Curing agent for heavy metal and organic matter combined polluted soil, and preparation and application methods for curing agent

Abstract

The invention discloses a curing agent for heavy metal and organic matter combined polluted soil. The curing agent comprises the following components in percentage by weight: 12-27% of calcium carbide sludge powder, 40-64% of calcium superphosphate powder, and 20-40% sodium percarbonate-supported charcoal powder. The curing agent can significantly reduce the leaching toxicity of heavy metal in the polluted soil, efficiently adsorbs and decomposes organic pollutants, and is particularly suitable for site soil with a higher heavy metal and organic pollutant content (the total content is greater than 10000 mg / kg) and types of pollutants, and the repaired polluted soil can be used as environmental-friendly material to realize resource utilization; meanwhile, the invention further provides a preparation method and an application method for the curing agent; the curing agent is low in cost and convenient to prepare and use, can be popularized and applied to solidification and stabilization repair of combined polluted sites in a large-scale manner, and can realize resource utilization of factory wastes.

Description

technical field [0001] The invention belongs to the technical fields of civil engineering and environmental geotechnical engineering, and specifically relates to a solidifying agent for heavy metal and organic compound polluted soil and a preparation and application method. The raw material for preparing the solidifying agent comes from industrial waste and is suitable for treating soil Medium and heavy metals and organic pollutants can be used for solidification, stabilization and restoration of polluted sites, and realize waste utilization. Background technique [0002] Due to the long history and rapid development of my country's high-pollution industries, various types of factories often change in the same area, resulting in obvious accumulation and complex components of the remaining pollutants, which makes the soil pollution of industrially polluted sites present the characteristics of diversity and complexity. Heavy metals and Cases of compound pollution by organic pol...

AI Technical Summary

Problems solved by technology

However, these traditional curing agents have many disadvantages, which limit their application in heavy metal and organic compound pollution sites: this type of curing agent only seals such organic pollutants, and does not decompose to reduce toxicity; Organic pollutants and high-concentration heavy metals such as zinc (Zn) can seriously inhibit the cement hydration reaction, thereby reducing the strength development of the repaired soil and affecting the final curing effect; cement clinker will release a large amount of heat during the hydration process, and its curing The internal temperature of the body can reach 50-60°C under the condition of 25°C curing, and a variety of organic pollutants volatilize at this temperature, such as acetone (boiling point 56.5°C), dichloromethane (boiling point 39.8°C), gasoline (boiling point 40- 200°C), etc.; the restored soil is highly alkaline (generally, the pH value is greater than 12), which is not conducive to the survival of microorganisms capable of degrading organic pollutants (adapted to an environment with a pH between 6.5 and 9.5). At the same time, it is easy to produce alkaline leachate under rainfall conditions, which changes the acid-base balance of the surrounding soil and water, and adversely affects the surrounding organisms; heavy metal hydroxide precipitation under high alkalinity is one of the main curing mechanisms of curing agents such as cement First, it is very easy to dissolve again under the condition of overacidity and overalkali in the surrounding environment; during the production and use of cement, a large amount of carbon dioxide (CO 2 ) gas, which accounts for about 5% of the world's total emissions, which undoubtedly causes great harm to the environment; in addition, complex environments such as drought, rainfall, seasonal and diurnal temperature differences, acidic carbon dioxide (CO 2 ) erosion, etc. will cause a sudden decrease in the strength of the repaired soil and the secondary dissolution of pollutants; in addition, the production costs of activated carbon and organic bentonite are relatively high, and the preparation of activated carbon requires a large amount of energy and precious wood resources. The preparation process of organobentonite is complicated, and the modifier quaternary ammonium salt itself is also a highly toxic environmental pollutant

[0004] To sum up, traditional curing agents have poor curing and stabilizing effects on organic pollutants in soil, and have poor effects on treating high-concentration heavy metal pollutants, so they are not suitable for complex pollution sites of heavy metals and organic pollutants, especially high-concentration Complex pollution site of heavy metals and organic pollutants

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