CN112920805B - Heavy metal compound passivating agent - Google Patents
Heavy metal compound passivating agent Download PDFInfo
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- CN112920805B CN112920805B CN202110070286.0A CN202110070286A CN112920805B CN 112920805 B CN112920805 B CN 112920805B CN 202110070286 A CN202110070286 A CN 202110070286A CN 112920805 B CN112920805 B CN 112920805B
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- 229910001385 heavy metal Inorganic materials 0.000 title claims abstract description 139
- 150000002736 metal compounds Chemical class 0.000 title claims abstract description 35
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 114
- 239000000843 powder Substances 0.000 claims abstract description 47
- 239000010902 straw Substances 0.000 claims abstract description 46
- 239000013049 sediment Substances 0.000 claims abstract description 45
- 229920001661 Chitosan Polymers 0.000 claims abstract description 42
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 38
- 239000010881 fly ash Substances 0.000 claims abstract description 35
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 33
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 33
- 239000011574 phosphorus Substances 0.000 claims abstract description 33
- 239000004113 Sepiolite Substances 0.000 claims abstract description 26
- 229910052624 sepiolite Inorganic materials 0.000 claims abstract description 26
- 235000019355 sepiolite Nutrition 0.000 claims abstract description 26
- 235000019738 Limestone Nutrition 0.000 claims abstract description 16
- 239000006028 limestone Substances 0.000 claims abstract description 16
- 239000010949 copper Substances 0.000 claims abstract description 14
- 239000002994 raw material Substances 0.000 claims abstract description 12
- 229910052802 copper Inorganic materials 0.000 claims abstract description 10
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 8
- 239000011651 chromium Substances 0.000 claims abstract description 8
- 239000002689 soil Substances 0.000 claims description 53
- 238000002161 passivation Methods 0.000 claims description 32
- 239000000203 mixture Substances 0.000 claims description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 29
- 239000010871 livestock manure Substances 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 17
- 239000002361 compost Substances 0.000 claims description 16
- 239000002245 particle Substances 0.000 claims description 12
- 238000002156 mixing Methods 0.000 claims description 11
- 239000000853 adhesive Substances 0.000 claims description 10
- 230000001070 adhesive effect Effects 0.000 claims description 10
- 238000001035 drying Methods 0.000 claims description 7
- 229910021645 metal ion Inorganic materials 0.000 claims description 7
- 238000003756 stirring Methods 0.000 claims description 7
- 238000002360 preparation method Methods 0.000 claims 4
- 230000000694 effects Effects 0.000 abstract description 29
- 229910052751 metal Inorganic materials 0.000 abstract description 7
- 239000002184 metal Substances 0.000 abstract description 7
- 210000003608 fece Anatomy 0.000 abstract description 5
- 229910052793 cadmium Inorganic materials 0.000 abstract description 4
- 229910019142 PO4 Inorganic materials 0.000 abstract description 3
- 239000010452 phosphate Substances 0.000 abstract description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 abstract description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 abstract description 2
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 abstract description 2
- 239000011701 zinc Substances 0.000 abstract description 2
- 229910052725 zinc Inorganic materials 0.000 abstract description 2
- 239000003673 groundwater Substances 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 18
- 238000009264 composting Methods 0.000 description 14
- 239000011148 porous material Substances 0.000 description 12
- 150000002500 ions Chemical class 0.000 description 11
- 230000008569 process Effects 0.000 description 8
- 239000010802 sludge Substances 0.000 description 8
- 238000001179 sorption measurement Methods 0.000 description 7
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000001514 detection method Methods 0.000 description 5
- 239000002905 metal composite material Substances 0.000 description 5
- 239000005909 Kieselgur Substances 0.000 description 4
- 230000007774 longterm Effects 0.000 description 4
- 238000010521 absorption reaction Methods 0.000 description 3
- 239000000292 calcium oxide Substances 0.000 description 3
- 235000012255 calcium oxide Nutrition 0.000 description 3
- 244000144972 livestock Species 0.000 description 3
- 244000005700 microbiome Species 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 235000015097 nutrients Nutrition 0.000 description 3
- 244000144977 poultry Species 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 241000196324 Embryophyta Species 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 2
- 241000209149 Zea Species 0.000 description 2
- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 description 2
- 235000002017 Zea mays subsp mays Nutrition 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 235000005822 corn Nutrition 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 238000002386 leaching Methods 0.000 description 2
- -1 silicate ions Chemical class 0.000 description 2
