The 10th International Conference on Water Resource and Environment (WRE 2024)

Abstract: The microplastics (MPs) in submicron range produced by anthropogenic and natural fracturing processes are emerging contaminants. Due to the small size, the treatment of submicron MPs by membrane processes necessitates membranes with a smaller cutoff, which not only requires greater pressure gradient but suffers from clogging. This study develops an electrophoretic separation system that utilizes the intrinsic negative surface charge of MPs to produce dilute stream free from submicron plastics particles. The separation relies on electrophoresis, at which an electric field was applied to produce an electrostatic force to counterbalance the drag force of permeation stream, preventing MPs to travel into dilute stream. Thus, the critical electric field (Ec) for complete removal of MPs could be estimated based on hydraulic condition, zeta potential, and size of MPs. The electrophoretic separation of MPs was investigated under various hydraulic condition, electric field, particle size, and initial concentration, verifying that the steady-state removal of MPs could achieve 99% at E > Ec. The distribution of MPs during electrophoretic separation was analyzed by control-volume approach, enabling the description of removal efficiency by hydraulic condition, applied and critical electric field. Ultimately, the specific energy consumption of electrophoretic separation was estimated to be comparable to conventional membrane processes.