., the amount of the oxidizing agent used in comparative example 8 is small, the oxidizing agent is effective to oxidize part of the hydroxyl groups in starch, cellulose and lignin in the kitchen waste slurry into carboxyl groups, which can reduce the association between the system molecules by hydrogen bonds to some extent and help to reduce the viscosity of the system, so that the hydrogen bond association between the molecular chains in the liquid sample of comparative example 8 which has not been sufficiently pre-oxidized is strong, resulting in a high viscosity of the system, the liquid having a high viscosity encounters a high resistance when passing through the nozzle of the spray gun, the spray distance is not long, and the liquid droplets are not easily dispersed in a mist form to move forward, so that the sample of comparative example 8 is not suitable for use as a liquid mulch, nor is the sample of comparative example 8 subjected to the subsequent other tests (including the average soil temperature, the average soil moisture content, the biodegradation rate, the urea cumulative release rate, and the small yield).
The results in Table 2 show that in application example 13, the average temperature of the field soil to which the emulsions of examples 1 to 5 were sprayed, respectively, was 3.7 to 3.8℃higher than the average temperature of the soil of the bare field without any emulsion sprayed; meanwhile, the water content of the soil with the soil layer depth of 5cm is 11.8% -12.5% higher than that of the soil with the soil layer depth of 5 cm. Whereas the sample of comparative example 11 was only 0.72 ℃ higher than the soil temperature of the field without any emulsion sprayed; while the water content of the soil with the depth of 5cm is only 1.3% higher than that of the soil with the depth of 5 cm. I.e., the sample of comparative example 11 has limited effect on improving soil temperature and soil moisture content. This is because the acrylic monomer mixture in comparative example 11 is used in a small amount. The polyacrylate part can be obtained through polymerization of acrylate monomers, the polyacrylate has good film forming property, the prepared emulsion of the sprayable film forming type slow release urea fertilizer can form a film on the surface of soil, and the film forming can block gaps among soil particles and prevent heat and moisture in the soil from being lost, so that the effects of heat preservation and moisture preservation of the soil are achieved; in contrast, the acrylic monomer mixture of comparative example 11 was used in a smaller amount, which resulted in a smaller amount of polyacrylate, resulting in a smaller amount of film-forming substance, and resulted in a sample having difficulty in blocking the voids between soil particles, i.e., poor effects of heat and moisture preservation on soil.
The traditional plastic mulching film (such as LDPE mulching film) has great damage to the ecological environment of agricultural soil because of non-biodegradability, so that the well-developed biodegradable mulching film is also one of the important targets pursued by the invention for adapting to the recyclable green ecological agriculture. It is considered that the sample has a biodegradability exceeding 60% within one hundred days, and that the sample has good biodegradability. The results in Table 2 show that the liquid mulch films of examples 1-5 have a biodegradation rate of 76.7% -77.5% within one hundred days, and thus the liquid mulch films of examples 1-5 all have good biodegradability. While the biodegradation rate of the mulch film of comparative example 9 was only 41.3% in one hundred days, i.e., the mulch film sample of comparative example 9 was 36.2% lower than the liquid mulch film of example 3, indicating that the biodegradability of the mulch film sample of comparative example 9 is much lower than the liquid mulch film of example 3. This is because the kitchen waste in comparative example 9 is an important biomass raw material with good biodegradability, and the kitchen waste in comparative example 9 is small in dosage, which correspondingly reduces the biodegradability of the mulch film sample in comparative example 9.