- 239000003381 stabilizer Substances 0.000 description 2
- 231100000419 toxicity Toxicity 0.000 description 2
- 230000001988 toxicity Effects 0.000 description 2
- 238000009423 ventilation Methods 0.000 description 2
- QJZYHAIUNVAGQP-UHFFFAOYSA-N 3-nitrobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid Chemical compound C1C2C=CC1C(C(=O)O)C2(C(O)=O)[N+]([O-])=O QJZYHAIUNVAGQP-UHFFFAOYSA-N 0.000 description 1
- 241000894006 Bacteria Species 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- 102000004190 Enzymes Human genes 0.000 description 1
- 108090000790 Enzymes Proteins 0.000 description 1
- 229910000616 Ferromanganese Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000007605 air drying Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000000711 cancerogenic effect Effects 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 231100000315 carcinogenic Toxicity 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 238000010668 complexation reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000012272 crop production Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- GUJOJGAPFQRJSV-UHFFFAOYSA-N dialuminum;dioxosilane;oxygen(2-);hydrate Chemical compound O.[O-2].[O-2].[O-2].[Al+3].[Al+3].O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O GUJOJGAPFQRJSV-UHFFFAOYSA-N 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 239000002920 hazardous waste Substances 0.000 description 1
- 239000004021 humic acid Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 1
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910052914 metal silicate Inorganic materials 0.000 description 1
- 229910052901 montmorillonite Inorganic materials 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 235000021049 nutrient content Nutrition 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 230000000270 postfertilization Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000003516 soil conditioner Substances 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 230000001954 sterilising effect Effects 0.000 description 1
- 238000004659 sterilization and disinfection Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 230000002792 vascular Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K17/00—Soil-conditioning materials or soil-stabilising materials
- C09K17/40—Soil-conditioning materials or soil-stabilising materials containing mixtures of inorganic and organic compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
-
- 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
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K2101/00—Agricultural use
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K2109/00—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE pH regulation
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Soil Sciences (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Inorganic Chemistry (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Processing Of Solid Wastes (AREA)
- Treatment Of Sludge (AREA)
- Fertilizers (AREA)
Abstract
The invention relates to the technical field of metal passivating agents, in particular to a heavy metal compound passivating agent, which comprises the following raw materials in mass: 20 to 40 parts of diatomite, 1 to 10 parts of fly ash and phosphorus-rich tailings, 20 to 30 parts of sepiolite, 10 to 30 parts of straw powder and 1 to 10 parts of chitosan, and limestone is added to adjust the PH to 7 to 7.6; the invention changes the pollution of groundwater caused by phosphate used by the existing passivating agent, and also solves the problems that the traditional passivating agent has slow effect and can not directly passivate copper, zinc, cadmium and chromium in sediment and feces for a short time and for a long time.
Description
Technical Field
The invention relates to the technical field of metal passivating agents, in particular to a heavy metal compound passivating agent.
Background
The dredging substrate sludge is mainly used as a soil conditioner for agriculture, however, the sludge contains a certain amount of heavy metals and cancerogenic substances, and untreated exposure can cause secondary pollution in the nature.
The passivating agent is used for treating polluted dredging sediment, and has the advantages of low cost, quick effect, simple operation, no influence on crop production and the like. Passivation techniques rely on passivating agents to reduce the mobility and bioavailability of heavy metals in the sediment, which are present in more stable forms in the soil. The physical and chemical reactions such as adsorption, complexation, coprecipitation and the like are carried out between the heavy metal in the bottom mud and the passivating agent to regulate and change the existence form of the heavy metal in the bottom mud, mainly reduce the biological effectiveness of the heavy metal, further reduce the toxicity of the heavy metal to biological receptors such as plants, human bodies and the like, and achieve the purpose of restoring polluted soil. Generally, the relationship between heavy metal morphology and bioavailability is sized to be represented as exchangeable states > carbonate bound states > ferro-manganese oxide bound states > organic bound states > residue states. The organic binding state and the residue state are almost ineffective for plants and are relatively stable existing forms.
