Preparation of reusable UHMWPE/TiO2 photocatalytic microporous membrane reactors for efficient degradation of organic pollutants in water

A photocatalytic membrane reactor is an effective method to degrade organic pollutants in water and air. This method has many advantages, such as a complete degradation of organic pollutants, no secondary pollution to the environment, environmental protection, and high efficiency. Thus, how to efficiently manufacture membrane reactors with high catalytic efficiency is essential. In this study, ultra-high molecular weight polyethylene (UHMWPE)/inorganic particle photocatalytic microporous membrane reactors with high porosity and high loading capacity were prepared using a melt-blending method. In the preparation process, UHMWPE, liquid paraffin (LP), and nanoparticles, which acted as a binder, porogen, and photocatalyst, respectively, were completely dispersed and mixed in a self-developed pulsating tensile stress mixer. Then, the LP was extracted to obtain a microporous membrane reactor with high porosity and high loading of inorganic particles. This reactor had the advantages of excellent catalytic efficiency, industrial manufacture and application, recyclable and reusable, and environmental protection. In this study, inorganic titanium dioxide (TiO2) nanoparticles were used as photocatalysts to prepare the microporous membrane reactor. The effects of the ratios of UHMWPE to LP, the contents and sizes of inorganic particles, the thickness of the membrane, and biaxial tension treatment on the structure of the membrane reactors and the catalytic efficiency of organic dyes and hormone pollutants in water were studied. Results showed that the photocatalytic microporous membrane reactor with 75% porosity and 80 wt% of TiO2 had the best photocatalytic performance. Under ultraviolet photocatalysis, the degradation rate of the 20-mg/L methyl orange solution reached 98.5% within 60 min. Moreover, the degradation rate of the methylene blue solution reached 98.4% within 60 min, and that of the 20-mg/L Congo red solution reached 100% within 40 min. Furthermore, the degradation rate of the 50-mg/L tetracycline hydrochloride solution exceeded 96.6% within 80 min.