CN111533613A - Nano-cellulose gel-based water-retaining slow-release fertilizer and preparation method thereof - Google Patents
Nano-cellulose gel-based water-retaining slow-release fertilizer and preparation method thereof Download PDFInfo
- Publication number
- CN111533613A CN111533613A CN202010219009.7A CN202010219009A CN111533613A CN 111533613 A CN111533613 A CN 111533613A CN 202010219009 A CN202010219009 A CN 202010219009A CN 111533613 A CN111533613 A CN 111533613A
- Authority
- CN
- China
- Prior art keywords
- cellulose
- nano
- fertilizer
- bacterial
- slow
- 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.)
- Granted
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05C—NITROGENOUS FERTILISERS
- C05C9/00—Fertilisers containing urea or urea compounds
-
- 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
- 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
- C05G3/80—Soil conditioners
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Pest Control & Pesticides (AREA)
- Soil Sciences (AREA)
- Fertilizers (AREA)
Abstract
The invention relates to a nano-cellulose gel-based water-retaining slow-release fertilizer and a preparation method thereof. The fertilizer is obtained by taking nano-cellulose or oxidized nano-cellulose as a matrix and adsorbing a fertilizer aqueous solution. The method comprises the following steps: mixing the nano-cellulose or the oxidized nano-cellulose with the fertilizer aqueous solution, and adsorbing the fertilizer aqueous solution. The method has the advantages of simple process, easy operation, no special production equipment requirement, good slow release performance after fertilization, excellent water retention performance, easily obtained raw materials, environmental protection, complete environmental degradation, good market application prospect and important significance in the aspects of agricultural production, environmental protection and the like.
Description
Technical Field
The invention belongs to the field of slow release fertilizers and preparation thereof, and particularly relates to a nano-cellulose gel-based water-retention slow release fertilizer and a preparation method thereof.
Background
Bacterial Nanocellulose (BNC) is an extracellular product produced by bacteria, also known as Bacterial cellulose, a biopolymer with a nano-network structure. Plant cellulose is an important component of plant cell walls, and the material source is wide. Compared with plant cellulose, BNCs have many excellent properties, such as high purity, high specific surface area, nanoscale three-dimensional network structure, excellent mechanical properties, good biocompatibility and biodegradability, etc. Two types of cellulose have been widely used in various fields such as paper making, food, medical, textile materials, and the like. The two types of cellulose can also be oxidized by an oxidant to prepare oxidized cellulose, and the preparation process is simple. As a gel-based water-retaining slow-release fertilizer, the nano-cellulose slow-release fertilizer has the dual functions of fertilizer slow release and water absorption and retention, and can wrap and adsorb a large amount of fertilizer; the release time of the fertilizer is controlled, the volatilization and the loss of the fertilizer are reduced, the surplus soil moisture is adjusted, the interaction of water and fertilizer is promoted, the utilization rate of the water and the fertilizer is improved, and meanwhile, the nano-cellulose can be biodegraded, is green and environment-friendly, and can not cause environmental pollution.
The fertilizer is an important agricultural production data and is an important material investment in agricultural production. As a big agricultural country, the improvement of crop yield is also important in agricultural development, and the application of chemical fertilizers becomes an important means for improving the yield. Agricultural practices show that the problems of unreasonable fertilizer application, low fertilizer utilization rate, environmental pollution and the like exist in the application of chemical fertilizers in China, so that the development of green and environment-friendly slow-release fertilizers becomes a hot spot of current scientific research.
Chinese patent No. CN110590454A discloses a slow-release fertilizer and a preparation method thereof, the structure is complex, the fertilizer is composed of a fertilizer core, a binder and an outer layer coating, although the slow-release effect is good, the variety of required raw materials is too many, the preparation process is complicated, and higher requirements are required for using equipment.
Chinese patent CN101225009A discloses a synthesis process and a production method of a gel-based water-retaining slow-release urea fertilizer, which utilizes chemical polymerization reaction to mix a plurality of compounds with the fertilizer, then adds a cross-linking agent and a free radical initiator to finally obtain gel, and then the gel-based water-retaining slow-release urea fertilizer is obtained after post-treatment. Although the water absorption rate of the water-retaining slow-release fertilizer can be improved, and the opportunity of water fertilizer effect is increased, the used raw materials are chemical raw materials, so that environmental pollution is easy to generate, the cost is high, the synthesis process is complex, and the reaction has overhigh temperature requirement.
Disclosure of Invention
The invention aims to solve the technical problem of providing a nano-cellulose gel-based water-retaining slow-release fertilizer and a preparation method thereof, so as to overcome the defects of low fertilizer utilization rate, environmental pollution and the like in the prior art.
The invention provides a nano-cellulose gel-based water-retaining slow-release fertilizer which is obtained by taking nano-cellulose or oxidized nano-cellulose as a matrix and adsorbing a fertilizer aqueous solution. The nanocellulose can absorb a large amount of fertilizers by utilizing the excellent characteristics of the nanocellulose, such as a three-dimensional nanostructure; the oxidized nano-cellulose is obtained by oxidizing cellulose, wherein a large number of charged active groups exist, so that the properties of the oxidized nano-cellulose can be fully utilized, and a large number of fertilizers can be stably adsorbed in an electrostatic adsorption mode.
The fertilizer may refer to a variety of fertilizers used in agricultural production, including macroelement fertilizers (e.g., carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, etc.), secondary macroelement fertilizers (e.g., calcium, magnesium, sulfur, etc.), trace element fertilizers (e.g., boron, copper, iron, manganese, molybdenum, zinc, etc.), or complex fertilizers.
The invention also provides a preparation method of the nano-cellulose gel-based water-retaining slow-release fertilizer, which comprises the following steps:
mixing nano-cellulose or oxidized nano-cellulose with a fertilizer aqueous solution, and adsorbing the fertilizer aqueous solution to obtain the nano-cellulose gel-based water-retaining slow-release fertilizer, wherein the mass ratio of the nano-cellulose or oxidized nano-cellulose to the fertilizer is 1: 1-1: 50.
The nanocellulose comprises microbial source nanocellulose (namely, bacterial nanocellulose) or plant source nanocellulose.
The form of the bacterial nano cellulose is a common bacterial nano cellulose film, a freeze-dried bacterial nano cellulose film, a bacterial nano cellulose homogenate or a bacterial nano cellulose flocculent fiber.
The generic bacterial nanocellulose membrane is hydrogel-like.
The freeze-dried bacterial nano cellulose membrane is spongy.
The form of the plant source nano-cellulose is plant source nano-cellulose suspension, plant source nano-cellulose gel and freeze-dried plant source nano-cellulose.
The oxidized nanocellulose comprises microbial-derived oxidized nanocellulose (i.e., oxidized bacterial nanocellulose) or plant-derived oxidized nanocellulose.
The form of the oxidized nano-cellulose is oxidized nano-cellulose suspension, oxidized nano-cellulose gel and freeze-dried oxidized nano-cellulose, and the fertilizer is physiological acid fertilizer (such as one of ammonium salt and potassium salt).
The oxidized bacteria nano-cellulose is obtained by oxidizing bacteria nano-cellulose turbid liquid with an oxidant.
The culture strain of the bacterial nano-cellulose is acetobacter xylinum.
The bacterial nano-cellulose is obtained by strain in-situ static culture or dynamic culture.
The plant source nano-cellulose and the plant source oxidized nano-cellulose are purchased from the market.
The oxidized bacteria nano-cellulose is prepared by oxidizing bacteria nano-cellulose by TEMPO oxidation method or NaIO4Preparing by an oxidation method; the culture strain of the bacterial nano-cellulose is acetobacter xylinum; the bacterial nano-cellulose is obtained by strain in-situ static culture or dynamic culture.
