Structural Characterization of Activated Carbon Prepared from Passion Fruit By-Product for Removal of Cholesterol and Toxic Compound in Liquid Food

Abstract

This study aimed to determine the structural characteristics and adsorption capacities of a novel activated carbon prepared from passion fruit by-product. Passion fruit peel was carbonized and structurally modified using phosphoric acid-potassium hydroxide reagent before carbon activation. Industrial-activated carbon was used as a control sample. The surface functional groups and adsorption capacities of the activated carbon samples were determined. The results showed that the chemical-modified activated carbon had anhydride and carboxylic acid as the main functional groups on the carbon surface, together with several conformations of the hydroxyl group. These hydroxyl confirmations were in alkoxy and carboxylate forms but not phenoxy. The peel-based activated carbon had a smoother carbon surface with multiple micropores, whereas the carbon surface of industrial activated carbon was rough with multiple meso- and macropores. The methylene blue adsorption capacity (0.1 mg/mL methylene blue) of the peel-based activated carbon (99.97±0.01%) was comparable to the industrial activated carbon (100.00±0.01%). But the peel-based activated carbon had better cholesterol and albumin adsorption capacities than the industrial activated carbon. Since activated carbon prepared from the fruit peel has better adsorption capacities of cholesterol and other chemicals in liquid foods, it can replace the wood-based activated carbon in food and pharmaceutical applications.