A photocatalytic degradation self-cleaning composite membrane for oil-water separation inspired by light-trapping effect of moth-eye

• Published in: Journal of membrane science Vol. 669; p. 121337
• Main Authors: Li, Zhaoxin, Yin, Liang, Jiang, Shuyue, Chen, Liang, Sang, Shengtian, Zhang, Haifeng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.03.2023
• Subjects: asymmetric membranes; crosslinking; durability; hydrophilicity; irradiation; Light-trapping; magnetism; nanoparticles; Oil-water separation; photocatalysis; Photocatalytic degradation; polyvinyl alcohol; Redox reaction; redox reactions; Self-cleaning; solar radiation; tannins; titanium dioxide; water pollution; Oil-water separation; Photocatalytic degradation; Self-cleaning; Light-trapping; Redox reaction
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2022.121337

Membrane separation technology with superwetting surfaces is ideal for treating water pollution. However, the fouling problem of membranes limits their practical application in this field. Membranes with self-cleaning property during the separation are the key to solve this problem. In this study, inspired by the light-trapping effect of the moth-eye, a kind of composite membrane with efficient self-cleaning by photocatalytic degradation was proposed. The composite membrane is based on polyvinyl alcohol cross-linked tannic acid (PVA-TA) and its photocatalytic function is achieved by doping magnetic titanium dioxide nanoparticles (MTiO2) as well as MXene. Meanwhile, its surface was constructed by magnetically controlled self-assembly method using MTiO2 to mimic the moth-eye structure. The composite membrane has superhydrophilic/underwater superoleophobic, excellent oil-water separation efficiency (99.85%) and long service life (64 cycles). In addition, due to the light-trapping effect of the bionic moth-eye structure and the redox reaction at the interface of MTiO2-MXene composites under sunlight irradiation, the membrane can achieve efficient and convenient photocatalytic degradation self-cleaning by sunlight irradiation. This study will provide new insights into the self-cleaning method of oil-water separation materials. [Display omitted] •Construction of high light absorption efficiency surface by magnetron self-assembly method inspired by the light-trapping effect of moth-eye structure.•Redox reaction occur at the interface of MTiO2 and MXene composite under sunlight irradiation.•The composite membrane shows excellent oil-water separation performance and long service life.•The composite membrane has excellent sunlight-catalyzed degradation self-cleaning property.