CN116673002A - CaO-coconut shell biochar composite material and preparation method and application thereof - Google Patents
CaO-coconut shell biochar composite material and preparation method and application thereof Download PDFInfo
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- CN116673002A CN116673002A CN202310617006.2A CN202310617006A CN116673002A CN 116673002 A CN116673002 A CN 116673002A CN 202310617006 A CN202310617006 A CN 202310617006A CN 116673002 A CN116673002 A CN 116673002A
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- 239000002131 composite material Substances 0.000 title claims abstract description 108
- 238000002360 preparation method Methods 0.000 title claims abstract description 17
- 229910019142 PO4 Inorganic materials 0.000 claims abstract description 96
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims abstract description 96
- 239000010452 phosphate Substances 0.000 claims abstract description 96
- 239000000843 powder Substances 0.000 claims abstract description 48
- 235000013162 Cocos nucifera Nutrition 0.000 claims abstract description 38
- 244000060011 Cocos nucifera Species 0.000 claims abstract description 38
- 239000002689 soil Substances 0.000 claims abstract description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 23
- 239000000203 mixture Substances 0.000 claims abstract description 20
- 239000002245 particle Substances 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 22
- 238000004140 cleaning Methods 0.000 claims description 16
- 238000001035 drying Methods 0.000 claims description 16
- 238000007873 sieving Methods 0.000 claims description 16
- 238000002156 mixing Methods 0.000 claims description 10
- 238000003756 stirring Methods 0.000 claims description 10
- 238000001816 cooling Methods 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 8
- 239000007788 liquid Substances 0.000 claims description 8
- 230000006872 improvement Effects 0.000 claims description 5
- 238000001179 sorption measurement Methods 0.000 abstract description 80
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 abstract description 35
- 229910052698 phosphorus Inorganic materials 0.000 abstract description 35
- 239000011574 phosphorus Substances 0.000 abstract description 35
- 230000000694 effects Effects 0.000 abstract description 16
- 238000010000 carbonizing Methods 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 40
- 239000010865 sewage Substances 0.000 description 19
- 230000008569 process Effects 0.000 description 16
- 238000009792 diffusion process Methods 0.000 description 10
- 239000010903 husk Substances 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 238000010521 absorption reaction Methods 0.000 description 5
- 239000003463 adsorbent Substances 0.000 description 5
- 230000008859 change Effects 0.000 description 5
- 239000003610 charcoal Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 239000011550 stock solution Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 4
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 4
- 239000011575 calcium Substances 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 238000002835 absorbance Methods 0.000 description 3
- APUPEJJSWDHEBO-UHFFFAOYSA-P ammonium molybdate Chemical compound [NH4+].[NH4+].[O-][Mo]([O-])(=O)=O APUPEJJSWDHEBO-UHFFFAOYSA-P 0.000 description 3
- 229940010552 ammonium molybdate Drugs 0.000 description 3
- 235000018660 ammonium molybdate Nutrition 0.000 description 3
- 239000011609 ammonium molybdate Substances 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 238000001878 scanning electron micrograph Methods 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000012086 standard solution Substances 0.000 description 3
- KQROHCSYOGBQGJ-UHFFFAOYSA-N 5-Hydroxytryptophol Chemical compound C1=C(O)C=C2C(CCO)=CNC2=C1 KQROHCSYOGBQGJ-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 241000196324 Embryophyta Species 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 2
- 229960005070 ascorbic acid Drugs 0.000 description 2
- 235000010323 ascorbic acid Nutrition 0.000 description 2
- 239000011668 ascorbic acid Substances 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 238000007865 diluting Methods 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000002052 molecular layer Substances 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- 239000002028 Biomass Substances 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 241000254068 Cetoniinae Species 0.000 description 1
- 241000195493 Cryptophyta Species 0.000 description 1
- 238000001157 Fourier transform infrared spectrum Methods 0.000 description 1
- 241001465754 Metazoa Species 0.000 description 1
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 229910003873 O—P—O Inorganic materials 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
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- 230000002238 attenuated effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010170 biological method Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 238000009388 chemical precipitation Methods 0.000 description 1
- 210000001072 colon Anatomy 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000003760 magnetic stirring Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 229910000402 monopotassium phosphate Inorganic materials 0.000 description 1
- 235000019796 monopotassium phosphate Nutrition 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 125000002467 phosphate group Chemical group [H]OP(=O)(O[H])O[*] 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- GNSKLFRGEWLPPA-UHFFFAOYSA-M potassium dihydrogen phosphate Chemical compound [K+].OP(O)([O-])=O GNSKLFRGEWLPPA-UHFFFAOYSA-M 0.000 description 1
- LWIHDJKSTIGBAC-UHFFFAOYSA-K potassium phosphate Substances [K+].[K+].[K+].[O-]P([O-])([O-])=O LWIHDJKSTIGBAC-UHFFFAOYSA-K 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000009790 rate-determining step (RDS) Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000004626 scanning electron microscopy Methods 0.000 description 1
- 235000015170 shellfish Nutrition 0.000 description 1
- 238000002798 spectrophotometry method Methods 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/04—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of alkali metals, alkaline earth metals or magnesium
- B01J20/041—Oxides or hydroxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
- B09C1/08—Reclamation of contaminated soil chemically
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2220/00—Aspects relating to sorbent materials
- B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
- B01J2220/48—Sorbents characterised by the starting material used for their preparation
- B01J2220/4875—Sorbents characterised by the starting material used for their preparation the starting material being a waste, residue or of undefined composition
- B01J2220/4881—Residues from shells, e.g. eggshells, mollusk shells
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2220/00—Aspects relating to sorbent materials
- B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
- B01J2220/48—Sorbents characterised by the starting material used for their preparation
- B01J2220/4875—Sorbents characterised by the starting material used for their preparation the starting material being a waste, residue or of undefined composition
- B01J2220/4887—Residues, wastes, e.g. garbage, municipal or industrial sludges, compost, animal manure; fly-ashes
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/105—Phosphorus compounds
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Hydrology & Water Resources (AREA)
- Water Supply & Treatment (AREA)
- Soil Sciences (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
The application discloses a CaO-coconut shell biochar composite material, a preparation method and application thereof, and belongs to the technical field of biochar and application, wherein the CaO-coconut shell biochar composite material is prepared by carbonizing a shell powder and coconut shell powder mixture at high temperature, and is applied to adsorbing phosphate in water, when the initial pH is 6, the phosphate adsorption effect is best, and the optimal input amount of the CaO-coconut shell biochar composite material is 0.4g/L; the composite material absorbing phosphate is put into soil, so that the pH value and the content of available phosphorus in each soil layer are effectively improved. In conclusion, the CaO-coconut shell biochar composite material has good adsorption performance on phosphate, and the composite material for adsorbing phosphate can effectively improve soil properties.
