Critical review on advances and perspectives of ultrasound assisted membrane technologies for water purification

In the previous decades, membrane-based separation technologies have found numerous applications in various industries. However, efficient membrane system operation necessitates cost-effective, environmentally friendly means with reduced consumption of chemicals and energy to address restrictions by polarization and membrane fouling. Ultrasound stands out as a distinct approach among current methods for manipulating the physics and chemistry of complex feed fluids in membrane filtration processes, exhibiting satisfactory performance in mass transfer and membrane cleaning. This review provides an overview of the current academic and practical insights, emphasizing physicochemical strategies for diverse ultrasound-assisted membrane systems. The objective is to summarize recent literature related to the use of ultrasound as kernel to improve the separation performance. Based on the technical perspective employing physics and chemistry principles in ultrasound for the liquid transfer, advanced ultrasound-assisted pressure-driven membrane system strategies, compatible ultrasonics applications in membrane bioreactors, and emerging ultrasound-assisted vapor pressure-driven membrane distillation are discussed. The study also covers theories and applications pertaining to acoustic cavitation, cavitation collapse, standing waves, and sonochemical radical effects. Finally, the limitations of current status are elaborated, and the deficiencies of present technologies are reflected upon for the sake of inspiration for novel ultrasound assisted membrane technologies development.