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- ItemComparative Reactivity of Triphenylmethane, Anthraquinone and Nitro Dyes towards Degradation using Titania Photocatalyst(South African Chemical Institute, 2024) Omolola Titilayo Odeyemi, John Augustine Lawal and Abimbola George OlaremuTitania (TiO2) photodegradation of three dyes in aqueous media: picric acid (PA), alizarin red-S (ARS), and crystal violet (CV) showed a practical wastewater remediation technique in this work. The process unfolded in a photoreactor equipped with a 20 W UV-lamp, aerators, and heating elements. Spectroscopic characterization of TiO2 and dyes was achieved using Fourier Transform Infrared (FTIR), X-ray diffraction (XRD) and UV-visible methods. Simulated dye wastewater were treated with TiO2, and photodegradation rates were monitored by UV-Visible Spectrophotometry. Effect of pH, temperature, catalyst concentration, and dye concentration on the degradation rates was determined. Comparative analysis of dye reactivities was conducted utilizing desirability response derived from historical data within the framework of Response Surface Methodology. FTIR spectra of TiO2 post-degradation revealed the adsorption of dye chromophores, Triphenyl methane, Anthraquinone and Nitro from CV, ARS and PA respectively. XRD and UV-vis spectra revealed the rutile phase of TiO2 with a bandgap of 2.852 eV. Maximum percent degradation followed the order: CV > ARS > PA, reaching 72.1%, 59.8%, and 44.1%, respectively. This study accentuates the preference for lower temperatures, with CV emerging as the most reactive to TiO2, and predicts the degradation efficiency of the photocatalyst for various compositions of dye wastewater.
- ItemOptimal water-cement ratio and volume of superplasticizers for blended cement-bamboo leaf ash high-performance concrete(2022) Samson Olalekan Odeyemi, Michael Oluwasegun Adisa, Olumoyewa Dotun Atoyebi, Uwemedimo Nyong Wilson, Omolola Titilayo OdeyemiAttention on the use of High-Performance Concrete (HPC) for construction works has soared considerably due to the need for large volume of concrete with high level of strength for such works. The mechanical properties of HPC with Bamboo Leaf Ash (BLA) as partial replacement of cement with varying proportions of superplasticizer and water-cement ratio was investigated in this paper. The percentage of BLA was fixed at 5%, while the proportion of superplasticizer ranged from 0 to 1.5% by weight of cement. The concrete mix was designed to attain a characteristic strength of 41 N/mm² after 28 days of curing. X-ray Fluorescence (XRF) and X-ray Diffraction (XRD) were employed in determining the chemical constituents and crystallinity of the BLA respectively. The slump of the fresh HPC was also established. Concrete cubes (for water absorption and compressive strength) were cast and immersed fully in water for 56 days. Water absorption and compressive strength were established on the fully cured HPC. The optimal combination of materials at the end of the curing period is 0.360 water-cement ratio at 0.128 % superplasticizer. This resulted in a slump height of 49 mm, compressive strength of 53.61 N/mm2 and 4.77% water absorption capacity.
- ItemDetermination and Comparison of Ascorbic Acid Contents in Selected Fruits and Vegetables obtained from Ilorin Metropolis(2019) Odeyemi Omolola Titilayo, Amira Esther Oluwatoyin and Hassan Iyabo RihanatThe ascorbic acid contents of eight different fruits and four vegetable types were determined by iodometric titration method using standardized sodium thiosulphate against ascorbic acid in the fruit and vegetable extracts. A blank titration was first carried out on the thiosulphate only followed by titration with the extracts. From the blank titre, the total amount of water-soluble iodine produced in the reaction was calculated while the amount of water-soluble iodine that reacted with the sample was obtained from the test titre. The quantity of ascorbic acid in milligrams, present in each fruit and vegetable sample was obtained by calculations. The results showed that the amount of ascorbic acid in the selected fruits was in the order of Orange > Tangerine > Water melon > Pineapple > Grape > Apple > Lemon > Lime and the vegetables, in the order of Pumpkin > Bitter leaf > Water leaf > Amaranth leaf.
- ItemComparative activities of Titania, Ni-Titania and Co-Titania in photocatalytic degradation of picric acid dye(Prince of Songkla University, 2020-09) Odebunmi, Ezekiel Oluyemi and Odeyemi, Omolola TitilayoTitania (TiO2) photocatalyst was synthesized by the sol-gel method involving acid hydrolysis followed by oxidation with hydrogen peroxide. Cobalt and nickel metal ions were impregnated at 1, 5 or 10 % concentrations using metal nitrate salt solutions. The photocatalysts were characterized by various techniques. Scanning Electron Microscopy (SEM) and Diffused Reflectance Spectroscopy (DRS) showed that the doped TiO2 were smaller in size and had smaller band gap than pure TiO2, while X-ray Diffraction (XRD) and X-ray Fluorescence (XRF) spectroscopy showed that all the photocatalysts were rutile phase and contained the expected elements. The percent degradation of Picric acid dye at pH 3, initial dye concentration 10 ppm, catalyst concentration 0.10 g/l, and temperature 55 oC, had rank order: TiO2 < 1 % doped < 5 % doped < 10 % doped TiO2, showing that the photocatalytic activities of the Co-TiO2 and Ni-TiO2 increased with dopant concentration.
- ItemMechanical Properties and Microstructure of High-Performance Concrete with bamboo leaf ash as additive(Elsevier, 2022) S.O. Odeyemi, O.D. Atoyebi, O.S. Kegbeyale, M.A. Anifowose, O.T. Odeyemi, A.G. Adeniyi, O.A. OrisadareThe demand for High-Performance Concrete (HPC) is on the increase for its good workability, high strength, and better durability. HPC are obtained by incorporating supplementary Cementitious Materials (SCM) into concrete to attain a long-term strength and durability performance. Though, several SCM have been investigated in HPC, the use of Bamboo Leave Ash (BLA) in HPC as an SCM has not been considered. Thus, this research investigated the use of BLA as SCM in HPC. The bamboo leaves were calcined in an electric furnace at a temperature of 700 °C. The ash was characterized using Energy Dispersive X-ray Fluorescence (EDXRF) and were found to possess pozzolanic properties with silica content above 70%. Cement was replaced by BLA at 5%, 10%, 15%, and 20% by weight of cement. Concrete made from these combinations were tested for compressive and splitting tensile strengths at 7, 28 and 56 days of curing. It was observed that optimum strength was attained at 5% replacement at 56 days of curing. The microstructures of the concrete revealed that at 5% incorporation of BLA in concrete, there was a better interlocking of concrete grain. It was concluded that cement can be replaced with 5% BLA in High Performance Concrete.