DEPARTMENT OF CHEMICAL ENGINEERING

Postharvest spoilage of perishable crops such as okra (Abelmoschus esculentus), tomato (Solanum lycopersicum), and fish (Clarias gariepinus) remains a major challenge in Nigeria, leading to food waste, economic loss, and reduced availability of nutrient-rich food. This study aimed to evaluate the effectiveness of an effective preservative method for these commodities
and to monitor changes in their nutritional composition during storage by determining optimal preservative parameters, evaluating variations in key nutrients, including protein, carbohydrate, and vitamin C. Controlled oven-drying was carried out for the three samples at 60°C to ensure uniform heat transfer while preventing oxidative degradation. Moisture, protein, carbohydrate, and vitamin C contents were analyzed using standard laboratory methods. Drying kinetics were studied using first-order reaction models, and the Arrhenius equation was used to estimate the activation energy (Ea) for moisture diffusion. These analyses provided insights into both drying efficiency and nutrient stability across the three samples. Results revealed that drying significantly reduced the moisture content of all samples, improving shelf life and reducing microbial activity. Protein content increased slightly in fish (24.72 to 25.61%), okra (2.73 to 2.75%), and tomato (1.62 to 1.65%) due to moisture concentration effects. Vitamin C decreased considerably, ranging from 40 to 80% losses, confirming its thermolabile nature, while carbohydrates remained largely stable. Fish further exhibited a distinct drying kinetics, following first-order behavior with drying rate constants (k) of 0.0153, 0.0189, and 0.0191 min⁻¹ at 60°C, 80°C, and 100°C, respectively. The calculated activation energy of 6.093 kJ/mol indicated a moderate energy requirement, suggesting that moisture removal occurred primarily through surface evaporation and mild internal diffusion. These findings demonstrate that moderate drying temperatures around 60°C can preserve nutritional quality while enhancing product stability, making them suitable for industrial processing in tropical environments while higher temperature i.e 100°C will result in higher moisture loss.

This study investigated the production of biodiesel from waste cooking oil using a catalyst derived from chicken manure impregnated with nickel sulfate. The catalyst was prepared by calcining chicken manure followed by a sol-gel process to incorporate nickel, and characterizedas a porous material with a surface area of 115 m²/g. Using Response Surface Methodology, the reaction conditions were optimized, identifying a methanol-to-oil ratio of 12:1, 3% catalyst loading, 55°C temperature, and 90 minutes reaction time as optimal, resulting in a biodiesel yield of 95.67%. The biodiesel met flash point safety standards but showed higher viscosity, density, and acid value than international fuel specifications, indicating the presence of residual free fatty acids that require pretreatment or purification. This work demonstrates that chicken manure can serve as a cost-effective catalyst precursor in converting waste cooking oil to biodiesel, promoting sustainable waste utilization and renewable energy production

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 from 400°C to 700°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 focused on the photodegradation of cassava wastewater. The potential use of titanium dioxide, periwinkle shell and roof tiles, a sustainable and biodegradable catalyst to adsorb the pollutant from the aqueous solutions was investigated. The catalyst was prepared by calcination and characterised by X-ray fluorescence (XRF), Brunauer-Emmet-Teller (BET), Scanning Electron Microscopy (SEM) and Fourier transform infrared spectrometry (FTIR) analysis. In this study, we explore the viability of using both activated and unactivated periwinkle shell and roof tiles powder to effectively the contaminants from the cassava wastewater. During the degradation process, the effects of some process variables such as contact time, concentration of the wastewater, and catalyst dose were investigated. The results of batch adsorption study showed that for unmodified and modified catalyst, increasing the catalyst dosage and contact time resulted in increased percentage removal while increasing the concentration lead to a decrease in percentage removal. The optimum conditions for maximum percentage removal for unmodified and modified adsorbent are 3g catalyst dosage, 150 minutes contact time, and 100ml/l concentration of the wastewater. For adsorption Isotherm, Langmuir model was the best model for modified catalyst with a correlation coefficient of r2 ≥ 0.2989 and in comparing the correlation coefficient r2 obtained from the Langmuir and Freundlich model, it clearly shows that the experimental analysis fit Freundlich model with r 2 ≥ 0.8742 for unmodified catalyst. For adsorption kinetics, Pseudo second order reaction showed a better fit (r2 ≥ 0.9999, r2 ≥ 0.9998) than both Langrande pseudo first-order (r2 ≥ 0.9782, r2 ≥ 0.9982) and the intra particle diffusion (r2 ≥ 0.9552, r2 ≥ 0.9494) for the modified and unmodified catalyst.