Heavy metals such as Cu, zn and Cd in the traditional dredging sediment are subjected to combined pollution, the activity and biological effectiveness of each heavy metal are different, the heavy metals with low activation degrees such as the combination state of Cu, zn and Cd, organic combination state and the like are slowly and continuously released along with the comprehensive actions of temperature, humidity, microorganisms and the like in a soil system, so that the activity and biological effectiveness of the heavy metals continuously exist in a specific period, the effectiveness and timeliness of the passivating agent are relatively low, the due effect of the conventional soil heavy metal passivating agent cannot be completely realized in the aspect of medium-and-long-term soil heavy metal pollution, in addition, the passivating effect of the chemical passivating agent is better, but the chemical passivating agent is often polluted to the environment, and the research on the type and passivation mechanism of the biological passivating agent is insufficient, and needs to be further explored and perfected.
Therefore, on the other hand, the traditional dredging sediment has higher water content and more intercellular bound water, and the sludge and water in the bound are not easy to adsorb, so that the heavy metals in the sediment are passivated.
China contains a large amount of sandy soil, contains more sand grains, has larger inter-grain pores and good ventilation performance, and has loose soil, but water is easy to leak and difficult to maintain; the soil is easy to dry and not drought-enduring, the sandy soil contains less nutrients, and has poor fertilizer absorbing and retaining capability, and the applied nutrients are easy to run off along with water; the sandy soil has good ventilation, vigorous activity of aerobic microorganisms, fast nutrient conversion, insufficient post-fertilization strength, low organic matter content and nutrient content, and inhibited enzyme activity, thereby affecting the life activity of microorganisms in the soil and being difficult to develop and utilize.
Patent CN202010652613.9, heavy metal stabilizer for dredging sediment and heavy metal stabilization method for dredging sediment, comprising mixing montmorillonite powder and carboxymethyl cellulose salt with sediment, stirring uniformly, and standing and curing the mixed sediment in dark place. The heavy metal stabilizer for dredging sediment has the effects of high efficiency, low cost and no secondary pollution. The problems that the traditional passivating agent is slow in effect and short-term and long-term passivation is not realized are not solved.
Patent CN201510964820.7, a heavy metal passivating agent and application thereof, wherein the metal passivating agent consists of straw, biochar and biological humic acid, has the effects of improving the quality of compost and improving soil, is used for passivating heavy metals in livestock and poultry manure in the composting process, and meanwhile, the passivated compost is applied to the soil to further passivate the heavy metals in the soil. The problems that the traditional passivating agent is slow in effect and short-term and long-term passivation is not realized are not solved.
Heavy metal removal of dredging sediment and improvement of sandy soil with low cost.
Disclosure of Invention
The invention aims to provide a metal compound passivating agent, which changes the pollution of underground water caused by phosphate used by the existing passivating agent, and also solves the problems that the traditional passivating agent takes effect slowly and cannot directly passivate copper, zinc, cadmium and chromium in sediment and feces for a short time and for a long time.
In order to achieve the above purpose, the invention adopts the following technical scheme:
the heavy metal compound passivating agent comprises the following raw materials in mass: 20 to 40 parts of diatomite, 1 to 10 parts of mixture of fly ash and phosphorus-rich tailings, 20 to 30 parts of sepiolite, 10 to 30 parts of straw powder and 1 to 10 parts of chitosan, and limestone is added to adjust the PH to 7 to 7.6.
Further, the mass ratio of the fly ash to the phosphorus-rich tailings is 1:3 to 5.
Further, the grain diameter range of the phosphorus-rich tailings is 1-10 mm, the grain diameter range of the fly ash is 0.01-5 mm, and the grain diameter range of the straw powder is 1-10 mm.
Further, the particle size range of the heavy metal compound passivating agent is 3-15 mm.
Further, the water content of the straw powder is below 15%, and the water content of the heavy metal composite passivating agent is below 15%.
Further, the passivation efficiency of the heavy metal passivating agent on metal ions in the dredging sediment is as follows: the passivation efficiency of chromium and copper reaches more than 60 percent.
According to the proportion, chitosan and straw powder are mixed to obtain an adhesive mixture; and secondly, mixing and reacting the mixture of diatomite, fly ash and phosphorus-rich tailings to prepare the prefabricated passivating agent, thirdly, uniformly stirring the mixture prepared in the first step and the second step, adding limestone to adjust the PH to 7-7.6, and drying to prepare the heavy metal passivating agent.
