Cotton Cloth@ Polydimethylsiloxane -Graphene Flakes- Titanium Dioxide Composite Membrane for Wastewater Purification

Abstract

Interfacial solar steam generation (ISSG) has been regarded as a simple and highly-efficient method for wastewater purification. Herein, we prepared a superhydrophobic composite membrane, in which polydimethylsiloxane employed as binders to pack graphite flakes and titanium dioxide tightly onto cotton cloth (defined as cotton cloth@PDMS-C-P25). Benefiting from its powerful photothermal effects, cotton cloth@PDMS-C-P25 exhibited high evaporation flux of 1.86 kg m−2 h−1 and 1.73 kg m−2 h−1 for pure water and seawater, respectively. Meanwhile, the prepared composite membrane fulfilled the targets of sewage purification set by its photocatalytic properties, which demonstrated a degradation rate of 66.1 % for Rhodamine B (RhB), and antibacterial efficiency of over 99.99 % for Escherichia coli (E. coli). Furthermore, cotton cloth@PDMS-C-P25 surface was endowed with superhydrophobic and low-adhesion characteristics mainly owing to the synergy of multiscale structure and low surface energy matter, which contribute to the anti-adhesion effect of 97.9 % for E. coli at a high concentration of 107 colony forming units (CFUs). In this work, the cost-effective, environmentally friendly, long-term stable, and superhydrophobic solar-absorber holds a potential prospect for wastewater treatment and desalination in a typical pollution-induced water shortage area.