Self-cleaning, underwater writable, heat-insulated and photocatalytic cellulose membrane for high-efficient oil/water separation and removal of hazardous organic pollutants

Abstract

In this work, the fabrication and characterization of a multifunction cellulose membrane is reported: (і) high stable in harsh environment (acid/alkali solution, high temperature, abrasion, underwater writable, heat-insulated and self-cleaning), (іі) oil-water separation with high efficiency, and (ііі) effective and rapid photocatalytic degradation of hazardous environmental contaminants. This multifunction cellulose membrane was successfully prepared through depositing Fe2O3 particles and subsequent modification of stearic acid (STA). The results showed that this multifunction cellulose membrane had excellent superhydrophobic and self-cleaning properties with a high static water contact angle of 167.2 ± 2°. Moreover, it possessed unusual repellent properties towards acid/alkali solution, abrasion, high temperature and heat-insulated properties. This membrane could also be used for writing underwater and keep satisfactory superhydrophobic performance for a long time with a water contact angle of 154.2 ± 2°. It also showed a high separation efficiency (>89.0 %) and a high separation flux (greater than 80 Lm−2 h−1) for these three oils (toluene, trichloromethane and n-Hexane). After repeated separation for 6 cycles, the separation flux and separation efficiency of n-Hexane has not changed significantly. It also demonstrated reliable photocatalytic ability, a useful property for resisting organic contaminations. Compared with conventional cellulose membrane, it is anticipated that this multifunction superhydrophobic cellulose membrane is not only really competitive in complex and harsh environment, but also demonstrates great potentials in the field of effective underwater treatment, fire-proof applications, oil-water separation field and photocatalytic property.