Description
Technical Field
The application relates to the technical field of biochar and application, in particular to a CaO-coconut shell biochar composite material and a preparation method and application thereof.
Background
The current society rapidly develops, a large amount of phosphorus-containing wastewater is always generated in the process of industrial production of industrial and agricultural industries at the present stage, and enrichment of nitrogen and phosphorus nutrients in a water body can cause rapid propagation of algae and other plankton, and finally the content of dissolved oxygen in the water body is reduced, so that aquatic animals and plants are attenuated and even extinct, which is very unfavorable for the stability of a human ecological system. The biological carbon is adopted to adsorb phosphate in the water body, and the phosphate is adsorbed from the sewage due to the characteristics of high efficiency, low consumption and high removal rate, so that not only can the water resource be purified, but also the recovery of phosphorus can be realized, and the adsorbed solid provides phosphorus fertilizer for crops, thereby having very remarkable environmental benefit and economic effect.
The current phosphorus recovery methods include chemical precipitation and biological methods. However, the above methods have limitations such as a small amount of water to be treated, difficulty in separation, high cost, and the like. Phosphorus element in waste water is retrieved through adsorbent, hasHas the advantages of no secondary pollution, easy granulation and separation, low cost, etc. Since the surface of directly prepared biochar has a large amount of negative charges and phosphorus exists in the form of phosphate in water mostly, such biochar has a limit on adsorption of phosphate. Some personnel perform modification experiments on biochar, such as composite MgO and LaCl 3 、FeCl 3 And the electropositivity of the surface of the biochar is increased, so that the adsorption effect of the biochar is improved.
Coconut coir is a byproduct of the coconut industry, and the composition of the coconut coir mainly comprises cellulose (46% -63%), lignin (31% -36%), and can be used for preparing biochar materials. The total quantity of shellfish living things cultured for a year exceeds tens of millions of tons, and the first place in the world. The waste shells are difficult to be utilized in the current stage treatment technology, and long-term untreated shells generate NH 3 、H 2 S and other harmful gases. However, the adsorption performance of the biochar prepared from the coconut coir and the shells on phosphate in water is not reported. Therefore, the application provides a CaO-coconut shell biochar composite material, and a preparation method and application thereof.
Disclosure of Invention
The application provides a CaO-coconut shell biochar composite material, a preparation method and application thereof, which not only realize the idea of recycling waste generated by preparing biochar from coconut shell and shells, but also achieve the technical effect of efficiently and high-capacity adsorbing phosphate in water.
The application provides a preparation method of a CaO-coconut shell biochar composite material, which is characterized by comprising the following steps:
s1, cleaning and drying coconut clothes to constant weight, crushing and sieving to obtain coconut clothes powder; cleaning and drying the shell to constant weight, crushing and sieving to obtain shell powder;
s2, uniformly mixing the coconut shell powder and the shell powder in the S1 in a ball mill to obtain a mixture, heating the mixture to 650-800 ℃ in a muffle furnace, maintaining for 2-3 h, and cooling to obtain the CaO-coconut shell biochar composite material.
Preferably, in S1, the particle size of the coconut powder is less than 0.125mm.
Preferably, in S1, the particle size of the shell powder is less than 0.125mm.
Preferably, in S2, the mass ratio of the coconut powder to the shell powder is 1:0.5-2.
Preferably, in S2, the initial temperature of the temperature rise is 15-25 ℃, and the temperature rise rate is 4-6 ℃/min.
The application also provides the CaO-coconut shell biochar composite material prepared by the preparation method.
The application also provides application of the CaO-coconut shell biochar composite material in adsorbing phosphate in water, which is characterized in that the application is as follows: and (3) putting the CaO-coconut shell biochar composite material into a phosphate solution with an initial pH value of 5-7, and stirring and adsorbing for 1-480 min at a rotating speed of 60-120 r/min to obtain the phosphate-adsorbed composite material.
