Sorption of thiamin (vitamin B1) onto micro(nano)plastics: pH dependence and sorption models

As the carrier of various inorganics and organics from various media, micro(nano)plastics have an impact on the environment and human health. Recently, many studies have examined the sorption of various organics including antibiotics. However, while vitamins have critical roles in the environment and microsystems from humans to plant life, the sorption of vitamins onto micro(nano)plastics are still uninvestigated. Therefore, the aim of this study was to examine the sorption of vitamin B1 onto various micro(nano)plastics from food packages under different pHs using batch technique; sorption kinetics and isotherms models were investigated as well. The results indicated that higher capacities were obtained between 360 min to 1440 min in polypropylene and polyethylene micro(nano)plastics, and similar kinetic behaviors observed in different pHs. However, the sorption responses (sorption capacity, equilibrium time) of polyethylene terephthalate and polystyrene were varied. The sorption kinetics between vitamin B1 and micro(nano)plastics showed that the pseudo-first-order model was better to fit for polyethylene terephthalate and polystyrene compared to the pseudo-second-order kinetics, however it was changed for polypropylene and polyethylene. Moreover, the obtained results suggest a complex nature of vitamin B1 sorption, including both chemical and physical sorption occur under various pHs and polymer types.