The application of the heavy metal compound passivating agent in passivating compost or soil for passivating heavy metals.
Further, the step of the heavy metal passivating agent for passivating heavy metals in compost is as follows:
the heavy metal passivating agent and livestock manure or dredging sediment mixed and composted products are applied to soil, and the application amount of the heavy metal passivating agent and livestock manure or dredging sediment mixed and composted products is 1000 kg-3000 kg/mu of soil;
further, the mass water content of the livestock manure or the dredging sediment is 40-85%.
Further, the mass ratio of the heavy metal passivating agent to the livestock manure or dredging sediment is 1:3 to 8.
The invention has the beneficial effects that:
according to the invention, chitosan and straw powder are used as raw materials to obtain an adhesive mixture, and the chitosan is adhered to the straw powder; taking diatomite, fly ash and phosphorus-rich tailings as raw materials, mixing the raw materials with quicklime for reaction to prepare a prefabricated passivating agent, granulating, and drying to prepare the long-acting heavy metal passivating agent; the fly ash and the phosphorus-rich tail are rich in silicon dioxide, the diatomite and the sepiolite have large surface areas and extremely strong adsorptivity, heavy metal ions in soil can be fixed through physical adsorption, the quicklime gradually participates in the reaction to form silicate and phosphate, the silicate is hydrolyzed in the soil to release silicate ions, and then the silicate ions act with the metal ions in the soil to generate metal silicate with extremely low solubility; meanwhile, the quicklime can neutralize the acidity of the soil, the acidity and alkalinity of the soil directly influence the dispersion degree of the heavy metal passivating agent, and the heavy metal passivating agent in the neutral soil has strong hydrophilicity, better hydrophilicity, more uniform dispersion and higher passivation rate; with the increase of the dosage of the heavy metal compound passivating agent, the removal rate is finally stable, but the removal rate is less than 100%; the multiple effects of passivating soil heavy metals, improving acid soil and promoting crop yield are realized, excellent passivation effect is given to the passivating agent, and long-acting passivation is realized together.
The invention adopts the mixture of diatomite, fly ash and phosphorus-rich tailings, sepiolite, straw powder and chitosan, and has the best technical synergistic effect through experimental demonstration. Solves the problem that the passivating agent is not quantified in the industry, and has the following technical defects that the quantitative proportioning of each cost is not realized: under the condition of inaccurate proportion among diatomite, sepiolite and chitosan, the pores of the diatomite and the sepiolite are easily blocked by the chitosan, so that the inner surface area is reduced, the permeability among the pores is reduced, and the effect of a product is affected. As shown in fig. 1, the straw powder is combined with chitosan and then attached to the surfaces of diatomite and sepiolite, and the straw powder is not fixedly attached to the diatomite and sepiolite, so that the pores of the diatomite and sepiolite can be prevented from being blocked by the chitosan.
The comprehensive effect of the limestone, the fly ash, the chitosan and the straw powder is beneficial to further removing intercellular bound water when the heavy metal passivating agent treats heavy metals in dredged sludge, so that the heavy metals in compact sludge particles are removed conveniently, the purpose of uniformly removing the heavy metals is achieved, the heavy metals in loose sludge are mainly removed by the traditional metal passivating agent, the heavy metals in the particles in the sludge with intercellular binding are not removed sufficiently, the chitosan kills bacteria in the intercellular bound water, the heat absorption of the limestone is matched with the extremely strong water absorption of the chitosan, the absorption of free water is enhanced by the fly ash, the straw powder is physically blocked, the heavy metals in the compact sludge particles containing the intercellular bound water are further dehydrated and passivated, and the short-term passivation effect is improved.
After the heavy metal passivating agent is used for passivating the heavy metal contaminated soil, the concentration of heavy metal ion leaching solution of the passivated heavy metal contaminated soil is far lower than the standard limit value of hazardous waste identification standard leaching toxicity identification (GB 5085.3-2007). The metal passivating agent is used for passivating heavy metals in livestock and poultry manure in the composting process, and meanwhile, the passivated compost is applied to soil, so that the heavy metals in the soil can be further passivated, and the construction of a fertilizer-soil heavy metal resistance control system is facilitated.
