Biomass Hydrogel Solar-Driven Multifunctional Evaporator for Desalination, VOC Removal, and Sterilization

Abstract

Solar-driven photothermal interfacial evaporation technology is currently perceived as one of the most green and effective freshwater production strategies available. However, when dealing with actual complex water bodies, it remains a challenge to combine steam generation with removing volatile organic compounds (VOCs) and inactivating bacteria at the same time to achieve multiple water purification effects. In this paper, a solar evaporator (SA/CCC/Cu²⁺) integrating photothermal and photocatalytic effects was successfully constructed by using a Cu²⁺ cross-linked biomass sodium alginate (SA) hydrogel as the basic skeleton and carbonized carboxymethyl chitosan (CCC) embedded internally as the photothermal material. During the solar evaporation process, the SA/CCC/Cu²⁺ evaporator successfully realized the separation of distilled water from bulk water containing VOCs, achieving the VOC removal efficiency of 96.77% while maintaining an evaporation rate of 2.54 kg m^–2 h^–1. In addition, it demonstrated remarkable capacity in inactivating Escherichia coli (E. coli), eliminating 100% of the bacteria within 40 min. With the rapid evaporation rate and impressive water purification effect, this design is anticipated to be a new path for solar-driven interfacial evaporative freshwater production.