CN108570326B

CN108570326B - Composition for in-situ passivation of heavy metals in acidic soil and preparation method and application thereof

Info

Publication number: CN108570326B
Application number: CN201810499577.XA
Authority: CN
Inventors: 秦汉俊; 徐建东; 李华; 杨静静
Original assignee: Anhui Guozhen Ecological Technology Co ltd
Current assignee: Anhui Guozhen Ecological Agriculture Technology Co.,Ltd.
Priority date: 2018-05-23
Filing date: 2018-05-23
Publication date: 2020-10-13
Anticipated expiration: 2038-05-23
Also published as: CN108570326A

Abstract

The composition for in-situ passivation of acid soil heavy metal comprises the following raw materials in parts by weight: 30-80 parts of biomass ash, 3-50 parts of rice hull carbon, 3-30 parts of ammonium lignosulfonate and 5-30 parts of ferrous sulfate. According to the invention, the heavy metal Cd and Pb in-situ passivator is researched and developed by the synergistic effect of multiple components such as biomass ash, rice husk charcoal, ammonium lignosulfonate and ferrous sulfate, the pH value of soil is increased, meanwhile, rich medium and trace elements are provided for the soil, and the yield and quality of crops are increased. The problems of stacking of biomass ash, dust, high pH value and other environmental pollution generated by a biomass power plant are solved, and comprehensive utilization of waste resources such as the biomass ash and rice hulls is realized.

Description

Composition for in-situ passivation of heavy metals in acidic soil and preparation method and application thereof

Technical Field

The invention belongs to the technical field of soil remediation, and particularly relates to a composition for in-situ passivation of heavy metals in acidic soil, and a preparation method and application thereof.

Background

At present, heavy metal pollution in soil in China is serious and has a rising trend due to the influence of factors such as planting mode, large application of inorganic fertilizer, discharge of industrial waste, abuse of pesticide, climate and the like. At present, the cultivated land area polluted by cadmium, arsenic, chromium, lead and other heavy metals in China is nearly 20.0 x 10³

km

²1/5, which accounts for approximately the total arable area; wherein, the three industrial wastes pollute the cultivated land by 10.0 x 10³km²The farmland area irrigated by sewage reaches 3.3 x 10³km². Heavy metal pollution brings the following hazards: (1) the serious economic loss is that 1000 more than ten thousand tons of grains are reduced due to heavy metal pollution every year in China, the crop is reduced even is not harvested due to the serious heavy metal pollution, in addition, the grains polluted by the heavy metal are more than 1200 ten thousand tons every year, and the total economic loss is at least more than 200 million yuan. (2) The quality of crops is seriously influenced, and the contents of heavy metals such as fortune, chromium, arsenic, lead and the like in food such as grains, vegetables, fruits and the like in many places exceed the standard and are close to the critical value. (3) The heavy metal is seriously harmful to human health, accumulated in plants (animals) and enriched in human and animal bodies through food chains, thus causing harm to human and animal health, cancer and other diseases.

The acidic soil in China is far more than 3 hundred million mu, the soil in the south of Yangtze river is even and acidic, and particularly, the soil in the south of Hunan is acidified, so that heavy metal pollution is serious. Most acid soils have a pH of less than 5.5, and some even less than 4.5. Soil acidification presents the following hazards: (1) the Cation Exchange Capacity (CEC) and salt saturation decrease, resulting in a decrease in soil fertility; (2) the fixation of other nutrient elements (such as phosphorus) is promoted, and the effective utilization rate of the phosphorus element is greatly reduced; (3) promoting the release, activation and dissolution of certain toxic elements (such as heavy metal, aluminum ions and the like), polluting soil and water environment and even threatening human health; (4) inhibiting the growth of beneficial microorganisms in soil, and influencing the decomposition of organic matters in the soil and the circulation of C, N, P and S in the soil; with the increasing aggravation of non-renewable energy crisis, the biomass power generation technology is rapidly developed in China, 665 biomass power plants in China produce more than 2660 ten thousand tons of biomass ash annually at present, and the treatment mode is only simple landfill or land renting stacking at present, so that the environmental atmosphere, soil and water are seriously polluted.

