Low-cost quartz filtration for oil–water separation: Efficiency, morphology, and scalability

Oil–water separation remains a pressing environmental and industrial challenge, particularly in regions needing affordable and scalable solutions. This study evaluates raw quartz as a low-cost filtration medium for oily wastewater. Morphological analysis by scanning electron microscopy (SEM) revealed rough surfaces with micro-asperities that promote oil droplet entrapment, while Raman spectroscopy confirmed quartz’s crystalline stability. Oil and grease analysis showed a reduction from 59,201.7 mg/L in the influent to 64.8 mg/L in the effluent, achieving ~99.9% removal efficiency. Two novel indices were developed for performance evaluation: the Quartz Separation Factor (QSF), which captures oil-capturing capacity, and the Upscaling Performance Index (UPI), which quantifies scalability. Results indicated strong separation efficiency across laboratory, pilot, industrial, and municipal levels, with removal efficiencies ranging from 85–98%. These findings position quartz as a sustainable and cost-effective alternative to conventional filtration media. Future work will investigate regeneration cycles, hybrid system integration, and field-scale validation to optimize deployment for industrial and municipal wastewater treatment.