DEPARTMENT OF CHEMICAL ENGINEERING

This study explored the optimization of the microwave aided biodiesel production from neem oil with a bio-waste catalyst derived from cow bones and rice bran using central composite design, an experiment analysis on response surface model. The bio-waste catalyst was synthesized by the carbonization and sulphonation of rice bran to produce an acid precursor, while cow bones was calcined and treated with KOH to create the basic precursor. Both precursors were then impregnated using the wet-impregnation method. Also, a model was developed to simulate the process and examine the interactive effect of process input variables on neem oil biodiesel yield using the central composite approach. These inputs generated about 50 runs to be carried out with the catalyst using methanol under optimal conditions. In this study, we aimed to optimize biodiesel production from neem oil using a microwave- assisted process with a bifunctional heterogeneous catalyst synthesized from cow bones and rice bran. Oil characterization was carried out according to the ASTM standards, the catalyst failed to facilitate the transesterification reaction resulting in no biodiesel formation. Biodiesel production was carried out using sodium hydroxide which proved the viability of the oil and this outcome underscores the critical importance of proper catalyst synthesis and activation in biodiesel production. Additionally, the presence of impurities or moisture during catalyst preparation could have led to deactivation, further inhibiting the reaction. Fresh catalyst samples have been impregnated and are awaiting analysis results

This research aimed to develop a sustainable and efficient method for making biodiesel from a mix of neem and yellow oleander oils, using a catalyst made from chicken bones. The oils' properties were examined, created and tested the catalyst, optimized the transesterification process, and checked that the biodiesel meets ASTM D6751 and EN14214 standards. The oil analysis looked at free fatty acids (FFA), viscosity, density, iodine value, and fatty acid profiles. Neem oil had an FFA of 5.2%, viscosity of 5.93 mm²/s, and an iodine value of 76.4; yellow oleander oil had an FFA of 3.8%, viscosity of 4.02 mm²/s, and iodine value of 73.86. The catalyst was prepared by calcining chicken bones at 800°C for 3 hours, resulting in calcium oxide with a surface area of 154 m²/g. Tests with SEM, XRD, XRF, FTIR, and BET confirmed it was effective and stable. By optimizing the transesterification process through Response Surface Methodology (RSM), a biodiesel yield of 88.46% was achieved. The optimal conditions identified were a methanol-to- oil ratio of 14:1, a reaction duration of 180 minutes, a catalyst loading of 6% by weight, all maintained at a steady temperature of 65°C

The influence of dye concentration, adsorbent dosage, and contact time on the % removal of methylene blue dye (textile effluent) from aqueous solution was optimized and evaluated using a three-variable Box-Behnken design (BBD) in combination with response surface methodology (RSM). Coconut shell was utilized to make the adsorbent, which was then activated with H3PO4 after being carbonized at 600°C for an hour. Three variables dye concentration (50–200 mg/l), adsorbent dosage (g/100 ml), and contact time (10–60 mins), were varied to treat the dye solution. The responses of the linear and quadratic models that were developed for % dye removal from aqueous solution were significantly influenced by all three parameters, according to a statistical analysis of the data with p < 0.0001, the models were significant and demonstrated a strong fit with the experimental data. The adsorbent dosage and contact time had a positive impact on the percentage of dye removal. The process was optimized, and the maximum dye removal of 82% was attained at optimum dye concentration, adsorbent dosage, and contact time of 125 mg/l, 0.55 g/100 ml, and 35 min