The method for treating heavy metal pollution in soil mainly comprises the following steps: a soil agrochemical conditioning control method, an engineering physical chemical method and a biological remediation method, wherein the engineering physical chemical method is suitable for treating the soil pollution of a factory and has high treatment cost. The bioremediation method does not fundamentally change the treatment from soil and is not a long-term treatment method. The soil agrochemical conditioning control method changes the water solubility of heavy metals in soil by adjusting factors such as the pH value of soil, organic matters, CEC, soil moisture and the like, improves the bioavailability, reduces the harm of heavy metal pollution, has low cost and is suitable for farmland heavy metal treatment. But the key is how to find the raw materials with large quantity and stable quality.

The domestic product for adjusting the pH of the soil is mainly quicklime which is a natural mineral substance fired by stone, consumes a large amount of energy in the production process, is applied for a long time, can cause soil hardening by supplementing a large amount of Ca element, is seriously acidified if being discontinuously used, and simultaneously solves the problem of uniform and stable content of heavy metals in the national quicklime.

The invention relates to a passivation material for repairing cadmium-copper polluted acid soil, a preparation method and application thereof, wherein the passivation material has a pH of 10-13, and is prepared by balling biomass power plant ash, lime and phosphate rock without adding a binder to passivate heavy metal cadmium-copper in acid soil; the invention CN 106010542A of China is a sludge biochar for heavy metal contaminated soil remediation and a preparation method thereof, the sludge-based biochar is prepared by mixing and gasifying municipal sludge and palygorskite, and is used as a heavy metal contaminated soil remediation agent, and the activity of heavy metals is reduced only by utilizing the adsorption of carbon; the invention provides a restoring conditioner for copper and cadmium polluted acid soil and a preparation method thereof, which are disclosed by CN 103242849A in China, and the restoring conditioner for restoring copper and cadmium polluted acid soil is prepared by utilizing an organic fertilizer, quicklime and nano hydroxyapatite. The materials and the principle used by the invention are different from those of the invention, the pH value of the soil is improved by using the medium trace elements in the biomass ash, the physical and chemical properties of the soil are improved, and conditions are created for passivating heavy metals; carbon in rice husk carbon and active SiO contained in the carbon₂After the plant absorbs the heavy metal Cd, Pb, Cr and the like, silicified cells are formed with plant cells, the strength of plant cell walls is improved, the cell membrane permeability is reduced, and the absorption of the plant to the heavy metal Cd, Pb, Cr and the like is inhibited; the activity of Cd and Pb is reduced by the complexation of ammonium lignosulphonate; reducing agent FeSO₄Middle Fe²⁺The heavy metal ions are adsorbed by the plant roots in the soil to form an iron film, so that the contact of the heavy metal ions and the plant roots is blocked; make Cr⁶⁺Conversion to Cr³⁺The activity of heavy metal Cr is reduced, the pH value of the passivation material is 10-13, and the passivation material has multiple principles and is compounded with synergistic passivation soilThe soil is heavy metal, and the effect is better.

The biomass ash is waste generated by a biomass power plant, the pH value is 10-13, the main components are metal oxides such as k, Si, Ca, Mg, Fe, Cu, Zn, Mn, B and the like, the elements are medium and trace elements which are necessary for plant growth and are deficient in soil, the content proportion of the elements is basically consistent with that required by plants, the pH value of the soil can be improved, metal cation elements in the soil are recovered, and the biomass ash has long-term and stable effect on the activity of passivated heavy metal ions; meanwhile, the active SiO in the biomass ash₂After being absorbed by plants, the plant cell passivator and plant cells form silicified cells, so that the strength of plant cell walls is improved, the cell membrane permeability is reduced, the absorption of plants to heavy metals such as Cd, Pb and Cr is inhibited, and the passivation effect is achieved.

Rice husk charcoal is a byproduct produced in rice production plants, and is carbonized in an oxygen-free state to produce rice husk charcoal, the main components of which are activated carbon and SiO₂(ii) a (1) The activated carbon has adsorbability, prevents heavy metals Cd and Pb in soil from being absorbed, and promotes the propagation and growth of microorganisms in the soil; (2) active SiO₂Absorbed by plants, forms silicified cells with plant cells, improves the strength of plant cell walls, reduces the permeability of cell membranes, inhibits the absorption of heavy metals Cd and Pb by the plants, and plays a role in passivation.

