Hollow glass microspheres incoporated conjugated microporous polymers composite aerogels for sustainable evaporation

Interfacial evaporation technology powered by solar energy is a clean and efficient solution for various scenarios, including seawater desalination, wastewater treatment, and sterilization. However, the intermittent nature of sunlight remains a challenge that must be overcome. In this study, a novel solar interfacial evaporator (CE) was prepared by mixing reduced graphene oxide (RGO) with conjugated microporous polymer hollow spheres (CMP-H) containing the phase change material tetradecanol (TD) and made into a coating, which was coated on an aerogel made of hollow glass microspheres (HGM). The evaporator has an evaporation rate of 1.68 kg·m−2·h−1 at 1 sun irradiation. In addition, our CE demonstrated exceptional continuous evaporation capabilities. For instance, after exposing the CE to two solar intensities for one hour and then turning off, the mass of evaporated water in our CE increased by 0.76 kg·m−2 compared to the CE without phase change material (PCM) until the surface temperature of the CE returned to its initial temperature. Furthermore, to enhance its versatility, the material has been modified to be oleophobic. The modified evaporator material was immersed in oil for 10 min. It was then evaporated in both oily water, achieving an evaporation rate of 1.62 kg·m−2·h−1 at 1 sun irradiation. These distinctive characteristics of our CE not only offer a novel solution to the constraints of the solar interfacial evaporation process caused by the intermittent nature of sunlight but also facilitate the efficient evaporation of oily wastewater, thus expanding the range of solar interfacial evaporation applications.