Membrane Distillation for Sustainable Water Desalination: A Review of Principles, Materials, and Applications

In response to the growing global water scarcity, research into sustainable desalination technologies has gained significant momentum. Membrane distillation (MD) has emerged as a promising solution, offering several key advantages, including low operating temperatures, high salt rejection, minimal pressure requirements, and reduced brine production. As a non-isothermal process driven by partial pressure differences across a membrane, MD is particularly attractive due to its energy efficiency and compatibility with renewable energy sources, which contribute to lower greenhouse gas emissions. Additionally, MD's lower chemical usage and minimal brine discharge help reduce both marine and chemical pollution, while its modular and scalable design minimizes land use impact, positioning it as a sustainable desalination technology. This review critically examines the latest advancements in MD, considering key operational parameters such as MD configurations (DCMD, SGMD, VMD, AGMD), membrane materials, and membrane types. A comparative analysis of advanced materials used in MD membranes is provided, with a focus on their desalination efficiency. Furthermore, a correlation is established between crucial membrane characteristics like pore size, porosity, water contact angle, and liquid entry pressure (LEP) and their impact on flux performance and wettability is thoroughly evaluated. By offering insights into these key parameters, this article contributes to the ongoing development of more efficient and sustainable desalination technologies.