College of Engineering
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Item Synthetic Heat Transfer Fluids: Alternative to Steam in Chemical Industries – A Review(Bioenergy and Biochemical Processing Technologies, Green Energy and Technology (Springer), 2022) Ayoola, Ayodeji Ayodele; Ogunlade, S.; Vershima, D.; Olomukoro, O.; Sonia, N.Item Synthesis of PET-Magnesium Oxide-Chitosan Nanocomposite Membranes for the Dehydration of Natural Gas(Periodica Polytechnica Chemical Engineering, 67(2),, 2023) Agboola, Oluranti; Oginni, Grace Ayomide; Oladokun, Olagoke; Efeovbokhan, Vincent; Ayeni, Augustine Omoniyi; Ayoola, Ayodeji Ayodele; Adedamola, Adedayo Adeyanju; Alagbe, Edith Egbimhanlu; Fayomi, O.S.I.; Moropeng, Lucey; Ogunlade, Stephen KehindeFlat thin-film magnesium oxide-chitosan nanocomposite membranes were synthesized with polyethylene terephthalate (PET) and employed for natural gas dehydration. The water vapor permeation was most pronounced with a nanocomposite membrane doped with 0.9 g MgO nanoparticles (NP) as a result of a significant upsurge in the permeability of water vapor in the membrane (0.87). With the increase in MgO NP, large macro-voids are created, substratum pore size, and thickness together with the water vapor permeation were upsurged. The dehydration of natural gas performance of magnesium oxide-chitosan nanocomposite membranes synthesized with PET was enhanced with the increase in MgO NP embedded in the membrane. Though water vapor permeation was restricted by the polyester non-woven material used as a support for the nano composite membranes, as the three membranes did not reach the permeation coefficient of 1. However, the permeation coefficient increased with an increased MgO NP, with three mambrane samples (M1, M2 and M3) having permeation coefficient of 0.763, 0.77 and 0.87 respectively. The gas reduced with an increase MgO NP, with M1, M2 and M3 having 3.46 × 10−2, 3.17 × 10−2 and 3.88 × 10−3 kg/m3 respectively. From the adsorption study, the discrepancy observed between CH4 and vapor with isotherm models was ascribed to the different adsorption behavior of CH4 and vapor on the membrane-active area. The cost of making the membrane cannot be considered as a terminal criterion because most of the cost-effective option is not always the optimum one. The membranes confirmed their suitability for the dehydration of natural gas.Item Kinetic and Thermodynamic Properties of Locally Sourced Calcium in the Zinc Phosphating of Mild Steel(Journal of Bio- and Tribo-Corrosion (Springer), 2024) Ayoola, Ayodeji Ayodele; Ogbuigbo, Chijioke Henry; Agboola, Oluranti; Fayomi, O.S.I.The present study is on the establishment of the kinetic and thermodynamic performance of the locally sourced calcium used in the zinc phosphating of mild steel substrates. Calcium oxide was obtained from the calcination of periwinkle shells (at 800 °C for 4 h) and then applied as an additive in the zinc phosphating bath formulation. Metal samples were coated in the bath at different temperature (50 °C and 70 °C), different coating time durations (35, 50 and 65 min) and different CaO concentrations (0, 0.7, 1.4 and 2.0 g/L). The coated samples were subjected to 3.5wt.% NaCl solution, for corrosion test. The surface morphology of phosphate coatings was examined using SEM coupled with EDX to establish the quality and uniformity of the coating on the mild steel. The addition of calcium in the coating process significantly enhanced the corrosion resistance of mild steel relative to uncoated specimens, as justified by the lowest corrosion rate results when calcium was utilized at 70 °C, 65 min and 2.0 g/L CaO concentration. Higher positive value of the equilibrium adsorption constant, Kads, obtained (2.857) at 70 °C compared to the value (0.139) at 50 °C indicated a higher and stronger affinity of the calcium molecules for the adsorbent surface, with Langmuir isotherm fitness of R2 of 0.9319. The feasibility of the electrochemical process and the spontaneity of the adsorption process were affirmed by the negative values of the change in Gibbs free energy obtained (−592.69 kJ/mol of Δ G at 50 °C and −335.51 kJ/mol of Δ G at 70 °C). −3.271 kJ/mol of Δs (negative change in entropy) implied that the particles actually move from a disordered state (liquid) to an ordered state (solid) and forming a complex compound on the metal surface. 