FIG. 2 shows the urea accumulation release curves of samples and pure urea after air-drying the emulsions of examples 1-5 to form films. As can be seen from fig. 2, the film samples of examples 1-5 all had lower urea release rates than pure urea, and the urea release rate of example 3 was the lowest, indicating that the film samples of examples 1-5 all had urea slow release effects. As can be seen from table 2, the cumulative urea release rate after 96h of immersion in water for the film samples of examples 1-5 ranged from 56.62% to 81.37%, with the sample of example 3 having the lowest cumulative urea release rate of 56.62%. Although comparative example 9 was a liquid mulch film prepared according to the procedure described in example 3, the cumulative urea release rate after 96 hours of immersion in water was 82.66% higher than that of the sample of example 3, i.e., the sample of comparative example 9 had a lower urea release effect than that of the sample of example 3; this is because in examples 1-5, the urea molecules are in a two-layer polymer network coating: the first layer of network is a polymer network of maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound, the second layer of network is a polymer network of maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound which is embedded in a polyacrylate network, and in the two layers of continuously wrapped polymer networks, the release rate of urea molecules is greatly weakened, so that the slow release effect of urea is realized; while the kitchen waste contains natural polymers rich in hydroxyl groups such as cellulose and protein, urea is adsorbed and wrapped by the natural polymers to reduce the release rate of urea, the kitchen waste in comparative example 9 has small dosage, so that urea cannot be effectively encapsulated in a polymer network of a maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound, and finally the release rate of urea is increased, and the slow release property of urea is reduced. Comparative example 10 was also a liquid mulch film prepared according to the procedure described in example 3, but the cumulative urea release rate after 96 hours of immersion in water was 93.58% for the sample of comparative example 10, which was 36.96% higher than for the sample of example 3, i.e., the slow urea release effect for the sample of comparative example 10 was much weaker than for the sample of example 3; this is because comparative example 10 does not prepare a slurry containing maleic anhydride-modified lignin-pre-oxidized kitchen waste-urea complex, but mixes maleic anhydride-modified lignin, pre-oxidized kitchen waste and urea directly with acrylic acid monomer mixture, emulsifier and water, which results in that no two-layer polymer network is formed in the sample of comparative example 10, that is, urea is not encapsulated in the complex polymer network formed by maleic anhydride-modified lignin and pre-oxidized kitchen waste, eventually causing an increase in the release rate of urea and a great decrease in the slow release property of urea. Comparative example 11 was also a liquid mulch film prepared according to the procedure described in example 3, but the cumulative urea release rate after 96 hours of immersion in water was 91.27% for the sample of comparative example 11, which was 34.65% higher than for the sample of example 3, i.e., the slow urea release effect was much weaker for the sample of comparative example 11 than for the sample of example 3; this is because the amount of acrylic monomer mixture used in comparative example 11 is small, which results in that the sample of comparative example 11 fails to effectively form the second polyacrylate network, i.e., the maleic anhydride-modified lignin-pre-oxidized kitchen waste-urea complex is not effectively embedded in the polyacrylate network, and finally causes an increase in the release rate of urea and a significant decrease in the slow release property of urea.
Table 2 shows that in application example 13, the yield of the Chinese cabbage in the field sprayed with the emulsions of examples 1 to 5, respectively, was 3.72 to 4.12kg, which is 98.9 to 120.3% higher than that of the Chinese cabbage in the bare field (1.87 kg) without any emulsion or liquid sprayed. Whereas comparative examples 9-11 correspond to fields with yields of only 54.0%, 18.2% and 14.9% higher than that of the bare soil cabbage, respectively. The emulsions of examples 1-5 therefore demonstrate significant yield increasing effect on field chinese cabbage, confirming the rationality and necessity of the corresponding parameter ranges recited in the claims.
Table 1 stability of the emulsions or liquids obtained in examples 1 to 5 and comparative examples 6 to 12 was evaluated by recording whether or not the emulsions appeared to delaminate within 30 days.
Table 2 viscosity and sprayability results of the emulsions prepared in examples 1 to 5 and the liquids prepared in comparative examples 8 to 11, and test results of soil average temperature, soil average water content, biodegradation rate, urea cumulative release rate for 96 hours, yield of chinese cabbage by spraying the emulsion and liquid of the above example and bare soil without any samples on each field in application example 13, respectively. In the table "-" indicates that the sample was not subjected to the corresponding project test, and bare soil indicates a field without any example sample sprayed.
