Purification of waste cooking oil-derived biodiesel using pomegranate peel bio-adsorbent: A sustainable approach

This study investigates the purification of biodiesel derived from waste cooking oil, synthesized using an alkaline-modified g-C₃N₄ nano-catalyst, through dry washing with a bio-adsorbent prepared from pomegranate peel (PP) powder. The performance of PP was compared with that of the commercial adsorbent Amberlite BD10 dry, using various concentrations (2 %, 3 %, 4 %, and 5 % w / v ). Characterization of the PP powder was conducted using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). FTIR analysis of the used PP revealed the emergence of new peaks at 1740 cm −1 and 1000–1300 cm −1 , along with increased intensity near 2900 cm −1 , indicating the adsorption of esters, hydrocarbons, and oxygenated compounds. SEM imaging showed the presence of surface-adsorbed particles post-purification, while EDS analysis confirmed increased carbon and potassium levels with a notable reduction in oxygen content, validating the adsorption of both organic and inorganic impurities. Physicochemical property analysis of biodiesel before and after purification further supported the effective adsorption capacity of PP powder. These findings establish PP as a viable, sustainable, and economical alternative to synthetic adsorbents for biodiesel purification.