表面活性剂强化修复NAPLs污染土壤机理研究进展

Progress on the mechanism of surfactant-enhanced aquifer remediation of NAPLs-contaminated soil

表面活性剂强化修复(SEAR)是一项通过表面活性剂来有效修复多孔介质中的NAPLs污染的技术。表面活性剂对NAPLs污染土壤的修复机理主要包括增流作用、增溶作用和乳化作用,通过增加NAPLs在水相中的溶解性及可移动性,从而提高修复NAPLs污染土壤的效率。增流作用主要体现在通过表面活性剂增强截留在孔隙中的NAPLs的流动性,修复游离相NAPLs;增溶作用主要以胶束增溶为主,通过形成包含污染物的纳米级团聚体来增强多孔介质中NAPLs到水相的传质,减小残余相NAPLs在土壤中的含量;乳化作用由油相和水相之间的密度差引起,通过将NAPLs分散为微滴,增加其向液相的传质,从而达到强化修复的效果。在总结表面活性剂对NAPLs污染土壤的各类修复作用机理及其影响因素的基础上,对该技术的未来发展进行了展望。

Surfactant-enhanced aquifer remediation(SEAR)is a technique for the enhanced remediation of NAPLs in porous media through surfactant.The mechanisms of surfactant remediation of NAPLs contamination are mainly classified as Mobilization,Solubilization and Emulsification,increasing the solubility and mobility of NAPLs in the aqueous phase to improve the efficiency of NAPLs remediation.Mobilization is mainly reflected in the enhancement of the mobility of the NAPLs trapped in the pores by surfactants and the repair of free phase NAPLs.Solubilization is mainly based on micelle solubilization,which forms nanoscale agglomerates containing contaminants to enhance the transfer of NAPLs from the porous me-dium to the aqueous phase,reducing the amount of residual NAPLs in the soil.Emulsification,caused by the density difference between the oil and water phases,disperses NAPLs into microdroplets and increases their mass transfer to the liquid phase,resulting in enhanced remediation.Based on a summary of the mechanisms of the various types of remediation action of surfactants on NAPLs contamination and their influencing factors,the future development of this technology is envisaged.