MOHINI SINGH AND PUSHPA SAHNI
Abstract
Microplastic (MP) pollution has emerged as one of the most pressing environmental concerns due to its widespread occurrence in aquatic ecosystems and its potential adverse effects on aquatic organisms, food chains, and human health. Conventional wastewater treatment technologies are not specifically designed to remove these persistent particles, allowing significant quantities of microplastics to enter rivers, lakes, and other freshwater bodies. Existing treatment methods such as membrane filtration, coagulation, and advanced oxidation processes often involve high capital and operating costs, substantial energy consumption, and the generation of secondary pollutants. Consequently, there is an urgent need to develop sustainable, economical, and environmentally friendly technologies for the effective removal of microplastics from contaminated water. Biosorption has emerged as a promising green technology that utilizes natural, low-cost bio sorbents derived from waste agricultural residues, plant biomass, algae, fungi, and bacteria for the adsorption of contaminants. In the present study we have systematically explored the potential of bio sorbents including sugarcane bagasse and drumstick powder, for the removal of microplastics from aquatic environments. To understand the preferential adsorption behaviour of biosorbent in the natural systems, biosorption studies were carried out using synthetic microplastic solution and real Yamuna river water highly polluted with microplastics and other toxic pollutants. The removal efficiencies vary widely, with sugarcane bagasse and drumstick powder achieving 86% and 96.6% microplastic removal under laboratory conditions with synthetic microplastic solution. However, in natural real Yamuna River water sample, the removal efficiencies decreased with sugarcane bagasse (SBP) and drumstick powder (DSP) achieving 83.6% and 94.6% microplastic removal respectively. The bio sorbents (SBP and DSP) in the mixed ratio (1:2) showed excellent synergistic potential of the bio sorbents in removing microplastics from real River water system. Dynamic Light Scattering (DLS) analysis was performed to evaluate the particle size distribution of microplastics before and after adsorption. Field Emission Scanning Electron Microscopy (FESEM) revealed noticeable morphological changes on the biosorbent surface after treatment, confirming the adsorption of microplastic particles. Our findings also suggest that an optimized binary biosorbent system may be a promising and sustainable approach for microplastic remediation in real aquatic environments. Our future research directions would focus on enhancing adsorption efficiency greater than 99%, scaling up treatment processes for real water bodies (rivers, lakes, etc.), and ensuring environmental safety.