MoS2@ZIF-8-based aerogel with multiscale biomimetic structure achieving all-day desalination and wastewater purification

Abstract

In emerging freshwater generation strategy, solar driven evaporation technology has been brought into focus owing to its non-pollution and facile facilities. However, maintaining high freshwater yield remains a challenge under natural circumstances. Herein, MoS2@ZIF-8-based aerogel featuring a lotus root hourglass-shaped structure (denoted as LMZA) for efficient freshwater production via hybrid energy harvesting is ingeniously devised. After being integrated with metallic 1 T phase MoS2 and a vertically aligned porous structure, LMZA not only achieves an outstanding evaporation rate at different incident angles and intensities, but also utilizes wind or environmental energy for evaporation. More importantly, the proposed LMZA also achieved a fast evaporation rate of 8.47 kg m-2h−1 under 4.0 m s−1 without solar irradiation, which fully eliminated the impact of solar intermittency. Afterward, LMZA with a cross-scale hierarchical structure for desalination exhibits an evaporation rate of up to 2.08 kg m-2h−1 under one sun irradiation in 20 wt% brine, and possesses exceptional adaptability and stability. Besides, another advantage of LMZA is the effective purification of cadmium-containing wastewater through water evaporation and in situ adsorption. The removal efficiency is 74 % under one sun irradiation, and the condensed water with undetected Cd(II) heavy metal ions was obtained. More importantly, combined with ambient factors such as wind and ambient temperature in the natural environment, the home-made device achieves all-day freshwater generation with a daily yield of 27.08 kg m−2. The investigation of the device and LMZA pioneers a novel design concept for high yield freshwater generation in practical applications.