Climate change driven by increasing atmospheric CO₂ concentrations calls for urgent implementation of atmospheric CO2 reduction. However, adsorbents are mostly expensive and energy-intensive, especially for developing nations. Agricultural wastes, especially corn cobs, are a sustainable alternative due to their lignocellulosic composition, natural porosity,
and abundance as underutilized biomass. This study investigated the CO₂ adsorption potential of chemically activated corn cob-derived adsorbent through packed bed column experiments. Corn cobs were collected, processed, and activated using potassium hydroxide (KOH) at temperatures between 400-600°C. CO₂ gas was generated in-situ via CaCO₃-HCl reaction and
passed through glass columns (2.1 cm diameter, 5 cm bed height) at flow rates of 0.5-2.0 L/min. Four particle size ranges (100, 250, 500, and above 500 μm) were evaluated over 60- minute contact periods at ambient temperature (29±2°C).
Characterization via SEM-EDS revealed highly porous morphology with 90.05% carbon content and oxygen-containing functional groups favorable for CO₂ binding. The 100 μm particle size achieved the highest equilibrium adsorption capacity of 5,459 ppm·L/g, while 250 μm particles demonstrated optimal removal efficiency of 48.0%. Breakthrough analysis indicated that smaller particles delayed saturation, with 100 μm maintaining effectiveness beyond 45 minutes compared to 25 minutes for above 500 μm particles. Flow rate influenced performance, with reduced rates (0.5 L/min) compensating for larger particle sizes by increasing contact time. These findings reveal that corn bobs are a viable solution for carbon capture.

Background Of Study
Traditional chemical-based demulsifiers in the oil and gas industry has several major issues that can affect their effectiveness and environmental sustainability. Chemical-based demulsifiers can contaminate water sources and harm aquatic life, as well as contribute to the formation of microplastics and other pollutants (Deshpande et al., 2015; Esmaeili et al., 2018). These chemicals can corrode equipment and infrastructure, leading to high cost of maintenance and replacement, and every possibility of reacting with other materials used in oil and gas processing (Abdel-Raouf, 2012; Pereira et al., 2017).

Climate change driven by increasing atmospheric CO₂ concentrations calls for urgent implementation of atmospheric CO2 reduction. However, adsorbents are mostly expensive and energy-intensive, especially for developing nations. Agricultural wastes, especially corn cobs, are a sustainable alternative due to their lignocellulosic composition, natural porosity, and abundance as underutilized biomass. This study investigated the CO₂ adsorption potential of chemically activated corn cob-derived adsorbent through packed bed column experiments. Corn cobs were collected, processed, and activated using potassium hydroxide (KOH) at temperatures between 400-600°C. CO₂ gas was generated in-situ via CaCO₃-HCl reaction and passed through glass columns (2.1 cm diameter, 5 cm bed height) at flow rates of 0.5-2.0 L/min. Four particle size ranges (100, 250, 500, and above 500 µm) were evaluated over 60- minute contact periods at ambient temperature (29±2°C). Characterization via SEM-EDS revealed highly porous morphology with 90.05% carbon content and oxygen-containing functional groups favorable for CO₂ binding. The 100 µm particle size achieved the highest equilibrium adsorption capacity of 5,459 ppm·L/g, while 250 µm particles demonstrated optimal removal efficiency of 48.0%. Breakthrough analysis indicated that smaller particles delayed saturation, with 100 µm maintaining effectiveness beyond 45 minutes compared to 25 minutes for above 500 µm particles. Flow rate influenced performance, with reduced rates (0.5 L/min) compensating for larger particle sizes by increasing contact time. These findings reveal that corn bobs are a viable solution for carbon capture

Given Nigeria's abundant agro-industrial wastes, the study focused on optimizing a ternary blend of cassava peels (CP), coconut husk (CH), and sawdust (SD) to maximize bioethanol yields. Unlike previous studies that examined these feedstocks individually, this work investigated their co-processing potential to overcome disposal challenges and enhance their utilization. The characterization of the feedstocks revealed diverse compositions: CP was rich in hemicellulose, CH presented a balanced composition, and SD was cellulose-rich but highly recalcitrant due to its high lignin content. Utilizing a {3,2} Simplex Lattice Design (SLD) across 15 experimental runs, a Special Quartic model was developed to elucidate the relationship between blend ratios and sugar yield. This model demonstrated high significance (F-value = 88.93, p < 0.0001) and an excellent fit (R² = 0.9916), highlighting substantial synergistic interactions, especially between CP and CH. The optimized blend, consisting of 66.7% CP, 16.7% CH, and 16.7% SD, yielded an impressive experimental sugar yield of 370.31 mg/g, which significantly surpassed the yields from individual feedstocks. Subsequent validation of this optimized blend involved acid pretreatment, enzymatic hydrolysis, and fermentation using Saccharomyces cerevisiae, resulting in an experimental ethanol yield of 0.0644 g ethanol/g biomass. This achievement represents 85.4% of the theoretical yield, confirming a high fermentation efficiency and validating the strategic blending as an effective waste-to-wealth strategy for sustainable bioenergy production

Transport powered by fossil fuels is becoming more dependent on global industrialization, which is accelerating the loss of these resources and exacerbating climate change. Beyond environmental issues, this dependence impedes socio-economic progress and the Sustainable Development Goals. Using calcined calcium phosphate effluent from sugar refining as a solid heterogeneous catalyst,
this research aims to manufacture biodiesel.

