Exploring nanostructured membranes and hybrid bioelectrochemical systems in microbial desalination cells for sustainable water-energy recovery

The Microbial Desalination Cell (MDC) is a system designed to augment traditional desalination techniques. This system enables the concurrent treatment of wastewater, electricity generation, and desalination. Through the simultaneous treatment of wastewater, reduction of salinity, and recovery of bioelectrochemical energy, MDCs have the potential to contribute to SDG 6 (Clean Water and Sanitation), particularly through improved wastewater treatment and water reuse, and to SDG 7 (Affordable and Clean Energy) through energy recovery and reduced external energy demand. Despite the progress recorded, they suffer some setbacks. Since its inception, MDC technology has rapidly advanced in design and use; yet, it has several challenges, including membrane fouling and resistance, ion selectivity, and system integration, which still render it impractical for large-scale implementation. Consequently, this review seeks to advance the field by methodically suggesting two suggestions for improvement: the integration of hybrid bioelectrochemical systems and nanostructured ion exchange membranes to improve water-energy recovery capabilities. Firstly, the basic mechanisms, system configurations, and important performance measures of MDCs are briefly examined to provide an overview of the operational environment that controls desalination and power generation. Membrane nanostructuring approaches are extensively highlighted, with a detailed explanation of surface-functionalized interfaces aimed at mitigating biofouling. Furthermore, this review emphasises performance improvements attained by the strategic integration of reverse osmosis fuel cells, ion exchange resins, microbial electrolysis cells, and solar-assisted systems, in addition to material-level advancements.