Abstract
Being a basic element for the every existence of any form of life on earth, water is one of the most abundant resources on earth, covering three-fourth of the planet's surface. However, there is a shortage of freshwater in many areas worldwide. Desalination seems to be the most suitable solution. Major conventional desalination processes, such as distillation and reverse osmosis, consume a large amount of energy derived from oil and natural gas as heat and electricity, which is responsible for harmful CO2 emission. Solar desalination has emerged as a promising renewable energy-powered technology for producing freshwater. Solar membrane distillation (MD) is the best option in decentralized regions with scattered population and lack of infrastructures jointly with hard climate conditions make it difficult or at least not cost-effective to scale down bigger desalination technologies, such as RO or MSF, designed for very big water productions. Moreover, MD compared to conventional thermal desalination is less demanding regarding vapor space and building material's quality leading to potential lower construction costs. The aim of this paper is to present the state-of-the-art review of developments in solar MD technology. In this review, membrane configurations, module design, and recent applications of this technology were discussed in detail.