Membrane distillation (MD) is a thermally driven separation method for desalination that uses low-grade heat and has a high salt rejection rate. It has considerable potential to support addressing the world's water shortage as part of Sustainable Development Goal 6 (SDG 6) on access to clean water. Recent MD studies have transitioned from traditional methodologies to sustainable practices, utilizing sustainable materials in their fabrication techniques. Nonetheless, current reviews lack a comprehensive framework that integrates material sustainability, membrane fabrication, addressing techno-performance trade-offs, and environmental implications in membrane development for producing hydrophobic membranes for the MD desalination process. This paper addresses the existing gap by examining the "greening" of MD through a bibliometric analysis and a literature review. The study initially defines pinpointing emerging trends in eco-fabrication techniques that are shifting from non-toxic solvents to green solvents, as well as the potential of biopolymers to substitute for petroleum-based polymers. It then critically examines the trade-offs between eco-friendly design and techno-performance, with a particular emphasis on preserving wetting resistance and flux. The review also looks at the environmental footprints of greening MD processes using Life Cycle Assessment (LCA). Finally, a holistic framework is proposed to guide the future development of sustainable hydrophobic membranes for the MD process, ensuring that next-generation desalination technologies are both high-performing and environmentally benign. • A comparative framework links green-solvent properties directly to MD performance outcomes. • Engineering biopolymer hydrophobicity using benign fillers and surface architecture with wetting-onset insights. • Quantitative benchmarking of LEP-flux-rejection trade-offs and durability under hypersaline and organic-laden feeds. • LCA reveals that green solvents and biopolymers do not automatically ensure a low environmental footprint. • A decision roadmap integrating material selection, scalability, performance evidence, and footprint/cost for sustainable MD.
Khotimah et al. (Fri,) studied this question.