The ammonium lignosulfonate is an aromatic macromolecular compound, has complexing and chelating effects, and can be used for complexing heavy metals Cd and Pb, reducing the activity and playing a role in passivation; meanwhile, the complex is complexed with metal cations such as Ca, Mg, Fe, Cu, Zn, Mn and the like in the biomass ash, so that the loss with water is reduced, and the utilization rate of medium and trace elements is improved.

Ferrous sulfate (FeSO)₄) The functions of (1): (a) fe²⁺The heavy metal ions are adsorbed by the plant roots in the soil to form an iron film, so that the contact of the heavy metal ions and the plant roots is blocked; (b) fe²⁺Make Cr⁶⁺Reduction to Cr³⁺The activity and toxicity of heavy metal Cr are reduced; (c) SO (SO)₄ ^2-With Pb²⁺Formation of slightly water-soluble PbSO₄Plays a role in passivation; (d) supplementing iron element to soil and promoting chlorophyll formation.

The research and development of the heavy metal Cd and Pb in-situ composite passivator product in soil are initiated at home by utilizing the synergistic effect of multiple components such as biomass ash, rice hull carbon, ammonium lignosulfonate and ferrous sulfate.

Disclosure of Invention

The technical problem to be solved is as follows: the invention provides a composition for in-situ passivation of heavy metals in acidic soil, and a preparation method and application thereof. According to the invention, the heavy metal Cd and Pb in-situ passivator is researched and developed by the synergistic effect of multiple components such as biomass ash, rice husk charcoal, ammonium lignosulfonate and ferrous sulfate, the pH value of soil is increased, meanwhile, rich medium and trace elements are provided for the soil, and the yield and quality of crops are increased. The problems of stacking of biomass ash, dust, high pH value and other environmental pollution generated by a biomass power plant are solved, and comprehensive utilization of waste resources such as the biomass ash and rice hulls is realized.

The technical scheme is as follows: the composition for in-situ passivation of the heavy metal in the acid soil comprises the following raw materials in parts by weight: 30-80 parts of biomass ash, 3-50 parts of rice hull carbon, 3-30 parts of ammonium lignosulfonate and 5-30 parts of ferrous sulfate.

Preferably, the feed additive comprises the following raw materials in parts by weight: 50 parts of biomass ash, 25 parts of rice husk charcoal, 10 parts of ammonium lignosulfonate and 15 parts of ferrous sulfate.

The preparation method of the composition for in-situ passivation of the heavy metals in the acid soil comprises the following steps: (1) mixing and stirring biomass ash, rice hull charcoal, ammonium lignosulfonate and ferrous sulfate for later use; (2) removing iron from the mixture obtained in the step (1) through an iron remover, and conveying the mixture to a granulator; (3) and drying and cooling the granulated semi-finished product, screening and subpackaging to obtain the finished product.

The composition for passivating the heavy metal in the acid soil in situ is applied to the preparation of a passivator for corn or wheat planting.

Has the advantages that: (1) the biomass ash is waste of a biomass power plant, the pH value of the biomass ash is 10-13, the main components of the biomass ash are metal oxides such as k, Si, Ca, Mg, Fe, Cu, Zn, Mn and B, the elements are medium and trace elements which are necessary for plant growth and are lacked in soil, the content proportion of the medium and trace elements is basically consistent with the proportion required by plants, and the medium and trace elements are high-quality raw materials for passivating heavy metals Cd and Pb. (2) Activity in Rice husk charcoalThe carbon adsorption function can block the movement of Cd and Pb, play a role in passivation and promote the propagation and growth of microorganisms in soil; active SiO in rice husk charcoal₂Absorbed by plant root system, forms silicified cell with plant cell, improves plant cell wall strength, reduces cell membrane permeability, inhibits plant absorption of heavy metal Cd and Pb, and has passivation effect. (3) The ammonium lignosulphonate is a macromolecular aromatic compound, has complexing and chelating effects, is complexed with heavy metals Cd and Pb, and reduces the activity of Cd and Pb; meanwhile, the complex is complexed with cations of Ca, Mg, Fe, Cu, Zn, Mn and other elements in the biomass ash, so that the absorption of plants is promoted, the loss is reduced, and the utilization rate of medium and trace elements is improved. (4) Ferrous sulfate FeSO₄Form slightly water-soluble PbSO with Pb ions₄Plays a role of passivation to lead Cr to be⁶⁺Reduction to Cr³⁺Reducing the activity and toxicity of heavy metal Cr, and promoting the formation of chlorophyll by applying iron fertilizer to plants.