/>
Claims (8)
1. A preparation method of a sprayable film-forming slow-release urea fertilizer comprises the following preparation steps:
(1) Mixing lignin sulfonate, maleic anhydride and water to obtain a solution, regulating the pH value of the obtained mixed solution to 10-11 by using a NaOH solution with the concentration of 1mol/L, stirring at 50-75 ℃ for reaction, cooling the mixed solution to room temperature after the reaction is carried out for 5-10h, regulating the pH value of the mixed solution to 1-2 by using a sulfuric acid solution with the concentration of 1.8mol/L, filtering the precipitate in the solution, repeatedly washing the precipitate by using water until the pH value of the filtrate is neutral, and drying the washed precipitate at 55-80 ℃ for 24-72h to obtain maleic anhydride modified lignin, wherein the mass ratio of lignin sulfonate, maleic anhydride and water is 1 (0.8-2): (5-15);
(2) Mixing kitchen waste with water, and crushing the obtained mixture into kitchen waste slurry by using a crusher, wherein the mass ratio of the kitchen waste to the water is 1: (1-2.5), sieving the kitchen waste slurry to ensure that the particle size of the kitchen waste slurry is less than 2mm, adding the sieved kitchen waste slurry into a reaction vessel provided with a stirrer, a thermometer and a condenser pipe, then adding an oxidant aqueous solution into the reaction vessel while stirring at 80-90 ℃, wherein the stirring speed is 500-1200r/min, and the stirring time is 1-3h, so as to obtain the pre-oxidized kitchen waste slurry, and the mass ratio of the sieved kitchen waste slurry to the oxidant aqueous solution is (3-5.3): 1, the oxidant aqueous solution in the step (2) is potassium persulfate or ammonium persulfate aqueous solution, and the mass percentage concentration of the potassium persulfate or ammonium persulfate is 6-12%;
(3) Stirring the maleic anhydride modified lignin obtained in the step (1), the pre-oxidized kitchen waste slurry obtained in the step (2) and urea at room temperature at a stirring speed of 800-2000r/min for 1.5-3.5h to obtain a slurry containing a maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound, wherein the mass ratio of the maleic anhydride modified lignin to the pre-oxidized kitchen waste to the urea is 1: (2.1-4.5): (4.4-9);
(4) Mixing the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3) with an acrylic acid monomer mixture, an emulsifier and water, and stirring the obtained mixture at 55-65 ℃ for 50-150min to obtain a pre-emulsion, wherein the stirring speed is 500-3000r/min, and the mass ratio of the slurry containing the maleic anhydride modified lignin-pre-oxidized kitchen waste-urea compound obtained in the step (3), the acrylic acid monomer mixture, the emulsifier and the water is (32-44): (15-21): 1: (36-56), wherein the acrylic monomer mixture in the step (4) comprises the components in a mass ratio of (5.8-6.8): (2.1-3.2): butyl acrylate, methyl methacrylate and acrylic acid of 1;
(5) Raising the temperature of the pre-emulsion obtained in the step (4) to 75-90 ℃, dropwise adding an initiator aqueous solution into the pre-emulsion at a dropping speed of 0.04-0.2mL/min while stirring, continuing to react for 2-8h after the initiator aqueous solution is added dropwise, cooling the reaction system to room temperature, and then regulating the pH value of the system to 6.8-7.3 by using ammonia water with a mass percentage concentration of 25%, thereby obtaining the emulsion which is used as the sprayable film-forming slow-release urea fertilizer, wherein the mass ratio of the pre-emulsion obtained in the step (4) to the initiator aqueous solution is (67-97): 1.
2. The process according to claim 1, wherein the lignosulfonate in step (1) is sodium lignosulfonate or calcium lignosulfonate.
3. The preparation method of claim 1, wherein the kitchen waste in the step (2) contains 7.2-9.5wt% of starch, 10.0-12.2wt% of cellulose, 2.1-4.3wt% of protein, 1.1-2.1wt% of grease and 40-64wt% of water.
4. The preparation method according to claim 1, wherein the emulsifier in the step (4) is a compound having a mass ratio of 1: (1.5-4.5) a mixture of a reactive emulsifier and octyl phenol polyoxyethylene ether (10), the type of the reactive emulsifier being LRS-10.
