Does Electrocoagulation Provide an Efficient Solution for Removing Microplastics from Synthetic Seawater?

Microplastics (< 5 mm) are widely present in seawater due to extensive plastic use, thus posing a serious risk to marine ecosystems. Electrocoagulation has emerged as an effective removal method, with its success influenced by particle properties and operational parameters. In this study, electrocoagulation was used to remove glitter-type microplastics from synthetic seawater. Particle size was determined using optical microscopy, and seawater composition was characterised by XRF analysis. Removal efficiency was evaluated using aluminium electrodes (AA6063), with a spacing of 2.5 cm, a constant current of 0.3 A, pH values of 5.5–7.5, and a treatment duration of 15–120 min. Removal efficiency increased with treatment duration and reached 62.5 %, 84.14 %, 75.82 %, and 77.12 % after 0.5 h, 1 h, 1.5 h, and 2 h, respectively. Optimal conditions were achieved after one hour, when a maximum efficiency of 84 % was recorded at pH 5.95 and salinity 28.9 ppt. The results confirm the potential of electrocoagulation, and contribute to a better understanding of the mechanisms of microplastic removal from synthetic seawater.