TIO2-MOS2 PAPER BASED MEMBRANE FOR SOLAR EVAPORATION

Abstract

Clean water scarcity is a critical issue faced by the world. It was caused by insufficient potable water supply and a high cost of water purification systems. As a result, a photothermal evaporator system with the property to absorb light/solar energy and then convert it to heat energy has been rapidly developed. In this work, a solar-driven water evaporation was designed for desalination. The solar evaporator comprises a photothermal molybdenum disulfide-titanium dioxide (MoS2-TiO2) composite layer supported onto a cheap filter paper attached. The filter paper was attached to polystyrene foam for support and cotton thread in the centre of the filter paper for water transportation. MoS2-TiO2 composite was synthesized and coated onto the filter paper using a simple vacuum-assisted method. Before the solar-driven water evaporation testing, the MoS2-TiO2 composite was first characterized using XRD and Raman spectroscopy. The characterization results indicate that MoS2 introduction into the TiO2 structure improved the photosensitivity due to the reduction of the bandgap energy from 3.1 eV for TiO2 to 1.6 eV. The performance of the developed solar evaporator was tested using 35,000 ppm NaCl solution under sunlight for 24 h intermittently. The TiO2-MoS2 solar evaporator was observed to have the highest photothermal ability, with 0.807 kg‧m-2‧h-1 evaporation performance and 55.9 % photothermal efficiency compared to other solar evaporators. This indicated that introducing the photothermal MoS2-TiO2 layer could enhance the solar evaporator performances, making it promising for the desalination application, particularly in impoverished areas with water scarcity.