16.431 kJ/mol of the Enthalpy change ( Δ H) revealed the amount of heat gained for the coating (adsorption) to take place. The significance of this study, as justified by the results obtained, is that the mass transfer coefficient, kf, is directly proportional to the calcium concentration and temperature, as observed with a good driving force of 1.9267 × 10− 7 kg/m2.s at CaO concentration of 2.0 g/L and coating temperature of 70 °C.Item Chemical deposition and corrosion perspectives on the development of pipe union steel in automobile industry(The International Journal of Advanced Manufacturing Technology (Springer), 2024) Omoegun, Olumide; Fayomi, O. S. I; Ayoola, Ayodeji Ayodele; Agboola, OlurantiPipe union steel development in the automobile industry necessitates a diversified strategy, notably in terms of surface protection, durability enhancement, and corrosion resistance. This comprehensive research dives into the domain of chemical deposition technologies, primarily electroplating and its derivatives to strengthen steel surfaces against environmental, thermal, and cyclic stressors inherent in car exhaust systems. Electroplating is a flexible technology with numerous applications ranging from corrosion protection and microstructure formation to alloying and the development of high-magnetic force actuators. The research examines electroplating mechanisms, classifies chemical deposition methods, and defines the parameters of an ideal electroplating process. It assesses thin film electrodeposition and autocatalytic or electroless metal deposition, analyzing their benefits, disadvantages, and real-world applications in the automotive industry. It also investigates current research on electroplating applications, environmental problems, and pipe union steel challenges in engineering applications, such as fracture inclinations and material fatigue. Furthermore, this study investigates studies that address environmental contamination caused by electroplating applications, as well as novel methods for reducing hazardous waste. Several experimental and computational researches on steel compositions, alloys, and alternative coatings provide vital insights into enhancing the durability and corrosion resistance of pipe union steel for automotive applications.Item Corrosion Inhibitive Behaviour of Moringa Oleifera in Acidic Medium(Springer Nature, 2022) Ayoola, Ayodeji Ayodele; Okwuonu, S. C.; Durodola,, B. M.; Alagbe, E. E.; Oladokun, O.; Agboola, Oluranti; Babalola, R.Item EVALUATION OF THE CORROSION INHIBITIVE BEHAVIOUR OF PAWPAW FLUID ON A315 MILD STEEL AND A304 STAINLESS STEEL IN H2SO4 MEDIUM(Rasayan J. Chem., 14(4), 2022) Ayoola, Ayodeji Ayodele; Fayomi, O. S. I.; Akande, Godwin I,; Mgbahurike,Chinemerem F.In this research work, the evaluation of the corrosion inhibitive performance of pawpaw fluid on A315 mild and 304 stainless steels in 0.5M H2SO4 (through weight loss approach) was investigated. The investigation involved the effects of variation in the inhibitor concentrations (0 – 10 %vol/vol) on weight loss, corrosion rate, inhibitor efficiency and the morphological structure of the metal samples. The weight-loss method involved the subjection of metal samples to the corrosion process in the acidic medium for 21 days. The results of both weight loss and corrosion rates revealed that pawpaw fluid inhibitor with a concentration of 10 %vol/vol gave the highest inhibitor efficiency of 89.9% and 87.1% for A315 mild and A304 stainless steels respectively. Also, results obtained showed that Langmuir adsorption isotherm accurately described the behavior of the adsorption mechanism and the physical adsorption (spontaneous) nature of the inhibitor was justified by the negative values of ∆Gads. Chemical composition results and the SEM analysis revealed that stainless steel has better corrosion resistance performance in 0.5M H2SO4 medium compared to mild steel (under the same experimental condition).Item CORROSION INHIBITION OF A36 MILD STEEL IN ACIDIC MEDIUM USING Citrus paradisi Rind Inhibitor(Rasayan J. Chem., 15(3), 2022-07) Ayoola, Ayodeji Ayodele; Olulesho, S; Durodola, Bamidee; Agboola, o.; Oladokun, O.; Ayeni, A.; Fayomi, O. S. I.; Babalola, R.The effectiveness of grapefruit (citrus paradisi rind) peel powder as a green corrosion inhibitor on A36 mild steel in 0.5M H2SO4 was examined. Gravimetric tests, SEM-EDS, and adsorption isotherm techniques were used to determine the corrosion inhibition features of the inhibitor on the surface of A36 mild steel. The tests were carried out with variation in concentration of inhibitor (0–0.4 %w/v), corrosion temperature (301K and 318K), and corrosion time (3 12 hours). The findings demonstrated that citrus paradisi rind powder effectively inhibited the corrosion of A36 mild steel on the surface with maximum corrosion inhibition efficiency of 85% at 0.4 w/v% inhibitor concentration at 310K corrosion temperature. The SEM-EDS analysis established the presence of sulphur, nitrogen, and oxygen (organic constituents), as well as the formation of a protective coating on the mild steel surface. Langmuir adsorption isotherm was found suitable for the prediction of the adsorption of citrus paradisi rind inhibitor on the mild steel surface. The thermodynamic considerations (∆𝐻 and (∆𝑆) indicated that the inhibition of A36 mild steel corrosion (using citrus paradisi rind inhibitor) was