The adsorption temperature is 25-30 ℃, and the adsorption time is 1-6 h.
The concentration of the fertilizer water solution is 200-500 g/L.
And drying the fertilizer water solution after adsorption, wherein the drying comprises the following steps: drying for 2-4 h at 30-60 ℃ or freeze drying for 48-72 h at minus 40-50 ℃.
The invention also provides application of the water-retaining slow-release fertilizer in crop planting. For example, the fertilizer is applied to improve the soil fertility and the yield per unit area of crops.
The invention relates to a bacterial nano-cellulose gel-based water-retaining slow-release fertilizer which mainly comprises 6 types, specifically comprising the following components:
the hydrogel bacterial nano-cellulose is directly soaked in the fertilizer water solution, and after the fertilizer water solution is completely adsorbed, the bacterial nano-cellulose gel-based water-retaining slow-release fertilizer in a wet state is obtained.
And (3) soaking the freeze-dried bacterial nano-cellulose in a fertilizer aqueous solution, and completely adsorbing the fertilizer aqueous solution to obtain the wet bacterial nano-cellulose gel-based water-retaining slow-release fertilizer.
Directly soaking the hydrogel bacterial nanocellulose in a fertilizer aqueous solution, completely adsorbing the fertilizer aqueous solution, and drying to obtain the dry bacterial nanocellulose gel-based water-retaining slow-release fertilizer.
And (3) soaking the freeze-dried bacterial nano-cellulose in a fertilizer aqueous solution, completely adsorbing the fertilizer aqueous solution, and drying to obtain the dry bacterial nano-cellulose gel-based water-retaining slow-release fertilizer.
Adsorbing physiological acidic fertilizer (such as ammonium sulfate) water solution with plant source nano cellulose suspension, and freeze drying to obtain dried nano cellulose gel-based water-retaining slow-release fertilizer.
Adsorbing physiological acidic fertilizer (such as ammonium sulfate) water solution with the oxidized nano cellulose suspension, and freeze drying to obtain dried nano cellulose gel-based water-retaining slow-release fertilizer.
The oxidized nano-cellulose in the invention has negative charge after ionization in water, and is combined with fertilizer elements (such as potassium fertilizer, phosphate fertilizer, nitrogen fertilizer and the like) with positive charge after ionization through electrostatic self-adsorption.
The invention takes the nano-cellulose or the oxidized nano-cellulose as the matrix to wrap and adsorb the chemical fertilizer, has good slow release effect and long period, wherein the sponge-state slow release fertilizer has better water absorption and retention property, is beneficial to the growth of crops and is easy to popularize and apply.
Advantageous effects
The gel-based water-retaining slow-release fertilizer is prepared by adopting the nano-cellulose or the oxidized nano-cellulose matrix which is nontoxic, biodegradable and low in preparation requirement and by utilizing the high specific surface area performance, the excellent three-dimensional net-shaped structure and a large number of surface active groups, and fully adsorbing the fertilizer, and is environment-friendly and has good commercial application prospect.
The invention has simple process, easy operation, no special production equipment requirement, good slow release performance after fertilization, excellent water retention performance, easily obtained raw materials, environmental protection, complete environmental degradation, good market application prospect and important significance on aspects of agricultural production, environmental protection and the like.
Compared with the traditional fertilizer application mode, the nano-cellulose gel-based water-retaining slow-release fertilizer obtained by the invention has the advantages that the nutrient release period is longer, the slow-release effect is obvious, and the dissolution rate of the fertilizer is reduced; the fertilizer has strong water absorption and retention capacity, increases the interaction between water and the fertilizer, restricts the loss of the fertilizer along with water, improves the utilization rate of macroelements (such as carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium and the like) and microelements (such as boron, copper, iron, manganese, molybdenum, zinc and the like), and greatly prolongs the fertilizer effective period.
The oxidized nano-cellulose in the invention has negative charge after ionization in water, and is combined with fertilizer elements (such as potash fertilizer, phosphate fertilizer, nitrogen fertilizer and the like) with positive charge after ionization through electrostatic self-adsorption, so that the efficiency is high, the release is slow, and the oxidized nano-cellulose is a good slow-release fertilizer.
Drawings
FIG. 1 is a graph showing the cumulative release effect of urea from the bacterial nano-cellulose gel-based water-retaining slow-release fertilizer prepared in examples 1 to 4 and pure flower soil mixed urea particles.
Fig. 2 is an appearance view of the bacterial nanocellulose gel-based water-retaining slow-release fertilizer prepared in example 1(a), example 2(B), example 3(C) and example 4 (D).
FIG. 3 is a graph showing the change of urea concentration in the eluates of the bacterial nano-cellulose gel-based water-retaining slow-release fertilizer prepared in examples 1 to 4 and pure flower soil mixed urea particles.
FIG. 4 is a graph showing the variation of the residual urea content in the urea granules mixed with pure flower soil in the process of slowly releasing urea, in the bacterial nano-cellulose gel-based water-retaining and slowly-releasing fertilizer prepared in examples 1 to 4.
FIG. 5 is a graph showing cumulative release effects of ammonium sulfate from the oxidized nanocellulose gel-based water-retaining slow-release fertilizer prepared in examples 5 to 6 and pure flower soil mixed with ammonium sulfate.
FIG. 6 is a graph showing the change of ammonium sulfate concentration in the dissolution liquid of the oxidized nanocellulose gel-based water-retention slow-release fertilizer prepared in examples 5 to 6 and pure flower soil mixed with ammonium sulfate.
Fig. 7 is a graph showing the variation of the residual ammonium sulfate content in the oxidized nanocellulose gel-based water-retaining slow-release fertilizer prepared in examples 5 to 6 and pure flower soil mixed ammonium sulfate during the slow release of ammonium sulfate.
Detailed Description
The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.
Example 1
(1) A macroelement fertilizer nitrogen fertilizer, such as urea, is taken to prepare a urea aqueous solution with the concentration mass fraction of 50 percent, and the preparation method comprises the following steps: 50g of urea (national chemical group, chemical Co., Ltd.) was weighed and dissolved in 100mL of deionized water.
(2) Taking acetobacter xylinum as a strain (the strain is Gluconacetobacter xylinus ATCC23770 which is purchased from American strain collection center), standing and culturing for 10 days at constant temperature of 30 ℃ in a liquid culture medium, taking out the bacterial nano cellulose membrane, placing the bacterial nano cellulose membrane in NaOH (national drug group chemical reagent Co., Ltd.) solution with the concentration of 10g/L, treating for 2 hours at 80 ℃, taking out, and rinsing with deionized water to neutrality to obtain the bacterial nano cellulose membrane; squeezing to remove excessive water.
(3) And (3) soaking the bacterial nano-cellulose hydrogel membrane with the cellulose solid content of 0.5g in the step (2) in the urea aqueous solution in the step (1) for 6 hours at 25 ℃ to completely adsorb the urea aqueous solution, wherein the using amount of the urea aqueous solution is 5mL (the mass ratio of nano-cellulose to urea is 1: 5).
(4) And (4) taking out the bacterial nano cellulose membrane soaked in the urea aqueous solution in the step (3) to obtain the bacterial nano cellulose gel-based water-retaining slow-release fertilizer.
In order to test whether the obtained bacterial nano-cellulose gel-based water-retaining slow-release fertilizer has the effect of slowly releasing urea, the obtained urea amount is slowly released. And (3) putting the obtained bacterial nano cellulose membrane into a sand core crucible, and flushing with deionized water to extract a dissolving liquid so as to detect the slow-release urea effect and the urea dissolving-out amount. A control group was prepared by mixing 10g of pure flower soil with 2.5g of urea granules.
