CHEMICAL ENGINEERING

Carbon dioxide is one of the major greenhouse gas that causes global warming, it is emitted from the burning of fossil fuels in industries, power plant and vehicles. Greenhouse gases leads to increased global warming and affects the balance of the environment and pollution of the environment. Fossil fuels are the primary source of global energy which make up over 80% of consumption, the remaining 20% which is contributed by nuclear and renewable energy sources. (Holechek et al., 2022). Carbon
dioxide is the main product which is generated from combustion processes in most industries. The emission of CO2 has increased in decades. By 2021, approximately 47% of emissions were generated from electricity and heat and around 25% was from transportation (i.e. vehicles). Industries (e.g. chemicals, petrochemicals, iron and steel, aluminium, cement or paper) generates about 18% of the total CO2 emission was generated(Ochedi et al., 2020).

The potential of calcined agrowastes particularly chicken eggshells (CES) impregnated with ripe plantain peels (RPP) as a suitable catalyst for the conversion of waste cooking oil to biodiesel (FAME) by trans-esterification was investigated. The catalyst derived from these agro-wastes was synthesized by dry impregnation using physical mixing. The free fatty acid (FFA) content of waste cooking oil used for transesterification was measured to be 0.131%. The reaction conditions with methanol to oil molar ratio of 6:1, reaction time of 90 minutes, catalyst loading of 2% oil weight and a temperature of 60°C was kept constant while the catalyst’s design mixing ratios of ‘RPP: CES’ was varied. The FT-IR, XRD and elemental analysis by XRF revealed the catalytic action of these materials (RPP and CES) is a result of their metallic content (K+ and Ca 2+ ) and their microstructural formation change is noticeable when calcined at above 700°C. The experiment was carried out by the trans-esterification of the oil using each of the different designed catalyst samples to investigate the influence of their different mixing ratios on biodiesel yield. The results of the chart plots using Microsoft Excel 2010 showed that the optimum biodiesel yield consistent with ASTM D-6751 and EN 14214 standards was 75.04 % and the catalyst mixing ratio of 1:3 by mass was the optimal design ratio

Fatty acid alkyl esters are produced by subjecting vegetable or animal fats to a transesterification process with a low molecular weight alcohol, using a suitable catalyst. This process creates biodiesel, often referred to as 'green fuel', due to its numerous advantages such as biodegradability, renewability, reduced toxicity, higher cetane number, and flash point. Consequently, biodiesel has gained recognition as a potential substitute for conventional petroleum-based diesel (Baig and Ng 2010). In the majority of current biodiesel production methods, which employ homogeneous catalysis, refined vegetable oils serve as the primary raw materials. However, these refined oils come at a considerable expense. The cost of these feedstocks significantly affects the economic aspects of biodiesel production, as highlighted in a review conducted by Marchetti and Gebremariam, (Akhabue et al. 2020) discovered that the economics of biodiesel production are notably affected by the expense of feedstocks. Studies have indicated that the expenditure on raw materials for biodiesel production may make up as much as 88% of the total production expenses. Therefore, a substantial rduction in the production cost of biodiesel can be achieved through the utilization of non-edible oils or waste cooking oil (Haas et al. 2016). The elevated levels of free fatty acids (FFA) in waste cooking oil and various non-edible oils lead to saponification by the alkali catalyst, resulting in a r duced biodiesel yield due to the challenge of separating the product. Moreover, the purification process generates waste water, causing environmental pollution concerns, which require the treatment of waste water before disposal or reuse (Daud et al. 2015). This, in turn, adds to the cost of biodiesel production

Climate change driven by increasing atmospheric CO₂ concentrations calls for urgent implementation of atmospheric CO2 reduction. However, adsorbents are mostly expensiveand energy-intensive, especially for developing nations. Agricultural wastes, especiallycorncobs, 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 reactionandpassed through glass columns (2.1 cm diameter, 5 cm bed height) at flowrates of 0.5-2.0L/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%carboncontent and oxygen-containing functional groups favorable for CO₂ binding. The 100µmparticle size achieved the highest equilibrium adsorption capacity of 5,459 ppm·L/g, while250 µm particles demonstrated optimal removal efficiency of 48.0%. Breakthrough analysisindicated that smaller particles delayed saturation, with 100 µm maintaining effectivenessbeyond 45 minutes compared to 25 minutes for above 500 µm particles. Flowrate influencedperformance, with reduced rates (0.5 L/min) compensating for larger particle sizes byincreasing contact time. These findings reveal that corn bobs are a viable solution for carboncapture.

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 result.

