Repair method of chromium-contaminated soil

Abstract

The invention discloses a repair method of chromium-contaminated soil, which belongs to the technical field of environment engineering. The method comprises the following steps: reducing hexavalent chromium in the chromium-contaminated soil, removing trivalent chromium and performing sewage treatment. Ferrous sulfate is added into the chromium-contaminated soil, and the reaction environment is adjusted, so that the efficiency for reducing the hexavalent chromium in the chromium-contaminated soil into the trivalent chromium is improved, and conditions are provided for removing chromium; chromium in the soil is extracted by adopting disodium ethylenediamine tetraacetate, the removal rate of the chromium in the soil is increased by adopting microwave heating, and the reaction time is shortened; sodium sulphide is added into chromium sewage, and the reaction environment is adjusted, so that the settling efficiency of heavy metals in the sewage is improved; and additionally, the sewage is converted into disodium ethylenediamine tetraacetate solution, so that resource recovery and utilization are realized. According to the method, the hexavalent chromium is converted into the trivalent chromium to be treated, so that the environmental risk in the repair process is reduced; the chromium-contaminated soil is converted into chromium sewage for treatment, so that the treatment efficiency is improved, and the treatment effect is guaranteed; and the method has the characteristics of no secondary pollution, high efficiency, rapidity, high resource utilization rate and the like.

Description

technical field [0001] The invention discloses a method for repairing chromium-contaminated soil, which belongs to the technical field of environmental engineering. Background technique [0002] At present, nearly 20 million hectares of arable land are polluted by heavy metals such as chromium in my country. It is estimated that 12 million tons of grains are polluted by soil every year, causing direct economic losses of more than 20 billion yuan. With the acceleration of urbanization and industrialization, more and more land is polluted by heavy metals, the strategic layout of cities has been readjusted, and a large number of heavy metal legacy sites are in urgent need of treatment. Soil heavy metal pollution is concealed, lagging and long-term, and it is difficult to repair. Heavy metals can enter the human body through the food chain, respiratory system, and skin to endanger human health; at the same time, heavy metals will also migrate and be exposed to groundwater and t...

AI Technical Summary

Problems solved by technology

[0004] At present, the remediation technology for chromium-contaminated soil mainly includes microbial removal method (Chinese Patent Publication No. CN201210355258.4, publication date September 21, 2012, invention name "A Microbial Remediation Method for Alkaline Chromium Contaminated Soil"), chemical method (pharmaceutical washing, thermal decomposition, etc.) (Chinese Patent Publication No. CN201310493630.2, published on October 18, 2013, title of the invention "Leaching method for hexavalent chromium-contaminated soil"), physical method (electrical method, solidification and stability Chemicals, etc.) (Chinese Patent Publication No. CN201110360190.4, published on November 15, 2011, the title of the invention is "Nano Zero-Valent Iron-Electromagnetic Rake Combined Restoration of Heavy Metal Contaminated Soil / Sludge Technology") and Plant Extraction (Chinese Patent Publication No. CN200910173646.9, open date September 8, 2009, invention name "Nano zero-valent iron-electromagnetic rake combined repair heavy metal contaminated soil / sludge process"), a large number of methods are still in the stage of laboratory research, and it is difficult to implement on site. , the existing chromium-contaminated soil treatment technology is relatively backward, resulting in low restoration efficiency, high cost, secondary pollution and environmental risks of chromium-contaminated soil