And (3) determining the concentration of urea in the dissolution liquid and the release amount of urea in the slow-release fertilizer:
establishing a standard curve:
preparing a p-dimethylaminobenzaldehyde color developing agent solution: 8.00g of p-dimethylaminobenzaldehyde (Biotechnology engineering, Shanghai, Ltd.) was accurately weighed and dissolved in 500mL of anhydrous ethanol, and 50mL of hydrochloric acid was added.
A urea standard solution (1000. mu.g/mL) was prepared: accurately weighing 1.00g of urea reference substance, dissolving with deionized water, transferring to a 1000mL volumetric flask, and diluting to constant volume to obtain stock solution.
Taking 7 25mL colorimetric tubes, adding 0, 0.50, 1.00, 2.00, 3.00, 4.00 and 5.00mL of standard solution respectively, and then supplementing 5.00, 4.50, 4.00, 3.00, 2.00 and 1.00mL of distilled water respectively. Then 5mL of color developing agent is added into each colorimetric tube, then distilled water is added to the colorimetric tube to reach the constant volume of 25mL, the mixture is uniformly mixed and kept stand for 20 min. And then taking the reaction solution of the first colorimetric tube as a reference solution, respectively measuring the absorbance of the reaction solution of the 7 colorimetric tubes at 420nm, subtracting the absorbance of a zero-concentration blank tube from the measured absorbance to obtain corrected absorbance, and drawing a standard curve by taking the absorbance value as a vertical coordinate and the concentration of the urea standard solution as a horizontal coordinate.
And (3) determining the concentration of urea in the dissolved liquid:
and (3) placing the bacterial nano cellulose membrane into a sand core crucible, periodically performing flushing with deionized water, and collecting filtrate. Diluting the filtrate by 10 times, accurately transferring 5mL of diluent, respectively adding into 25mL of colorimetric tubes, accurately adding 5mL of the prepared p-dimethylaminobenzaldehyde color developing agent solution into each colorimetric tube, diluting to scale with distilled water, standing for 20min, and measuring the absorbance value at the wavelength of 420 nm. The measured absorbance of each sample can be found from the standard curve for the corresponding concentration. And collecting the concentrations corresponding to the different sampling time points, and simultaneously recording the volumes of the dissolution liquid at the different sampling time points.
And (3) determining the release amount of urea in the gel-based slow release fertilizer:
and calculating the mass of the urea in the dissolution liquid according to the measured concentration of the urea and the volumes of the dissolution liquid obtained at different sampling time points, and calculating the residual urea content in the gel-based water-retention slow-release fertilizer.
Cumulative urea release rate: the urea cumulative release rate refers to the mass fraction of the mass of the urea released from the sample in a period of time in the mass of the urea contained in the sample before release, and is calculated according to the following formula:
and (4) taking the urea accumulative release rate corresponding to sampling at different time points as a vertical coordinate, and taking the horizontal coordinate as time, and drawing a urea accumulative release curve.
And (3) water absorption measurement:
weighing the prepared bacterial nano-cellulose gel-based water-retaining slow-release fertilizer, standing at 25 ℃ for 30min to absorb water, taking out, and weighing when no water drops appear on the white surface of the sample. The water absorption calculation formula is as follows:
and (3) water retention value determination:
taking a certain mass of bacterial nano-cellulose gel-based water-retaining slow-release fertilizer, standing at 25 ℃ for water absorption for 30min, taking out, putting into a centrifuge tube, centrifuging at 6800r/min for 15min by using a centrifuge, taking out, pouring out filtered water, weighing, drying the sample at 105 ℃ for 4h, and weighing. The water retention value calculation formula is as follows:
example 2
(1) The preparation method of the bacterial nano-cellulose film was the same as that of example 1 except that the bacterial nano-cellulose film was not required to be squeezed to remove excess water.
(2) And (2) freeze-drying the bacterial nano-cellulose hydrogel membrane in the step (1) at the temperature of minus 40-50 ℃ for 72 hours to obtain the freeze-dried bacterial nano-cellulose sponge.
(3) And (3) soaking 0.5g of the bacterial nano cellulose dry film subjected to freeze drying in the step (2) in the urea aqueous solution in the step (1) for 1h at 25 ℃ to completely adsorb the urea aqueous solution, wherein the using amount of the urea aqueous solution is 5mL (the mass ratio of the nano cellulose to the urea is 1: 5).
(4) And (4) taking out the bacterial nano cellulose membrane soaked in the urea solution in the step (3) to obtain the bacterial nano cellulose gel-based water-retaining slow-release fertilizer.
The urea release effect was tested according to the test method in example 1 (table 1).
The water absorption was tested according to the test method in example 1 (table 2).
The water retention values were tested according to the test method in example 1 (table 3).
Example 3
According to the example 1, the bacterial nano-cellulose hydrogel membrane soaked in the urea aqueous solution is taken out, dried at 60 ℃ for 4 hours, and the rest is the same as the example 1, so that the bacterial nano-cellulose gel-based water-retaining slow-release fertilizer is obtained.
The urea release effect was tested according to the test method in example 1 (table 1).
The water absorption was tested according to the test method in example 1 (table 2).
The water retention values were tested according to the test method in example 1 (table 3).
Example 4
(1) The preparation method of the bacterial nano-cellulose film was the same as that of example 1 except that the bacterial nano-cellulose film was not required to be squeezed to remove excess water.
(2) And (2) freeze-drying the bacterial nano-cellulose hydrogel membrane in the step (1) at the temperature of minus 40-50 ℃ for 72 hours to obtain the freeze-dried bacterial nano-cellulose sponge.
(3) And (3) soaking 0.5g of the bacterial nano-cellulose sponge subjected to freeze drying in the step (2) in the urea aqueous solution in the step (1) for 1h at 25 ℃ to completely adsorb the urea aqueous solution, wherein the using amount of the urea aqueous solution is 5mL (the mass ratio of the nano-cellulose to the urea is 1: 5).
(4) And (4) taking out the bacterial nano cellulose membrane soaked in the urea aqueous solution in the step (3), and drying for 2h at the temperature of 30 ℃ to obtain the bacterial nano cellulose gel-based water-retaining slow-release fertilizer.
The urea release effect was tested according to the test method in example 1 (table 1).
The water absorption was tested according to the test method in example 1 (table 2).
The water retention values were tested according to the test method in example 1 (table 3).
The gel-based water-retention slow-release fertilizer prepared in example 1 is represented by a (prepared by impregnating urea with a hydrogel BNC film), the gel-based water-retention slow-release fertilizer prepared in example 2 is represented by B (prepared by impregnating urea with a freeze-dried BNC film), the gel-based water-retention slow-release fertilizer prepared in example 3 is represented by C (prepared by impregnating urea with a gel BNC film and drying), the gel-based water-retention slow-release fertilizer prepared in example 4 is represented by D (prepared by impregnating urea with a freeze-dried BNC film and drying), and the pure flower soil mixed urea particles are represented by E (urea particle soil) as a control group.
Table 1 shows the water-retaining slow-release fertilizer prepared in examples 1-4 and the control group: the cumulative release rate of the urea after the slow release of the pure flower soil mixed urea particles.
