DEPARTMENT OF CHEMICAL ENGINEERING

The extensive use of synthetic fertilizers in agriculture has led to environmental concerns, necessitating the exploration of sustainable alternatives. Thisstudy investigates the optimization of organic fertilizer production from neem leaves (Azadirachta indicd) and evaluates its efficacy on maize (Zea mays Ld) growth and yield. This research determined the impact of drying temperature on the nutrient composition of neem leaf powder and established the optimal application rate for maize cultivation. The findings demonstrate that drying temperature significantly influenced the fertilizer's nutritional quality. While potassium content remained stable, nitrogen and phosphorus concentrations decreased markedly at temperatures exceeding 45°C, with losses exceeding 20% and 13%, respectively, at 65°C. Consequently, mild drying (< 45°C) was identified as the optimal processing parameter. In a field experiment using a Randomized Complete Block Design (RCBD), the application of the optimized neem leaf powder at 120 kg ha -1 resulted in the most significant improvements, enhancing soil pH, organic carbon, and available NPK. This treatment also produced the highest maize grain yield of 4.58 t ha -1 , a 90% increase over the unfertilized control, alongside superior plant height and a reduced anthesis-silking interval. The study concludes that NEEM processed by means of air-drying represents a viable, sustainable organic fertilizer source capable of replenishing soil nutrients depleted by maize production, offering environmental and economic benefits for small-scale farmers in tropical agricultural systems.

Palm Oil Mill Effluent (POME) is a wastewater byproduct of palm oil production, characterized by its high organic content and potential pollutant to water bodies and capable of causing significant environmental damage. This study therefore seeks to evaluate the treatment methods by coagulation and adsorption processes to remove suspended solids and pollutants, thereby purifying the wastewater for safe discharge or reuse. These methods are essential for environmental protection, resource recovery, and economic sustainability. The POME sample was collected, diluted, and analyzed to determine its physicochemical properties before treatment. Its pH was adjusted to both acidic and alkaline conditions using hydrochloric acid and sodium hydroxide, monitored with pH indicator paper. Processed periwinkle shell powder served as a natural coagulant and adsorbent. Standard laboratory instruments were used to assess parameters such as pH, turbidity, total dissolved solids, electrical
conductivity, and salinity before and after treatment. The study evaluated the effects of coagulant dosage, contact time, and pH on the treatment of Palm Oil Mill Effluent (POME) using a periwinkle shell–chitosan composite. Significant reductions in total dissolved solids (TDS) and salinity were achieved at moderate dosages (0.55– 0.82 g/L), contact times of 105–150 minutes, and near-neutral pH (7–8.2), showing effective coagulation and adsorption. X-ray diffraction (XRD) analysis revealed crystalline peaks at 2θ values of 23.9°, 26.5°, 27.5°, 33.4°, 36.4°, 38.1°, 41.4°, 43.1°, 46.0°, 48.6°, 50.5°, and 53.1°, corresponding to aragonite, muscovite, quartz, and orthoclase phases. Crystallite sizes (111–702 Å) confirmed a fine heterogeneous structure with high surface activity, making the composite suitable for efficient and sustainable POME purification

The global petroleum industry faces continuous and costly challenges in resolving stable water-in-oil (W/O) emulsions, a process that traditionally relies on expensive, non-biodegradable synthetic demulsifiers. This study investigated the development and optimization of a sustainable, bio-based demulsifier derived from a synergistic blend of extracts from Citrus sinensis (orange) and Musa spp. (banana) peels, aiming to provide an environmentally responsible alternative. The demulsifier was prepared via solvent extraction of the agricultural waste. Characterization showed the blended formulation possessed an optimal pH of 5.8 and a density of 998.0 kg/m³. Chemical analysis using Fourier-Transform Infrared Spectroscopy (FTIR) confirmed the presence of non-ionic, amphiphilic functional groups (O-H, C-H, and C-O), indicative of a surfactant-type demulsifier system4. The demulsification performance was optimized using Response Surface Methodology (RSM), analyzing the interactive effects of demulsifier dosage, temperature, and demulsification time to maximize the final water cut percentage. The resulting quadratic model demonstrated a strong correlation and predictive power, indicated by an excellent Coefficient of Determination (R²) of 0.9768. The synergistic blend achieved a peak demulsification efficiency under the tested conditions, with the maximum recorded water cut being 20 v/v%. This efficiency is attributed to the complementary action of the constituent compounds: the lipophilic D-limonene (C. sinensis) acts as a solvent to weaken the interfacial film, while the hydrophilic saponins and phenolic compounds (Musa spp.) competitively adsorb at the interface to promote rapid droplet coalescence.

