Efficient removal of polyethylene and polyvinyl chloride microplastics from water using a modified coagulation process supported by the addition of a surfactant

Polish National Science Centre

In water and wastewater, microplastics (MPs) are regarded as one of the emerging contaminants. Understanding how microplastics are removed in the current wastewater and water treatment system is important. The purpose of this study was to investigate how the coagulation process affected the removal of two different types of microplastics from tap water, including polyethylene (PE) and polyvinyl chloride (PVC) and their mixture. Regarding the effectiveness of microplastic removal, the effects of different types of coagulants, such as AlCl3 ·6H2 O and FeCl3 ·6H2 O, doses of coagulants, solution pH, microplastic concentration, and water characteristics, as well as addition of surfactant sodium dodecylbenzenesulfonate (SDBS), were thoroughly examined. The neutral pH value of tap water and the coagulant dose of 0.05 g/L resulted in the highest removal of MPs. When tap water was compared with ultrapure water, tap water with humic acid, and tap water with NaCl, the best coagulation efficiency was observed in tap water. The effectiveness of PE and PVC removal in both Al salt and Fe salt coagulation was greatly improved by the addition of SDBS. The elimination of PE and PVC was more than 90% successful for both tested coagulants at a dose of 0.025 g/L. Optimal parameters were also used to remove the analyzed materials in the mixture of PE and PVC. The efficiency of microplastic removal with the use of Al and Fe coagulants and SDBS was obtained at the level of 95.92% and 98.9%, respectively