MXene-Based Sustainable Semiconducting Materials for Integrated Wastewater Treatment and Energy Recovery Applications.

Wastewater treatment and sustainable energy recovery are two key approaches to achieve circular water management and carbon neutral technologies. The semiconducting MXene-based materials have gained widespread attention as multifunctional platform materials because of their easily tunable electronic structures, high number of surface functional groups, and efficient charge-transfer properties. The crystal chemistry, bandgap engineering, charge transport mechanisms, and rational design of semiconducting MXenes and their heterostructures are summarized. Recent developments in wastewater treatment applications including adsorption, photocatalysis, electrocatalysis, membrane separation, and capacitive deionization are critically evaluated, as well as energy recovery technologies like hydrogen production, microbial electrochemical systems, nutrient recovery, and integrated water-energy conversion. The practical implementation is further assessed by reactor engineering, performance benchmarking, stability, sustainability, and materials discovery by artificial intelligence. Last but not least, important challenges and future research directions are presented to accelerate the development of semiconducting MXene-based technologies for efficient wastewater and energy-positive environmental systems.