Heavy metals are classified as hazardous chemical substances. They are major environmental pollutants and these pollutants affects the welfare of the environment, reduces the quality of life and eventually causes death. They are a collection of metal sand metalloids that have an atomic density larger than 4 g/cm3. A major source of Pb(II) pollutant is the automobile battery waste in automobile worship. This study was done to investigate the transport of Pb (II) in soil using response surface methodology. This investigation was carried out using a packed bed, which is a cylindrical vessel filled with uncontaminated sand. The bulk density, porosity, moisture content and pH of the soil were determined using standard procedures. The soil was then contaminated with stock solutions of Pb (II). A two - level, two - factor central composite design (CCD) was used for the design of the study. The factors considered for this study were depth and time while the concentration of Pb (II) was the response. The concentration level of Pb (II) at each point was determined using the atomic adsorption spectrophotometer (AAS). The results showed that the transport of heavy metals in soil is greatly influenced by the physico – chemical properties of the soil. The time factor had only a marginal
effect on the concentration level of Pb (II) while an increase in depth showed a significant decrease in Pb (II) concentration. The optimum concentration level was found to be at 30cm deep, after 36hrs of contamination. The findings from this investigation shows that time and depth of the soil is the predominant factor in the transport of Pb (II) on packed bed

This study investigated the effect of process parameters, temperature, hydrolysis time, and acid concentration in the pretreatment of cassava peels and sawdust on sugar yield. The pretreatment steps were performed using the Box Behnken full factorial of a central composite design (CCD) in a response methodology (RSM) with DESIGN EXPERT. Dilute acid was applied in the pretreatment process to enhance the generation of fermentable sugar yields by the DNS method. Forty six (46) experimental runs were carried out at parameters range of; temperature (30 – 100°C), HCl concentration (1 – 5%w/w), and time (15 – 90 mins). The concentration of the reducing sugar produced for each was used to study the effect of variation of process parameters. The results reveal that temperature, time and acid concentration significantly affected sugar yield. The optimum amount of the reducing sugar yield 6327.77 mg/L was obtained at 5/5g, 65°C, 52.5min, 3%w/w.

This study aims to optimize the extraction of bioactive compounds from guava leaves using the Soxhlet extraction method to investigate the impact of key variables such as mass of the solvent, temperature and extraction time (hours) on the bioactive extraction yield, to characterize the extracted bioactive compounds to identify key functional groups, and to optimize the bioactive yield. The study employed a central composite design (CCD), with 19 experimental runs where Response Surface Method (RSM) was utilized to optimize extraction conditions, evaluating the effects of mass (1.00-10.00 g), extraction time (30-300 min), and temperature (50-90°C). ANOVA and quadratic regression models assessed the influence of these variables on the yields of terpenoids and flavonoids. The qualitative and quantitative analysis of extracted compounds was conducted using colorimetric chemical tests and FTIR spectroscopy. Statistical validation included model significance testing (p-values), R², adjusted R², predicted R², and adequate precision. The qualitative analysis of guava leaf extract identified flavonoids (yellow), terpenoids (reddish- brown), saponins (froth), alkaloids (reddish-brown precipitate), and tannins (greenish-black). Quantitative results showed the highest percentages in flavonoids (15%) and terpenoids (16%), followed by saponins (2%), alkaloids (1.75%), and tannins (0.183%). Extraction efficiency was highest at intermediate conditions, with significant quadratic effects observed for all three independent variables. The regression models yields for the two major extract, terpenoid and flavonoid, demonstrated high accuracy with R2 is 0.7915 for terpenoid and R² = 0.8957 for flavonoid, with ANOVA confirming model significance (F-value = 0.17, p = 0.9585) and (F- value = 8.59, p = 0.0019) for terpenoid and flavonoid respectively. Also, the extraction yield was significantly affected by mass, time, and temperature. Terpenoid yield declined beyond 55 g and 165 min due to solvent saturation, while flavonoids degraded above 70°C. Optimal conditions enhanced solubilization and diffusion, but excessive parameters caused thermal degradation, volatilization, poor solvent penetration, and reduced extraction efficiency. These findings support guava leaves as a rich source of bioactive compounds with antioxidant, anti- v | P a g e inflammatory, and antimicrobial properties, valuable for pharmaceutical and nutraceutical applications.

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.