Sonoactivated Nanomaterials: A potent armament for wastewater treatment

The world is currently facing a critical issue of water pollution, with wastewater being a major contributor. It comes from different types of pollutants, including industrial, medical, agricultural, and domestic. Effective treatment of wastewater requires efficient degradation of pollutants and carcinogens prior to discharge. Commonly used methods for wastewater treatment include filtration, adsorption, biodegradation, advanced oxidation processes, and Fenton oxidation, among others.The sonochemical effect refers to the decomposition, oxidation, reduction, and other reactions of pollutant molecules in wastewater upon ultrasound activation, achieving pollutants removal. Furthermore, the micro-flow effect generated by ultrasonic waves creates tiny bubbles and eddies. This significantly increases the contact area and exchange speed of pollutants and dissolved oxygen, thereby accelerating pollutant degradation. Currently, ultrasonic-assisted technology has emerged as a promising approach due to its strong oxidation ability, simple and cheap equipments, and minimal secondary pollution. However, the use of ultrasound in wastewater treatment has some limitations, such as high energy consumption, lengthy treatment time, limited water treatment capacity, stringent water quality requirements, and unstable treatment effects. To address these issues, the combination of enhanced ultrasound with nanotechnology is proposed and has shown great potential in wastewater treatment. Such a combination can greatly improve the efficiency of ultrasonic oxidation, resulting in an improved performance of wastewater purification. This article presents recent progress in the development of sonoactivated nanomaterials for enhanced wastewater disposal. Such nanomaterials are systematically classified and discussed. Potential challenges and future prospects of this emerging technology are also highlighted.