Efficiency of Optimized Fabrication Process for Light-absorbing Membranes from Sewage Sludge Applied in Solar-driven Steam Generation Systems

Solar-driven evaporation systems have been studied to provide clean water, especially for islandic areas. Carbon materials made from sludge in domestic wastewater treatment plants have been studied to produce light-absorbing membranes in solar-to-steam (STS) systems. However, the technical limitation of this method is that the water evaporation rate is still low. In this study, the process of manufacturing light-absorbing membranes was optimized to simplify the process while increasing the water evaporation rate and testing the application of converting seawater into fresh water. The optimal evaporation rate was 2.65 kg.m-2.h-1, higher than the system using vacuum drying membranes (1.88 kg.m-2.h-1) under 0.6 kW/m2 illumination conditions. When illuminated, the surface temperature of the TN_0.1 light-absorbing membrane reached 36.5°C, meaning 2.5°C higher than that of the reference membrane (without carbon material). The results of analyzing some anion and cation indicators in the harvested water showed that the fabricated STS systems could be applied well to convert seawater into fresh water for domestic use. Especially, the treatment efficiencies for , , , reach 99.87%, 94.35%, 99.5%, 99.98%, and 99.44%, respectively.