MXene-PVA@AG aerogel evaporators with high stability and oil resistance are used for High-efficiency solar interfacial evaporation and wastewater treatment

Directionally aligned MXene-PVA@AG aerogel with anisotropic water channels. • 97.22% solar-thermal conversion efficiency under 1 sun. • Stable evaporation for 7 days and under extreme pH conditions. • Excellent oil-resistance in oil-water emulsion systems. • 99% removal of metal ions and efficient dye purification. Solar interfacial evaporation has emerged as a potential solution for wastewater treatment. In this study, an MXene-PVA@AG composite aerogel evaporator (PAMX) with vertically oriented channels is fabricated via directional freeze drying. Results show that the PAMX evaporator exhibits an evaporation rate of 1.82 kg·m −2 ·h −1 under 1 sun illumination, corresponding to a photothermal conversion efficiency of 97.22%. Furthermore, the PAMX evaporator exhibits remarkable purification effects on metal salt ions and organic dyes, such as MO and MB, and sustain strong evaporation performance in oil-containing systems. Overall, this work presents a feasible strategy for treating complex water bodies. Scheme 1. Flow chart for the preparation of PAMX aerogel. Solar interfacial evaporation has emerged as a potential solution for wastewater treatment due to its high energy utilization efficiency. However, evaporators often face problems such as limited photothermal conversion capacity, poor stability, and insufficient water supply. In this study, an MXene-PVA@AG composite aerogel evaporator (PAMX) with vertically oriented channels is fabricated via directional freeze drying. Utilizing the broad-spectrum absorption of MXene and the continuous water supply from the PVA/AG porous network, synergistic regulation of solar absorption, localized heat management, and water transport is achieved. Results show that the PAMX evaporator exhibits an evaporation rate of 1.82 kg·m −2 ·h −1 under 1 sun illumination, corresponding to a photothermal conversion efficiency of 97.22%, while maintaining stable output under different light intensities. Owing to the excellent photothermal conversion performance of MXene, the PAMX evaporator exhibits remarkable purification effects on metal salt ions and organic dyes, such as MO and MB. Furthermore, using polyvinyl alcohol and agarose as matrix materials endows the evaporator with good structural stability, allowing it to maintain high evaporation rates even after one week of continuous evaporation, and sustain strong evaporation performance in oil-containing systems. Overall, this work presents a feasible strategy for the design of efficient, environmentally friendly, and pollution-resistant interfacial evaporators for treating complex water bodies. Download: Download high-res image (161KB) Download: Download full-size image