Promoting removal of polystyrene microplastics from wastewater by electrochemical treatment

Microplastics (MPs) are emerging contaminants with potential ecological and human health impacts, necessitating effective remediation technologies. Recently, electrochemical oxidation (EO) has garnered attention as a suitable method for treating water contaminated with MPs. However, research on EO's effectiveness remains limited. This study investigates the EO treatment of 1.0 μm polystyrene (PS) MPs in a lab-scale reactor using boron-doped diamond (BDD) electrodes. Various operational parameters, such as electrolyte composition and concentration, initial PS concentration, and applied current density, were examined for their impact on PS degradation efficiency. Optimal degradation was achieved using Na 2 SO 4 (0.02 M) as a supporting electrolyte, an initial PS concentration of 60 mg L −1 , and an applied current density of 60 A/m 2 for 5 h. The degradation mechanism likely involved indirect EO through the formation of highly oxidizing radicals rather than direct EO between the anode and PS molecules. High current densities induced morphological changes in the PS microparticles. Fourier transform infrared spectroscopy confirmed new functional groups on the PS surface, indicating oxidation. These findings suggest that EO using BDD electrodes is a promising approach for treating microplastic-polluted water. However, further studies are needed to optimize the process, particularly concerning power requirements, electrode costs, and reactor configuration. • Removal of polystyrene MPs by EO process using BDD electrodes was investigated. • PS removal efficiency increased with increasing applied current density. • Self-combination reactions among the electrogenerated SO 4 •− decreased PS removal. • SEM analyses showed morphological changes and deformations of PS microparticles. • FTIR analyses suggested formation of additional functional groups on the plastic surface.