DEPARTMENT OF CHEMICAL ENGINEERING,

The components of bio-waste are particularly abundant in essential minerals like calcium and potassium, which are essential for the manufacture of effective biocatalysts for biodiesel. This study evaluated the potential of bio-based heterogeneous catalyst of fused cockle shells and watermelon peels for the transesterification of waste vegetable oil. At 900°C and 500℃, the waste materials were dried, calcined, and carbonized, respectively. In order to evaluate the compositional, morphological, structural, and thermal features of both the catalyst and the precursor materials, they were both characterized. The Box-Behnken design was utilized to generate 29 experimental runs to examine the impact of operational parameters such catalyst loading, temperature, methanol-to-oil molar ratio, and reaction time. The presence of basic (calcium and potassium) and acidic oxides (silicon and nickel) demonstrated that the catalyst was bifunctional. The catalyst's surface area (105.35 m2 /g) and pore volume (0.60 cm3 /g) obtained from the BET analysis contributed to a 91.77% biodiesel yield at 63.34 °C reaction temperature, 149.41 min reaction time, 1.05wt% catalyst loading, and a 14.45:1 methanol to oil ratio. The physicochemical parameters of the biodiesel produced were measured and determined to be acceptable according to the European National (EN) and American Society for Testing of Materials (ASTM) quality standards, demonstrating the product's suitability for use as fuel.

For its bio- and environmentally friendly properties, low cost, and relative abundance, clay has become increasingly relevant and used. Based on their components and layer patterns, clay minerals have a variety of morphological and physicochemical characteristics., in addition to its well-established uses in adsorbent development, water treatment, and construction. In order to determine whether clay samples from the Ikpeshi town in the Akoko-Edo LGA could be used in an industrial process, its physical and chemical characteristics were examined. The study involved the analysis of elemental content, mineral constituent, functional groups of compounds content, surface morphology, and thermal stability with EDXRF, XRD, FTIR, SEM, BET and TGA respectively. Results revealed that the sample was kaolinite with SiO2 45.116 wt%, and Al2O3 20.39 wt% as the most predominant elements. Wave numbers of 909.47043cm-1 to 998.92654cm-1 with bold peaks revealed the presence of SiO4-4. The overall study revealed
kaolinite characteristics and strong thermal stability thus possesses properties for clay suitable for lining furnace kilns.

The main goal of this research was to explore the effectiveness of slow pyrolysis of sawdust in generating high-quality biochar with beneficial characteristics for different uses, such as soil improvement and water purification. By adjusting the pyrolysis temperature and duration, the study sought to identify the ideal conditions for producing biochar with improved physicochemical properties. Sawdust, an abundant byproduct of the timber industry, underwent slow pyrolysis in a low-oxygen environment. The process was carried out at various temperatures, ranging from400°Cto700°C, to evaluate how temperature affects both the yield and characteristics of the resulting biochar. The produced biochar was analyzed through several techniques, such as surface area measurement, pH analysis, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy(FTIR), Brunauer-Emmett-Teller (BET) analysis, iodine number assessment, and yield percentage evaluation. The research revealed that slow pyrolysis of sawdust produced high-quality biochar with desirable characteristics. The biochar showed elevated carbon content, a porous structure, and an almost neutral pH, making it well-suited for use in agriculture and water purification. Both laboratory and field experiments confirmed that biochar effectively enhanced soil quality, boosted water retention, and improved nutrient availability. The research also showed that up to 55% of the material could be converted into solid biochar, while the rest was produced as bio-oil and syngas. These results emphasize the sustainable and versatile advantages of utilizing slow pyrolysis of sawdust for biochar production.

This study aim to optimize biogas production from the co-digestion of cassava, yam, and potato peels with cow dung as inoculum, addressing the dual challenges of agricultural waste management and renewable energy generation in Nigeria. The research sought to determine the most effective substrate mixing ratios and associated process conditions that enhance biogas yield and methane content while providing sustainable solutions for converting abundant agricultural residues into clean energy. The optimization was conducted through batch anaerobic digestion at laboratory scale using asimplex lattice mixture design approach. The study involved three consecutive batches with four experimental runs each, totaling twelve runs over an 8-day hydraulic retention time per batch. Fresh cattle rumen was obtained from Abattoir Oluku, while cassava peels were sourced from the Ogba community, and yam and potato peels were collected from Ekosodin, Ugbowo community, all in Edo State, Nigeria. The feedstocks underwent systematic pre treatment including washing, oven drying at 100 - 130°C for 18 hours, grinding usingmortar and pestle followed by manual hand grinding, and sieving through 500-micromeshtoachieve uniform particle size. Proximate analysis determine moisture content, ash content, volatile matter, and fixed carbon, while ultimate analysis using Energy – Dispersive X-ray Fluorescence (EDXRF) spectrometry establish elemental composition including carbon-nitrogen ratios. A fixed mass of 50g cow dung dissolved in 150ml water served as inoculum for each experimental run. The biogas volume was measured using the water displacement method with Buchner flask setups, and statistical analysis was performed using Response Surface Methodology and Analysis of Variance (ANOVA) through Design Expert software to evaluate model significance and develop predictive equations. The results revealed that pure yam peel produced the highest biogas yield of 180ml/50g.week with excellent methane concentration of 88.2%, significantly outperforming cassava peel (98.4 ml/50g.week, 86.7% CH₄) and potato peel (70 ml/50g.week, 82.5%CH₄). The binary blend of yam and cassava peels demonstrated synergistic effects with147.5ml/50g.week yield and 87.9% methane content, while yam-potato combinations exhibitedstrong antagonistic interactions producing only 25 ml/50g.week. Statistical validation confirmed excellent model fit with R² values of 0.9982 for biogas yield (Special Quartic model) and 0.9523 for methane concentration (Quadratic model), both significant at p<0.001. The cow dung characterization revealed substantial nutrient content including calcium(36.20%), potassium (14.65%), phosphorus (9.62%), and nitrogen (3.89%), confirming its suitability as an effective inoculum. These findings demonstrate that strategic substrate blending, particularly yam-cassava combinations, can optimize biogas production from agricultural waste while providing practical guidelines for small-scale biogas system sin resource-limited settings.