DSpace Repository :: Browsing by Author "Folawewo Abayomi David"

Browsing by Author "Folawewo Abayomi David"

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Carbon-covered alumina-supported ZnO nanocatalysts with enhanced visible light photocatalytic performance for the removal of dyes
(Environmental Technology & Innovation, 2022) Folawewo Abayomi David; Bala Muhammad D.
In this study, environmentally sustainable catalysts were prepared economically as a positive step in directly using visible light to degrade wastewater polluted with industrial dyes. Hence, zinc oxide (ZnO) nanocatalysts doped with carbon-covered alumina (CCA) were fabricated by the sol–gel technique using zinc acetate as the precursor and CCA as the support. Various methods were used to characterize the catalysts, including XRD, TEM, EDS-SEM UV/Vis-DRS, EIS, PL, and BET. The new CCA-supported catalysts are crystalline with high surface areas. The photocatalytic capability of the catalysts was studied using azo dyes as model pollutants. Hence, sunset yellow and tartrazine were degraded up to 99% by the catalysts, which were also recycled five times without loss in activity. Details on the kinetics and mechanistic mode of catalyst action are presented and analysed. Chemical oxygen demand measurements further confirmed the mineralization of the dyes. The study showed that the ZnO/CCA/Vis photocatalysis has good prospects of adoption for large-scale pre-treatment of dye-polluted wastewaters. This technique is suited to the food, textile and allied industries that employ substantial quantities of colourants.
Effects of Different pH Values on Dissolution and Recovery of Zinc and Manganese from Spent Zinc– Carbon Batteries Using Ascorbic Acids
(Chemical Science International Journal, 2017) Folawewo Abayomi David; Bankole O. E.; Samson E. A.; Adebisi S. A.; Ogunbowale S. K.
The improper disposal of solid batteries containing manganese and zinc has adverse effects from both an environmental and economic standpoint. It would therefore be useful to be able to recover the compounds of zinc and manganese in these batteries so that these materials might either be re-used or properly disposed of. This research presents the results of the effects of different pH values on the dissolution of zinc and manganese from waste zinc – carbon batteries using mixtures of ascorbic acid and sulfuric acids.The waste batteries were manually separated into various components, and the inner cathode and anode electrodes were ground into powder. This was followed by the extraction of 10 g of battery paste with a mixture of 15 g/dm3 ascorbic acid, 0.5 M or 1.0 M H2SO4 at different pH values from 2 to 12 (at about 80°C) and an agitation speed of about 20 rpm. The resulting solutions analyzed using atomic absorption spectrophotometry (AAS) showed that the concentration of Mn extracted from the battery was higher than that of Zn at pH’s of 2, 4, 6. The concentrations ranged from 1200 – 10000 mg/kg and 200 – 4200 mg/kg for Mn and Zn, respectively. This indicates that more Mn than Zn would be extracted at lower pH than at higher pH values. The extraction of both metals into the solution decreased with increased in pH of the solution mixture and these results are shown to be consistent with a kinetic model. It was also observed that the recovery of metals from the battery was pH dependent and that more was recovered using NaOH rather than KOH solutions.
Environmental Influence on the Oxidative Rancidity of Tropical Soybean Oil in Ogun State Nigeria
(International Journal of Research and Development, 2017) Folawewo Abayomi David; Madu Alexander Nnamdi; Njoku Michael Ikechukwu
The environmental influence on the oxidative rancidity of tropical soybean oil found in local markets in Ogun state Nigeria has been investigated in aqueous, alkaline, neutral, metal and acid environments and the results shows that the peroxide values measured as MeqO2/Kg were in the range of 3.48 – 11.82 for the acid environment, 3.24 – 10.94 in alkaline environment, 3.27 – 10.22 in metal environment, 3.16 – 9.86 in aqueous environment and 2.48 – 4.46 in neutral or normal environment. The peroxide value showed significantly high values for the acid environment and closely followed by the alkaline and metal environments. The aqueous environment also showed high values as compared to the neutral or normal environment. The % FFA showed similar profiles in the range of 1.46 8.87 for the acid environment, 1.42 – 8.66 in alkaline environment, 1.28 – 6.48 in metal environment, 1.24 – 6.22 in aqueous environment and 1.12 – 2.48 in neutral or normal environment with the acid and alkaline environments showing high values of over 8.7. There was an observed close relationship in the acid and alkaline environments as well as metal and aqueous environments as shown in the plot. The Saponification values measured as mg(KOH)/g of oil also showed similar trend in the range of 194 – 284 for the acid environment, 192 – 285 in alkaline environment, 188 – 278 in metal environment, 186 – 273 in aqueous environment and 182 – 248 in neutral or normal environment. The effect of increasing the temperature on the peroxide value of the oil was also marked. It was shown that as the temperature increased from 30 °C to 120 °C, the peroxide value increased from 3.16 Meq/Kg to 15.22 MeqO2/Kg.