Preferably, when the concentration of the phosphate solution is 50mg/L, the feed liquid ratio of the CaO-coconut shell biochar composite material to the phosphate solution is 0.2-1.2 g/1L.
Preferably, the phosphate-adsorbed composite is used for soil improvement.
Compared with the prior art, the application has the beneficial effects that:
according to the application, the CaO-coconut shell charcoal composite material is prepared by carbonizing a mixture of shell powder and coconut shell powder at high temperature, and is applied to adsorbing phosphate in water, when the initial pH is 6, the phosphate adsorption effect is best, and the optimal input amount of the CaO-coconut shell charcoal composite material is 0.4g/L; the adsorption process of phosphate accords with a quasi-secondary kinetic model, and the adsorption process has physical adsorption and chemical adsorption; the multi-molecular layer adsorption accords with the Freundlich model, and the maximum saturated adsorption capacity can reach 171.547mg/g; the thermodynamic model analysis result shows that the adsorption process is a spontaneous endothermic process, and the rising of the temperature is favorable for the adsorption reaction. In conclusion, the CaO-coconut shell biochar composite material has good adsorption performance on phosphate, can be used for removing the phosphate by adsorption in water, and effectively improves the pH value and the content of available phosphorus in each soil layer by putting the phosphate-adsorbed composite material into soil.
Drawings
FIG. 1 is a standard curve for phosphorus of the present application;
FIG. 2 is an SEM image of CaO-coconut husk biochar composite material prepared in example 1 of the present application;
FIG. 3 is an SEM image of a CaO-coconut-coated biochar composite material adsorbing phosphate according to example 1 of the present application;
FIG. 4 is a FTIR chart before and after adsorption of phosphate by CaO-coconut coir biochar composite material of example 1 of the present application;
FIG. 5 is an XRD pattern before and after phosphate adsorption by the CaO-coconut coir biochar composite of example 1 of the present application;
FIG. 6 is a graph showing the input amount of CaO-coconut husk biochar composite material and the average phosphate removal rate in example 1 of the present application;
FIG. 7 is a graph showing the adsorption removal rate of phosphate from phosphate solutions of different initial pH values for the CaO-coconut coir biochar composite material of example 1 of the present application;
FIG. 8 is a schematic diagram of simulated first order kinetics of phosphate adsorption process of the CaO-coconut husk biochar composite material of example 1 of the present application;
FIG. 9 is a schematic diagram of simulated second-level kinetics of phosphate adsorption process of the CaO-coconut husk biochar composite material of example 1 of the present application;
FIG. 10 is a graph showing the intra-granular diffusion model of the CaO-coconut husk biochar composite material of example 1 of the present application for the adsorption process of phosphate;
FIG. 11 is a diagram of a Langmuir isothermal adsorption model according to the present application;
FIG. 12 is a diagram of a Freundlich isothermal adsorption model in accordance with the present application;
fig. 13 is a graph of a thermodynamic model fit of the present application.
Detailed Description
In order that those skilled in the art will better understand the technical solution of the present application, the present application will be further described with reference to specific examples, but the examples are not intended to limit the present application. The following test methods and detection methods, if not specified, are conventional methods; the reagents and starting materials, unless otherwise specified, are commercially available.
Example 1
The preparation method of the CaO-coconut shell biochar composite material comprises the following steps: .
S1, cleaning and drying coconut clothes to constant weight, crushing and sieving to obtain coconut clothes powder with the particle size of less than 0.125 mm; cleaning and drying the shells to constant weight, crushing and sieving to obtain shell powder with the particle size of less than 0.125 mm;
s2, uniformly mixing the coconut shell powder and the shell powder in the mass ratio of 1:0.5 in a ball mill to obtain a mixture, heating the mixture to 650 ℃ in a muffle furnace with an initial temperature of 15 ℃ at a speed of 4 ℃/min, maintaining for 2 hours, and cooling to obtain the CaO-coconut shell biochar composite material.
The application of the CaO-coconut shell biochar composite material in adsorbing phosphate in water body is as follows: and (3) putting the CaO-coconut shell biochar composite material into a phosphate solution with an initial pH value of 5, and stirring and adsorbing for 1min at a rotating speed of 60r/min to obtain the phosphate-adsorbed composite material.
When the concentration of the phosphate solution is 50mg/L, the feed liquid ratio of the CaO-coconut shell biochar composite material to the phosphate solution is 0.2 g/1L.
And putting the phosphate-adsorbed composite material into soil, and detecting the pH value and available phosphorus in the soil before and after putting.
Example 2
The preparation method of the CaO-coconut shell biochar composite material comprises the following steps:
s1, cleaning and drying coconut clothes to constant weight, crushing and sieving to obtain coconut clothes powder with the particle size of less than 0.125 mm; cleaning and drying the shells to constant weight, crushing and sieving to obtain shell powder with the particle size of less than 0.125 mm;
s2, uniformly mixing the coconut shell powder and the shell powder in the mass ratio of 1:2 in a ball mill to obtain a mixture, heating the mixture to 800 ℃ in a muffle furnace with an initial temperature of 25 ℃ at a speed of 6 ℃/min, maintaining for 3 hours, and cooling to obtain the CaO-coconut shell biochar composite material.