This study investigates the optimization of biobutanol production from cassava bagasse through simultaneous saccharification and fermentation (SSF) using Clostridium acetobutylicum. Cassava bagasse, sourced from Uselu market, Benin City, was compositionally characterized, revealing 53.33% cellulose, 16.67% hemicellulose, and 3.00% lignin. Alkaline pretreatment using 2% NaOH at 121°C for 60 minutes effectively disrupted the lignocellulosic structure, as confirmed by FTIR spectroscopy showing reduced lignin and enhanced cellulose accessibility. Response Surface Methodology based on Central Composite Design was employed to optimize three critical SSF parameters: pH (4.5-6.5), inoculum size (5-15% v/v), and temperature (30-40°C). The quadratic model developed demonstrated excellent predictive accuracy (R² = 0.9624, adjusted R² = 0.9286) with pH and inoculum size identified as the most significant factors. Parametric validation studies confirmed maximum butanol production of 15.13 g/L at pH 6.0 and 15.45 g/L at 13% v/v inoculum size. Kinetic models were successfully developed describing the relationships between process parameters and butanol concentration, with second-order polynomials achieving R² values exceeding 0.98. The final optimal conditions identified were pH 6.0, inoculum size 12% v/v, and temperature 36°C, yielding a predicted butanol concentration of 15.4 g/L. This research establishes cassava bagasse as a viable, sustainable feedstock for biobutanol production, offering environmental waste valorization, economic opportunities for cassava-processing regions, and contribution to Nigeria's renewable energy security. The developed optimization framework and kinetic models provide a foundation for industrial-scale implementation of lignocellulosic biobutanol production

This study investigates the optimization of biobutanol production from cassava bagasse through simultaneous saccharification and fermentation (SSF) using Clostridium acetobutylicum. Cassava bagasse, sourced from Uselu market, Benin City, was compositionally characterized, revealing 53.33% cellulose, 16.67% hemicellulose, and 3.00% lignin. Alkaline pretreatment using 2% NaOH at 121°C for 60 minutes effectively disrupted the lignocellulosic structure, as confirmed by FTIR spectroscopy showing reduced lignin and enhanced cellulose accessibility. Response Surface Methodology based on Central Composite Design was employed to optimize three critical SSF parameters: pH (4.5-6.5), inoculum size (5-15% v/v), and temperature (30-40°C). The quadratic model developed demonstrated excellent predictive accuracy (R² = 0.9624, adjusted R² = 0.9286) with pH and inoculum size identified as the most significant factors. Parametric validation studies confirmed maximum butanol production of 15.13 g/L at pH 6.0 and 15.45 g/L at 13% v/v inoculum size. Kinetic models were successfully developed describing the relationships between process parameters and butanol concentration, with second-order polynomials achieving R² values exceeding 0.98. The final optimal conditions identified were pH 6.0, inoculum size 12% v/v, and temperature 36°C, yielding a predicted butanol concentration of 15.4 g/L. This research establishes cassava bagasse as a viable, sustainable feedstock for biobutanol production, offering environmental waste valorization, economic opportunities for cassava-processing regions, and contribution to Nigeria's renewable energy security. The developed optimization framework and kinetic models provide a foundation for industrial-scale implementation of lignocellulosic biobutanol production

The discharge of untreated textile wastewater containing synthetic dyes poses significant environmental and public health risks due to its toxicity and resistance to conventional degradation processes. This research explores a sustainable and cost-effective solution by developing and evaluating a novel activated carbon (AC) adsorbent derived from a blend of two abundant agricultural wastes: Palm Kernel Shell (PKS) and Coconut Shell (CS).This study aimed to treat synthetic wastewater contaminated with Methyl Red dye. The PKS and CS were individually carbonized and chemically activated using potassium hydroxide (KOH). The resulting activated carbons were blended in a 1:1 ratio to create a composite adsorbent (PKS-CS AC). The adsorbent was extensively characterized using Brunauer-Emmett-Teller (BET) analysis, which revealed a specific surface area of 275.762 m²/g and a well-developed microporous and mesoporous structure, complemented by Fourier-Transform Infrared Spectroscopy (FTIR) that identified key functional groups (O-H, C=O, C-O) crucial for adsorption.A series of batch adsorption experiments were conducted, and the process was optimized using Response Surface Methodology (RSM) based on a Central Composite Design (CCD). The influence of critical operational parameters—adsorbent dosage (PKS-AC and CS-AC), contact time, and initial dye concentration—on Methyl Red removal efficiency was investigated. The ANOVA of the quadratic model confirmed its high significance, with an R² value of 0.9501, indicating the model accurately represented the experimental data. The optimization results identified the optimal conditions as 1.65 g/L of CS-AC, 6.13 g/L of PKS-AC, a contact time of 70.75 minutes, and an initial dye concentration of 328.1 mg/L, achieving a predicted dye removal efficiency of 93.75%