To optimize crucial process variables, this work utilized EDX analysis Response Surface Methodology (RSM) to convert waste cooking oil (WCO) into biodiesel. The catalyst, calcium phosphate scum, is derived from the sugar refining industry and is heterogeneous. After 29 iterations with a 5-level-4 factor Central Composite Design, a quadratic polynomial model was finalized. Reaction time (60-90 min), catalyst-to-oil weight ratio (1-4%), reaction temperature (40-70 °C), and methanol-to-oil ratio (6:1-18:1) were all fine-tuned in the study. It was proven that under these perfect conditions, used cooking oil may be transesterified.

Calcium zinc hydrogen phosphate (47%), fluorapatite (33%), osumilite (13.8%), and quartz (6.5%) were the solid mineral components found in the catalyst characterization results. These components were calcined to calcium oxides at a temperature of 1000℃. A significant pore capacity of 0.213cc/g and a high surface area of 235.505m2/g were found in the catalyst, respectively, according to the analytical analysis. This allows reactants to permeate quickly into the catalyst's interior. Based on the catalyst's elemental makeup, we know that it contains 50.4% silicon oxide (SiO2) and 41.436% aluminum oxide (Al2O3). FTIR study of catalyst indicated a medium stretch peak of methyl (C-H) group. SEM microscopy showed homogeneous spherical particles. EDS examination of catalyst revealed the presence of calcium and phosphorus in weight concentration at 62.67% and 25.99% respectively. Other elements were in trace levels.

With a reaction temperature of 55°C, a catalyst-to-oil weight ratio of 5%, a reaction time of 90 minutes, and a methanol to oil ratio of 12:1, numerical optimisation gave a maximum biodiesel yield of 93.2%.Notably, the reaction was highly impacted (p < 0.0001) by the catalyst concentration, time, and methanol-to-oil ratio. Consequently, it was found that Calcium Phosphate Scum derived from sugar refining businesses offers a cost-effective and efficient substitute for calcium oxide heterogeneous catalysts in biodiesel synthesis.

The adsorption of crystal violet from textile waste water onto carbon produced from sawdust that was activated by phosphoric acid and potassium hydroxide was an experiment that was carried out under room temperature. Adsorption is a separation process where the molecules of a solute in an aqueous solution are adsorbed to the surface of another molecule. The materials used for this experiment are phosphoric acid, potassium hydroxide, crystal violet dye, distilled water and activated carbon made from sawdust. In order to obtain the aim of the experiment, different experiment were performed which are; effect of initial concentration, effect of adsorbent dosage, effect of contact time, effect of temperature and adsorption isotherms were studied in order to find out the activating agent which best fit for the removal of the crystal violet. The percentage removal of the crystal violet was calculated to be 86.03% and 86.50% for the basic and acidic activating agents respectively for the adsorbent dosage experiment. Also, the determination coefficient value, R2 for the acid treated sawdust activated carbon for Langmuir isotherms was 0.9992, maximum adsorption capacity, QO was 29.1545mg/g and the dimensionless separation parameters, RL was found to be favorable with value 0.0448. In conclusion, the acid activated carbon was found to be more effective in the removal of crystal violet when compared to the alkaline activated carbon since its R2 value is higher.

The increasing demand for renewable energy sources has driven research into advanced biofuels like biobutanol, which offers several advantages over ethanol. This study focuses on optimizing Simultaneous Saccharification and Fermentation (SSF) for biobutanol production from elephant grass (Pennisetum purpureum), a promising lignocellulosic feedstock due to its high biomass yield and cellulose content. The research aimed to evaluate SSF efficiency by optimizing key parameters, including enzyme concentrations, pH, temperature, and inoculum size, to maximize
biobutanol yield.