The application of the CaO-coconut shell biochar composite material in adsorbing phosphate in water body is as follows: and (3) putting the CaO-coconut shell biochar composite material into a phosphate solution with an initial pH value of 7, and stirring and adsorbing for 480 minutes at a rotating speed of 120r/min to obtain the phosphate-adsorbed composite material.
When the concentration of the phosphate solution is 50mg/L, the feed liquid ratio of the CaO-coconut shell biochar composite material to the phosphate solution is 1.2 g/1L.
And putting the phosphate-adsorbed composite material into soil, and detecting the pH value and available phosphorus in the soil before and after putting.
Example 3
The preparation method of the CaO-coconut shell biochar composite material comprises the following steps:
s1, cleaning and drying coconut clothes to constant weight, crushing and sieving to obtain coconut clothes powder with the particle size of less than 0.125 mm; cleaning and drying the shells to constant weight, crushing and sieving to obtain shell powder with the particle size of less than 0.125 mm;
s2, uniformly mixing the coconut shell powder and the shell powder in a ball mill according to the mass ratio of 1:1 to obtain a mixture, heating the mixture to 700 ℃ in a muffle furnace with the initial temperature of 20 ℃ at the speed of 5 ℃/min, maintaining for 2.5h, and cooling to obtain the CaO-coconut shell biochar composite material.
The application of the CaO-coconut shell biochar composite material in adsorbing phosphate in water body is as follows: and (3) putting the CaO-coconut shell biochar composite material into a phosphate solution with an initial pH value of 6, and stirring and adsorbing for 10min at a rotating speed of 90r/min to obtain the phosphate-adsorbed composite material.
When the concentration of the phosphate solution is 50mg/L, the feed liquid ratio of the CaO-coconut shell biochar composite material to the phosphate solution is 0.4 g/1L.
And putting the phosphate-adsorbed composite material into soil, and detecting the pH value and available phosphorus in the soil before and after putting.
Example 4
The preparation method of the CaO-coconut shell biochar composite material comprises the following steps:
s1, cleaning and drying coconut clothes to constant weight, crushing and sieving to obtain coconut clothes powder with the particle size of less than 0.125 mm; cleaning and drying the shells to constant weight, crushing and sieving to obtain shell powder with the particle size of less than 0.125 mm;
s2, uniformly mixing the coconut shell powder and the shell powder in a ball mill according to the mass ratio of 1:1.5 to obtain a mixture, heating the mixture to 750 ℃ in a muffle furnace with the initial temperature of 18 ℃ at the speed of 6 ℃/min, maintaining for 2.25h, and cooling to obtain the CaO-coconut shell biochar composite material.
The application of the CaO-coconut shell biochar composite material in adsorbing phosphate in water body is as follows: and (3) putting the CaO-coconut shell biochar composite material into a phosphate solution with an initial pH value of 5, and stirring and adsorbing for 240min at a rotating speed of 75r/min to obtain the phosphate-adsorbed composite material.
When the concentration of the phosphate solution is 50mg/L, the feed liquid ratio of the CaO-coconut shell biochar composite material to the phosphate solution is 0.6 g/1L.
And putting the phosphate-adsorbed composite material into soil, and detecting the pH value and available phosphorus in the soil before and after putting.
Example 5
The preparation method of the CaO-coconut shell biochar composite material comprises the following steps:
s1, cleaning and drying coconut clothes to constant weight, crushing and sieving to obtain coconut clothes powder with the particle size of less than 0.125 mm; cleaning and drying the shells to constant weight, crushing and sieving to obtain shell powder with the particle size of less than 0.125 mm;
s2, uniformly mixing the coconut shell powder and the shell powder in a ball mill according to the mass ratio of 1:1.25 to obtain a mixture, heating the mixture to 680 ℃ in a muffle furnace with the initial temperature of 22 ℃ at the speed of 4 ℃/min, maintaining for 2.75h, and cooling to obtain the CaO-coconut shell biochar composite material.
The application of the CaO-coconut shell biochar composite material in adsorbing phosphate in water body is as follows: and (3) putting the CaO-coconut shell biochar composite material into a phosphate solution with an initial pH value of 7, and stirring and adsorbing for 120min at a rotating speed of 115r/min to obtain the phosphate-adsorbed composite material.
When the concentration of the phosphate solution is 50mg/L, the feed liquid ratio of the CaO-coconut shell biochar composite material to the phosphate solution is 0.8 g/1L.
And putting the phosphate-adsorbed composite material into soil, and detecting the pH value and available phosphorus in the soil before and after putting.
Example 6
The preparation method of the CaO-coconut shell biochar composite material comprises the following steps:
s1, cleaning and drying coconut clothes to constant weight, crushing and sieving to obtain coconut clothes powder with the particle size of less than 0.125 mm; cleaning and drying the shells to constant weight, crushing and sieving to obtain shell powder with the particle size of less than 0.125 mm;
s2, uniformly mixing the coconut shell powder and the shell powder in the mass ratio of 1:0.8 in a ball mill to obtain a mixture, heating the mixture to 720 ℃ in a muffle furnace with an initial temperature of 20 ℃ at a speed of 5 ℃/min, maintaining for 3 hours, and cooling to obtain the CaO-coconut shell biochar composite material.