TABLE 1
| Sample (I) | Cumulative release rate of urea |
| A (example 1) | 58％ |
| B (example 2) | 62％ |
| C (example 3) | 68％ |
| D (example 4) | 64％ |
| E (control group) | 93％ |
As can be seen from the above table, compared with the effect of releasing urea from pure flower soil, the gel-based water-retaining slow-release fertilizer has an obvious urea slow-release effect, wherein the release effect of the water-retaining slow-release fertilizer which takes the bacterial nanocellulose in the hydrogel state as the matrix and is not dried is the best. A (example 1) the bacterial nano cellulose membrane in hydrogel state, although the network is deformed by squeezing to remove water, after absorbing urea solution, the nano network structure is recovered, which is beneficial to the slow release of urea. After freeze-drying, the bacterial nano cellulose membrane in example 2 causes the nano network to be affected to a certain extent, and the specific surface area becomes small to a certain extent, so that the slow release effect in the gel state cannot be achieved. After the bacterial nano cellulose membrane in the hydrogel state absorbs the urea solution and is dried, the network structure is damaged, hardening occurs, urea is separated out of the surface of the membrane, and release is accelerated. The same problem exists in D (example 4) and C (example 3), the drying has an effect on the network, and the urea particles are mostly located on the surface of the membrane, resulting in a faster release rate than in a (example 1) and B (example 2). The E (control group) is the flower soil, has no network structure and no slow release effect, so the urea is released most quickly. In summary, the hydrogel bacterial nano cellulose membrane of a (example 1) is not freeze-dried or oven-dried, and the structure is less affected by external force, so the slow release effect is the best.
Table 2 shows the water-retaining slow-release fertilizer prepared in examples 1-4 and the control group: water absorption of pure flower soil mixed urea particles.
TABLE 2
| Sample (I) | Water absorption rate |
| A (example 1) | 11％ |
| B (example 2) | 123％ |
| C (example 3) | 20％ |
| D (example 4) | 91％ |
| E (control group) | 17％ |
As can be seen from the above table, in the experiment, a (example 1) is a hydrogel film, and without any drying operation, the network space is occupied by a large amount of water, so the water absorption rate is low. The water absorption effect of B (example 2) was the best, with a water absorption of 123%, since the freeze-dried BNCs were sponge-like and contained a nano-network structure, and although they adsorbed the urea solution, the urea solution did not occupy all the space completely, and the remaining space was available for water absorption, so the water absorption was the highest. Although D (example 4) was also freeze-dried to have a sponge-like and net-like structure, after adsorbing urea and drying, its net-like structure was sufficiently compressed and did not have a large space to absorb water, so that the water absorption rate was low. C (example 3) the hydrogel film was dried, the network collapsed and was not easily recovered in a short time, and the water absorption was low. E (control group) the flower soil is changed from dry to wet, and certain water absorption performance exists.
Table 3 shows the water-retaining slow-release fertilizer prepared in examples 1-4 and the control group: water retention value of pure flower soil mixed urea granules.
TABLE 3
As can be seen from the above table, the water retention is best for the lyophilized BNC wet film (example 2) and then for the lyophilized BNC dry film (example 4), which have higher water absorption and higher water retention at later stages. Hydrogel BNC has low water absorption and therefore also has a low relative water retention value.
In examples 1 to 4, experiments were conducted using only urea, which is one of the fertilizers, to demonstrate the slow-release effect of the bacterial nanocellulose gel-based water-retention slow-release fertilizer, but the material can be used for slow release of various fertilizers, such as ammonium sulfate and sodium nitrate in the nitrogen fertilizer, potassium sulfate and potassium nitrate in the potassium fertilizer, and calcium superphosphate in the phosphate fertilizer. Although the fertilizer used in the experiment was different, the slow release effect of the material was similar to the above experimental results.
As can be seen from FIG. 1, the slow release effect of the hydrogel BNC wet film slow release fertilizer of A (example 1) is the best, the cumulative release rate of the urea slow release within 24h is 58%, which is lower than the release rates of the slow release fertilizers of other experimental groups (examples 2-4) and is further lower than the release rate of E (control group) by 34%; this indicates that the cellulose film fertilizer that was not freeze-dried and oven-dried had excellent slow-release effects. Compared with the control group, the release rate of other experimental groups is 25 to 31 percent different. The bacterial nano-cellulose gel-based water-retaining slow-release fertilizer has a good urea slow-release effect.
Fig. 2 is an appearance view of the material. A is the material obtained in example 1: the hydrogel BNC impregnated wet film is a gel-based water-retaining slow-release fertilizer obtained by adsorbing a fertilizer aqueous solution on a wet bacterial nano cellulose film. After the hydrogel BNC film adsorbs urea aqueous solution, the film thickness is not changed before and after dipping, the appearance of the hydrogel film has no change of color and shape, and the cellulose film is still in a gel state. B is the material obtained in example 2: the freeze-dried BNC dipped wet film is a gel-based water-retaining slow-release fertilizer obtained by freeze-drying wet bacterial nano cellulose to obtain a sponge-state bacterial nano cellulose film and adsorbing a fertilizer aqueous solution. When the BNC membrane subjected to freeze drying treatment adsorbs urea aqueous solution, the surface of the BNC membrane in a sponge state shrinks or caves, and the surface of the cellulose membrane restores to a gel state. C is the material obtained in example 3: the hydrogel BNC is soaked in the dried film, and the dried film is obtained by adsorbing a fertilizer water solution on the wet bacterial nano cellulose film and then drying the bacterial nano cellulose film. As the drying treatment is carried out, the moisture in the hydrogel film is fully evaporated, the network structure of the hydrogel film is fully compressed, the overall structure of the cellulose film is changed, the cellulose film becomes thin, the edge of the cellulose film is curled, and the cellulose film becomes uneven. Drying results in water loss and massive salt damage to the cellulose surface. D is the material obtained in example 4: the freeze-dried BNC dipped and dried film is obtained by freeze-drying wet bacterial nano cellulose to obtain a spongy bacterial nano cellulose film, adsorbing a fertilizer water solution and drying. Moisture of the cellulose membrane after freeze drying is fully removed, the cellulose is changed into a hydrogel state after urea aqueous solution is added, the obtained moisture is removed again after drying treatment, the internal structure is compressed, a large amount of salt stains are arranged on the surface, the cellulose membrane is thinned, and the color of the surface of part of the membrane is lightened.
As can be seen from FIG. 3, the urea concentration in the eluate of the control group was very high at 2-6 h, but the concentration was sharply reduced at 8h, and then the concentration change slowly started to become stable, compared to the eluate of the experimental group (examples 1-4), which indicates that the urea burst released at the initial stage of the experiment in E (control group), while the eluate of the experimental group (examples 1-4) did not change to a great extent, indicating that the fertilizer slow-release effect of the bacterial nano-cellulose gel-based water-retaining slow-release fertilizer is superior to that of the soil without network structure.
As can be seen from fig. 4, the amount of urea contained in the sample gradually decreases with the time, and after 24h of the experiment, the residual amount of urea in the control group E is the least, while many urea residues in the experiment groups (examples 1 to 4) are not completely released, and the residual amount of urea in the hydrogel BNC dry film (example 3) in the experiment group is the least because the network is compressed by a large amount and there is no space for storing urea inside, so that urea is on the surface and released quickly, but the residual amount of urea is still 0.6g more than that in the control group E. This shows that the bacterial nano-cellulose gel-based water-retaining slow-release fertilizer has a good urea slow-release effect.
Example 5
(1) A method for preparing a 35% ammonium sulfate aqueous solution by taking a unit fertilizer nitrogen fertilizer, such as ammonium sulfate (chemical reagent of national drug group Co., Ltd.) comprises the following steps: 35g of ammonium sulfate was weighed and dissolved in 100mL of deionized water.
