Method for electrically restoring soil and underground water

Abstract

The invention provides a method for electrically restoring soil and underground water, which is realized in a way that: soil or underground water which needs to be restored is used as the conducting medium, metallic iron is used as the anode, a ferric salt solution is used as the working solution, the anode iron is oxidized into ions after losing electrons, the ions enter the anode working solution and move towards the cathode into the soil or underground water as the current carrier with positive charges under the action of an electric field; and copper or copper-coated iron or iron is used as the cathode, a cupric salt or ferric salt solution is used as the working solution, cupric ions or trivalent ferric ions are reduced into elementary substance copper or bivalent ferric ions, meanwhile, small amounts of heavy metal cations transferring from the soil to the cathode working liquid are also reduced, and acid radicals of cupric salts or ferric salts move towards the anode under the action of the electric field and enter the soil and the underground water. The method can restore soil and underground water which are polluted by heavy metals, acids or alkalis, does not change the pH value of the soil and the underground water, does not produce hydrogen, oxygen or chlorine with hidden danger and has the advantages of high current efficiency, low price and easy obtainment of the anode material.

Description

technical field [0001] The invention relates to an electric restoration technology for polluted soil and underground water. Background technique [0002] When the waste water and solid waste generated in the industrial production process enter the soil, it will lead to soil and groundwater pollution. When the site is changed to residential, agricultural and other purposes with strict soil quality requirements, soil and groundwater restoration must be carried out. , to remove pollutants from soil and groundwater. [0003] The main methods of soil and groundwater remediation are: (1) physical remediation: physical separation remediation, curing / stabilization remediation, steam leaching remediation, electric (electrochemical) remediation; (2) chemical remediation: chemical leaching remediation, solvent leaching (3) Bioremediation: prepared bed method, soil composting method, mud bioreactor method, land cultivation method. [0004] Among them, the electric repair technology us...

AI Technical Summary

Problems solved by technology

At present, the electrodes used in electric repair technology are corrosion-resistant and anti-oxidation inert electrodes. The working fluid is mainly alkali metal salts such as KCl. During the repairing process, water is electrolyzed to generate hydrogen ions or hydroxide ions, releasing O 2 、H 2 or Cl 2 gas, which causes soil and groundwater acidification while removing pollutants from the soil and groundwater

During the repair process, due to the H + ions and OH - The electromigration speed of ions is much higher than that of other ions, so that the actual current used for pollutant migration accounts for less than 1% of the total current, and the current efficiency is extremely low. At the same time, it also limits the improvement of the repair voltage, making the repair time as long as possible. Months or even years, the effect is unstable

Soil and groundwater acidification, extremely low current efficiency, and electrode corrosion issues severely restrict the widespread use of this technology

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