The application of the CaO-coconut shell biochar composite material in adsorbing phosphate in water body is as follows: and (3) putting the CaO-coconut shell biochar composite material into a phosphate solution with an initial pH value of 6, and stirring and adsorbing for 360 minutes at a rotating speed of 100r/min to obtain the phosphate-adsorbed composite material.
When the concentration of the phosphate solution is 50mg/L, the feed liquid ratio of the CaO-coconut shell biochar composite material to the phosphate solution is 1.0 g/1L.
And putting the phosphate-adsorbed composite material into soil, and detecting the pH value and available phosphorus in the soil before and after putting.
To further illustrate the effect of the present application, the present application provides a comparative example as follows:
comparative example 1
The difference compared with example 3 is that the mass ratio of the coconut powder to the shell powder is adjusted to 1:0.2.
Comparative example 2
The difference compared with example 3 is that the mass ratio of coconut powder to shell powder is adjusted to 1:3.
Comparative example 3
The difference from example 3 is that the temperature rise rate was adjusted to 3℃per minute.
Comparative example 4
The difference from example 3 is that the temperature rise to 700 ℃ was adjusted to 850 ℃.
1. Test section:
1. test drug: monopotassium phosphate (superior purity, chengdu Colon chemical Co., ltd.); ascorbic acid (analytically pure, chengdu Kelong chemical reagent plant); ammonium molybdate (analytically pure, adult coulong chemicals limited); potassium antimonoxytartrate (analytically pure, chengdu Corp.); sulfuric acid (analytically pure, chengdu Corp.); hydrochloric acid (analytically pure, chengdu Corp., inc.).
2. Characterization means: the application characterizes the biochar through FTIR, SEM scanning electron microscope and XRD, and explores the microstructure of the CaO-coconut shell biochar composite material and the change of microscopic surface functional groups of the CaO-coconut shell biochar composite material before and after adsorption.
2.1 SEM image
The surface structure of the CaO-coconut husk biochar composite material of example 1 is shown in FIGS. 2 and 3 by SEM analysis. As can be seen from fig. 2: the CaO-coconut shell biochar composite material has a plurality of pores due to CO in the process of firing the biochar 2 Escape from the interior of the solid, thereby forming pores on the surface of the biochar. And a plurality of groups are attached to the surface of the CaO-coconut shell biochar, and the result shows that the CaO-coconut shell biochar composite material is successfully prepared. As can be seen from fig. 3: the CaO-coconut shell biochar composite material surface after absorbing phosphate forms a plurality of precipitates and floccules, so that the phosphate is absorbed on the CaO-coconut shell biochar.
2.2 FTIR images
The test results are shown in fig. 4. Obviously, the wavenumber of CaO-coconut husk biochar before adsorption is 3636.64032cm -1 、3455.05929cm -1 、2361.26482cm -1 、1417.3193cm -1 And 873.3083cm -1 The absorption is at all positions. Therein 3636.64032cm -1 And 3455.05929cm -1 The peak at the position is the-OH stretching vibration positionA peak caused; 2361.26482cm -1 The peak at this point is believed to be caused by a small amount of-C.ident.C on the CaO-coconut coir biochar surface; and 1417.3193cm -1 The peak at which is caused by-c=c; 873.3083cm -1 The treatment is caused by-CO. The wavenumber is 3440.31621cm as can be seen in the FTIR spectrum of CaO-coconut shell charcoal after adsorbing phosphate -1 The absorption peak at this point was significantly broadened, which suggests that the degree of association of hydroxyl groups was increased, and thus it could be judged that some reaction related to the association of hydroxyl groups occurred during the adsorption. But other than 1033.20158cm -1 、603.95257cm -1 563.63636cm -1 Besides the position, the positions and the intensities of other absorption peaks have no obvious change compared with the FTIR spectrogram before absorption; in the newly added absorption peak, 1033.20158cm -1 It is obvious from PO 4 3- Is caused by asymmetric vibrations of (a); 603.95257cm -1 And 563.63636cm -1 The phosphate is caused by the flexural telescopic vibration of O-P-O, which shows that the phosphate is indeed adsorbed on CaO-coconut coir biochar.
2.3 XRD patterns
The XRD test results are shown in fig. 5, and the biological carbon has obvious diffraction peaks at 23.02 °, 28.64 °, 29.36 °, 32.16 °, 34.04 °, 35.94 °, 37.34 °, 39.4 °, 43.16 °, 47.44 °, 48.46 °, 50.8 °, 53.82 °, 57.38 ° and 64.58 ° before adsorption. In comparison with standard cards, it can be derived that: peaks at 32.16 °, 37.34 °, 64.58 ° in 2θ are caused by CaO diffraction; diffraction peaks at 23.02 °, 29.36 °, 35.94 °, 39.4 °, 47.44 °, 48.46 °, 57.38 ° 2θ are due to CaCO 3 Diffraction-induced; peaks at 28.64 °, 34.04 °, 50.8 ° and 53.82 ° and a shoulder at 47.16 ° are Ca (OH) 2 Is a diffraction peak of (2). Thus, the main component of the material is CaO, caCO 3 With Ca (OH) 2 . This is probably because Ca (OH) is formed by the moisture in the coconut coir biomass and the calcium-containing component of the flower beetles during the charcoal firing process 2 This result indicates that CaO-coconut shell biochar has been successfully prepared. And as evident in XRD results of biochar after adsorption: caO and CaCO in raw materials 3 The diffraction peak generated largely disappears, and the diffraction peak is expressed as 2 thetaCa is present at 25.9 °, 31.94 °, 39.6 °, 46.7 ° and 49.5 ° 5 (PO 4 ) 3 The diffraction peak of OH, which indicates that the CaO-coconut husk biochar has a chemical reaction in the process of adsorbing phosphate, is consistent with the dynamic result.