Drawings
FIG. 1, schematic adsorption diagram of chitosan, straw powder, diatomaceous earth and sepiolite;
fig. 2, microscopic cross-section with 100-fold enlargement of corn stalk powder.
Description of the embodiments
The following detailed description of the invention is provided for exemplary and explanatory purposes only and should not be construed as limiting the scope of the invention, as it is intended to provide a better understanding of the invention as defined by the appended claims.
The heavy metal compound passivating agent comprises the following raw materials in mass: 20 to 40 parts of diatomite, 1 to 10 parts of mixture of fly ash and phosphorus-rich tailings, 20 to 30 parts of sepiolite, 10 to 30 parts of straw powder and 1 to 10 parts of chitosan, and limestone is added to adjust the PH to 7 to 7.6.
Preferably, the mass ratio of the fly ash to the phosphorus-rich tailings is 1:3 to 5.
Preferably, the grain size range of the phosphorus-rich tailings is 1-10 mm, the grain size range of the fly ash is 0.01-5 mm, the grain size range of the straw powder is 1-10 mm, the cross-sectional view of the straw powder is shown in fig. 2, and a is intercellular pores caused by a vascular bundle.
Preferably, the particle size range of the heavy metal compound passivating agent is 3-15 mm.
Preferably, the water content of the straw powder is below 15%, and the water content of the heavy metal composite passivating agent is below 15%.
Preferably, the passivation efficiency of the heavy metal passivating agent on metal ions in the dredging sediment is as follows: the passivation efficiency of chromium and copper reaches more than 60 percent.
The application of the heavy metal compound passivating agent in passivating compost or soil for passivating heavy metals.
According to the proportion, chitosan and straw powder are mixed to obtain an adhesive mixture; and secondly, mixing and reacting the mixture of diatomite, fly ash and phosphorus-rich tailings to prepare the prefabricated passivating agent, thirdly, uniformly stirring the mixture prepared in the first step and the second step, adding limestone to adjust the PH to 7-7.6, and drying to prepare the heavy metal passivating agent.
Preferably, the step of the heavy metal passivating agent for passivating heavy metals in compost is as follows: the heavy metal passivating agent and livestock manure or dredging sediment mixed and composted products are applied to soil, and the application amount of the heavy metal passivating agent and livestock manure or dredging sediment mixed and composted products is 1000 kg-3000 kg/mu of soil;
preferably, the mass water content of the livestock manure or the dredging sediment is 40-85%.
Preferably, the mass ratio of the heavy metal passivating agent to the livestock manure or dredging sediment is 1:3 to 8.
As shown in fig. 1, sepiolite and diatomite are independently mixed with chitosan, and the pores and surfaces of the sepiolite and the diatomite are blocked by the chitosan, so that the adsorption capacity of the sepiolite and the diatomite to heavy metals is reduced, as shown in (1) in fig. 1; separately mixing the straw powder with chitosan, wherein the chitosan is dissolved in pores in the straw powder, as shown in (2) in fig. 1; the straw powder, the sepiolite and the diatomite are directly mixed with the chitosan, the chitosan is dissolved in the pores of the straw powder, and the pores and the surface of the sepiolite and the diatomite are also mostly blocked by the chitosan, so that the adsorption capacity of the sepiolite and the diatomite is reduced, as shown in (4) in fig. 1; the pores of the chitosan dissolved in the straw powder are then mixed with sepiolite and diatomite, as shown in (3) in fig. 1, the chitosan is not easy to exude, so that the pores of the diatomite and the sepiolite are blocked, and the binding capacity of 4 people to heavy metal ions is improved. The chitosan is dissolved in straw powder, and the straw powder is gradually decomposed in the composting process and the soil forming process, so that the chitosan is released, sterilization and heavy metal ion adsorption are carried out, and the chitosan is gradually adsorbed in the pores of diatomite and sepiolite after the adsorption.
Example 1
The heavy metal compound passivating agent comprises the following raw materials in mass: 20 parts of diatomite, 1 part of a mixture of fly ash and phosphorus-rich tailings, 20 parts of sepiolite, 10 parts of straw powder and 1 part of chitosan, and then limestone is added to adjust the pH to 7.6. According to the proportion, chitosan and straw powder are mixed to obtain an adhesive mixture; and secondly, mixing and reacting the mixture of diatomite, fly ash and phosphorus-rich tailings to prepare the prefabricated passivating agent, thirdly, uniformly stirring the mixture prepared in the first step and the second step, adding limestone to adjust the PH to 7-7.6, and drying to prepare the heavy metal passivating agent.
