A kind of composite leaching agent and its application

Abstract

The invention discloses a compound leaching agent and its application. The composite leaching agent can selectively remove the heavy metal lead in soil, and simultaneously has high lead removal efficiency at one time. The composite leaching agent does not introduce additional salt, which avoids the secondary damage of the soil during the remediation process and the difficulty in post-treatment of the leaching agent. The weak alkaline of the composite leaching agent overcomes the prejudice that the soil leaching agent in the prior art is medium-strong acidic, and the weakly alkaline leaching agent does not have a great impact on the pH of the soil, so that after restoration The soil can be used for agriculture, which is more practical. The soil treated by the composite leaching agent will not cause secondary pollution, and at the same time, the composite leaching agent has low cost and is more favorable for large-scale application.

Description

technical field [0001] The invention relates to the field of soil restoration, in particular to a composite leaching agent and its application. Background technique [0002] With the continuous development of society, soil pollution is becoming more and more common in our country. It has been reported that in heavy industrial areas, many soils are polluted with high concentrations of heavy metals. The report of the 2014 National Soil Pollution Survey pointed out that the lead content in 1.5% of the soil samples exceeded the national standard, which poses a huge threat to the sustainable use of land resources and the safety of agricultural products. Compared with the "Soil Environmental Quality Standard GB15618-1995", the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard (Trial) (GB 15618-2018)" has stricter requirements for lead content in soil. Lead is not an essential element for plants, animals or humans. After it enters the human body t...

AI Technical Summary

Problems solved by technology

The use of traditional inorganic solution cleaning agents to remediate heavy metal-contaminated soil, although the removal effect is good and fast, but the strong change of pH value during the leaching process will destroy the physical and chemical properties of the soil and indigenous microorganisms, and cause the loss of soil nutrients. The soil loses its agricultural function. At the same time, the existing leaching agents are generally acidic and medium-strong acidic. Although they have good effects, they have a greater impact on the pH value of the repaired soil, and they will also lose The problem of agricultural value, and, for the widely used Na in soil remediation 2 EDTA will also lead to a sharp increase in the sodium content of the repaired soil, causing salinization of the repaired soil and increasing the difficulty of subsequent eluent treatment

[0004] Therefore, it is necessary to provide a leaching agent with low salinity and good remediation effect while not causing secondary damage to the repaired soil to meet the unachievable effect of current leaching agents

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