Reinforced electric repair method of heavy metal polluted soil using anode liquor as eluant

Abstract

The invention discloses composite technology combining an electrodynamic method and a chemical leaching method, namely a process for performing high speed in situ restoration on heavy metal pollution soil without secondary pollution, wherein a natural organic complexing agent and an acidic anode working solution are used as a leaching agent; a leaching liquid containing heavy metals is migrated to a cathode processing area through electroosmotic flow; and combining the advantages that the electromigration can pass through low-permeability soil and a low pH anode working solution and can strengthen the desorption of solid heavy metals, the leaching agent can be selected as comparably mild natural organic acid so as to avoid the secondary pollution at source; simultaneously, with the repair process, pH jump points formed near a cathode are leached intermittently, an acid migration belt is controlled to advance continuously so that the pH jump points appear in the cathode processing area, and the problem of the reduction of the current efficiency with the time because of the decline of the local conductivity caused by the neutralization reaction between an acid surface and an alkali surface at a restoring part is avoided.

Description

technical field [0001] The invention relates to a high-speed in-situ restoration process without secondary pollution to heavy metal polluted soil, and belongs to the technical field of environmental protection and energy saving. Background technique [0002] Soil is the basis of food and clothing for human beings. In today's highly developed industrial technology, with the massive discharge of domestic sewage, industrial wastewater, waste gas, and waste residue, the soil environment is being polluted by unprecedented heavy metals. In the soil of some sewage irrigation areas, the area of ​​cadmium pollution exceeding the standard has increased by 14.6% in the past 20 years. In the southeast region, the area of ​​mercury, arsenic, copper, zinc and other elements exceeding the standard accounted for 45.5% of the total polluted area. In some cities in the Yangtze River Delta, 10,000 mu of contiguous farmland is polluted by heavy metals such as cadmium, lead, arsenic, copper, and...

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Problems solved by technology

Acar proposed an enhanced repair method to neutralize the OH produced by hydrolysis by adding acidic and alkaline solutions to the cathode and anode - and H + , to control the pH change of the system, using acetic acid to enhance the remediation of lead-contaminated soil, the removal rate of Pb was improved after 98 days of experiments, but about 55% of Pb was deposited near the cathode area, which blocked the soil pores and prevented the removal of pollutants Further migration and removal

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