A review of MXene-based sonocatalytic degradation for water purification

MXene-based sonocatalysis is an emerging advanced oxidation process for removing recalcitrant dyes, endocrine-disrupting compounds, and pharmaceuticals from water, where conventional treatment may achieve very limited removal by coagulation and chlorination. This review was motivated by the need to clarify how MXene structure, water quality, and ultrasound conditions control contaminant degradation, mineralization, stability, and practical applicability. We hypothesized that MXenes enhance sonochemical oxidation by promoting pollutant adsorption, cavitation, charge separation, and reactive oxygen species generation, particularly in engineered heterostructures. Recent studies were critically analyzed with respect to MXene composition and surface chemistry, ultrasound frequency and power, water-matrix effects, degradation mechanisms, hybrid sonophotocatalytic/sono-Fenton processes, mineralization, and catalyst reusability. MXene-based systems achieved up to >99% antibiotic removal, approximately 70% acetaminophen mineralization, and 80% rhodamine B degradation in 20 min; ^•OH and O₂^•- predominantly governed oxidation, while several catalysts retained more than 80-90% removal over five cycles and exhibited limited leaching. Overall, MXenes provide a versatile platform for efficient water purification by integrating conductive, adsorptive, cavitation-nucleating, and interfacial charge-transfer functions, although real-water validation, standardized evaluation, energy-efficient reactor scale-up, and toxicity assessment remain necessary for environmental deployment.