This research project looks into the viability of using agricultural waste (coconut shells) as a source of biochar, a porous carbon material with excellent CO2 adsorption capabilities, for carbon capture. This will involve preparing biochar from coconut shells, characterizing the prepared biochar sample, and using this biochar sample to adsorb CO2, in a bid to demonstrate the possibility of using agricultural waste for carbon capture. The biochar was prepared by carbonizing coconut shells. The residue obtained was activated in batches using NaOH and Phosphoric acid to obtain biochar samples with slightly different properties. A 1:1 coconut shell and palm kernel shell blend was prepared to test the effect of blending. Preliminary characterization was carried out to select the biochar sample with the highest adsorption potential for further characterization. An iodine number test was carried out to determine the adsorption capacity of the biochar samples, indicating their level of activation. The CO2 capture test involves measuring the amount of CO2 adsorbed by the biochar sample in a fixed-packed bed adsorption column to determine the adsorption capacity. This was achieved by measuring CO2 concentrations at the bottom and top of the column to determine the amount of CO2 adsorbed by the biochar adsorbent. The analysis of the final biochar sample (sample 3) showed promising characteristics, making it suitable as an adsorbent material with a micropore surface area of 719.886 m2 /g and a micropore volume of 0.256 cc/g. These values are within typical ranges found in commercial adsorbents. For the first run of CO2 adsorption experiment using 30g of biochar an adsorption capacity of 16.28 mg CO2/g of biochar was obtained. Subsequent runs with smaller amounts of biochar resulted in decreasing adsorption capacities, demonstrating that using greater amounts of biochar increases the performance. These results are consistent with previous research on CO2 capture. Overall, the biochar sample derived from coconut shells showed sufficient adsorption capacity for use in CO2 capture systems, despite the simple production process without sophisticated equipment. The research findings suggest that coconut shell-derived biochar shows promise for carbon capture applications.

This study investigated the effectiveness of activated coconut shell as an adsorbent for carbon dioxide (CO₂) capture, with a specific emphasis on the influence of particle size and gas flow rate on the adsorption efficiency. Coconut shells were collected locally from Benin City, Nigeria, and subjected to carbonization at 400°C for one hour, followed by acid activation using 10% hydrochloric acid. The carbonized material was classified into four particle size fractions: >500 μm, 250-500 μm, 100-250 μm, and <100 μm.

The relative utilization ofactivated carbon has constantly increased with the advancementinmoderntechnology.Inabidtomakeuseofalternativeprecursorsfor activatedcarbonproduction,periwinkleshellswereused. Thisstudyexploredtheuseofperiwinkleshellsfortheproductionofperiwinkleshell
activatedcarbon(PSAC)preparedusingpotassiumhydroxide(KOH)activationmethod.
The adsorbentwas characterized using the FourierTransformed Infrared (FTIR)
analysis.Centralcompositedesign(CCD)inresponsesurfacemethodology(RSM)was
usedfortheoptimizationofPSACproductionconditions.QuadraticmodelsandlinearmodelweredevelopedforthepercentageyieldofPSAC,thesurfaceareaandthe porosity.ModelsuitabilitywasvalidatedusingAnalysisofVariance(ANOVA).TheFTIR
analysisshowedthepresenceofstretchingvibrationbandssuchascarbonateion
( ),aliphaticN-H and heterocyclicN-H.Theoptimum conditionsforPSAC
productionwas536.375oCand82.087minutesforactivationtemperatureandactivation
time respectively.Thisled to maximized responses;PSAC’syield percentage of
95.147%,surfaceareaof71.525m2/gandporosityof36.695.Thecorrelationcoefficient
R2obtainedwereveryhighforeachresponse;99.47%,99.98%and97.77%forPSAC’s
yield,surfaceareaandporosityrespectivelyindicatingthattheresultsofexperimental
Studies were in perfect agreement with thosesuggested from model.Thus,the
predictionbythemodelwasingoodconformitywithactualresults.Periwinkleshells were found to attain PSAC that had a very high yield as well as excellent surface area
andporosity

This project is aimed to optimize the production of gluconic acid using ternary feedstocks composed of pineapple peels, watermelon peels, and orange peels. Employing Design Expert software, a D-optimal mixture design was implemented, with Penicillium chrysogenum selected as the fermenting microorganism. The methodology involved varying the proportions of pineapple peel, watermelon peel, and orange peels in the fermentation medium according to the experimental design generated by Design Expert. Following fermentation, gluconic acid yield was quantified, and the results were compared with the predictions obtained from the D-optimal mixture design. The analysis of the experimental data demonstrated a close relationship between the predicted gluconic acid yields and the actual values obtained from the fermentation experiments. For instance, in Run 1, the actual gluconic acid yield was 19.7 g/L, whereasthe D-optimal predicted value was 20.97 g/L. Similarly, in Run 5, the actual yield was 23.66 g/L, in close agreement with the predicted value of 23.98 g/L. The optimal run, determined based on the highest gluconic acid yield, was Run 8, with an actual yield of 25.63 g/L, closely matching the D-optimal predicted value of 25.46 g/L. This study shows the efficiency of using ternary feedstocks for gluconic acid production and highlights the value of mixture design methodology in optimizing fermentation processes for bioproduct synthesis.

Poor waste management practices have led to significant environmental pollution, with methods like landfilling, burning, and open dumping, contributing to air pollution and public health hazards. Over time, innovative approaches have been developed to tackle these issues. One such approach is anaerobic digestion, which relies on microbial degradation of organic waste material in the absence of oxygen. The feasibility of generating biogas from combining cow dung and tiger nut waste through anaerobic digestion was investigated. The materials were mixed in a 5:1 ratio with distilled water, and the pH was adjusted from 4.7 to 6.7 using NaOH. Biogas collection was conducted using a water displacement method with a graduated cylinder. The experiment spanned six days, during which the initial properties of the feed, including volatile solids (14.31%), total solids (14.57%), water content (85.43%), pH (6.7), ash content (0.26%), nitrogen (8.64%), potassium (298 mg/kg), phosphorus (76.28 mg/kg), and ammonium (0.08 mg/kg)
were recorded. Biogas volume changes were monitored and recorded daily. The results showed the progressive increase in the volume of biogas produced until the last day of retention. The results demonstrated that anaerobic digestion is an effective method for biogas production, providing a potential solution for improving waste management practices and reducing environmental pollution.