A Novel Application of Ultrasound for Removal of Aqueous Microplastics

Abstract

Microplastics (MPs) pollution has become an urgent global environmental issue due to its widespread distribution and persistence in aquatic ecosystems. Although there is growing interest in remediation technologies, effective methods for microplastic (MP) removal remain limited. In this study, we report for the first time the application of bath-type ultrasonication for MP remediation, representing a novel and chemical-free approach in this field. Results demonstrated that ultrasonic treatment effectively removed MPs from water within 5 s, with removal efficiency positively correlated with particle concentration and strongly influenced by material density─achieving over 90% removal for high-density polyvinyl chloride (PVC), while only ∼13% for low-density polyethylene (PE). Interestingly, under the tested power level of 500 W, the removal efficiency was largely independent of treatment duration, and no significant difference was observed between 200 and 500 W. The removal mechanism was attributed to ultrasound-induced particle motion that facilitated agglomeration and subsequent sedimentation. This pioneering work fills a critical knowledge gap in the ultrasonic remediation of MPs pollution and introduces a new physical treatment method for addressing this pressing environmental challenge.