Assessment of Catalyst Efficiency in Biodiesel Production from Waste Cooking Oil

Thesis Abstract

The escalating demand for sustainable and cost-effective alternative fuels has intensified research efforts into biodiesel production from waste cooking oil, highlighting the necessity to optimize catalyst performance to enhance yield and quality. Despite the widespread application of conventional homogeneous catalysts, their environmental drawbacks and recovery inefficiencies prompt critical evaluation of heterogeneous catalysts to improve process sustainability and economic viability. This study aims to assess the efficiency of different catalysts in biodiesel production from waste cooking oil, with specific objectives including evaluating catalytic activity, optimizing reaction conditions, and analyzing catalyst reusability. Employing an experimental research design, the study systematically investigates three catalysts—namely, potassium hydroxide (KOH), calcium oxide (CaO), and a novel biodiesel-supported metal oxide catalyst (e.g., NiO-CaO composite). The population comprises waste cooking oil samples obtained from local restaurants, with a total of 60 samples collected over three months to account for variability. A factorial experimental setup was used to identify optimal reaction parameters, such as temperature, catalyst loading, methanol-to-oil ratio, and reaction time. Data collection instruments included Gas Chromatography-Mass Spectrometry (GC-MS) for methyl ester quantification, Fourier Transform Infrared Spectroscopy (FTIR) for functional group analysis, and X-ray Diffraction (XRD) for catalyst characterization. The validity and reliability of the analytical instruments were ensured through calibration with standard compounds and duplicate analyses, respectively. Data were analyzed primarily via Analysis of Variance (ANOVA) to determine significant differences in catalyst performance across various conditions, complemented by regression analysis to model the relationship between operational parameters and biodiesel yield. Additionally, catalyst reusability was assessed through repeated batch experiments, measuring activity retention over five cycles. It is anticipated that the findings will reveal distinctive performance profiles among the catalysts, with the novel NiO-CaO composite expected to demonstrate superior activity, enhanced biodiesel yield (aiming for at least 90%), and better reusability compared to conventional counterparts. These results are expected to contribute to the theoretical understanding of catalyst mechanisms in waste oil transesterification, supported by the application of the Green Chemistry Framework and the Catalytic Efficiency Theory. The study also aims to establish an empirical model predicting biodiesel yield based on operational parameters, facilitating process optimization. This research substantially advances existing knowledge by providing a comparative assessment of catalysts under realistic operational settings and proposing an effective, sustainable catalyst for waste cooking oil transesterification. The main conclusion will emphasize that heterogeneous catalysts, particularly metal oxide composites, offer viable alternatives to traditional methods, with implications for scaling up biodiesel production in industrial contexts. Recommendations will include the adoption of the most efficient catalyst identified, further exploration of catalyst modification strategies to improve activity and stability, and recommendations for policymakers to promote sustainable biodiesel initiatives. In sum, the study promises to contribute valuable insights to the fields of industrial chemistry and renewable energy, fostering environmentally friendly and economically feasible biodiesel production practices.