Fundamental studies on the removal of an oily contaminant in aqueous solutions by the application of the LB technique

应用Langmuir-Blodgett技术构建了一个定义良好的模型系统，用于研究水溶液中含油污染物的去除过程。用γ-氨丙基三乙氧基硅烷和甲基三乙氧基硅烷对石英玻璃平板进行表面处理。硅烷化降低了衬底的润湿性。未经处理和MTES处理的二氧化硅玻璃带负电荷，APTES处理的玻璃在水中带正电荷。以花生四烯酸为模型油性污染物。获得了花生四烯酸在水中扩散单分子膜的表面压力-面积等温线和Brewster角显微图像，并采用垂直浸渍的方法将固体凝聚膜转移到基片上。在水溶液中超声洗涤含有LB膜的底物。从底物的FT-IR光谱的变化来评价的去污力由于硅烷化的结果而降低，尤其是APTES…更多经过处理的玻璃。基材的润湿性和表面电荷对去污力起着重要作用。APTES处理后的玻璃中LB膜的脱除量随表面活性剂或乙醇浓度的增加而增加。去除速率强烈依赖于温度。将花生酸的单分子膜转移到石英晶体微天平(QCM)的金电极上，然后在含有氯化钠、氢氧化钠、表面活性剂和/或乙醇的水溶液中清洗QCM。用实验测得的接触角和表面自由能计算了花生四酸薄膜与金表面在接触区内的液膜穿透自由能变化，两者之间有很好的相关性。研究表明，花生四酸的碱皂化和渗透作用对脱油有一定的作用。在空气中照射172 nm紫外准分子，然后进行超声波清洗是有效的去除方法。较少

A well-defined model system was constructed by the application of the Langmuir-Blodgett technique to investigate the removal processes of oily contaminants in aqueous solutions.. Silica glass plates were treated with γ -aminopropyltriethoxysilane (APTES) and methyltriethoxysilane (MTES). The wettability of the substrates decreased by the silanization. Untreated and MTES-treated silica glass were negatively charged and APTES-treated glass was positively charged in water. Arachidic acid was used as a model oily contaminant. The surface pressure-area isotherms and the Brewster angle microscopic images of the spreading monolayers of arachidic acid on water were obtained, and the solid-condensed films were transferred onto the substrates by the vertical dipping method. The substrates with the LB films were ultrasonically washed in aqueous solutions. The detergency evaluated from the change in FT-IR spectra of the substrate decreased as a result of the silanization, especially for the APTES … More treated glass. The wettability and the surface charge of the substrate played important roles in the detergency. The removal of the LB films from the APTES-treated glass increased with increasing surfactant or ethanol concentration. The removal rate was strongly dependent on temperature. The monolayers of arachidic acid were transferred onto the gold electrodes of the quartz crystal microbalance (QCM) and then the QCM was cleaned in aqueous solutions containing sodium chloride, sodium hydroxide, surfactants and/or ethanol. The detergency was evaluated from the frequency change of the QCM.The detergency had a good correlation with the free energy change due to the penetration of a thin liquid layer between the arachidic acid films and the gold surface in the zone of contact, which was calculated using the experimentally determined contact angles and surface free energies. The saponification of arachidic acid by alkali as well as the penetration was shown to contribute to the oil removal. The exposure of the 172 nm UV eximer in air and the following ultrasonic washing were effective for the removal. Less