冻结技术在水土重金属污染净化与修复中的应用及进展

Application and progress of freezing technology in purification and remediation of heavy metal pollution in water and soil

随着工业化进程的加快,水土重金属污染事件逐渐增多,对其治理与修复成为当前的迫切工作。冻结技术在治理修复污染水土时,其修复过程只向地层输入“冷量”,属于绿色修复技术,无二次污染风险,受到越来越多的关注。详细总结了冻结技术的修复机理,及其在污水、污泥、重金属污染土壤治理修复中的应用现状和最新研究进展。冻结修复机理是通过冰的自净作用和固-液相平衡原理来实现污染物的定向驱赶和富集,而黏性土壤颗粒的吸附和阻滞作用使单一技术对重金属污染土壤的修复难度增大,其他修复手段与冻结技术联合处理成为一种新的思路。利用冻结土体的低渗透性,还可有效降低污染物的迁移速度,封闭不同种类污染物,形成阻隔污染物扩散的冻结屏障。冻结修复技术在水土重金属污染净化及修复领域具有良好的应用前景。

With acceleration of industrialization process,water pollution and heavy metal pollution incidents in the soil have gradually increased,and management and remediation of the environment has become an urgent need.When freezing technology is used to purify and remediate contaminated soil and water,only“cold ener⁃gy”is input to the formation.There is no secondary pollution in the treatment process,which makes the freezing technology receive more and more attention in the environmental field.This paper introduces in detail the mecha⁃nism of freezing technology to remediate polluted water and soil and summarizes the application status and latest research progress of freezing technology in sewage,sludge and heavy metal contaminated soil.The mechanism of freezing remediation is to achieve the directional drive and enrichment of pollutants through the self-purifica⁃tion effect of ice and the principle of solid-liquid phase equilibrium.However,due to adsorption and retardation between cohesive soil particles,the difficulty of remediation of heavy metal contaminated soil with single meth⁃od is more complicated.Freezing technology combined with other remediation technology is a new treatment method.The low permeability of frozen soil can effectively reduce the migration speed of pollutants to block dif⁃ferent types of pollutants and form a frozen barrier to prevent pollutants diffusion.Freezing remediation technolo⁃gy has a good market application prospect in environmental remediation.