Drawings

FIG. 1: a trend graph of the concentration change of heavy metals Cd and Pb in the corn planting soil;

FIG. 2: a trend graph of the concentration change of heavy metals Cd and Pb in the wheat planting soil;

FIG. 3: the yield change trend chart of the crops corn and wheat.

Detailed Description

The following examples are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Example 1

The preparation method comprises the following steps: 50 parts of biomass ash, 25 parts of rice husk charcoal, 10 parts of ammonium lignosulfonate and 15 parts of ferrous sulfate.

(1) Mixing and stirring biomass ash, rice hull charcoal, ammonium lignosulfonate and ferrous sulfate for later use;

(2) removing iron from the mixture obtained in the step (1) through an iron remover, and conveying the mixture to a granulator;

(3) and drying, cooling, screening, subpackaging and warehousing the granulated semi-finished product.

Purpose of the test

In order to verify the field use effect of passivators with different formulas, the applicant tests on urban corn and wheat crops in Biquan county of Anhui province, verifies the effect and the economic benefit, and provides scientific basis for large-area popularization and application of passivators with heavy metals Cd and Pb according to the formula and the dosage.

2 general description of the test

2.1 test site and soil conditions

The test site is selected from towns in Linquan county, the soil is clay, and the current situation of the soil is shown in the following table 1.

TABLE 1 analysis of soil nutrient in plots before test

2.2 test article

Two crop trials, corn, huawan 267; wheat, wan wheat 38.

2.3 test fertilizers and passivating agents

45% of Anhuihongternary compound fertilizer (28:6:6), 40% of Anhuihongternary compound fertilizer (25:12:8) and 45% of Anhuihongternary compound fertilizer, and different heavy metal passivators are applied.

2.4 test formulation design

The experiment was run in 5 treatments, each treatment was repeated 3 times, and randomized block wise. Test area of each treatment was 100m²。

The test plot is rectangular, small plastic film ridges are formed among all the cells of the corn, single irrigation and single row are formed, water and fertilizer serial exchange among different treatment rooms is prevented, and the treatment settings are as follows:

TABLE 2 passivator, Fertilizer formula and dosage table

The test is corn and wheat, and is carried out from corn, and the two crops are treated identically.

The test dosage of each treatment of the passivator is 150 kg/mu, the seedlings are basically the same, other agricultural measures of each treatment are consistent, and single difference is kept.

2.5 corn test

Fertilizing and passivating the corns in 2015 for 6 months and 1 day, wherein the fertilizer and passivating agent dosage is carried out according to the table; sowing 6-month corn seeds, and harvesting 16-9-month corn seeds

TABLE 3 statistics of physical and chemical properties and yield of soil under different formula treatment conditions of corn

As can be seen from table 3, the heavy metals Cd, Pb in the soil are very significantly different between control 1 and treatment 5:

(1) passivating Cd: compared with the comparison 1, the treatment 2 to the treatment 5 have passivation effect on heavy metal Cd, and from the passivation effect analysis, the passivation effect is improved along with the synergistic effect of the multi-component complexing agent, and the passivation effect of the complexing agent of the treatment 5 is the best, and the effective state is reduced by 88.14%;

(2) passivating Pb: compared with the comparison 1, the treatment 2 to the treatment 5 have passivation effect on heavy metal Pb, from the passivation effect analysis, the passivation effect is more and more excellent along with the synergistic effect of the multi-component complexing agent, the passivation effect of the complexing agent of the treatment 5 is the best, and the effective state is reduced to 89.55%;

(3) the pH of the acid soil is improved by 2 to 5, the best effect is that the pH of the acid soil is improved by 3, the pH is improved by 0.8, and the pH of the acid soil is improved by 0.4 in 5.