5. The preparation method according to claim 1, wherein the aqueous initiator solution in the step (5) is an aqueous potassium persulfate or ammonium persulfate solution, and wherein the mass percentage concentration of the potassium persulfate or ammonium persulfate is 2.2-3.1%.
6. The process according to any one of claims 1 to 5, wherein the water used is deionized water.
7. A sprayable film-forming slow release urea fertilizer produced by the method of any one of claims 1-6.
8. The use of a sprayable film-forming slow release urea fertilizer of claim 7 in agricultural slow release fertilizers and agricultural liquid mulch films.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311248747.4A CN117263749A (en) | 2022-08-09 | 2022-08-09 | Preparation method of modified lignin-based sprayable slow-release urea fertilizer |
| CN202311248550.0A CN117285393A (en) | 2022-08-09 | 2022-08-09 | Slow-release urea-based compound sprayable film-forming fertilizer and preparation method thereof |
| CN202311248311.5A CN117843412A (en) | 2022-08-09 | 2022-08-09 | Slow-release fertilizer based on preoxidized kitchen waste compound and preparation method thereof |
| CN202210950870.XA CN115160089B (en) | 2022-08-09 | 2022-08-09 | Spray-coated film-forming type slow-release urea fertilizer and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210950870.XA CN115160089B (en) | 2022-08-09 | 2022-08-09 | Spray-coated film-forming type slow-release urea fertilizer and preparation method thereof |
Related Child Applications (3)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311248747.4A Division CN117263749A (en) | 2022-08-09 | 2022-08-09 | Preparation method of modified lignin-based sprayable slow-release urea fertilizer |
| CN202311248550.0A Division CN117285393A (en) | 2022-08-09 | 2022-08-09 | Slow-release urea-based compound sprayable film-forming fertilizer and preparation method thereof |
| CN202311248311.5A Division CN117843412A (en) | 2022-08-09 | 2022-08-09 | Slow-release fertilizer based on preoxidized kitchen waste compound and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115160089A CN115160089A (en) | 2022-10-11 |
| CN115160089B true CN115160089B (en) | 2023-09-19 |
Family
ID=83480014
Family Applications (4)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311248311.5A Pending CN117843412A (en) | 2022-08-09 | 2022-08-09 | Slow-release fertilizer based on preoxidized kitchen waste compound and preparation method thereof |
| CN202210950870.XA Active CN115160089B (en) | 2022-08-09 | 2022-08-09 | Spray-coated film-forming type slow-release urea fertilizer and preparation method thereof |
| CN202311248747.4A Pending CN117263749A (en) | 2022-08-09 | 2022-08-09 | Preparation method of modified lignin-based sprayable slow-release urea fertilizer |
| CN202311248550.0A Pending CN117285393A (en) | 2022-08-09 | 2022-08-09 | Slow-release urea-based compound sprayable film-forming fertilizer and preparation method thereof |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311248311.5A Pending CN117843412A (en) | 2022-08-09 | 2022-08-09 | Slow-release fertilizer based on preoxidized kitchen waste compound and preparation method thereof |
Family Applications After (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311248747.4A Pending CN117263749A (en) | 2022-08-09 | 2022-08-09 | Preparation method of modified lignin-based sprayable slow-release urea fertilizer |
| CN202311248550.0A Pending CN117285393A (en) | 2022-08-09 | 2022-08-09 | Slow-release urea-based compound sprayable film-forming fertilizer and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (4) | CN117843412A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1646451A (en) * | 2002-03-26 | 2005-07-27 | 佐治亚-太平洋树脂公司 | Slow release nitrogen fertilizer |
| CN107056468A (en) * | 2017-05-05 | 2017-08-18 | 南京林业大学 | Thiourea slow release fertilizer and preparation method thereof is prepared using lignin and montmorillonite as raw material |
| CN107285898A (en) * | 2017-07-31 | 2017-10-24 | 句容市锦鸿家庭农场 | A kind of preparation method of spacetabs type succulent cultivation nutrient solution |
| CN113816794A (en) * | 2021-10-14 | 2021-12-21 | 兰州理工大学 | Preparation method of lignin-based water-retaining double-layer controlled-release fertilizer |
