Assessment of Catalyst Performance in Biodiesel Production from Waste Cooking Oil

Thesis Abstract

The increasing demand for sustainable and eco-friendly energy sources has propelled biodiesel production as a viable alternative to fossil fuels, with waste cooking oil (WCO) serving as a cost-effective and environmentally sustainable feedstock. However, the variability in feedstock composition and the efficiency of catalysts used in transesterification reactions significantly influence biodiesel yield and quality, thus necessitating a comprehensive assessment of catalyst performance. This study aims to evaluate the catalytic efficiency, stability, and reusability of selected solid and homogeneous catalysts in biodiesel synthesis from WCO, thereby identifying optimal catalysts for industrial application. The specific objectives are to quantify biodiesel yield and purity obtained with different catalysts, examine the influence of process parameters such as temperature, catalyst loading, and reaction time on conversion efficiency, and analyze the catalyst degradation and regeneration potential over multiple reaction cycles. The methodology adopts an experimental research design employing a factorial arrangement to systematically investigate the effects of variables on catalyst performance. The population comprises laboratory-scale batches of WCO collected from local eateries, with a sample size of 60 reactions for each catalyst type, totaling 180 experimental runs to ensure statistical robustness. Data collection involves gravimetric measurement of biodiesel yield, Fourier-transform infrared spectroscopy (FTIR), and gas chromatography-mass spectrometry (GC-MS) for biodiesel quality analysis, alongside catalyst characterization using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The validity and reliability of the analytical instruments are confirmed through calibration with standard references and repeat analyses. Data analysis techniques include analysis of variance (ANOVA) to compare catalyst efficiencies, regression analysis to model the effects of process variables, and t-tests for catalyst reusability assessment. A theoretical framework grounded in the Langmuir-Hinshelwood adsorption theory and the green chemistry principles guides the interpretation of catalytic reactions and process optimization. Key expected findings include significant differences in biodiesel yield between catalysts, with heterogeneous catalysts demonstrating higher reusability and stability over multiple cycles. The study anticipates that catalyst activity correlates positively with reaction temperature up to an optimal point, beyond which thermal degradation diminishes performance. Catalyst characterization is expected to reveal morphological and compositional changes associated with deactivation, informing regeneration strategies. The findings aim to establish clear relationships between catalyst properties, process conditions, and biodiesel quality, thereby filling existing research gaps concerning catalyst longevity and environmental sustainability in biodiesel production. This research contributes novel insights into the comparative performance of various catalyst types in converting waste cooking oil into biodiesel, emphasizing the importance of catalyst stability and recyclability in scaling up sustainable biofuel processes. It enhances understanding of the mechanistic aspects of catalysis in heterogeneous systems and provides empirical data supporting the development of cost-effective, environmentally benign catalysts tailored for waste feedstocks. Conclusively, the study recommends specific catalyst schemes and process configurations to optimize biodiesel yield and quality while minimizing operational costs and environmental impact. Further studies are suggested to explore nanostructured catalysts and continuous process optimization for industrial implementation, thus advancing the transition toward sustainable bioenergy systems.