Sustainable Valorization of Palm Fatty Acid Distillate into Green Diesel Using Ni–Co Catalysts Supported on Zeolite from Kaolin Waste under Solvent- and Hydrogen-Free Conditions

Abstract

The use of low-cost, nonedible feedstocks has proven to be a promising route for catalytic deoxygenation reactions aimed at producing diesel-like hydrocarbons. In this study, palm fatty acid distillate, a byproduct of crude palm oil refining, was converted into green diesel via thermal and catalytic deoxygenation using zeolite-supported Ni, Co, and NiCo catalysts (10 wt % metal, synthesized from kaolin residue). The reactions were carried out at 250–350 °C for 30 min without solvent or hydrogen. The process was evaluated using thermogravimetric analysis, and kinetic parameters were estimated via the Coats–Redfern method. Both the thermal and catalytic routes yielded 60–65% organic liquid products, with 77–83% hydrocarbons in the C8–C17range. The catalytic route resulted in high yields of diesel-range hydrocarbons (C15–C17), with 86% for NiZ, 75% for CoZ, and 65% for NiCoZ, whereas the thermal route reached only 45%. Thermodynamic evaluation further demonstrated that cobalt-based catalysts enhanced deoxygenation selectivity while limiting secondary cracking. This study presents a sustainable and scalable approach. This study presents a sustainable and scalable approach for converting industrial waste into high-quality green diesel using waste-derived catalysts under mild, hydrogen-free conditions.