(2) The method comprises the steps of taking acetobacter xylinum as a strain, performing static culture at constant temperature through a liquid culture medium, taking out the bacterial nano cellulose membrane, placing the bacterial nano cellulose membrane in NaOH solution with the concentration of 10g/L, treating the bacterial nano cellulose membrane at 80 ℃ for 2 hours, taking out the bacterial nano cellulose membrane, and rinsing the bacterial nano cellulose membrane to be neutral by using deionized water to obtain the bacterial nano cellulose membrane.
(3) Weighing 10g of purified bacterial nano cellulose gel film, shearing the gel film, and then scattering the gel film in a high-speed homogenizer, wherein the scattering time at 20000rpm/min is 5min, so as to obtain bacterial nano cellulose suspension (the solid content is 0.5 g).
(4) And (3) oxidizing the bacterial nano-cellulose suspension (solid content is 0.5g) obtained in the step (3) by a TEMPO/NaBr/NaClO mixed oxidation system of 100mL at room temperature for 6h, wherein the use level of TEMPO is 0.1mmol/g cellulose, and NaBr is 1mmol/g cellulose. The reaction was started by adding NaClO solution in an amount of 5mmol/g cellulose. The pH of the reaction system was maintained at 10 ± 0.5 by adding a NaOH solution dropwise, and when the NaOH solution was no longer consumed, the reaction was terminated by adding ethanol. The obtained Oxidized Bacterial cellulose (TEMPO Oxidized Bacterial nanocellose, ToBNC) is subjected to centrifugation, rinsing and autoclaving, and then is stored at 4 ℃.
(5) And (2) taking the ammonium sulfate aqueous solution prepared in the step (1), adjusting the pH to about 6.5, dropwise adding the ammonium sulfate aqueous solution into 50mL of the oxidized bacteria nano-cellulose suspension prepared in the step (4), reacting at 25 ℃ for 1h, repeatedly centrifuging and rinsing the product, and finally performing freeze drying at-40-50 ℃ for 72h to obtain the oxidized bacteria nano-cellulose/ammonium sulfate water-retention slow-release fertilizer. The dosage of the ammonium sulfate aqueous solution is 5mL (the mass ratio of the nano-cellulose to the ammonium sulfate is 1: 3.5).
In order to test whether the obtained bacterial nano-cellulose gel-based water-retaining slow-release fertilizer has the effect of slowly releasing ammonium sulfate, the amount of the obtained ammonium sulfate is slowly released. And (3) putting the obtained oxidized bacteria nano-cellulose/ammonium sulfate water-retention slow-release fertilizer into a sand core crucible, spraying with deionized water, and extracting a dissolution liquid so as to detect the effect of slow-release ammonium sulfate and the dissolution amount of ammonium sulfate. 10g of pure flower soil was mixed with 1.75g of ammonium sulfate granules as a control group.
And (3) measuring the concentration of ammonium sulfate in the dissolution liquid and the release amount of ammonium sulfate in the slow release fertilizer:
establishing a standard curve:
preparing a nano reagent: 16g of NaOH was weighed, dissolved in 50mL of water, and sufficiently cooled to room temperature. Further weighing 7g potassium iodide and 10g mercury iodide, dissolving in water, adding the solution into NaOH solution under stirring, diluting with water to 100mL, storing in polyethylene bottle, and storing in sealed stopper.
Preparing a potassium sodium tartrate (Shanghai Yizhen chemical industry Co., Ltd.) solution: 50g of sodium potassium tartrate is weighed and dissolved in 100mL of water, heated and boiled to remove ammonia, cooled and the volume is 100 mL.
Preparing an ammonium standard stock solution: 3.819g of high-grade pure ammonium chloride (national pharmaceutical group chemical reagent Co., Ltd.) dried at 100 ℃ was weighed and dissolved in water, transferred into a 1000mL volumetric flask, and diluted to the marked line.
Ammonium standard solution used: 5mL of the ammonium standard solution was aspirated, transferred to a 500mL volumetric flask, and diluted to the marked line.
Drawing a standard curve: taking 6 colorimetric tubes with the volume of 50mL, respectively adding 0, 0.50, 1.00, 3.00, 7.00 and 10.0mL of standard solution, adding deionized water to the marked line, adding 1.0mL of potassium sodium tartrate solution, mixing and shaking uniformly. Then 1.5mL of Narse reagent was added, mixed and shaken well. Standing for 10min, then taking the reaction solution of the first colorimetric tube as a reference solution, respectively measuring the absorbance of the reaction solution of the 6 colorimetric tubes at 420nm, subtracting the absorbance of a zero-concentration blank tube from the measured absorbance to obtain corrected absorbance, and drawing a standard curve by taking the absorbance value as a vertical coordinate and the concentration of the ammonium standard solution as a horizontal coordinate.
And (3) measuring the concentration of ammonium sulfate in the dissolution liquid: placing the oxidized bacteria nano-cellulose/ammonium sulfate water-retention slow-release fertilizer into a sand core crucible, periodically flushing with deionized water, and collecting filtrate. Diluting the filtrate by 10 times, accurately transferring 10mL of diluent, respectively adding into a 50mL colorimetric tube, adding deionized water to the marked line, adding 1.0mL of potassium sodium tartrate solution, mixing and shaking up. Then 1.5mL of Narse reagent was added, mixed and shaken well. Standing for 10min, and measuring absorbance at 420 nm. The measured absorbance of each sample can be found from the standard curve for the corresponding concentration. And collecting the concentrations corresponding to the different sampling time points, and simultaneously recording the volumes of the dissolution liquid at the different sampling time points.
And (3) measuring the release amount of ammonium sulfate in the gel-based slow release fertilizer: and calculating the mass of urea in the dissolution liquid according to the measured ammonium sulfate concentration and the volumes of the dissolution liquid obtained at different sampling time points, and calculating the content of residual ammonium sulfate left in the gel-based slow-release fertilizer.
Calculating the cumulative release rate of ammonium sulfate: the cumulative release rate of ammonium sulfate refers to the mass fraction of the cumulative release amount of ammonium sulfate released from a sample in a period of time to the mass of ammonium sulfate contained in the sample before the release, and is calculated according to the following formula:
and drawing an ammonium sulfate cumulative release curve by taking the ammonium sulfate cumulative release rates corresponding to sampling at different time points as a vertical coordinate and taking the horizontal coordinate as time.
The water absorption was tested according to the test method in example 1 (table 5).
The water retention value was tested according to the test method in example 1. (Table 6).
Example 6
(1) The preparation of the aqueous ammonium sulfate solution was the same as in example 5.
(2) The bacterial nanocellulose suspension was prepared in the same manner as in example 5.
(3) The bacterial nano-cellulose suspension obtained in the step (1) is put under the condition of keeping out of the sun at 40 ℃ and at the concentration of 0.05mol/LNaIO4The solution was stirred in 100mL and oxidized for 6 h.
(4) Oxidizing the bacteria nanocellulose (DABNC) of the sample subjected to the reaction in the step (3), taking out, adding 0.1mol/L glycol solution for soaking until excessive IO is removed4 -. And washing the sample with deionized water for multiple times for later use.
(5) Adding 0.05mol/L NaClO into the sample obtained in the step (4)2100mL, adjusting the pH value to 10.5-11, stirring at the room temperature of 30 ℃, and reacting for 72 hours in a dark place.
(6) And (5) irradiating the sample obtained in the step (5) to decompose the oxidant, and washing the sample for multiple times by using deionized water until the oxidant is removed.
