Concentration of landfill leachate by solar driven surface vaporization performed on nanosecond-laser-treated titanium surface

Abstract

The use of solar evaporators to concentrate landfill leachate is a sustainable approach for reducing wastewater volume and generating clean water. Recent studies have investigated numerous interfacial solar evaporators. However, achieving a high evaporation rate under low optical concentrations remains challenging. This research develops mono and bifacial titanium photo-thermal material for solar-based landfill leachate treatment. Its strong absorbency, photo-thermal, thermal insulation, and quick water delivery characteristics enable the fabricated material to reach a high evaporation rate, including 2.02 and 1.71 kg/h under one sun for double and single-sided panels, respectively. Under one sun for a single-sided panel, the photo-thermal conversion effectiveness reached nearly 80.00%, resulting in a high interfacial water evaporation efficiency of 86.00%. It was possible to easily position the fabricated photo-thermal panels at any angle and implement them to optimize irradiation from incidence light. In comparison with raw landfill leachate, the concentrated landfill leachate displayed high turbidity, total suspended solids, solid suspended concentration, and total dissolved solids. Additionally, in the purified water, 98.70%, 91.20%, and 99.70% removal efficiencies were obtained for Cr2+, Ni2+, and Fe2+. Besides, COD (chemical oxygen demand), TOC (total organic carbon), and NH3-N (ammonia nitrogen) were removed at 90.36%, 86.13%, and 69.3%, respectively. Based on the results of this study, the super-hydrophilic titanium photo-thermal material is a potential candidate solar absorber for simultaneously concentrating wastewater and producing clean water.