DEPARTMENT OF CHEMICAL ENGINEERING

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.

This research endeavor seeks to develop an innovative catalyst for the pyrolysis procedure, transforming waste plastic (polyethylene terephthalate PET) into a liquid fuel source. The objectives include preparation of waste PET and clay specimens, the fabrication of a zeolite catalyst from clay, and the subsequent examination and characterization of this catalyst. The experimental setup entailed weighing 500 g of PET particles and 25 g of zeolite catalyst, purging the system with nitrogen gas to establish an oxygen-free milieu, and commencing pyrolysis at 450°C with a heating gradient of 15°C/min and a reaction duration of 30 min in a diminutive fixed-bed reactor.
The findings indicate the efficacy of calcined clay soil in the pyrolysis of discarded PET containers. Structural analysis revealed specific surface area, bulk density, particle size, and porosity values of 86.10 m²/g, 1.285 g/cm³, <100μm, and 48%, respectively. Spectroscopic analysis underscored a notable composition of calcium oxide in the catalyst, corroborating its catalytic prowess. Furthermore, the catalytic pyrolysis process yielded a greater volume of oil compared to non-catalytic pyrolysis, as exemplified in Table 4.3. The physiochemical attributes of the resultant oil conformed to ASTM standards, with caloric value, flash point, kinematic viscosity, and specific gravity measured at 16.42 kcal/kg, 78°C, 2.80 mm²/s, and 0.8601, respectively.
In conclusion, this study proffers a promising approach to address the issue of plastic waste by converting PET bottles into a valuable liquid fuel source utilizing a novel clay-based catalyst. The developed catalyst exhibits advantageous structural and spectroscopic properties, enhancing the efficiency of the pyrolysis process. Moreover, the resulting fuel meets industry benchmarks, intimating its potential for practical applications in energy production and waste management.

The study investigated the use of palm kernel shells and snail shells in the synthesis of a bio-based bifunctional heterogeneous catalyst. Using impregnation methods, palm kernel shells (PKS) biochar was functionalized with calcined snail shell doped with copper sulphate. The catalytic activity of the resulting catalyst was tested through the simultaneous esterification and transesterification of palm kernel oil (PKO). The characteristics of the catalyst were examined using X-ray diffraction spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray fluorescence (XRF). The results showed that catalyst formulation with 90wt% CaO catalyst and 10 wt% activated PKS biochar generates the greatest biodiesel yield of 93.2%; this was reached with 3 wt% catalyst loading, 12:1 methanol to PKO molar ratio at 60 C within 1 hour and 30 minutes of reaction time. The bifunctional heterogeneous catalyst is chemically stable and can be reused up to five times, producing 72.6% biodiesel in the final cycles. The results show that the biodiesel produced meets the worldwide standards. The use of waste material to create an effective bifunctional catalyst for biodiesel synthesis from palm kernel oil (PKO) has significant commercialization potential in the future.

Biogas is a gas mixture consisting mainly of methane and carbon(IV)oxide resulting from the biological process of anaerobic digestion of various organicmaterials. The percentage of methane in biogas will vary depending on the processconditions and the type of organic matter fermented. This study investigatedtheeffects of thermal and alkaline pretreatment methods on cattle rumen content andincrease the biogas yield. In the course of this study, sodiumhydroxide (NaOH) was the alkali of choice and temperature ranges of 70ºc 80ºc and 90ºc in a BoxBehnken design. Modelling was carried out with using Response Surface Methodology (RSM) which was used for the Analysis of Variance (ANOVA) andmultiple regression analysis of the data obtained. The R2 value of 0.9768for NaOH, contour plots, ANOVA analysis all shows how suitable the RSMmodel is for theexperiment. The optimum conditions necessary for maximum feedstock degradation for the alkaline was examined and it was found by using NaOH atatemperature of 80.171ºC, timed 13.086 minutes and a molar concentration of 2.05M and the degree of degradation is 56.83%.