Removal of Polyethylene Microplastics Using Wood Sawdust

Microplastics (MPs) increasingly threaten environmental and human health due to their widespread presence in aquatic, terrestrial, and atmospheric systems. Yet scalable, cost-effective removal technologies remain limited for MPs despite rising concern. This study investigated the use of wood sawdust, both unmodified (UMSD) and chemically modified (MSD) with tannic acid and ferric chloride (FeCl₃), as removal technologies for polyethylene (PE) MP remediation in aquatic systems. MSD was synthesized via a simple aqueous-phase reaction, enhancing its surface functionality and increasing its negative surface charge. In a fixed-bed column setup, both UMSD and MSD achieved over 99% removal efficiency for pristine PE MPs, sized 40 and 150 μm. Physical entrapment was the dominant mechanism of capture, with van der Waals forces likely contributing secondarily. The comparable performance of UMSD suggests that lignocellulosic biowaste holds potential for MP capture. These findings support the development of low-cost, regenerative materials for water purification and warrant further study of their interactions with broader contaminant classes.