Department of Analytical Chemistry, University of Torino, 10125, Torino, Italy.
Environ Sci Pollut Res Int. 2011 Jun;18(5):783-9. doi: 10.1007/s11356-010-0427-7. Epub 2010 Dec 17.
Surfactant-assisted soil washing and photocatalysis are well-known remediation processes of environmental concern. The application of photocatalysis to treat soil washing extracts containing 4-methylphenol, 4-ethylphenol and 4-tert-butylphenol in the presence of nonionic (C(12)E(8) and C(12)E(23)) and anionic (SDS) surfactants and some of their binary mixtures was investigated in this work by studying the pollutants degradation in the presence of TiO(2) dispersions irradiated with simulated solar light.
Clean soil samples were spiked with the investigated alkylphenols. Aqueous solutions of the chosen surfactants were placed in contact for some hours with the spiked soil samples in a rotatory mixer. The pollutants recoveries were evaluated via HPLC analysis. Photocatalytic experiments were performed in solarbox on aqueous solutions and on aqueous surfactant solutions containing the pollutants.
The pollutants removal from the soil was proven effective using the examined surfactant solutions. The photocatalytic treatment of the wastes was faster using Brij 35, but also SDS and C(12)E(8)-SDS mixtures can be applied. After 2-5 h the complete pollutants abatement was obtained, depending on the surfactant chosen and on the amount of TiO(2) employed. On the contrary, the treatment of wastes containing C(12)E(8) was an extremely slow process.
The photocatalytic approach can be applied to remove the examined aromatic pollutants from the washing wastes, confirming the viable coupling between this advanced oxidation method and the surfactant-based soil remediation treatments. Surfactant adsorption onto TiO(2) and micelles concentration play a dominant role.
表面活性剂辅助土壤洗脱和光催化是两种众所周知的环境修复工艺。本研究采用光催化技术，在非离子（C（12）E（8）和 C（12）E（23））和阴离子（SDS）表面活性剂及其二元混合物存在的条件下，处理含有 4-甲基苯酚、4-乙基苯酚和 4-叔丁基苯酚的土壤洗脱液，考察污染物在模拟太阳光照射下 TiO2 分散体存在时的降解情况。
将所选烷基酚加入到清洁土壤样品中。将选定的表面活性剂水溶液与添加污染物的土壤样品在旋转混合器中接触数小时。通过高效液相色谱分析评估污染物的回收率。在太阳能箱中进行光催化实验，研究污染物在水溶液和含污染物的表面活性剂水溶液中的去除情况。
用所考察的表面活性剂溶液可有效去除土壤中的污染物。使用 Brij 35 进行光催化处理时，废水中的污染物去除速度较快，但也可以使用 SDS 和 C（12）E（8）-SDS 混合物。根据所选表面活性剂和 TiO2 的用量，2-5 小时后可完全去除污染物。相反，处理含 C（12）E（8）的废水是一个极其缓慢的过程。
光催化方法可用于去除洗脱废水中的芳烃污染物，证实了这种先进氧化方法与基于表面活性剂的土壤修复处理的有效结合。表面活性剂在 TiO2 上的吸附和胶束浓度起着主导作用。
