Ultra-stable mineralizing and application thereof in remediation of heavy metal contaminated soil

Abstract

The invention discloses an ultra-stable mineralizing agent and application thereof in remediation of heavy metal contaminated soil. The ultra-stable mineralizing agent is prepared by quickly adding anenvironment-friendly metal ion solution and a precipitant into a micro-liquid membrane reactor; the use process can be implemented in a sowing or slurry spraying mode. The ultra-stable mineralizing agent is slightly alkalescent, does not cause soil acidification, and is very suitable for southern areas with serious soil pollution. Comparing adsorbent, the ultra-stable mineralizing agent preparedby the invention has very high activity; heavy metal ions such as copper, cadmium and manganese in soil can be quickly anchored in crystal lattices of the ultra-stable mineralizing agent in an isomorphous substitution or dissolution-reconstruction mode, hydrotalcite with a more stable structure is formed through mineralization, and the heavy metal ions are extremely difficult to dissociate from the hydrotalcite and are in an ultra-stable mineralization state. Besides, due to the ion radius matching rule, the ultra-stable mineralizing agent prepared by the invention also shows good selectivityand has a very good effect in in-situ remediation of soil heavy metal pollution.

Description

technical field [0001] The invention belongs to the field of inorganic material synthesis and soil repair, and in particular relates to an ultra-stable mineralizer and its application in repairing heavy metal polluted soil. Background technique [0002] Soil is one of the basic elements to maintain the national economy and people's livelihood. However, due to the non-standard disposal of pollutants, geological changes and other reasons, the soil pollution situation in my country is severe. According to data released by the state in 2014, the proportion of polluted soil in the country was 16.1%, of which agricultural land pollution accounted for 19.4% (about 400 million mu), and some typical land plots and surrounding land pollution accounted for as high as 36.3%. The harm caused by polluted soil to human health is shocking, such as "rice with excessive cadmium". On August 31, 2018, my country's first soil law "Soil Pollution Prevention and Control Law of the People's Repub...

AI Technical Summary

Problems solved by technology

[0004] Passivation agent is the core of in-situ passivation technology. Common passivation agents on the market, such as organic carbon, sepiolite, palygorskite, etc., mainly rely on the electrostatic attraction and surface adsorption of materials to passivate heavy metal ions. , this passivation method has a weak force and is easily affected by external conditions, resulting in the desorption of pollutants and the formation of pollution again.

In addition, due to the complexity of soil composition and the diversity of pollution sources, not only heavy metal ions but also a large number of other ions that are harmless or even beneficial exist in polluted soil, and various ions interfere with each other. Implementing passivation of heavy metal ions poses challenges

Furthermore, due to the large total area of ​​soil pollution, the economic cost must be considered while ensuring the repair effect. Conventional passivators are cheap in unit price but have small adsorption capacity, and are easy to desorb, which makes the amount and frequent use lead to a total High cost; MOF, MXene and other materials with excellent adsorption effect have cumbersome preparation process, harsh conditions, high cost, and it is difficult to achieve large-scale use

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