Effect of Acid Pretreatment of Coconut Pulp on Peroxides Removal in used Frying Oil

Abstract

Oxidation process during frying oil produce many compounds such as peroxides which are detrimental to health. One way to improve quality of used cooking oil is using adsorbent. Coconut pulp is one of adsorbent because contain 37.1 % cellulose. In this research, coconut pulp treated by hydrochloric acid (HCl) 0.1 N and acetic acid (CH3COOH) 0.1 N. Coconut pulp before and after treated by acids were analyzed using FTIR. The adsorption process of peroxides in used cooking oil was carried out using coconut pulp treated by acids. Then, adsorption isotherm and kinetics of coconut pulp treated by acids were analyzed. The results showed that after treated by HCl and acetic acid, some wavelength and intensity of functional groups change and present new functional group. HCl and acetic acid may decomposed of mineral salts in coconut pulp.The highest percentage reduction of peroxide value is obtained after adsorption onto HCl treated coconut pulp while percentages of reduce is 56.206%. The adsorption of peroxides using coconut pulp treated by HCl and acetic acid are included to pseudo-second-order and were well described with Freundlich isotherm model. Adsorption capacity of coconut pulp treated by HCl is 0.686 mg/g while adsorption capacity of coconut pulp treated by acetic acid is 0.454 mg/g.