3. Adsorption experiment: the experiment adopts a static adsorption method, and the concentration of phosphorus in the solution is measured according to an ammonium molybdate spectrophotometry. 0.4394g KH was weighed out 2 PO 4 The solid (AR) is dissolved and fixed to a volume of 2000mL to prepare a phosphate stock solution of 50ug/mL, and the phosphate stock solution is diluted as required when in use. Measuring a quantitative stock solution in a 50mL colorimetric tube with a plug, adding a proper amount of CaO-coconut shell biochar composite adsorbent, reacting at 25 ℃ at a rotating speed of 60r/min at fixed time, filtering out the reaction solution with a 0.45 μm filter membrane, and measuring absorbance. The apparent adsorption amount of phosphate was calculated according to the following formula.
Wherein: q is adsorption quantity, mg/g; c (C) 0 mg/L for pre-adsorption concentration; ce is concentration after adsorption equilibrium, mg/L; v is the solution volume, L; m is the mass of the adsorbent and g.
The phosphate removal rate (η) is calculated as follows:
wherein: eta is the phosphate removal rate,%.
4. Standard curve
Preparing a phosphate standard solution: 0.4394g of analytical grade KH is weighed and dried at 110℃for 2h and cooled in a desiccator 2 PO 4 Dissolving deionized water, transferring to a 2000mL volumetric flask, diluting to a fixed volume to a marked line, and uniformly mixing to obtain a phosphorus standard stock solution (50 mg/L). Transferring 10.0mL of standard stock solution into a 250mL volumetric flask, diluting with deionized water to the marked line, and uniformly mixing to obtain the phosphorus standard solution with the concentration of 2 mg/L. It is ready for use.
Drawing a standard curve: to a 50mL stoppered cuvette, 0, 0.50, 1.00, 3.00, 5.00, 10.0, 15.0mL of phosphate standard solution (50 mg/L) was added, respectively, and the volume was fixed to the scale. 1mL of 10% ascorbic acid solution was added to each of the 7 color comparison tubes and mixed well, and after waiting for 30s, 2mL of ammonium molybdate solution was added and mixed well. After 15min of standing at 25℃the absorbance was measured spectrophotometrically (using a cuvette with a thickness of 1cm, adjusting the wavelength at 700nm, using distilled water as reference and the phosphate concentration was measured afterwards). Drawing a standard curve according to the obtained data, wherein the ordinate is absorbance (A), the abscissa is phosphorus concentration (C), and the standard curve equation is as follows: y= 0.5049X-0.00817 as shown in fig. 1.
5. Optimum input amount of CaO-coconut shell biochar composite material
50mL of 50mg/L phosphate solution is taken in a 50mL colorimetric tube with a plug, 0.005g, 0.01g, 0.015g, 0.02g, 0.04g and 0.06g of CaO-coconut shell biochar composite material are respectively taken and placed in the colorimetric tube, stirred and adsorbed for 10min at the rotating speed of 60r/min, and the concentration of the residual phosphorus in the solution is calculated and measured.
The effect of CaO-coconut shell biochar composite addition on adsorption is shown in figure 6. Along with the increase of the adding amount of CaO-coconut shell biochar, the average removing rate of phosphate is improved; however, the average removal rate of phosphate tends to be stable with the addition of biochar to 0.4g/L. When the addition amount of the biochar is small, the adsorption sites provided by the biochar are limited, and the removal rate of phosphate is changed along with the addition amount of the biochar; however, as the amount of the additive increases, the adsorption amount of the phosphate increases rapidly first and then reaches equilibrium, and the removal rate reaches a certain stable value. From the graph, it can be seen that the optimum amount of biochar is 0.4g/L.
6. Initial optimum pH of phosphate solution
Taking 50mL of 50mg/L phosphate solution with different pH values in a 50mL colorimetric tube with a plug, taking the optimal dosage of the charcoal mass, and taking the pH values of the solution to be 3, 4, 5, 6, 7, 8 and 9. And (3) placing the CaO-coconut shell biochar composite material into a colorimetric tube, adsorbing and stirring for 10min at the rotating speed of 60r/min, and calculating and measuring the concentration of the residual phosphorus in the solution. To explore the optimum pH.
The effect of initial pH of the solution on adsorption is shown in FIG. 7, over a range withThe increase in pH gradually increases the phosphate removal rate, and after the pH reaches peak 6 the phosphate removal rate begins to decrease, which is probably because when the pH is small, the phosphorus in the solution becomes H 3 PO 4 In the form of (2) the electrostatic adsorption is reduced. And the structure of the CaO-coconut shell biochar composite material is likely to be damaged in a strong acid environment, so that a good adsorption effect cannot be achieved. When the pH is increased to a certain value, a large amount of OH exists in the solution - With PO (PO) 4 3- Rob the adsorption sites, resulting in reduced phosphate removal. It can be seen that the optimum pH condition for the biochar is 6.
