Engineering trace AuNPs on monodispersed carbonized organosilica microspheres drives highly efficient and low-cost solar water purification

Abstract

Gold nanoparticles (AuNPs) have been recently utilized in solar water evaporation due to their favorable photothermal conversion efficiency resulting from localized surface plasmon resonance (LSPR). However, the exorbitant price of Au severely hinders its extensive application for water purification in practice. This work reports a simple interfacial reaction for in situ engineering a trace amount of AuNPs on carbonized organosilica (c-silica) microspheres toward water desalination and decontamination. With the deposition of AuNPs@c-silica hybrids onto filter fiber paper (FFP), the as-prepared AuNP@c-silica/FFP (GSP) membrane can achieve a superior solar thermal conversion efficiency up to 94.6% under only one sun irradiation with Au usage of only 25 μg cm⁻². The high solar thermal conversion efficiency of the GSP membrane can be attributed to the synergistic photothermal effect between AuNPs and c-silica, which is verified by the COMSOL simulation. The GSP membrane also possesses a high elimination capability that allows it to produce drinkable water from seawater and wastewater. Additionally, the reliability evaluation indicates that the microstructures and performance of AuNPs@c-silica hybrids are invariant before and after reclamation. This technically easy route offers a low-cost, reusable, and highly efficient membrane for solar water purification that can be envisaged for practical use.