Solar-driven desalination using salt-rejecting plasmonic cellulose nanofiber membrane.

Solar-driven steam generation is a promising, renewable, effective, and environment-friendly technology for desalination and water purification. However, steam generation from seawater causes severe salt formation on the photothermal material, which hinders long-term and large-scale practical applications. In this study, we develop salt-rejecting plasmonic cellulose-based membranes (CMNF-NP) composed of an optimized ratio of Au/Ag nanoparticles, cellulose micro/nanofibers, and polyethyleneimine for efficient solar-driven desalination. The CMNF-NP exhibits a water evaporation rate of 1.31 kg m-2h-1 (82.1% of solar-to-vapor conversion efficiency) for distilled water under 1-sun. The CMNF-NP shows a comparable evaporation rate for 3.5 wt% brine, which has been maintained for 10 h; the evaporation rate of the filter paper-based counterpart severely decreases because of salt-scaling. The efficient salt-rejecting capability of the CMNF-NP membrane is attributed to the compact structure and electrostatic repulsion of cationic ions of salt that originate from cellulose nanofibers and the amine-functionalized polymer, polyethyleneimine, as a structural binder. This simple fabrication method of casting the CMNF-NP solution on the substrate followed by drying allows a facile coating of a highly efficient and salt-rejecting photothermal membrane on various practical substrates.

Efficiency Enhancement of Electro-Adsorption Desalination Using Iron Oxide Nanoparticle-Incorporated Activated Carbon Nanocomposite.

Capacitive deionization (CDI) technology is currently considered a potential candidate for brackish water desalination. In this study, we designed iron oxide nanoparticle-incorporated activated carbon (AC/Fe2O3) via a facile and cost-effective hydrothermal process. The as-synthesized material was characterized using several techniques and tested as electrodes in CDI applications. We found that the distinctive properties of the AC/Fe2O3 electrode, i.e., high wettability, high surface area, unique structural morphology, and high conductivity, resulted in promising CDI performance. The electrosorptive capacity of the AC/Fe2O3 nanocomposite reached 6.76 mg g-1 in the CDI process, with a high specific capacitance of 1157.5 F g-1 at 10 mV s-1 in a 1 M NaCl electrolyte. This study confirms the potential use of AC/Fe2O3 nanocomposites as viable electrode materials in CDI and other electrochemical applications.