The straw powder used in this example was corn straw powder.
The mass ratio of the fly ash to the phosphorus-rich tailings is 1:3. the grain diameter range of the phosphorus-rich tailings is 1mm, the grain diameter range of the fly ash is 0.01mm, and the grain diameter range of the straw powder is 1. The particle size range of the heavy metal compound passivating agent is 3mm. The water content of the straw powder is below 15%, and the water content of the heavy metal composite passivating agent is below 15%. The passivation efficiency of the heavy metal passivating agent on metal ions in the dredging sediment is as follows: the passivation efficiency of chromium and copper reaches more than 60 percent.
The heavy metal passivating agent is used for passivating heavy metals in compost, and comprises the following steps:
the heavy metal passivating agent and livestock manure or dredging sediment mixed and composted products are applied to soil, and the application amount of the heavy metal passivating agent and livestock manure or dredging sediment mixed and composted products is 1000 kgg/mu of soil;
the mass water content of the livestock manure or the dredging sediment is 40%. The mass ratio of the heavy metal passivating agent to the livestock manure or dredging sediment is 1:3.
example 2
The heavy metal compound passivating agent comprises the following raw materials in mass: 40 parts of diatomite, 10 parts of a mixture of fly ash and phosphorus-rich tailings, 30 parts of sepiolite, 30 parts of straw powder and 10 parts of chitosan, and then limestone is added to adjust the pH to 7.3. The mass ratio of the fly ash to the phosphorus-rich tailings is 1:5. according to the proportion, chitosan and straw powder are mixed to obtain an adhesive mixture; and step two, preparing a prefabricated passivating agent by mixing and reacting a mixture of diatomite, fly ash and phosphorus-rich tailings, step three, uniformly stirring the mixture prepared in the step two, adding limestone to adjust the PH to 7.3, and drying to obtain the heavy metal passivating agent.
The grain diameter range of the phosphorus-rich tailings is 10mm, the grain diameter range of the fly ash is 5mm, and the grain diameter range of the straw powder is 10mm. The particle size range of the heavy metal compound passivating agent is 15mm. The water content of the straw powder is below 15%, and the water content of the heavy metal composite passivating agent is below 15%. The passivation efficiency of the heavy metal passivating agent on metal ions in the dredging sediment is as follows: the passivation efficiency of chromium and copper reaches more than 60 percent.
The heavy metal passivating agent is used for passivating heavy metals in compost, and comprises the following steps: the heavy metal passivating agent and livestock manure or dredging sediment mixed and composted products are applied to soil, and the application amount of the heavy metal passivating agent and livestock manure or dredging sediment mixed and composted products is 3000 kg/mu of soil;
the mass water content of the livestock manure or the dredging sediment is 85%. The mass ratio of the heavy metal passivating agent to the livestock manure or dredging sediment is 1:8.
example 3
The heavy metal compound passivating agent comprises the following raw materials in mass: 30 parts of diatomite, 7 parts of a mixture of fly ash and phosphorus-rich tailings, 24 parts of sepiolite, 18 parts of straw powder and 7 parts of chitosan, and then limestone is added to adjust the PH to 7.0. According to the proportion, chitosan and straw powder are mixed to obtain an adhesive mixture; and step two, preparing a prefabricated passivating agent by mixing and reacting a mixture of diatomite, fly ash and phosphorus-rich tailings, step three, uniformly stirring the mixture prepared in the step two, adding limestone to adjust the PH to 7.0, and drying to obtain the heavy metal passivating agent.
The mass ratio of the fly ash to the phosphorus-rich tailings is 1:4. the grain diameter range of the phosphorus-rich tailings is 7mm, the grain diameter range of the fly ash is 3mm, and the grain diameter range of the straw powder is 6mm.
The particle size range of the heavy metal compound passivating agent is 11mm. The water content of the straw powder is below 15%, and the water content of the heavy metal composite passivating agent is below 15%.
The passivation efficiency of the heavy metal passivating agent on metal ions in the dredging sediment is as follows: the passivation efficiency of chromium and copper reaches more than 60 percent.
