School of Chemistry and Environment, South China Normal University , Guangzhou, Guangdong 510006, China.
Environ Sci Technol. 2017 Jun 20;51(12):7055-7064. doi: 10.1021/acs.est.6b05477. Epub 2017 May 26.
Limited aqueous availability of hydrophobic organic contaminants and nonaqueous phase liquids in subsurface environment may seriously impair the effectiveness of traditional in situ chemical oxidation (ISCO). To tackle the issue, a combination of surfactants and thermally activated persulfate was proposed to enhance the aqueous availability and consequent oxidation of organic contaminants. The compatibility of eight representative nonionic, monovalent anionic, and divalent anionic surfactants with persulfate at various temperatures was first studied, to identify suitable surfactants that have high aqueous stability and low oxidant demands to couple with thermally activated persulfate. C-MADS (sodium dodecyl diphenyl ether disulfonate, a representative divalent anionic surfactant) stands out as the most compatible surfactant. Batch treatability study with coal tar, an example of challenging scenarios for traditional ISCO, was then conducted. The results show that C-MADS can significantly enhance not only the oxidation of polyaromatic hydrocarbons contained in coal tar but also oxidant utilization efficiency, indicating the potential of the proposed coupling process for the treatment of organic contaminants with low aqueous availability.
疏水性有机污染物和非水相液体在地下环境中的水相可用性有限，可能会严重降低传统原位化学氧化（ISCO）的效果。为了解决这个问题，提出了将表面活性剂和热活化过硫酸盐结合使用的方法，以提高有机污染物的水相可用性和随后的氧化效果。首先研究了八种代表性的非离子型、单价阴离子型和二价阴离子型表面活性剂在不同温度下与过硫酸盐的相容性，以确定与热活化过硫酸盐结合具有高水性稳定性和低氧化剂需求的合适表面活性剂。C-MADS（十二烷基二苯醚二磺酸钠，一种代表性的二价阴离子型表面活性剂）是最相容的表面活性剂。然后进行了含有煤焦油的批量可处理性研究，煤焦油是传统 ISCO 的挑战性场景的一个例子。结果表明，C-MADS 不仅可以显著提高煤焦油中所含多环芳烃的氧化程度，还可以提高氧化剂的利用效率，表明该耦合工艺在处理低水相可用性有机污染物方面具有潜力。
