A multifunctional and environmentally safe superhydrophobic membrane with superior oil/water separation, photocatalytic degradation and anti-biofouling performance

Wastewater is typically complicated with spilled oil, water soluble toxic dyes and microorganisms, making it hard to be processed and causing a significant threat to the environmental safety and human health. In this paper, we demonstrate a simple solution immersion method to obtain a multifunctional cellulose-based membrane (CBM) that possesses both superhydrophobicity with a water contact angle of 163 degrees and superior functionalities including self-cleaning, oil-water separation, anti-biofouling, and photocatalytic degradation capabilities. The achievement of separation efficiency (96%), comparatively high flux (141 L.m(-2).h(-1)) and recyclable (7 times) oil/water separation performance is attributed to the robust superhydrophobicity enabled by the synergy of metal oxide (i.e., CuO) nanostructure coating and stearic acid (SA) modification. The superhydrophobic CBM also preferentially adsorbs organic dyes in aqueous solution, e.g., methylene blue (MB), promoting their efficient decomposition (about 70.3% of MB decomposed in 3 h) with high recyclability under UV irradiation. Most remarkably, the CBM exhibits superior anti-biofouling capability and persistently resists the algae adhesion in long duration (over 20 days), as a result of the self-cleaning ability as well as the antimicrobial property of CuO nanoparticles. Our finding here paves the way to use simple, cost-effective, environmentally safe, and reliable method to fabricate multifunctional materials for wastewater treatment in complex environments. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

In this study, a simple solution immersion method was used to fabricate a multifunctional cellulose-based membrane (CBM) with superhydrophobicity and superior functionalities including self-cleaning, oil-water separation, anti-biofouling, and photocatalytic degradation capabilities. The CBM exhibited high separation efficiency, comparatively high flux, and recyclability for oil-water separation. It also showed efficient adsorption and decomposition of organic dyes, as well as superior anti-biofouling capability. This finding offers a promising approach for wastewater treatment in complex environments using a simple, cost-effective, environmentally safe, and reliable method.