The heavy metal passivating agent is used for passivating heavy metals in compost, and comprises the following steps:
applying the heavy metal passivating agent and livestock manure or dredging sediment mixed composted products into soil, wherein the application amount of the heavy metal passivating agent and livestock manure or dredging sediment mixed composted products is 1800 kg/mu of soil; the mass water content of the livestock manure or the dredging sediment is 65%.
The mass ratio of the heavy metal passivating agent to the livestock manure or dredging sediment is 1:5.
comparative example 1
In this comparative example, no fly ash and phosphorus-rich tailings were added, and the same amount of diatomaceous earth was used instead, as in example 3.
Comparative example 2
In this comparative example, no chitosan was added, and the same amount of diatomaceous earth was used instead, as in example 3.
Comparative example 3
In the comparative example, the chitosan and straw powder were not mixed to obtain an adhesive mixture, but all the raw materials of the heavy metal compound passivating agent were directly mixed to prepare the adhesive mixture, and the adhesive mixture was otherwise the same as in example 3.
Comparative example 4
All raw materials of the heavy metal compound passivating agent in the comparative example comprise the following components in mass: 30 parts of diatomite, 7 parts of a mixture of fly ash and phosphorus-rich tailings, 24 parts of sepiolite, 18 parts of straw powder and 16 parts of chitosan, and then limestone is added to adjust the PH to 7.0. Otherwise, the same as in example 3 was conducted.
Detection of passivation effect of heavy metals on soil containing livestock and poultry manure
Heavy metal passivation effect detection is carried out on examples 1-3 and comparative examples 1 and 2 of the invention respectively, and the detection results are shown in table 1:
the detection method comprises the following steps: preparing a soil sample containing exchangeable heavy metal ions with the content of 0.2mg/kg, mixing the passivating agents prepared in the embodiment and the comparative example with the soil sample applied with livestock manure according to the mass ratio of 1:60, respectively standing for reaction for 1, 6 and 12 months, and measuring the reduction rate of exchangeable heavy metal ions in the soil sample;
reduction rate (%) = (exchangeable heavy metal ion content in original soil sample-exchangeable heavy metal ion content in soil sample after one month of application of soil passivating agent)/exchangeable heavy metal ion content in original soil sample;
the higher the reduction rate of exchangeable heavy metal ions is, the better the passivation effect of the soil heavy metal ions is.
Table 1: and (5) performance detection results.
As can be seen from the test data in the above table, since the fly ash and the phosphorus-rich tailings are not added in the comparative example 1, the heavy metal passivation effect of the comparative example 1 is deteriorated, and at the same time, the chitosan is not added in the comparative example 2, and the long-acting passivation effect cannot be maintained; the chitosan of comparative examples 3 and 4 was not pretreated and not quantitatively added, causing blocking of sepiolite and diatomaceous earth, causing a decrease in passivation effect; therefore, the addition of the fly ash and the phosphorus-rich tailings not only improves the passivation effect of the passivating agent, but also improves the long-acting passivation capability of the passivating agent. Therefore, the addition of the fly ash, the phosphorus-rich tailings and the chitosan not only improves the passivation effect of the passivating agent, but also improves the short-term and long-term passivation capability of the passivating agent.
Determination of the passivation effect of a Metal passivating agent
And respectively collecting compost samples before and after composting, respectively sampling according to three layers of high, medium and low at the middle of the composting, uniformly mixing the samples and naturally air-drying. The heavy metal species were measured by BCR continuous extraction (as shown in Table 2) using ICP-OES (Optima 5300DV, perkin-Elmer).
TABLE 2 continuous extraction of compost heavy metal morphology classification
The concentration, distribution rate and distribution rate of exchangeable Cu and exchangeable Cd in the compost obtained by the method of the Tai lake dredging sediment before composting and after composting were detected, and the results are shown in Table 3, wherein the heavy metal passivating agent in the examples is added to perform composting on the Tai lake dredging sediment, and comparative examples 1 and 2 show that the metal passivating agent is not aggravated in the composting process.