(7) And (3) taking an ammonium sulfate aqueous solution (the preparation method is the same as that in the embodiment 5), adjusting the pH to about 6.5, dropwise adding the ammonium sulfate aqueous solution into 50mL of the oxidized bacteria nano-cellulose suspension prepared in the step (6), reacting at 25 ℃ for 1h, repeatedly centrifuging and rinsing the product, and finally performing freeze drying at-40-50 ℃ for 72h to obtain the oxidized bacteria nano-cellulose/ammonium sulfate water-retention slow-release fertilizer. The dosage of the ammonium sulfate aqueous solution is 5mL (the mass ratio of the nano-cellulose to the ammonium sulfate is 1: 3.5).
The ammonium sulfate slow release effect was tested according to the test method in example 5 (table 4).
The water absorption was tested according to the test method in example 1 (table 5).
The water retention value was tested according to the test method in example 1. (Table 6).
The gel-based water-retaining slow-release fertilizer prepared in example 5 is denoted by F: ToBNC, the gel-based water-retaining slow-release fertilizer prepared in example 6 is denoted by G: DABNC. Pure soil mixed ammonium sulfate granules as a control group are denoted by H: ammonium sulfate granular soil.
Table 4 shows the water-retaining slow-release fertilizer prepared in examples 5-6 and the control group: the cumulative release rate of the ammonium sulfate after the pure flower soil mixed ammonium sulfate particles are slowly released.
TABLE 4
As can be seen from the above table, compared to the effect of releasing ammonium sulfate from pure flower soil, the oxidized BNC gel-based water-retention slow-release fertilizer has a significant slow-release effect of ammonium sulfate, wherein the TOBNC (example 5) gel-based water-retention slow-release fertilizer has the best slow-release effect. Because the ammonium sulfate is combined with the oxidized BNC through electrostatic adsorption and has tight binding force, the release is slow.
Table 5 shows the water-retaining slow-release fertilizer prepared in examples 5-6 and the control group: the water absorption of the pure flower soil mixed ammonium sulfate particles.
TABLE 5
| Sample (I) | Water absorption rate |
| F (example 5) | 3300％ |
| G (example 6) | 3014％ |
| H (control group) | 62％ |
As can be seen from the above table, in the experiment, TOBNC (example 5) has the best water absorption effect, the water absorption rate is 3300%, and DABNC (example 6) has a very high water absorption rate, because freeze-dried oxidized BNC is in the form of sponge, and is itself a nano-network structure, and a large amount of water can be adsorbed by making full use of the network space.
Table 6 shows the water-retaining slow-release fertilizer prepared in examples 5-6 and a control group: water retention value of pure flower soil mixed ammonium sulfate particles.
TABLE 6
| Sample (I) | Water retention value |
| F (example 5) | 4248％ |
| G (example 6) | 4082％ |
| H (control group) | 57％ |
As can be seen from the above table, the water retention is preferably TOBNC (example 5) and then DABNC (example 6), and the higher water absorption and the later water retention are relatively higher.
As can be seen from fig. 5, the slow release effect of the TOBNC (example 5) water-retaining slow release fertilizer is the best, the cumulative release rate of the released ammonium sulfate within 24 hours is 48%, the slow release effect of the DABNC (example 6) water-retaining slow release fertilizer is also excellent, the cumulative release rate of the ammonium sulfate within 24 hours is 61%, the slow release rates of the experimental groups are all lower than that of the control group, and a large difference exists, which indicates that the bacterial nanocellulose gel-based water-retaining slow release fertilizer has a good slow release effect.
As can be seen from fig. 6, at 2-6 h, compared with the concentration of the eluate of the experimental group (examples 5-6), the concentration of ammonium sulfate in the eluate of the control group is very high, and at 8h, the concentration is sharply reduced, and then the concentration change slowly begins to become stable, which indicates that the soil cannot be tightly combined with ammonium sulfate in the initial stage of the experiment of the control group, so that ammonium sulfate is suddenly released, while the concentration of ammonium sulfate in the eluate of the experimental group does not change to a great extent, which indicates that the bacteria nano-cellulose gel-based water-retaining slow-release fertilizer has a good ammonium sulfate slow-release effect.
As can be seen from FIG. 7, the amount of ammonium sulfate contained in the sample gradually decreases with the time, and after 24h of the experimental process, the residual amount of ammonium sulfate in the control group is the least, and a large amount of ammonium sulfate remains in the experimental group and is not completely released, which indicates that the bacterial nano-cellulose gel-based water-retaining slow-release fertilizer has a good slow-release effect of ammonium sulfate.
In examples 5 to 6, experiments were conducted with only one ammonium fertilizer, ammonium sulfate, among the chemical fertilizers, to show the slow release effect of the oxidized bacteria nanocellulose gel-based water-retention slow-release fertilizer, but the material can be used for the slow release of a variety of fertilizers, such as most of ammonium salts, potassium salts, and the like. Although the fertilizer used in the experiment was different, the slow release effect of the material was similar to the above experimental results.
Example 7
(1) A method for preparing a nitrogen fertilizer unit, such as ammonium sulfate (chemical reagent of national drug group, Inc.) into an ammonium sulfate aqueous solution with the concentration of 10 percent by mass, comprises the following steps: ammonium sulfate, 10g, was weighed and dissolved in 100mL of deionized water.
(2) A plant source nano Cellulose (NFC) suspension (solid content is 0.5g) is taken, and deionized water is used as a solvent. The crystallinity of the plant source nano-cellulose (Zhongshan Naoxine New Material Co., Ltd.) is 86%, and the viscosity is 1050 mPa.s.
(3) And (3) taking an ammonium sulfate aqueous solution, adjusting the pH to about 6.5, dropwise adding the ammonium sulfate aqueous solution into 50mL of the plant source nano-cellulose suspension obtained in the step (2), reacting at 25 ℃ for 1h, and finally performing freeze drying at minus 40-50 ℃ for 72h to obtain the plant source nano-cellulose/ammonium sulfate water-retention slow-release fertilizer. The dosage of the ammonium sulfate aqueous solution is 5mL (the mass ratio of the nano-cellulose to the ammonium sulfate is 1: 1).
(4) The ammonium sulfate sustained-release effect was tested according to the test method of example 5 using 10g of pure flower soil mixed with 0.5g of ammonium sulfate granules as a control group (table 7).
(5) The water absorption was tested according to the test method in example 1 (table 8).
(6) The water retention value was tested according to the test method in example 1. (Table 9).
Example 8
(1) The preparation of the aqueous ammonium sulfate solution was the same as in example 7.
(2) A plant-derived Oxidized nano Cellulose (ONFC) suspension (solid content is 0.5g) is taken, and deionized water is taken as a solvent. The plant source oxidized nano-cellulose (Zhongshan Naoxine New Material Co., Ltd.) has a carboxyl content of 1.18mmol/g and a viscosity of 31550 mPa.s.
(3) And (3) adjusting the pH value of an ammonium sulfate aqueous solution to about 6.5, dropwise adding the ammonium sulfate aqueous solution into 50mL of the plant source oxidized nano-cellulose suspension prepared in the step (2), reacting at 25 ℃ for 1h, and finally performing freeze drying at minus 40-50 ℃ for 72h to obtain the plant source oxidized nano-cellulose/ammonium sulfate water-retention slow-release fertilizer. The dosage of the ammonium sulfate aqueous solution is 5mL (the mass ratio of the nano-cellulose to the ammonium sulfate is 1: 1).
(4) The ammonium sulfate sustained-release effect was tested according to the test method of example 5 using 10g of pure flower soil mixed with 0.5g of ammonium sulfate granules as a control group (table 7).
(5) The water absorption was tested according to the test method in example 1 (table 8).
