Analysis and removal of free fatty acid and peroxides from waste cooking oil using Fuller’s earth-China clay adsorbent by titration methods

The current study investigated the suitability of Fuller’s Earth-China Clay (FECC) as an adsorbent for removing toxicants, including free fatty acid (FFAs) and peroxides, from waste cooking oil (WCO). Key quality indicators, such as FFAs, peroxide value (PV), and color change, were measured to evaluate the effectiveness of using indigenous FECC material. FECC was activated using sodium hydroxide (NaOH) and acetic acid to enhance its adsorption ability, surface area, and active sites. The structural and functional properties of activated FECC were characterized using techniques like Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), BET surface area analysis, and scanning electron microscopy (SEM). The FFA content in the WCO reduced from 2.98 % to 0.91 % after being treated with activated FECC, having a reduction percentage of 69.64 %, and the peroxide value reduced from 5.5 meq/1000 g to 1.0 meq/1000 g, thus, having a reduction percentage of 81.82% and RSD<2%. There was a marked increase in the oil's quality, with significant absorption capacity, with about 80-85% of the oil purified. These results show that activated FECC can be potentially used as an efficient, environmentally friendly, and economical solution for purifying waste cooking oil. This research provides a promising method to enhance oil quality and a step towards addressing food safety challenges, with the potential for broader application of oil refining in the food sector.