It is estimated that Reverse Osmosis (RO) desalination will produce, by 2025, more than 2,000,000 end-of-life membranes annually worldwide. This review examines the implementation of circular economy principles in RO technology through a comprehensive analysis of the RO membrane life cycle (manufacturing, usage, and end-of-life management). Future RO design should incorporate a biobased composition (biopolymers, recycled materials, and green solvents), improve the durability of the membranes (fouling and chlorine resistance), and facilitate the recyclability of the modules. Moreover, proper membrane maintenance at the usage phase, attained through the implementation of feed pre-treatment, early fouling detection, and membrane cleaning methods can help extend the service time of RO elements. Currently, end-of-life membranes are dumped in landfills, which is contrary to the waste hierarchy. This review analyses up to now developed alternative valorisation routes of end-of-life RO membranes, including reuse, direct and indirect recycling, and energy recovery, placing a special focus on emerging indirect recycling strategies. Lastly, Life Cycle Assessment is presented as a holistic methodology to evaluate the environmental and economic burdens of membrane recycling strategies. According to the European Commission’s objectives set through the Green Deal, future perspectives indicate that end-of-life membrane valorisation strategies will keep gaining increasing interest in the upcoming years.

A thin and robust organic solvent cation exchange membrane (CEM) was successfully fabricated for the first time using dissolved Kevlar aramid nanofibers as the casting solution and 4-aminobenzenesulfonic acid (ABS) as the negatively charged functional group via an amide condensation reaction. The synthesized Kevlar CEMs inherited the advantages of Kevlar aramid nanofibers, achieving an excellent ion exchange capacity as high as 1.0 mmol g⁻¹ (with 22.5% water content), a low swelling rate of ∼2.0%, a low membrane surface electrical resistance of 2.95 Ω cm², a high mechanical strength of over 9.0 kPa of a water column (the membrane thickness was 5.0 μm) and a high membrane limiting current density of 45.0 mA cm⁻² (in 0.1 M NaCl solution). In electrodialysis, the Kevlar CEMs demonstrated an exceptional cation/anion separation in dilute and concentrated cells. After 72 h of immersion in aqueous acetone solutions (25%, 50%, 75% and 100%, V_acetone/V_water), the resulting membranes still exhibited a significant separation in ED. This work demonstrates the promising potential application of Kevlar aramid nanofibers in the preparation of organic solvent CEMs.