重金属污染土壤修复研究进展

世界范围内的土壤中广泛存在重金属污染,正确认识土壤中重金属的存在形式有利于采取适当的方式进行土壤修复。现有技术中,根据修复原理可分为物理、化学、生物、电气和热修复五种,具体方法为覆盖、封装、填埋、土壤冲洗、电动萃取、稳定化/固化、玻璃化、植物修复及微生物修复。这些技术具有相应的优缺点和适用性,覆盖、封装和填埋适用于污染严重面积小的区域;土壤冲洗工程量大,需要对螯合剂进行处理;电动萃取适用于浅层、低浓度污染场地,处理时间长;稳定化/固化应用广泛但不能从土壤中根除重金属;植物修复需提高效率。合适的修复技术对于重金属污染土壤再利用至关重要,需结合污染的类型和程度、修复目标、场地特征、成本效益、修复时间。

Research Progress on Remediation of Heavy Metal Contaminated Soil

Heavy metals (arsenic, cadmium, chromium, mercury, lead, etc.) are widely polluted in the world. Correct understanding of the forms of heavy metals in the soil is conducive to adopting appropriate methods for soil remediation. The existing remediation technologies can be divided into physical, chemical, biological, electrical and thermal remediation according to the principle of remediation, and the specific methods include capping, encapsulation, landfill, soil washing, electric extraction, stabilization/solidification, vitrification, phytoremediation and bioremediation. These technologies have specific advantages and disadvantages and applicability. Capping, encapsulation and landfill are suitable for areas with serious pollution and small area. Because of the large amount of soil washing, it is necessary to treat the chelating agent. Electric extraction is suitable for shallow and low concentration contaminated sites, and the treatment time is long. Stabilization/solidification is widely used but does not remove heavy metals from the soil. Phytoremediation needs to be more efficient. Appropriate remediation technology is crucial for the reuse of heavy metal contaminated soil, which should be combined with the type and degree of pollution, remediation objectives, site characteristics, cost-effectiveness, and remediation time.