An Efficient and Low-Cost Hybrid Methodology for Removal of Nano-plastics in High-Strength Wastewater towards Agricultural Reuse

چکیده مقاله

The pervasive contamination of water resources by nano-plastics and polymeric nano-fragments, particularly from industrial sources such as polyester manufacturing, represents a critical and escalating environmental challenge. These nano-scale pollutants, originating from high-strength wastewater (COD >100,000 mg O₂/L), exhibit unique threats due to their high mobility, large surface area, and potential for bioaccumulation, posing direct risks to aquatic life, soil health, and agricultural safety. Conventional wastewater treatment processes are largely ineffective at removing these persistent nano-polymers. This study presents a novel, low-cost hybrid methodology specifically designed for the efficient removal of nano-plastic contaminants and their dissolved organic precursors from polyester wastewater. The process integrates a one-step distillation unit with a subsequent granular activated carbon adsorption system. The thermal stage not only separates volatile organics but also promotes polymerization and agglomeration reactions, effectively transforming soluble nano-polymeric precursors and oligomers into larger, more adsorbable species. The adsorption stage then captures these agglomerated compounds and remaining nano-scale contaminants. This synergistic approach achieved a 95% reduction in chemical oxygen demand (COD) and significantly altered the wastewater's pollutant profile, as confirmed by GC-MS analysis. Molecular dynamics simulations provided fundamental insights, revealing that the removal efficiency is governed by the solubility parameter (δ), where pollutants with lower δ values exhibit a higher affinity for adsorption onto the carbon surface. The treated effluent, characterized by a neutral pH and a substantially reduced organic load, demonstrates strong potential for safe agricultural reuse, addressing the urgent need for practical solutions at the intersection of industrial wastewater management, nanopollutant mitigation, and sustainable water resource recovery. This work establishes a scalable and efficient physical treatment framework for combating nano-plastic pollution from industrial sources.