Modified porous membrane with high solar-to-thermal conversion and oil resistance performance for solar steam generation

Abstract

The utilization of solar steam generator via photothermal conversion is a sustainable and highly sufficient solution for addressing long-standing water scarcity. Due to its extensive optical absorption, dopamine has been considered as a promising photo-thermal conversion material. In this work, by co-depositing Fe3+ and 3-glycidyloxypropyltrimethoxysilane (KH550) with polydopamine (PDA), a high-performance, low-cost, and scalable modified membrane (called PVDF/PDA@KH550@Fe3+) with superior oil resistance was developed. Under one sun illumination, the resulting PVDF/PDA@KH550@Fe3+ membrane generated solar steam with a high efficiency of 90.33% and a high evaporation rate of 1.40 kg m−2 h−1. More importantly, the evaporation rate still performs well even in oil-contaminated water due to the improvement of hydrophilicity and anti-fouling capabilities of the modified membrane. In oil-in-water emulsion, the evaporation rate approaches 1.33 kg m−2 h−1 and the evaporation efficiency reaches 85.49%. This study demonstrated that solar steam generation using PVDF/PDA@KH550@Fe3+ membrane could be a viable option for seawater and oily wastewater purification.