TABLE 3 exchangeable heavy metal concentration distribution in composting Process
As can be seen from the data in table 3, the comparative example group treated exchangeable fraction increased from 7.6% and 7.8% before composting to 7.89% and 8.03% after composting for heavy metal Cu, exhibiting an activation trend. Examples 1-3 the exchangeable Cu partitioning rate was reduced and passivation of the exchangeable Cu was achieved. For heavy metal Cd, the exchangeable distribution rate of the comparative example group treatment is reduced from before composting to after composting. The exchangeable Cd distribution rate of examples 1-3 is greatly reduced compared with the comparative example, and the long-term passivation effect of Cd in the compost is improved.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to facilitate an understanding of the method of the present invention and its core ideas. The foregoing is merely illustrative of the preferred embodiments of this invention, and it is noted that there is objectively no limit to the specific structure disclosed herein, since numerous modifications, adaptations and variations can be made by those skilled in the art without departing from the principles of the invention, and the above-described features can be combined in any suitable manner; such modifications, variations and combinations, or the direct application of the inventive concepts and aspects to other applications without modification, are contemplated as falling within the scope of the present invention.
Claims (9)
1. The preparation method of the heavy metal compound passivating agent is characterized by comprising the following raw materials in mass: 20 to 40 parts of diatomite, 1 to 10 parts of mixture of fly ash and phosphorus-rich tailings, 20 to 30 parts of sepiolite, 10 to 30 parts of straw powder and 1 to 10 parts of chitosan, and limestone is added to adjust the pH value to 7 to 7.6; according to the proportion, firstly, chitosan and straw powder are mixed to obtain an adhesive mixture; and step two, preparing a prefabricated passivating agent by mixing and reacting a mixture of diatomite, fly ash and phosphorus-rich tailings, step three, uniformly stirring the mixture prepared in the step two, adding limestone to adjust the pH value to 7-7.6, and drying to obtain the heavy metal passivating agent.
2. The preparation method of the heavy metal compound passivating agent according to claim 1, characterized in that the mass ratio of the fly ash to the phosphorus-rich tailings is 1:3 to 5.
3. The method for preparing the heavy metal compound passivating agent according to claim 1, wherein the particle size range of the phosphorus-rich tailings is 1-10 mm, the particle size range of the fly ash is 0.01-5 mm, and the particle size range of the straw powder is 1-10 mm.
4. The method for preparing the heavy metal compound passivating agent as defined in claim 1, wherein the particle size of the heavy metal compound passivating agent is in a range of 3-15 mm.
5. The method for preparing the heavy metal compound passivating agent according to claim 1, wherein the water content of the straw powder is below 15%, and the water content of the heavy metal compound passivating agent is below 15%.
6. The preparation method of the heavy metal compound passivating agent according to claim 1, wherein the passivating efficiency of the heavy metal passivating agent on metal ions in dredging sediment is as follows: the passivation efficiency of chromium and copper reaches more than 60 percent.
7. The application of the heavy metal compound passivating agent prepared by the preparation method of the heavy metal compound passivating agent according to any one of claims 1-6, which is characterized in that the application of the heavy metal compound passivating agent in passivating compost or soil for passivating heavy metals.
8. The use according to claim 7, characterized in that: the heavy metal compound passivating agent is used for passivating heavy metals in compost, and comprises the following steps:
the heavy metal compound passivating agent and livestock manure or dredging sediment mixed composted products are applied to soil, and the application amount of the heavy metal compound passivating agent and livestock manure or dredging sediment mixed composted products is 1000 kg-3000 kg/mu of soil;
the mass water content of the livestock manure or the dredging sediment is 40-85%.
9. The use according to claim 8, characterized in that: the mass ratio of the heavy metal compound passivating agent to the livestock manure or dredging sediment is 1:3 to 8.
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CN105623670A (en) * | 2015-12-21 | 2016-06-01 | 农业部规划设计研究院 | Heavy metal passivator and application thereof |
CN110184075A (en) * | 2019-07-12 | 2019-08-30 | 湖南双晟科技信息咨询有限公司 | A kind of mercury contaminated soil passivation conditioner and preparation method thereof |
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CN105623670A (en) * | 2015-12-21 | 2016-06-01 | 农业部规划设计研究院 | Heavy metal passivator and application thereof |
CN110184075A (en) * | 2019-07-12 | 2019-08-30 | 湖南双晟科技信息咨询有限公司 | A kind of mercury contaminated soil passivation conditioner and preparation method thereof |
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