Electrochemical Degradation of PET Microplastics and Its Mechanism

Polyethylene terephthalate (PET) is a common packaging plastic that degrades extremely slowly in the environment, with low efficiency in both photodegradation and biodegradation. This study investigates the electrochemical degradation of PET MPs. First, the electrochemical degradation process of PET MPs in aquatic environments was examined. Under the condition of no additional catalyst, the degradation efficiency was measured using a weight loss method, and more efficient electrolysis efficiency was obtained through orthogonal experiment. After 6 h of electrolysis, the weight loss was as high as 68%. The analysis shows that electrolysis temperature is a more critical factor than current density, pH, and surfactant concentration. Second, by studying the changes of soluble organic pollutants in PET MPs and electrolyte with time and temperature during the reaction process, indicating that the increased crystallinity of PET MPs limits the enhancement of degradation efficiency. Furthermore, it was pointed out that the oxidation–reduction reaction of the electrode reaction was enhanced by the surfactant. Combined with the active species analysis, hydroxyl radicals (•OH) and sulfate radicals (SO4•–) play a role in the degradation of PET MPs. The mechanism of electrochemical degradation of PET MPs was hypothesize. The electrochemical degradation method used in this study is characterized by a short treatment time and high efficiency, providing a feasible solution for improving microplastic degradation efficiency, and also provides an effective reference for electrochemical degradation of insoluble pollutants in water.