Material and system design: an all-weather multi-functional interface solar evaporator

Interfacial solar evaporation is a promising technology for water treatment. However, its practical application is limited by variable light conditions, salt accumulation, and secondary pollution of the condensate. In this study, carbon obtained by co -pyrolysis of sludge and corn cob (SC) was combined with sodium alginate (SA) and polyvinyl alcohol (PVA) to fabricate an SC@SA@PVA gel evaporator. The evaporator was mounted on a salt-resistant evaporation substrate. Evaporation experiments were conducted under two auxiliary modes: electric heating and solar concentrator assistance. Benefiting from the adsorption and photocatalytic properties of the sludge-derived carbon, the system enabled simultaneous water evaporation and the evaporated phenol removal. A removal efficiency of 80.6 % was achieved for a 10 mg·L −1 phenol solution. Coupled with the electric heating and solar concentration devices, the evaporation rate increased from 2.28 to 4.19 kg·m −2 ·h −1 , corresponding to an 83.8 % enhancement. In addition, an evaporation rate of 1.39 kg·m −2 ·h −1 was maintained at night. Moreover, the salt-resistant evaporation substrate provided water transportation, salt resistance, and heat management. These functions ensured the long-term stable operation of the system. Through the integration of sludge resource utilization and a multifunctional system design, this study provides a new path for the development of efficient, stable, and water-purifying next-generation interfacial evaporation technologies.