Epoxidation of Waste Palm Cooking Applied With Hybrid Zeolite Catalyst Derived From Natural Clinoptilolite/Synthetic ZSM ‐5

Abstract

ABSTRACT Catalyst development for epoxidation is constrained by the trade‐off between efficiency, cost, and sustainability. Homogeneous catalysts such as sulfuric, hydrochloric, and acetic acids exhibit high activity but are limited by corrosiveness, environmental concerns, and low selectivity. Alternatively, heterogenous catalyst of natural zeolites offer a sustainable alternative due to their abundance, recyclability and low cost, however; it is suffering from intrinsic variability, resulting in inconsistent of performance. On the other hand, synthetic zeolites provide high surface area and stability, but their high production cost restricts practical application. To address this gap, a novel hybrid zeolite catalyst was synthesized by integrating natural clinoptilolite with synthetic ZSM‐5 via an impregnation method. The optimal conditions for synthesis catalyst was natural‐to‐synthetic mass ratio of 0.5:1.0, 0.5 M HCl solution, and calcination temperature at 550°C. SEM analysis confirmed the successful formation of the hybrid catalyst, exhibiting a well‐defined crystalline morphology with regular crystal shapes and smooth surfaces. FTIR analysis verified the successful epoxidation of waste palm cooking oil through the enhanced intensity of the characteristic oxirane absorption band at 852 cm −1 . Despite a 15.82% reduction in specific surface area, hybrid zeolite catalyst achieved RCO yields comparable to synthetic ZSM‐5 catalyst which is 50.45% ± 1.74%. It is indicating that catalytic performance is governed not only by the specific surface area, but also by active‐site effectiveness and mass‐transfer characteristics. Physicochemical analyses further confirmed the superior epoxidation performance of the hybrid catalyst through the greatest reduction in iodine value and the corresponding increase in viscosity. Kinetic modeling using MATLAB, integrated with a Genetic Algorithm and the ODE45 solver, validated the superior catalytic performance of the hybrid system. The kinetic rate constants obtained were k 1 a = 1.9460 mol L −1 min −1 , k 1 b = 11.4667 mol L −1 min −1 , k 2 = 0.2265 mol L −1 min −1 , and k 3 = 0.0019 mol L −1 min −1 . These results highlight the effectiveness of the hybrid catalyst system and demonstrate its potential as a cost‐effective and sustainable catalyst design strategy.