The aim of this study is to evaluate the effect of blending ratios of Jatropha biodiesel with fossil diesel on compression ignition engines. The main goal is to compare the physical and chemical properties of Jatropha biodiesel and fossil diesel and evaluate engine performance,such as power output,torque,and fuel consumption,for different blend ratios and also examine the emissions characteristics (TVOC, CO, PM) that arise from various blend compositions. Physiochemical analysis confirms the suitability of esterified Jatropha oil for industrial applications. Engine performance tests reveal favourable metrics for biodiesel blends, with varying emissions characteristics across blends. Operational assessment indicates blenddependent differences in construction time, emissions, and particulate matter. Cost-benefit analysis shows economic feasibility and environmental benefits of Jatropha biodiesel. The optimal blending ratio considering performance, emissions, and economic factors suggested B30 and B40 blends for specialized applications and B10 for general use.

Chromium is one of the most notorious heavy metals released by various industries such as tanning and leather industries, manufacturing industries, catalyst and pigments, fungicides, ceramics, crafts, glass, photography, electroplating industry and corrosion control application. This study was aimed at sorption of chromium(VI) ion from aqueous solution by adsorbent derived from used tyres. Waste tyre was collected from Uwelu spare part market in Edo state. The collected tire was washed and rinsed with distilled water to remove debris, oven dried for 3hours at 180oC and ground into powder. This dried powder was carbonized and activated by charging into a muffle furnace for 2hrs at 500oC and then treated with 4M nitric acid. The efficacy of chromium removal of the adsorbent is determined by investigating the various parameters such as adsorbent dose, agitation time and shaking speed. The adsorbent was characterized by Scanning Electron Microscopy (SEM), Energy dispersive X-ray (EDX) and Fourier Transform Infra-Red (FTIR) spectroscopy. The total pore volume of the adsorbent was observed to bet P/P0=0.988646762:0.624668 cm3/g. The percentage of C and O was found to be 30.50% and 20.23%. Analysis of Variance for the response surface quadratic model showed that the Model F-value of 75.25 implies that the model is significant. The Lack of Fit F-value of 0.9763 implies that the Lack of Fit is not significant relative to the pure error. The high R-square value (coefficient of determination) of 0.9898 indicates that the fitted model predicts the metal ion removal with reasonable precision

This study explored the optimization of the microwave aided biodiesel production from waste cooking oil using a bio-waste catalyst derived from clamshell and cocoa pods via the Taguchi Optimization Approach.The bio-waste catalyst was synthesized by the carbonization and sulphuration of cocoa pods to produce an acid precursor, while clam shells was calcined and treated with KOH to create the basic precursor. Both precursors were then impregnated using the wet-impregnation method. The bi-functional catalyst produced was characterized using standard techniques to establish its catalytic potency.Characterization involved SEM,EDXRF,XRD,FTIR,BET/BJH techniques and GCMS for the oil and biodiesel .Also, a model was developed to simulate the process and examine the interactive effect of process input variables on Waste cooking oil(WCB)yield using the Taguchi L16 approach. A reusability test was used to evaluate the catalyst's commercial viability by analyzing its effects on WCB yield and Acid Value. This test was carried out over five consecutive runs with the catalyst cleaned using methanol and reused, based on the optimal circumstances. The BET analysis showed the catalyst to have a BET surface area of 393.3 m2/g, Pore volume and diameter 0.02349 cm3/g and 2.421 nm, respectively and the average micropore size calculated to be 5.520 nm in width and 0.1785 cc/g in volume, while the micropore surface area found to be 502.1 m2/g. From the XRF result it is seen that calcium oxide has 68.431% followed by phosphorous pentoxide which contains 13.527% .The best combination of the input variables determined for the process is a heating power of 600W, methanol:WCO of 15:1, time of 5 min,v reaction speed of 1000rpm and Catalyst loading of 2 wt% with an optimum WCB yield of 92.737 wt.% and AV of 0.408 mg KOH/g. It was shown that the WCB yield was significantly influenced by the reaction time, reaction speed,power of the reaction and the methanol to oil molar ratio but the catalystloading, reaction speed, power of reaction and reaction time were the factors that had the biggest influence on the AV of the WCB.The WCB produced met standard specifications for biodiesel according to ASTM D6751 and EN 14214 requirements.Applying a microwave to the WCO transesterification helped to speed up the reaction's completion.The study found that clam shells and cocoa pods are viable feedstock for low-cost, environmentally friendly biodiesel manufacturing