7. Adsorption kinetics exploration
0.02g of CaO-coconut shell biochar composite material is weighed into 50mL of 50mg/L phosphate solution, and stirred at the rotating speed of 60r/min immediately at constant temperature. Setting stirring time to 1min, 3min, 5min, 10min, 20min, 30min, 60min, 90min, 120min, 240min, 360min, 720min. Immediately after magnetic stirring, the solution in the cuvette with plug was taken out, and the concentration of phosphorus remaining in the measured solution was calculated.
The data were fitted using quasi-first order, quasi-second order kinetics and intra-particle diffusion equations.
A first order equation: ln (q) e -q t )＝ln q e -k 1 t
Quasi-second-order equation:
intra-particle diffusion equation: q t ＝k p t 0.5 +C i
Wherein: q t Phosphate adsorption quantity at time t (min), mg/g; qe is adsorption quantity at adsorption equilibrium, mg/g; k (k) 1 Is a quasi-first order kinetic model constant, min -1 ；k 2 G/(mg.min) is a quasi-second-order kinetic model constant; k (k) p Mg/(g.h) as the rate constant of the intra-particle diffusion model 0.5 )；C i Mg/g is the intra-particle diffusion model parameter.
To describe the adsorption process of the CaO-coconut shell biochar composite material on phosphate, test data are fitted by using three kinetic models, and the results are shown in figures 8-10, table 1 and table 2. The highest fitting degree of the quasi-second-level kinetic model indicates that the adsorption process has chemical adsorption besides physical adsorption. From the intra-particle diffusion model graph, it can be seen that the adsorption of phosphate by the adsorbent can be divided into two stages: the first stage is an internal diffusion stage of particles, the adsorption rate of the biochar to the phosphate is high in the stage, and the fitted curve does not pass through the origin of coordinates, so that the internal diffusion process of the particles in the stage is not a main rate limiting step; the diffusion rate of the second stage is gradually reduced, and finally the phosphate reaches adsorption equilibrium on the biochar. The adsorption speed limiting step of CaO-coconut husk biochar on phosphate can be controlled by various factors, and the relation between time t and qt can be obtained: the greater the initial concentration, the longer it takes to reach adsorption equilibrium.
TABLE 1 kinetic fitting parameter Table for intra-particle diffusion model
TABLE 2 Primary and second dynamics fitting parameter Table
8. Adsorption isotherm
Phosphate with the concentration of 10mg/L, 20mg/L, 50mg/L, 75mg/L, 100mg/L, 150mg/L and 200mg/L is respectively measured in a series of colorimetric tubes, 0.020g CaO-coconut shell biochar is weighed and put into the colorimetric tubes, and the mixture is stirred for 180min at the rotating speed of 60r/min, so that the concentration of the phosphorus is measured. And adopting a Langmuir equation and a Freundlich equation to fit data, and researching the equilibrium adsorption behavior of the CaO-coconut shell biochar.
Langmuir equation:
freundlich equation:
wherein: k (K) L For Langmuir constant, L/mg, the larger the value, the more stable; q m Is the theoretical adsorption saturation quantity, mg/g; k (K) F Is Freundlich constant; n is related to the adsorption strength.
In the part, the initial phosphate concentration is changed under different temperature conditions, so that different biochar equilibrium adsorption capacities are obtained. The data were fitted using Langmuir and Freundlich isothermal equations, and the fitting results and associated data are shown in fig. 11, fig. 12 and table 3. As the initial concentration of phosphate increases, the adsorption capacity of biochar for phosphate also increases gradually. As can be seen from the Langmuir model diagram, the equilibrium adsorption capacity at 40℃is greater than the equilibrium adsorption capacity at 50℃when Ce is before 15 ug/mL. But the freeundlich model fits better at each temperature than the Langmuir model. And the theoretical maximum adsorption capacity predicted by a formula is 171.547mg/g at 303.15K, which indicates that the adsorption of the biochar to phosphate is multi-molecular layer adsorption with heterogeneous surface. 1/n in the Freundlich equation reflects the adsorption difficulty of the adsorbent, is easy to adsorb when 0.1 is less than 1/n is less than 0.5, and is difficult to adsorb when 1/n is more than 2. In this experiment (Table 3), 0.2 < 1/n < 0.3 indicates that the adsorption of phosphate belongs to the easy adsorption process.
TABLE 3 isothermal adsorption model fitting parameter table
9. Adsorption thermodynamic investigation
The experimental data were linearly fitted using the Vant-Hoff equation with 1/T as abscissa and lnK as ordinate, and the enthalpy change (Δh) and entropy change (Δs) of the adsorption process were calculated from the slope and intercept of the fitting equation, and the gibbs free energy change (Δg) was calculated from the following equation.
ΔG＝－RTlnK
The test data were subjected to thermodynamic model fitting as shown in fig. 13, and thermodynamic parameters were further calculated, and the calculation results are shown in table 4. It can be seen that: ΔH > 0, indicating the adsorption process absorbs heat; Δs > 0, indicating that CaO-coconut shell biochar has adsorption affinity for phosphate, and adsorption reaction is easy to perform; within the range of 303.15-323.15K, delta G is less than 0, which shows that the adsorption reaction of CaO-coconut shell biochar on phosphate can be carried out spontaneously, and delta G gradually decreases along with the temperature rise, thus showing that the rising temperature is more favorable for the adsorption reaction.