(4) Yield: compared with the control, the yield of the treatments 2 to 5 is increased, the yield of the treatment 4 is increased by 34.95%, the yield of the treatment 5 is increased by 35.39%, and the effect is ideal.

And (3) corn test: the composite passivator with the formula of biomass ash, rice husk charcoal, ammonium lignosulfonate and ferrous sulfate has the best effect of passivating heavy metals Cd and Pb in soil, and the corn yield is increased by more than 35.59%.

2.6 wheat test procedure

Applying fertilizer and passivator to the wheat in 2015, 10 months and 20 days according to the table 1; wheat was sown 10 and 25 days 2015, and harvested 6 and 2 days 2016.

TABLE 4 statistical table of soil biological properties and yield under different formula treatment conditions of wheat

As can be seen from table 4, the heavy metals Cd, Pb in the soil are very significantly different between control 1 and treatment 5:

(1) passivating Cd: compared with the control 1, the treatment 2 to the treatment 5 have passivation effect on heavy metal Cd, from the passivation effect analysis, the passivation effect is more and more obvious along with the synergistic effect of the multi-component complexing agent, the treatment 5 has the best composite passivator effect, and the effective state is reduced to 84.52%;

(2) passivating Pb: compared with the comparison 1, the treatment 2 to the treatment 5 have passivation effect on heavy metal Pb, and from the passivation effect analysis, the passivation effect is more and more obvious along with the synergistic effect of the multi-component complexing agent, the treatment 5 has the best passivation effect, and the effective state is reduced to 89.94%;

(3) pH 2 to 5 treatment compared to control 1, the soil pH increased, with the best results being treatment 3, with a 1.0 pH increase, and treatment 5, with a 0.3 pH increase.

(4) Yield: compared with the control 1, the yield of the treatments 2 to 5 is increased, the yield of the treatment 4 is increased by 20.00 percent, the yield of the treatment 5 is increased by 19.61 percent, and the effects are ideal.

Wheat test: the formula is a multi-component synergistic composite passivator of biomass ash, rice husk charcoal, ammonium lignosulfonate and ferrous sulfate, which has the best passivation effect on heavy metals Cd and Pb in soil, and simultaneously, the yield of wheat is increased by 19.61%.

3 conclusion

The test uses a plurality of heavy metal passivators with different formulas, and the analysis results are shown in tables 3 and 4 and figures 1, 2 and 3: in tests of corn and wheat, all the formulas have passivation effects, the yield is increased, but the synergistic compound effect of the 5-component treatment is optimal, the pH value of soil is improved by using medium and trace elements in biomass ash, conditions are created for passivating heavy metals, and the synergistic effects of rice hull carbon, a complexing agent, a reducing agent and the like are compounded; the effective state of heavy metal Cd on corn is reduced to 88.14%, the effective state of Pb is reduced to 89.55%, the pH of soil is increased by 0.4, and the yield is increased by 35.59%. The effective state of heavy metal Cd on wheat in soil is reduced to 84.52%, the effective state of Pb is reduced to 52.10%, the pH of soil is increased by 0.3, and the yield is increased by 89.94%.

The multi-component synergistic composite acidic soil heavy metal passivator prepared from biomass ash, rice hull charcoal, ammonium lignosulfonate, ferrous sulfate and the like has obvious effects of providing medium trace elements for soil, improving the physical and chemical properties of the soil, increasing the pH value of the soil, passivating the activity of heavy metals Cd and Pb and improving the yield, and has popularization and application prospects.

Claims

1. The composition for in-situ passivation of heavy metals cadmium and lead in acid soil is characterized by comprising the following raw materials in parts by weight: 50 parts of biomass ash, 25 parts of rice husk charcoal, 10 parts of ammonium lignosulfonate and 15 parts of ferrous sulfate.

2. Use of the composition for in-situ passivation of acid soil heavy metals according to claim 1 in the preparation of a passivator for corn or wheat planting.