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

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.