Effects of surfactants on the chemical coagulation of aged microplastics by ultraviolet (UV)

Microplastic is a polymer present in various materials used in everyday life, such as cosmetics and cleaning products. Due to its inadequate disposal, it is found in large quantities in natural and wastewater. Surfactants are mainly used to manufacture detergents and are considered one of the main pollutants found in sewage. Therefore, the main objective of this research is to identify how the surfactants LAS and Tween-20 influence the removal by chemical coagulation of aged microplastics by oxidation using UV light. Removal with the surfactant Tween-20 showed efficiency greater than 90%. The removal with LAS showed a removal of 56.15% for a concentration of 140 mg L-1 of surfactant, due to its anionic character and the system entering into electrostatic repulsion. The structure of the microplastic was characterized by presenting changes after oxidation and chemical coagulation with surfactants, through the reduction of transmittance in the waves presented in the FTIR, instability in the colloidal suspension presented by the PZ, reduction in the size of the colloidal particles and an increase in the aggregated particles sedimented, with greater irregularities and micropores