Graphene oxide (GO) has shown great potential as a membrane material due to its unique properties, including high mechanical strength, excellent thermal stability, versatility, tunability, and outperforming molecular sieving capabilities. GO membranes can be used in a wide range of applications, such as water treatment, gas separation, and biological applications. However, the large-scale production of GO membranes currently relies on energy-intensive chemical methods that use hazardous chemicals, leading to safety and environmental concerns. Therefore, more sustainable and greener approaches to GO membrane production are needed. In this review, several strategies proposed so far are analyzed, including a discussion on the use of eco-friendly solvents, green reducing agents, and alternative fabrication techniques, both for the preparation of the GO powders and their assembly in membrane form. The characteristics of these approaches aiming to reduce the environmental impact of GO membrane production while maintaining the performance, functionality, and scalability of the membrane are evaluated. In this context, the purpose of this work is to shed light on green and sustainable routes for GO membranes’ production. Indeed, the development of green approaches for GO membrane production is crucial to ensure its sustainability and promote its widespread use in various industrial application fields.

Graphene oxide (GO) membranes have been proved to be ion-selective thanks to their oxidized functional groups, which are naturally present on its surface. This ion selectivity, together with good mechanical strength, low cost, and simple synthesis, makes GO a great alternative material to conventional costly polymers for the production of ion-exchange membranes. This work focuses on how to produce GO membranes as ion-exchange membranes with a scalable approach and tunable permselectivity. Their physicochemical properties were subsequently investigated by means of selected characterization techniques. Results showed that GO membranes present good ion selectivity and size exclusion towards monovalent cations, reaching a permselectivity of up to 96%. Interestingly, UV-light irradiation of GO membranes can also be proposed as a green reduction method. GO reduction increases the permselectivity due to both a decrease in the dimension of the nanochannels and a reduction in the swelling degree of the membranes. The addition of binders was also investigated to improve the membranes’ mechanical properties. Finally, the ionic resistance of the membranes was measured by impedance spectroscopy, achieving 4.6 Ω cm2, orders of magnitude lower than the state-of-the-art graphene oxide-based membranes.