Hollow ZIF-67-loaded sandy sediment for enhanced solar-driven water evaporation and PMS-activated pollutant degradation

Abstract

The integration of solar interfacial evaporation technology with pollutant degradation functions is crucial for addressing current challenges in freshwater scarcity and water pollution, but significant hurdles remain. In this study, hollow ZIF-67 loaded sandy sediment (H-ZIF-67@SS) was synthesized to construct a bifunctional reactor combining solar evaporation and PMS-based advanced oxidation processes. The results showed that the unique structure of H-ZIF-67 enhanced the multiple reflection effect and prolonged the contact time of light within the cavity, while inhibiting the escape of light from the cavity, thereby significantly improving light absorption and photothermal conversion at the evaporation interface. In addition, the oxygen-containing functional groups on the surface of H-ZIF-67@SS and the nanoscale confinement effect suppressed the hydrogen bonding interactions between water molecules, effectively reducing the enthalpy change of water evaporation. Consequently, the H-ZIF-67@SS exhibited an excellent water evaporation rate (1.62 kg·m⁻²·h⁻¹) and solar evaporation efficiency (93.12 %). Moreover, the nano-confined spatial structure enriched with Co-N active sites allows H-ZIF-67@SS to efficiently activate PMS and degrade the typical pharmaceutical contaminant carbamazepine (CBZ) simultaneously during the water evaporation process. Experimental results under various water environmental conditions further showed that this dual-function solar evaporation system displayed outstanding tolerance to different water environments, indicating its promising potential for practical applications.