A photocatalytic and superhydrophobic self-cleaning nanocellulose-based membrane based on Cu-MOF for highly efficient oil/water separation, the removal of dyes and anti-biofouling towards sewage remediation.

Multifunctional superhydrophobic nanocellulose-based membranes for self-cleaning, oil/water separation, photocatalytic degradation, and anti-biofouling are in great demand for sewage treatment. This demand led to the in situ deposition of Cu-MOF micro/nanoparticles on the surface of CB membranes, followed by stearic acid (STA) modification to provide excellent superhydrophobicity, which enables effective oil/water separation, photocatalytic degradation, and anti-biofouling. The CB/Cu-MOF/STA membranes created in this manner demonstrated good superhydrophobicity with a water contact angle of 160 ± 2° and superoleophobicity with an oil contact angle of 0°. The superhydrophobic CB/Cu-MOF/STA membrane also demonstrates remarkable stability under extreme conditions, including high temperatures, acid and alkali solutions, etc. Furthermore, it has a high separation efficiency of 98 % and a large separation flux of 127.71 L·m·h for the n-Hexane/water separation. After 8 cycles of separation, the n-Hexane/water mixture's separation efficiency was maintained at about 95 %. Additionally, the superhydrophobic CB/Cu-MOF/STA membrane shows good photocatalytic activity because of its high porosity and large specific surface area. Chlorella's capacity to cling to the superhydrophobic CB/Cu-MOF/STA membrane was significantly diminished, and the membrane demonstrated strong anti-biofouling capability. The superhydrophobic CB/Cu-MOF/STA membrane is thus demonstrated to have a significant impact on promoting the widespread development of superhydrophobic materials with a variety of applications.