Dual functional membrane with multiple hierarchical structures (MHS) for simultaneous and high-efficiency removal of dye and nano-sized oil droplets in water under high flux
作者：Zhenxing Wang, Shengqiang Ji, Jin Zhang, Fang He, Zhaodi Xu, Shaoqin Peng, Yuexiang Li
關鍵字：functional membrane
論文來源：期刊
具體來源：Journal of Membrane Science
發表時間：2018年
Dual functional membranes with super-wetting and adsorption capacity have drawn great attentions owing to their good application prospect in the treatment of mixed wastewater containing oil and dyes. Despite recent development in such functional membranes, there are still some obstacles need to be resolved. The one is how to further improve the dye adsorption capacity to realize the high-efficiency removal of dye under high permeation flux. The other is to improve the rejection towards nano-sized oil droplets in water. Herein, with porous polypropylene (PP) membrane as substrate, we show that constructing multiple hierarchical structures (MHS) on membrane surface is an effective way to solve the above mentioned problems. The MHS prepared by low-cost tannic acid, 3-Aminopropyltriethoxysilane (APTES), and polyethyleneimine (PEI) are composed of rough layer, nanospheres, and nano nodes with abundant amine groups. On the one hand, the MHS can endow the membrane with high adsorptive capacity (480 mg g-1 toward methyl blue). On the other hand, the MHS can also decrease the pore size of the membrane, making it suitable for separation of nano-sized oil droplets. Moreover, the MHS can also render the membrane superhydrophilicity and excellent anti-oil-adhesion properties. Thanks to these advantages derived from MHS, the obtained dual functional membrane can realize high-efficiency and simultaneous removal of high concentrated dye (10–50 ppm, removal efficiency>95%) and nano-sized oil droplets (about 50–300 nm, oil rejection>99%) from mixed wastewater under high flux (1680 L m-2 h-1). Considering the significantly enhanced performance, as well as the facile and cost-effective process, the as-prepared functional membrane with MHS has good application prospects. Besides, a new insight on the influence of hydrodynamic conditions on membrane fouling during emulsion separation is also proposed, which may guide better design of anti-fouling membranes.