Table 4 thermodynamic model fitting parameter table
2. Example application of sewage treatment plant
According to the application, caO-coconut shell biochar composite materials prepared in examples 1-6 are respectively put into a large-weir ballasting sewage treatment plant, a rice urban and rural sewage treatment plant and a fort ballasting sewage treatment plant, wherein the adding amount is 0.2g of CaO-coconut shell biochar composite material per liter of sewage, and the technical effects of examples 1-6 are approximate, the adsorption effect is illustrated by taking example 3 as an example, and the water temperature, pH value, chemical oxygen demand, ammonia nitrogen value, total phosphorus value and total nitrogen value at the inlet of the sewage treatment plant before adding and at the outlet of the sewage treatment plant after adding are detected, so that the results are shown in Table 5.
TABLE 5 Sewage index detection Table for sewage treatment plant
As can be seen from Table 5, the CaO-coconut husk biochar composite material prepared in the embodiment 3 of the application has certain influence on the chemical oxygen demand, ammonia nitrogen value, total phosphorus value and total nitrogen value of sewage in sewage treatment plants in different areas, wherein the total phosphorus content in sewage of sewage treatment plants with large weir and town is reduced from 4.98 to 0.11; the total phosphorus content in the sewage of the sewage treatment plant in the urban and rural areas is reduced from 8.85 to 0.21; the sewage content of the Baozhen sewage treatment plant is reduced from 10.11 to 0.22. Therefore, the CaO-coconut shell biochar composite material has obvious adsorption effect on phosphorus in sewage.
3. Application of phosphate-adsorbed composite material in soil improvement
The application puts the composite materials of the adsorption phosphate obtained in the examples 1 to 6 into soil with the putting amount of 70kg/100m 2 The pH value and available phosphorus of the soil before and after the throwing were detected, and since the technical effects of examples 1 to 6 were similar, examples 1 and 3 were used as examples only, and the improvement effect of the phosphate-adsorbed composite materials of comparative examples 1 to 4 on the soil was compared, and the detection results are shown in table 6.
Table 6 soil improvement effect of composite material after adsorbing phosphate
As is clear from Table 6, the phosphate-adsorbed composite materials obtained in examples 1 and 3 of the present application have a certain effect on the pH value of soil and available phosphorus, as compared with comparative examples 1 to 4. For the soil layer of 0-20 cm, the pH value is reduced from 8.57 to 7.87 and then to 7.11, and the effective phosphorus content is increased from 2.15mg/kg to 16.00mg/kg and then returned to 7.51mg/kg; for 20-40 cm layers of soil, the pH value is reduced from 8.27 to 7.77 and then to 7.25, and the effective phosphorus content is increased from 1.30mg/kg to 6.35mg/kg and then returned to 5.70mg/kg. In conclusion, the CaO-coconut shell biochar composite material is used for adsorbing phosphate, and then the adsorbed composite material is put into soil, so that the pH value and the effective phosphorus content of the soil are effectively improved.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims (9)
1. The preparation method of the CaO-coconut shell biochar composite material is characterized by comprising the following steps of:
s1, cleaning and drying coconut clothes to constant weight, crushing and sieving to obtain coconut clothes powder; cleaning and drying the shell to constant weight, crushing and sieving to obtain shell powder;
s2, uniformly mixing the coconut shell powder and the shell powder in the S1 in a ball mill to obtain a mixture, heating the mixture to 650-800 ℃ in a muffle furnace, maintaining for 2-3 h, and cooling to obtain the CaO-coconut shell biochar composite material.
2. The method of claim 1 wherein in S1 the coconut powder has a particle size of <0.125mm.
3. The method according to claim 1, wherein in S1, the particle size of the shell powder is <0.125mm.
4. The preparation method of claim 1, wherein in S2, the mass ratio of the coconut powder to the shell powder is 1:0.5-2.
5. The method according to claim 1, wherein in S2, the initial temperature of the temperature rise is 15 to 25 ℃, and the rate of the temperature rise is 4 to 6 ℃/min.
6. A CaO-coconut shell biochar composite material prepared by the preparation method of any one of claims 1 to 5.
7. Use of the CaO-coconut shell biochar composite material as recited in claim 6 for adsorbing phosphate in a body of water, wherein the use is: and (3) putting the CaO-coconut shell biochar composite material into a phosphate solution with an initial pH value of 5-7, and stirring and adsorbing for 1-480 min at a rotating speed of 60-120 r/min to obtain the phosphate-adsorbed composite material.
8. The use according to claim 7, wherein the feed liquid ratio of the CaO-coconut shell biochar composite material to the phosphate solution is 0.2-1.2 g when the concentration of the phosphate solution is 50 mg/L: 1L.
9. The use according to claim 7, characterized in that the phosphate-adsorbed composite is used in soil improvement.
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| CN117138740B (en) * | 2023-10-31 | 2024-01-09 | 农业农村部环境保护科研监测所 | Ca (OH) 2 With LaMnO 3 Preparation method and application of hybrid composite material |
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