Preparation and Interfacial Evaporation Desalination Performance of 3D Porous Materials

Solar-driven interfacial water evaporation technology offers an environmentally friendly and efficient approach for seawater desalination and wastewater treatment, addressing global water scarcity challenges. Biomass-derived three-dimensional (3D) photothermal materials have attracted significant attention for enhancing interfacial evaporation performance due to their superior light absorption and water transport capabilities. In this study, natural biomass (Chinese yam) was employed to fabricate 3D cylindrical (CCY) and conical (CO-CCY) porous carbon evaporators. Their structural features, light absorption, and water transport properties were systematically characterized. Salt tolerance in high-salinity brine, as well as outdoor desalination and water purification performance, were evaluated. The evaporators exhibited honeycomb-like interconnected pores, facilitating efficient water supply and vapor diffusion. In 3.5% NaCl solution, evaporation rates of CCY and CO-CCY reached 1.14 and 1.12 kg/(m²·h), respectively, with CO-CCY achieving a higher evaporation efficiency of 76.94%. Performance declined significantly in 20% NaCl solution, with evaporation rates decreasing to 0.64 and 0.53 kg/(m²·h). Additionally, ion concentrations of B³⁺, Na⁺, Mg²⁺, K⁺, and Ca²⁺ in desalinated water were reduced by 3~4 orders of magnitude compared to the original solution. Treatment of methylene blue and methyl orange dye wastewater resulted in nearly complete removal of absorption in the 300~800 nm wavelength range, yielding clear and transparent water. These results highlight the promising potential of the prepared porous carbon evaporators for solar-driven seawater desalination and wastewater treatment applications.