Biomass derived evaporator with highly interconnected structure for eliminating salt accumulation in high-salinity brine

Abstract

Solar-driven evaporator is regarded as an energy-saving and eco-friendly desalination technology. However, available unfriendly synthetic materials and salt crystallization problems limit the evaporator's performance and development, especially in high-salinity condition. Hence, inspired by the highly interconnected microchannels, a carbonized white gourd (CWG) derived self-desalting evaporator was developed to evaporate and desalinate seawater. To evaluate the efficacy of the porous features, the effect of different porosity configurations on water evaporation and anti-salt abilities of CWG was discussed. High and stable evaporation rates of 1.76 and 1.44 kg·m−2·h−1 were reached for 3.5 wt% and 20 wt% NaCl solutions, respectively, which were attributed to the highly efficient water transport and self-desalting capabilities, and it further increased to 2.19 kg·m−2·h−1 by adding an extra convective air (2 m/s) located at the evaporation interface. Moderate airflow effectively enhanced the evaporation efficiency and delayed re-crystallization of salt, promoting a long-term stable desalination process. Conversely, excessive convective flow (4 m/s) may directly impair evaporative stability and salt resistance. This research is expected to provide a new insight into the design of high performance, low cost, eco-friendly and salt-resistant evaporator applied to solar desalination.