Regeneration of used frying oils using adsorption processing

Abstract

AbstractOur study was carried out to improve the quality of used frying oils and to assess the feasibility of recycling by using an adsorption process. Experiments with used frying oils were conducted with a column method using four adsorbents, silica gel, magnesium oxide, activated clay, and aluminum hydroxide gel. Silica gel offered the most effective overall improvement in the quality of used frying oil of the four adsorbents. Although the limiting adsorption capacity of silica gel, as obtained from the Langmuir model, was 219 mg/g for total polar materials (TPM), the experimental maximal adsorption capacity of silica gel for TPM was 337 mg/g. For commercial application, silica gel used in the process must periodically be reactivated. Reactivated silica gel also was effective to some extent in the adsorption process, although the adsorption capacity decreased by 20–50%.