Solar-driven evaporation device based on coal-derived nanomaterials for efficient and stable desalination

Abstract

Solar-driven interfacial evaporation is considered as an effective and environmental-friendly pathway to address the issues of water shortages and pollution. Small-size evaporators with high evaporation rates based on expensive materials and complex preparation processes have been widely reported. However, attentions have rarely focused on the methods for continuous mass production of photo-thermal active materials, with which to develop a low-cost, efficient, and simple production evaporator with high performance. Herein, using low-cost materials such as coal-based carbon nanomaterial (CCN) based on wet ball milling and commercial filter paper, the CCN/filter paper evaporators are fabricated via solution impregnation method for solar-driven interface desalination. As a result, the CCN/filter paper evaporator under optimized conditions can achieve an evaporation rate of 1.40 kg m-2h−1 and conversion efficiency of 90.1%, even works in a 10% wt% NaCl solution, as well as stably working 10 h with an evaporation rate of 1.35 kg m-2h−1 without salt accumulation. Importantly, the large-scale evaporator developed for outdoor experiment can produce freshwater that meets the drinking water standard of WHO at an evaporation rate of about 6.48 kg m−2 day−1. The work demonstrates a simple and effective strategy for producing membrane evaporator with high-performance solar steam generation and superior salt rejection capability at low cost from a laboratory scale to an industrial scale, which can potentially be utilized in efficient, long-term and stable seawater desalination.