Comparative Evaluation of Electrocoagulation for the Removal of Polyethylene and Polyvinyl Chloride Microplastics...

The persistence of microplastics in aquatic environments has created a need for effective methods of their removal from wastewater. The physicochemical differences among the polymers can influence their behaviour during wastewater treatment and that poses a polymer-specific removal challenge. This study comparatively evaluates the removal behaviour of polyethylene (PE) and polyvinyl chloride (PVC) microplastics from synthetic wastewater using aluminium-copper electrodes and investigates the effect of electrolysis time on treatment performance. Batch experiments were conducted in a 500 mL reactor at 3 V and 0.012 A for 30, 60, 90 and 120 min. Removal and sludge capture were evaluated gravimetrically, while FESEM-EDS was employed to characterize the recovered microplastics and identify elemental deposition on their surfaces. FESEM-EDS analysis revealed the deposition of aluminium-containing coagulation products on the recovered PE and PVC surfaces following electrocoagulation. Maximum floc removal was obtained at 60 min, reaching 49.72% sludge removal for PE and 27.18% for PVC, with corresponding sludge capture efficiencies of 65.21% and 63.14%, respectively. Electrolysis treatment times below and above 60 min produced unstable flocs that in turn reduced the removal efficiency. The specific energy consumption at the studied condition was ~0.07 kWh m^-3 for both polymers. Overall, the results demonstrate polymer-dependent removal behaviour and highlight the influence of electrolysis time on the treatment performance of PE and PVC microplastics under investigated conditions.