Rhamnolipid: nature-based solution for the removal of microplastics from the aquatic environment

Over the past two decades, research into the accumulation of small plastic particles and fibers in organisms and environmental settings has yielded over 7,000 studies, highlighting the widespread presence of microplastics in ecosystems, wildlife, and human bodies. In recent years, these contaminants have posed a significant threat to human, animal, and environmental health, with most efforts concentrated on removing them from aquatic systems. Given this urgency, the purpose of this study was to investigate the potential of rhamnolipid, a biosurfactant, for the removal of microplastics from water. Specifically, this study evaluates the effects of water matrix, initial pH of the solution (7.0, 7.5, 8.0, 8.5, 9.0, 9.5, and 10.0), concentrations of alum (5, 10, 20, 30, 40, and 50 mg/L), and concentrations of rhamnolipid (1, 5, 10, 20, 40, 80, and 100 mg/L). Optimum removal was achieved at alum and rhamnolipid concentrations of 5.0 mg/L and 1.0 mg/L, respectively, with a solution pH of 8.0. In both types of water tested, a removal efficiency of about 74% was determined, indicating the potential of rhamnolipid as a nature-based solution to control microplastic pollution in surface waters.