Method for remediating farmland soil through combined chemical activation and electric ionization of heavy metal substances

Abstract

The invention discloses a method for remediating farmland soil through combined chemical activation and electric ionization of heavy metal substances. The method comprises the following steps: A, naturally oxidizing soil, and plowing farmland soil; B, directly pouring hydrogen peroxide into an aqueous soil solution, and discharging the aqueous hydrogen peroxide soil solution into a water storagetank for water purification treatment; C, directly pouring concentrated sulfuric acid into the hydrogen peroxide farmland soil solution; D, burying a positive electrode and a negative electrode in thesoil by using an aqueous sulfuric acid soil solution; E, after electrokinetic remediation, discharging an aqueous soil solution obtained after electrokinetic remediation into the water storage tank for treatment; F, injecting irrigation water into a paddy field, conducing soaking, and draining the aqueous soil solution; g, performing lime purification treatment on wastewater, adding lime, and further performing chemical purification through a reaction; and H, purifying the wastewater by using sodium hydroxide and sodium sulfide, adding sodium hydroxide into the residual wastewater for neutralizing, and adding sodium sulfide and conducting recycling. The method is safe, reliable and low in cost, and chemical reagents and instruments used for remediation are free of pollutants.

Description

technical field [0001] The invention belongs to the technical field of farmland soil heavy metal (copper, lead, zinc, cadmium, nickel, chromium, mercury and arsenic) pollution restoration technology, and more specifically relates to a (new) method for combining chemical activation and electrokinetic ionization of farmland soil heavy metal substances for restoration . Background technique [0002] Remediation of heavy metal pollution in farmland soil is an important task to ensure food safety production. The principle and idea of ​​the widely used technical method is to use physical and chemical methods to reduce the effective content of heavy metals in the soil, thereby reducing the content of heavy metals in crop grains. The method is called the passivation method. The bioremediation method uses organisms, including plants, animals and microorganisms, to absorb, adsorb and transform heavy metals in the soil. Electrodynamic remediation is a repair technology developed in rec...

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Problems solved by technology

[0004] The defects of this repair example are: 1. The repair effect is low. The mid-term test results show that the repair effect is not obvious. 2. Secondary pollution occurs. The heavy metal content is reduced, which prevents the migration and removal of heavy metal components in the soil. 4. During the leaching repair process, adding leaching agents phosphoric acid, phosphate and citric acid to form insoluble phosphate Cd 3 (PO 4 ) 2 Precipitation, and the ability to form complexes with organisms is very weak, so it also prevents the migration and removal of heavy metal components in the soil. 5 Deep plowing and plowing of the soil, the purpose is to make the soil closely contact with the air, oxidize and dissociate heavy metals, and form effective heavy metals Dissolved in the soil water solution to migrate and remove, but this restoration process is carried out in the open air, long-term water accumulation and planting hinder the contact between soil and air, weaken the ability of heavy metals to transform into effective states, and reduce the restoration effect.

[0006] make phytoremediation very poorly

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