(6) The water retention values were tested according to the test method in example 1 (table 9).
The gel-based water-retaining slow-release fertilizer prepared in example 7 is represented by I: and (4) NFC. The gel-based water-retaining slow-release fertilizer prepared in example 8 is represented by J: and ONFC. Pure soil mixed ammonium sulfate granules as a control group are denoted by K: ammonium sulfate granular soil.
Table 7 shows the gel-based water-retaining slow-release fertilizer prepared in examples 7 to 8 and a control group: the cumulative release rate of the ammonium sulfate after the pure flower soil mixed ammonium sulfate particles are slowly released.
TABLE 7
| Sample (I) | Cumulative release rate of ammonium sulfate |
| I (example 7) | 62％ |
| J (example 8) | 50％ |
| K (control group) | 89％ |
As can be seen from the above table, compared with the effect of releasing ammonium sulfate from pure flower soil, the NFC and ONFC gel-based water-retaining slow-release fertilizers have an obvious slow-release effect of ammonium sulfate, wherein the plant-derived oxidized nanocellulose J (example 8) gel-based water-retaining slow-release fertilizer has the best slow-release effect. Because the ammonium sulfate is combined with the plant source oxidized nano-cellulose through electrostatic adsorption, the binding force is tight, and the release is slow.
Table 8 shows the gel-based water-retaining slow-release fertilizer prepared in examples 7 to 8 and a control group: the water absorption of the pure flower soil mixed ammonium sulfate particles.
TABLE 8
| Sample (I) | Water absorption rate |
| I (example 7) | 3006％ |
| J (example 8) | 3020％ |
| K (control group) | 65％ |
As can be seen from the above table, in the experiment, the water absorption effect of both I (example 7) and J (example 8) is obvious, because the freeze-dried plant-derived nanofibers are in the form of sponges and are themselves in the form of nano-networks, and the network space can be fully utilized to absorb a large amount of water.
Table 9 shows the gel-based water-retaining slow-release fertilizer prepared in examples 7 to 8 and a control group: water retention value of pure flower soil mixed ammonium sulfate particles.
TABLE 9
| Sample (I) | Water retention value |
| I (example 7) | 4248％ |
| J (example 8) | 4082％ |
| K (control group) | 59％ |
As can be seen from the above table, I (example 7) and J (example 8) which are the most effective water-retaining agents in comparison with K (control) have a strong water-retaining ability, and their water absorption rates are higher, and the water-retaining value at the later stage is also relatively higher.
In examples 7 to 8, experiments were conducted with only one ammonium fertilizer, ammonium sulfate, of the fertilizers to show the slow release effect of the plant-derived nanocellulose and the plant-derived oxidized cellulose gel-based water-retaining slow release fertilizer, but the material can be used for the slow release of various fertilizers, and the plant-derived nanocellulose can be prepared into most of common fertilizers such as nitrogen, phosphorus, potassium and the like. The plant source oxidized nano-cellulose can be combined with most fertilizers such as ammonium salt, potassium salt and the like to prepare the gel-based slow-release fertilizer. Although the fertilizer used in the experiment was different, the slow release effect of the material was similar to the above experimental results.
Comparative example 1
A slow-release fertilizer is composed of a fertilizer core, a binder and an outer coating, wherein the fertilizer core comprises a fertilizer and bentonite, the binder comprises polyvinyl alcohol solution, and the outer coating comprises magnesium ammonium phosphate, super absorbent resin and rooting powder. Although the slow release effect is good, the fertilizer has a complex composition structure, too many types of required raw materials, a complex preparation process and high requirements on used equipment, and is not beneficial to agricultural popularization and use.
Comparative example 2
A gel-based water-retaining slow-release urea fertilizer is prepared through water-phase chemical polymerization reaction, mixing acrylic acid solution with a certain neutralizing degree with urea solution to obtain mixed solution, adding cross-linking agent and trigger, initiating polymerization reaction, and continuous complex polymerizing. Although the water absorption rate of the water-retaining slow-release fertilizer can be improved, and the opportunity of water fertilizer effect is increased, the used raw materials are chemical raw materials, so that the production cost is high, the operation is complicated, the synthesis process is complex, the requirement on overhigh temperature exists in the reaction, and the commercial popularization is limited.
Claims (10)
1. A nano-cellulose gel-based water-retaining slow-release fertilizer is characterized in that nano-cellulose or oxidized nano-cellulose is used as a matrix, and a fertilizer aqueous solution is adsorbed to obtain the nano-cellulose gel-based water-retaining slow-release fertilizer.
2. The slow release fertilizer of claim 1, wherein said fertilizer comprises a macroelement fertilizer, a secondary macroelement fertilizer, a micronutrient fertilizer, or a complex fertilizer.
3. A preparation method of a nano-cellulose gel-based water-retaining slow-release fertilizer comprises the following steps:
mixing nano-cellulose or oxidized nano-cellulose with a fertilizer aqueous solution, and adsorbing the fertilizer aqueous solution to obtain the nano-cellulose gel-based water-retaining slow-release fertilizer, wherein the mass ratio of the nano-cellulose or oxidized nano-cellulose to the fertilizer is 1: 1-1: 50.
4. The method of claim 3, wherein the nanocellulose comprises bacterial nanocellulose or plant-derived nanocellulose; the form of the bacterial nano cellulose is a common bacterial nano cellulose film, a freeze-dried bacterial nano cellulose sponge, a bacterial nano cellulose homogenate or a bacterial nano cellulose flocculent fiber; the form of the plant source nano-cellulose is plant source nano-cellulose suspension, plant source nano-cellulose gel and freeze-dried plant source nano-cellulose.
5. The method of claim 3, wherein oxidizing nanocellulose comprises oxidizing bacterial nanocellulose or plant-derived oxidizing nanocellulose; the oxidized nano-cellulose is in the form of oxidized nano-cellulose suspension, oxidized nano-cellulose gel and freeze-dried oxidized nano-cellulose.
6. The method according to claim 4, wherein the bacterial nanocellulose culture strain is Acetobacter xylinum; the bacterial nano-cellulose is obtained by strain in-situ static culture or dynamic culture.
7. The method of claim 5, wherein the oxidizing of the bacterial nanocellulose is performed by TEMPO oxidation or NaIO oxidation of bacterial nanocellulose4Preparing by an oxidation method; the culture strain of the bacterial nano-cellulose is acetobacter xylinum; the bacterial nano-cellulose is obtained by strain in-situ static culture or dynamic culture.
8. The method according to claim 3, wherein the adsorption temperature is 25-30 ℃ and the adsorption time is 1-6 h; the concentration of the fertilizer water solution is 200-500 g/L.
9. The method of claim 3, wherein the adsorbing the aqueous fertilizer solution is followed by drying to: drying for 2-4 h at 30-60 ℃ or freeze drying for 48-72 h at minus 40-50 ℃.