-
2022
- 2022-08-09 CN CN202311248311.5A patent/CN117843412A/en active Pending
- 2022-08-09 CN CN202210950870.XA patent/CN115160089B/en active Active
- 2022-08-09 CN CN202311248747.4A patent/CN117263749A/en active Pending
- 2022-08-09 CN CN202311248550.0A patent/CN117285393A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1646451A (en) * | 2002-03-26 | 2005-07-27 | 佐治亚-太平洋树脂公司 | Slow release nitrogen fertilizer |
| CN107056468A (en) * | 2017-05-05 | 2017-08-18 | 南京林业大学 | Thiourea slow release fertilizer and preparation method thereof is prepared using lignin and montmorillonite as raw material |
| CN107285898A (en) * | 2017-07-31 | 2017-10-24 | 句容市锦鸿家庭农场 | A kind of preparation method of spacetabs type succulent cultivation nutrient solution |
| CN113816794A (en) * | 2021-10-14 | 2021-12-21 | 兰州理工大学 | Preparation method of lignin-based water-retaining double-layer controlled-release fertilizer |
Also Published As
| Publication number | Publication date |
|---|---|
| CN117263749A (en) | 2023-12-22 |
| CN115160089A (en) | 2022-10-11 |
| CN117285393A (en) | 2023-12-26 |
| CN117843412A (en) | 2024-04-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101348395B (en) | Aqueous polymer-olefin dual-layer coated controlled release fertilizer and preparation thereof | |
| CN103833471B (en) | Mid-late ripening corn special environment protection degradable granule fertilizer coating liquid and preparation method thereof | |
| CN103159532B (en) | A kind of preparation method of porous lignin particle compound fertilizer | |
| CN106927951B (en) | Based on water dispersion nano SiO2Modified water-based polyacrylate coated controlled release fertilizer and preparation method thereof | |
| CN110423180A (en) | A kind of slow-release compound fertilizer and preparation method thereof for alkaline land improving | |
| CN107056468B (en) | Urea slow-release fertilizer prepared from lignin and montmorillonite and preparation method thereof | |
| CN107540994A (en) | A kind of preparation method and application of biodegradable plastic film | |
| Han et al. | Inorganic matter modified water-based copolymer prepared by chitosan-starch-CMC-Na-PVAL as an environment-friendly coating material | |
| CN113402325A (en) | Double-coated slow-release water-retention urea fertilizer and preparation method thereof | |
| CN102863587B (en) | Allylthiourea modified konjac glucomannan copolymer material and slow-release nitrogen fertilizer | |
| CN115160089B (en) | Spray-coated film-forming type slow-release urea fertilizer and preparation method thereof | |
| CN112167005A (en) | Preparation method of artificial soil particles based on sludge | |
| CN1618773A (en) | Organic substrate formula for soilless cultivating tomato and its formulating method | |
| CN110240733A (en) | Copper-loaded nanoparticle of ferroso-ferric oxide and preparation method thereof and preparation root resistance material in apply | |
| CN105907401A (en) | Slow-release oxidizing agent with calcium peroxide as matrix and starch as coating film and preparation method | |
| CN113024307A (en) | Organic matrix for planting and preparation method and application thereof | |
| CN108516887A (en) | A kind of preparation method of multifunction soil organic water retainer | |
| CN111233581A (en) | Tobacco special fertilizer for improving water retention performance of tobacco planting soil | |
| CN110627563A (en) | Novel naturally degradable fertilizer coating agent, preparation method and use method thereof | |
| CN110436972A (en) | A kind of organic fertilizer prilling process free of drying | |
| CN109851726A (en) | A kind of biodegradable graft copolymerized polymer composite material and preparation method | |
| CN115108867A (en) | Preparation method of improved saline-alkali soil product | |
| CN111454098B (en) | Double-film controlled-release fertilizer coating method | |
| CN108101626A (en) | A kind of ecology sustained release organic film fertilizer and preparation method | |
| CN1228360C (en) | One-step synthesis process of producing biodegradable high-hydroscopicity resin directly with corn powder |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |