Preparation of a superhydrophilic green ZnO membrane with high antifouling properties for effective treatment of dyes

Abstract

Ceramic membranes have been regarded as one of the most promising solutions for treating textile wastewater that poses serious harm to the environment. However, fouling and high preparation costs are critical challenges that affect their performance and large-scale industrial adaptation. Herein, antifouling strategies were adopted to develop a green, hydrophilic zinc oxide (ZnO) membrane for effective dye removal and long-term stability. The adoption of low-cost materials and a simple coating slurry method for membrane preparation offers a sustainable avenue for the large adaptation of ceramic membranes. The effects of different parameters, including green ZnO (GZnO) and polyvinyl alcohol (PVA) coating slurry percentages, operational conditions, and recyclability capacity, were investigated to control the stability and performance of the prepared membrane. The optimum membrane, prepared with 3 wt% of GZnO and 3 wt% of PVA, respectively, exhibited a high flux (138.2 L m^-2 h^-1) and good rejection efficiency (94%), as well as excellent antifouling properties (above 95%) with high reusability (100%) under sunlight irradiation, indicating its long-term efficiency in treating dyes. This suggests that the developed membrane could be applied to treat real industrial wastewater generated from textile industries.