an exothermic process and the inhibitor molecules were physically adsorbed on the metal surface.Item Production of waste vegetable oil biodiesel using calcined periwinkle shells as catalyst(Chemical Papers, 2023) Ayoola, Ayodeji Ayodele; Chiekweta, Gozirim; Agbede, Cedar; Michae, Oke; Babalola, PhilipAs part of the efforts in overcoming global energy crisis, this research work focuses on the transesterification of waste veg etable oil, using calcined periwinkle shells and wet impregnated zinc oxide as catalysts. Periwinkle shells were calcined at 850 °C for 3 h, using carbolite furnace to obtain CaO catalyst and part of the catalyst was wet impregnated with ZnO. The quality of the calcined CaO obtained (81.6%) was established through XRF analysis. The three parameters considered dur ing the transesterification of the treated waste oil were methanol/oil ratio (0.2–0.8 v/v), catalyst concentration (4–8 wt/wt%) and reaction time (1–2 h). At methanol/oil ratio of 0.34 v/v, catalyst concentration of 4.12 wt/wt% and reaction time of 2 h, the optimum biodiesel yield of 84.96% was obtained using calcined CaO catalyst and a yield of 81.33% using impregnated ZnO/CaO catalyst. Brake power of 4.47 kW was obtained for both the biodiesel produced and pure diesel standard. Other mechanical properties, physical properties, as well as the chemical composition of the biodiesel produced revealed high level of conformity of the biodiesel produced to ASTM standardsItem Mild steel corrosion control through locally sourced calcium oxide on zinc phosphating process(South African Journal of Chemical Engineering 44, 2023) Ayoola, Ayodeji Ayodele; Ajinomisanghan, Eworitsemogha; Durodola, Bamidee; Fayomi, O. S. I.Mild steel is vulnerable to corrosion, so its prevention is essential in order to sustain its wide applications in petroleum, food, electrical, chemical, and construction industries. This study investigated the corrosion control action of the locally sourced calcium oxide on the zinc phosphating process of mild steel. Varied concentrations of calcium oxide (0 – 2 g/L) and coating (phosphating) time (40–70 min) were considered during the phos phating of the pretreated mild steel samples at coating temperatures of 60 ◦ C and 80 were subjected to weight loss tests utilizing a solution of NaCl (3.5 wt.%) at 25 ◦ ◦ C. The phosphate samples C, in order to determine both the sample corrosion rates and corrosion inhibition efficiencies. As both the calcium oxide concentration and phosphating temperature increased, the results trend (in general) showed a decrease in corrosion rate and in crease in inhibition efficiency. Sample with the operating conditions of 70minutes coating time, 2.0 g/L calcium oxide in the bath at 80 ◦ ads C coating temperature exhibited the best inhibition efficiency of 81% and lowest corrosion rate of 0.029 mm/year. SEM analysis revealed that the crystals of the coated surface became finer and had a more surface coverage owing to the increase in the concentration of calcium oxide (from 0.7 to 2.0 g/L). ΔG values of close to -20 kJmol 1 obtained (from both Langmuir and Freundlich adsorption isotherms) revealed a spontaneous and physical adsorption process of calcium oxide on the sample surfaces. The calculated positive values of ΔH ads and ΔS ads established the phosphating (coating) process to be an endothermic process with increased randomness at the solid/liquid interface of the sample surface and bath solution.Item Corrosion inhibitive effects of calcium-modified zinc phosphate coating on A36 mild steel(Results in Engineering, 2023) Ayoola, Ayodeji Ayodele; Durodola, B. M.; Bablola, R.; Adeniyi, O. D.; Ilobinso C. E.In this work, the corrosion inhibitive performance of calcium modified zinc phosphate coating on A36 mild steel was studied. Treated A36 mild steel samples were subjected to coating through immersion in phosphating bath containing varied concentrations of calcium oxide (0–2.5 g/L) at different operating temperatures (60–80 C) and immersion time (30–60 min). The coated samples were then subjected to corrosion tests (weight loss and inhibition efficiency determination) in 3.5% NaCl solution, to examine the anticorrosion behaviour of the coated mild steel in NaCl solution. The calcium modified phosphating process which was carried out at 80 ◦ ◦ C with calcium concentration of 2.5 g/L gave a better and more uniform coating on A36 mild steel surface, as confirmed by visual inspection and SEM/EDS analysis. Also, Freundlich adsorption isotherm was found suitable for the prediction of the adsorption of both calcium and zinc particles on A36 mild steel, as indicated by the coefficient of determination (R 2 ) values of approximately one. The adsorption of both the zinc and calcium particles on A36 mild steel was found to be spontaneous and physical process, as revealed by the values of K ads and ΔG ads .