Pickering乳化强化地下水三氯乙烯NAPL修复

合成了4种不同长径比的SiO₂颗粒调控水/NAPL界面，考察所形成的Pickering乳化效果和稳定性，结果表明：长径比（L/D）为2.3的SiO₂颗粒分散的Pickering乳液液滴尺寸均匀，直径约10 μm，且10d内保持稳定，乳化指数高达63%.流变测试进一步证实所形成的Pickering乳化具有低剪切应变下乳液稳定的特性，利于地下水的原位修复技术的实施.同时考察胶体颗粒浓度，水中离子强度以及水/NAPL比例对Pickering乳化效果和稳定性的影响，为Pickering乳化技术在实际地下水修复应用提供理论基础.通过对比Pickering乳化和未乳化条件下NAPL溶解和氧化降解动力学过程，发现Pickering乳化通过增大两相间界面积显著提高NAPL的溶解速率，进而实现NAPL相污染物降解速率的提高.

Pickering emulsion for enhancing oxidative degradation of trichloroethylene nonaqueous-phase liquid in groundwater

Four kinds of SiO₂ particles were synthesized with different length to diameter (L/D) ratios to form oil -in-water Pickering emulsions so as to control the water/trichloroethylene (TCE) NAPL interface and improve TCE dissolution. The characteristics and stability of the formed Pickering emulsion and effects of colloidal particle concentration, ionic strength in water and water/NAPL ratio were investigated. Results showed that the droplets in the Pickering emulsion formed from SiO₂ particles with L/D ratio of 2.3 had uniform size of 10µm and remained stable within 10 days. The emulsion index was up to 63% in this system. Moreover, the formed Pickering emulsion exhibited stability under low shear strain, facilitating groundwater in situ remediation. The results from comparing the kinetics of NAPL dissolution and oxidative degradation under Pickering emulsified and non-emulsified conditions indicate that Pickering emulsification could significantly elevate the dissolution rate of NAPL by increasing the interface area between the two phases, thereby achieve an increase in the degradation rate of NAPL phase pollutants.