Self-catalyzed engineering of chelating sites onto a GO/PVA photothermal membrane: A strategy for synergistic solar desalination and thorough heavy metal removal

Solar-driven interfacial evaporation has emerged as a highly promising route, leveraging abundant solar energy for efficient desalination. However, many existing solar evaporators still face challenges such as salt accumulation and, crucially, fail to reduce heavy metal concentrations to the ultra-low levels required by drinking water standards. To address this gap, we have developed a room-temperature fabricated graphene oxide/siloxane-PVA hydrogel (GO/SPH) evaporator wherein solar-driven evaporation works in synergy with integrated chelating amino groups to achieve the thorough removal of heavy metal ions concurrent with desalination. The optimized 3.0 wt% GO/SPH composite demonstrates a remarkable evaporation rate of 2.21 kg m −2  h −1 under 1 sun irradiation, a two-fold improvement over the pristine SPH. This exceptional dual-function performance is underpinned by its synergistic architecture. For solar evaporation, GO within the matrix acts as a highly efficient photothermal agent, achieving 91.4% conversion efficiency. Concurrently, for heavy metal remediation, amino ligands derived from the APTMS crosslinker enable the selective sequestration of Cu 2+ , Cr 3+ , Cd 2+ , and Pb 2+ ions through specific coordination chemistry. Crucially, the entire evaporator is stabilized by a hydrolytically stable Si O Si network, which ensures robust multi-cycle performance by retaining over 95% of its initial efficiency and preserving its decontamination integrity over extended operation.