Purification of vegetable oils from acrylamide pollutants using metal-organic frameworks

Abstract

Acrylamide is a chemical compound that can form in certain foods during high-temperature cooking processes like frying, roasting, and baking. The presence of acrylamide in used cooking oil has environmental impact; therefore, the purification of used oils may reduce the environmental risks. Nowadays, biochar, a porous carbonaceous material derived from biomass pyrolysis can added to crystalline porous materials called metal-organic framework (MOF), these combination lead to fantastic properties for adsorption of contaminants. Here, ZIF-8@Biocharas adsorbents were synthesized for purification of the used frying oil from many pollutants, including, acrylamides, acids and peroxides. First, surface and pore properties, and morphologies of the adsorbents were determined using different characterization techniques. The used frying oil was treated with 0.5% (w/w) ZIF-8@Biochar and ZIF-8 MOF to remove free fatty acid (FFA), the results showed reduction by 80.6% and 32.2%, respectively. Likewise, peroxide value reductions ranged from 70.6% with the same adsorbent. The residues of acrylamide were determined by GC-MS/MS. whereas acid and peroxide values were determined by titration methods. This study showed an economical solution for reducing acrylamide, acid value, and peroxide value in used cooking oil for improving safety and quality of used oil.