Degradation and optimization of microplastic in aqueous solutions with graphene oxide-based nanomaterials

Microplastics can pass through many filtration systems due to their small size, making it difficult to remove them from water. In this study, we investigated the ability of graphene oxide-based metal oxide nanomaterials to degrade microplastic particles from polyethylene in aqueous solutions. The degradation experiments were conducted in a bath system under ultraviolet light to optimize the photocatalyst amount, initial pH, and contact time. After 480 min, a mass loss of 35.66–50.46% was achieved. The degradation kinetics fitted well with a pseudo-first-order model. Degradation was monitored with an optical microscope and FTIR, and the presence of carbonyl groups was recorded to ensure the degradation of the microplastic. The effects of time, nanocomposite to polyethylene ratio, and pH on degradation efficiency were also studied using response surface methodology (Box–Behnken design). The adequacy of the model was evaluated by analysis of variance (ANOVA). Based on the significant terms and model results, an empirical model was developed to theoretically predict the degradation efficiency. Our study demonstrated the potential advantages of graphene oxide-based metal oxide nanomaterials for the removal of polyethylene microplastic particles through an environmentally friendly and highly efficient process.