10. Use of the water-retaining slow-release fertilizer of claim 1 in crop planting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010219009.7A CN111533613B (en) | 2020-03-25 | 2020-03-25 | Nano-cellulose gel-based water-retaining slow-release fertilizer and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010219009.7A CN111533613B (en) | 2020-03-25 | 2020-03-25 | Nano-cellulose gel-based water-retaining slow-release fertilizer and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111533613A true CN111533613A (en) | 2020-08-14 |
| CN111533613B CN111533613B (en) | 2023-02-28 |
Family
ID=71971181
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010219009.7A Active CN111533613B (en) | 2020-03-25 | 2020-03-25 | Nano-cellulose gel-based water-retaining slow-release fertilizer and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111533613B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112142524A (en) * | 2020-10-06 | 2020-12-29 | 青岛一亩地农业科技有限责任公司 | Environment-friendly high-water-retention slow-release fertilizer and preparation method thereof |
| CN113880668A (en) * | 2021-10-11 | 2022-01-04 | 新疆生产建设兵团第三师农业科学研究所 | Composite microbial fertilizer and preparation method thereof |
| CN115108864A (en) * | 2022-05-17 | 2022-09-27 | 吉林省经济管理干部学院(吉林经济职业技术学院、吉林省电子信息技师学院、北方企业管理培训中心、吉林省农业干部培训中心) | Fertilizer beneficial to cyclic utilization of environmental resources and preparation method and application thereof |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103665439A (en) * | 2013-11-22 | 2014-03-26 | 东华大学 | Stimuli-responsive composite material made from bacterial nano cellulose as well as preparation method and application of stimuli-responsive composite material |
| CN104355784A (en) * | 2014-10-14 | 2015-02-18 | 成都新柯力化工科技有限公司 | Slow release fertilizer comprising fly ash gel and preparation method of slow release fertilizer |
| CN104557345A (en) * | 2014-12-30 | 2015-04-29 | 昆明理工大学 | Preparation method of hydrogel for nitrogenous fertilizer |
| CN106238001A (en) * | 2016-08-11 | 2016-12-21 | 四川大学 | A kind of hydrated ferric oxide. modified nanometer cellulose and application thereof |
| CN106831123A (en) * | 2017-01-19 | 2017-06-13 | 南京理工大学 | A kind of bacteria cellulose/concave convex rod composite biomass water keeping fertilizer and preparation method thereof |
| CN107722338A (en) * | 2017-10-31 | 2018-02-23 | 天津科技大学 | The preparation method and nano-cellulose aerogel of a kind of nano-cellulose aerogel |
| CN108160053A (en) * | 2018-02-06 | 2018-06-15 | 东北林业大学 | A kind of nano-cellulose gel and its preparation method and application |
| CN109503295A (en) * | 2018-10-15 | 2019-03-22 | 何誉 | A kind of porous super absorbent resin and preparation method thereof with slow-release fertilizer function |
-
2020
- 2020-03-25 CN CN202010219009.7A patent/CN111533613B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103665439A (en) * | 2013-11-22 | 2014-03-26 | 东华大学 | Stimuli-responsive composite material made from bacterial nano cellulose as well as preparation method and application of stimuli-responsive composite material |
| CN104355784A (en) * | 2014-10-14 | 2015-02-18 | 成都新柯力化工科技有限公司 | Slow release fertilizer comprising fly ash gel and preparation method of slow release fertilizer |
| CN104557345A (en) * | 2014-12-30 | 2015-04-29 | 昆明理工大学 | Preparation method of hydrogel for nitrogenous fertilizer |
| CN106238001A (en) * | 2016-08-11 | 2016-12-21 | 四川大学 | A kind of hydrated ferric oxide. modified nanometer cellulose and application thereof |
| CN106831123A (en) * | 2017-01-19 | 2017-06-13 | 南京理工大学 | A kind of bacteria cellulose/concave convex rod composite biomass water keeping fertilizer and preparation method thereof |
| CN107722338A (en) * | 2017-10-31 | 2018-02-23 | 天津科技大学 | The preparation method and nano-cellulose aerogel of a kind of nano-cellulose aerogel |
| CN108160053A (en) * | 2018-02-06 | 2018-06-15 | 东北林业大学 | A kind of nano-cellulose gel and its preparation method and application |
| CN109503295A (en) * | 2018-10-15 | 2019-03-22 | 何誉 | A kind of porous super absorbent resin and preparation method thereof with slow-release fertilizer function |
Non-Patent Citations (1)
| Title |
|---|
| 李忠正 主编: "《植物纤维资源化学》", 30 June 2012, 中国轻工业出版社 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112142524A (en) * | 2020-10-06 | 2020-12-29 | 青岛一亩地农业科技有限责任公司 | Environment-friendly high-water-retention slow-release fertilizer and preparation method thereof |
| CN113880668A (en) * | 2021-10-11 | 2022-01-04 | 新疆生产建设兵团第三师农业科学研究所 | Composite microbial fertilizer and preparation method thereof |
| CN115108864A (en) * | 2022-05-17 | 2022-09-27 | 吉林省经济管理干部学院(吉林经济职业技术学院、吉林省电子信息技师学院、北方企业管理培训中心、吉林省农业干部培训中心) | Fertilizer beneficial to cyclic utilization of environmental resources and preparation method and application thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111533613B (en) | 2023-02-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111533613B (en) | Nano-cellulose gel-based water-retaining slow-release fertilizer and preparation method thereof | |
| Shen et al. | Synthesis and characterization of double-network hydrogels based on sodium alginate and halloysite for slow release fertilizers | |
| Kundu et al. | Cellulose hydrogels: Green and sustainable soft biomaterials | |
| Wang et al. | Collagen/cellulose hydrogel beads reconstituted from ionic liquid solution for Cu (II) adsorption | |
| Sun et al. | Controlled pesticide release from porous composite hydrogels based on lignin and polyacrylic acid | |
| CN102604141B (en) | Method for preparing antibacterial film of quaternarized chitosan iodine complex | |
| Wang et al. | Water retention and fertilizer slow release integrated superabsorbent synthesized from millet straw and applied in agriculture | |
| CN110272314A (en) | A method of preparing cladded type stalk fibre based water-holding slow-release fertilizer | |
| CN107162747B (en) | Preparation method of multifunctional composite water-retention slow-release fertilizer | |
| Mohamed et al. | Development of hydrogel based on Carboxymethyl cellulose/poly (4-vinylpyridine) for controlled releasing of fertilizers | |
| Pimsen et al. | Efficiency enhancement of slow release of fertilizer using nanozeolite–chitosan/sago starch-based biopolymer composite | |
| CN106219657A (en) | A kind of modified biomass adsorbent and its preparation method and application | |
| CN104448660B (en) | Superabsorbent resin as well as preparation method and applications thereof | |
| Azeem et al. | Eco‐friendly three‐dimensional hydrogels for sustainable agricultural applications: Current and future scenarios | |
| Wang et al. | Research on preparation and properties of a multifunctional superabsorbent based on semicoke and humic acid | |
| Liu et al. | Eco-friendly superabsorbent composites based on calcined semicoke and polydimethylourea phosphate: Synthesis, swelling behavior, degradability and their impact on cabbage growth | |
| CN113861600B (en) | Bio-based porous material and preparation method and application thereof | |
| Sangeetha et al. | Super water-absorbing hydrogel based on chitosan, itaconic acid and urea: preparation, characterization and reversible water absorption | |
| Xu et al. | Preparation and performance of degradable slow-release fertilizer coating material by a new ionic crosslinked hydrogel material | |
| Dong et al. | Preparation and properties of multifunctional eco-friendly slow-release urea fertilizer encapsulated by diatomite filter aid waste-based superabsorbent | |
| Hua et al. | Preparation of pH/temperature-responsive semi-IPN hydrogels based on sodium alginate and humic acid as slow-release and water-retention fertilizers | |
| CN111187367B (en) | Urea formaldehyde modified sodium alginate copolymer and application thereof | |
| Wang et al. | Synthesis of cellulose modified material from waste straw and the growth-promotion effects on wheat | |
| CN104611786A (en) | Method for preparing persistent inhibition carbon fiber dressing | |
| Trirahayu et al. | Synthesis and Performance Evaluation of Cellulose-based Slow-release Fertilizer: A Review |
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 |