Solar/microwave-driven composite membrane evaporation and its application in seawater desalination

Abstract

Increased economic growth and population expansion has heightened the demand for water resources, leading to escalating levels of water scarcity. Sustainable seawater desalination methods, powered by renewable energy, offer promising solutions to the long-standing global water shortage. This study presents a method for seawater desalination that employs eco-friendly materials. The approach involves utilizing metakaolin-based porous geopolymer (GP) as the base material, and depositing graphene oxide (GO) to create a graphene oxide geopolymer (GOGP) composite membrane. The membrane undergoes in-situ self-reduction to obtain reduced graphene oxide geopolymer (rGOGP). The study examines the composition, microstructure, and water evaporation performance of the composite membrane under both solar/microwave-driven. The results show that, under microwave conditions with a frequency of 2450 MHz and power of 400 W, the evaporation rate can reach up to 4.13 kg·m⁻²·h⁻¹, doubling the evaporation rate achieved through solar-driven evaporation at an equivalent efficiency level. Furthermore, the evaporation rate of the composite membrane remains consistent when exposed to high-concentration saltwater of 15 wt%. Notably, the removal rates of Na⁺, K⁺, Ca²⁺, and Mg²⁺ all exceed 99 %, meeting the drinking water requirements established by the World Health Organization. This study provides a novel approach to seawater desalination utilizing environmentally friendly materials and clean energy sources.