Bridging solar evaporation and advanced oxidative degradation: A MXene-hydrogel platform for synergistic water treatment

The escalating global water pollution crisis calls for advanced purification technologies that simultaneously enable energy-efficient water recovery and effective pollutant removal. In this study, we report a mechanically robust double-network hydrogel composed of polyacrylamide, polyvinyl alcohol and MXene, designed for integrated interfacial solar evaporation (ISE) and advanced oxidation processes (AOPs). The incorporation of MXene nanosheets enhances photothermal conversion and promotes efficient solar evaporation, owing to their broadband solar absorption. Remarkably, according to the DFT calculation, upon introducing ammonium persulfate (APS) as an oxidant, MXene facilitates electron transfer under sunlight irradiation, triggering the decomposition of APS and the generation of reactive oxidizing species (ROSs). This synergistic system achieves a high solar evaporation rate of 3.07 kg·m⁻²·h⁻¹ while simultaneously degrading 96.13 % methylene blue dye or 91.70 % antibiotic sulfamethoxazole within 24 h. Outdoor validation demonstrates > 99 % pollutant removal efficiency and excellent cycling stability (∼90 % after 10 cycles). This work thus offers a scalable and integrated platform for sustainable water treatment by harmonizing physical separation with chemical decontamination.