Antibacterial Evaporator Based on Wood-Reduced Graphene Oxide/Titanium Oxide Nanocomposite for Long-Term and Highly Efficient Solar-Driven Wastewater Treatment

Herein, we developed antifouling and highly efficient solar absorbers consisting of poplar wood coated with titanium dioxide (TiO2) and reduced graphene oxide (RGO) nanocomposites (with different weight ratio of TiO2 to RGO). The antibacterial activity of all prepared nanocomposites against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was investigated. The results showed that T2G1 (a nanocomposite in which the weight ratio of TiO2 to RGO is 2:1) has the highest antibacterial activity among all nanocomposites (MIC of 0.08 and 0.08 mg mL-1 and MBC of 0.6 and 0.8 mg mL-1 for E. coli and S. aureus, respectively). Therefore, it was considered to be the most efficient photothermal material for interfacial solar desalination and solar-driven treatment of wastewater. Because of the broad-band solar absorption by T2G1, the solar absorber composed of T2G1 and wood (denoted as T2G1-w) showed a high energy conversion efficiency of 90.12% under 1 sun (1 kW m-2). T2G1-w also had a high stability for long-term cycles. T2G1-w also showed great performance of freshwater production from contaminated water containing dye or heavy metals. The concentration of heavy metals of Zn2+, Pb2+, Fe2+, Ni2+, and Cr6+ reduced from 1000 mg L-1 to near zero in the presence of the prepared solar absorber, indicating its great potential application for sewage treatment.