Extent of Industrial Accumulation of Poly-Substituted Organic Biphenyl Pollutants in Soil, Plant and Water Bodies in Agbara Industrial Area in Ogun State Nigeria
(International Journal of Multidisciplinary Research, 2017) Folawewo Abayomi David; Madu Alexander Nnamdi; Faboyede Adekemi Omolayo; Njoku Michael Ikechukwu; Bankole F. O
The level of poly-substituted organic biphenyl pollutants in the surrounding soils, plant and water bodies in Agbara Industrial area has been investigated and results show that the concentration of poly-substituted biphenyls were highest in the sewage and amounted to over 1.80 μg/L and closely followed by the sample from the lagoon having over 1.60 μg/L. The concentrations of the pollutants in the drainages fall within 1.20 μg/L to 1.30 μg/L. These values however show that the drainages form the route of the pollutants from neighboring industries while the lagoon and sewage form the receptacles and storage facility where they accumulate. The action limit for PCBs in sewage is 0.005 mg/L or 5.0μg/L. This shows that the sewage has PCBs level up to 36 % of the action limit. The PCBs obtained in the soils had the initial sample exceeding 5.6 x 102 μg/Kg or 0.56 mg/Kg amounting to 5.615 % of the action limit of 10 mg/Kg while the least sample had values exceeding 4.67 mg/Kg amounting to 4.7 % of the action limit. The plant samples analyzed accordingly had high values of 2.53 x 10-1 ng/Kg and lower values 1.161 x 10-1 ng/Kg amounting to 7.44 % and 4.74 % respectively of the action limit of 3.40 ng/Kg.
Investigations into the Properties of Waste Water within and around Agbara Industrial Estate of Ogun State, Nigeria
(actaSATECH, 2015) Folawewo Abayomi David; Madu Alexander Nnamdi; Njoku, Michael Ikechukwu; Agbasi U. M.; Ajibulu O. N.
Waste water within and around Agbara Industrial estate find their way into rivulets and streams which often times are sources of water supply both for domestic and agro-allied applications. Investigations reveal that the BOD values of seven waste water samples collected at different locations showed values between 1.30 and 7.60 except for sample G, all pH values ranged from 5.98 (acidic) to 8.30 (basic) with conductivity ranging from 475μs/cm to as high as 691μs/cm. The total hardness values range from 1.83 to as high as 6.50 whereas the calcium hardness range from 0.25 to 1.63 mg/100ml. Total Dissolved Solid (TDS) range from 1800 -3200mg/L and Total Suspended Solid (TSS) ranged from 6775 to 9860mg/L. Heavy metals ranged from 1.015 mg/100ml. to 1.421 mg/100ml. for Cu2+; 12.01 to 17.56 mg/100ml. for Fe2+ and 0.414 to 1.419 mg/100ml. for Zn2+ respectively. Mn2+, Pb2+ and As2+ had values ranging from; Mn2+ (1.720 to 2.53) mg/100ml, Pb2+ (2.052 to 3.421) mg/100ml.and As2+ (0.521 – 0.741) mg/100ml.
Nanocomposite Zinc Oxide-Based Photocatalysts: Recent Developments in Their Use for the Treatment of Dye-Polluted Wastewater
(Multidisciplinary Digital Publishing Institute, 2022) Folawewo Abayomi David; Bala Muhammad D.
This review highlights current developments in utilising zinc oxide (ZnO) composite materials as photocatalysts. Systematic analyses of the various synthetic methods for producing ZnO-based hetero-structured materials, the variety of methods for their characterisation, their mechanisms of action, and widespread applications for the degradation of pollutants are discussed. Structure/activity relationships and methods of improving on some of the recognised shortcomings of ZnO-based nanomaterial catalysts are also presented.
Physico-Chemical Properties of Wastewater within Agbara and Impact on Ologe Lagoon, Lagos.
(The Pacific Journal of Science and Technology, 2017) Faboyede Adekemi Omolayo; Folawewo Abayomi David; Madu Alexander Nnamdi; Muyideen Olaitan Bamidele
The physico-chemical analysis of effluents from diverse factories in Agbara and the fresh water bodies receiving these effluents in Ogun State, Nigeria was carried out to establish the effect of the effluents. The study analyzed the effect of industrial effluent discharge on Ologe Lagoon. Sampling points; W3, W4, W5, W6, and W7 were effluents discharged directly from the factories located within Agbara industrial estate. Sampling points W1 to W7 were chosen along the water body before and after discharged of these effluents to reflect the contribution and the effect of the industrial and domestic effluents. The study revealed that BOD values were 13.04, 75.99, 13.04, 16.48, 14.92, 14.37 and 14.82 for sample W1, W2, W3, W4, W5, W6, and W7, respectively. Except for sample W7, all pH values were all in the basic region with conductivity ranging from 64 μs/cm to as high as 631 μs/cm. The total hardness value ranges from 1.83 to as high as 6.50 whereas the calcium hardness ranges from 0.25 to 1.63. The mean concentration of heavy metals ranges from 2.01ppm – 7.60 ppm, 0.45-1.42 ppm, and 3.0-8.0 ppm for Cu2+, Fe2+, Pb2+, Cr2+ and Zn2+ respectively. With the exception of zinc and iron, the discharge of copper exceeded the maximum permissible limit given by the Federal Environmental Protection Agency of Nigeria (FEPA) and WHO. Similarly, mean level of total suspended solids (TSS), values are 700 mg/L, 1700 mg/L, 2200 mg/L, 200 mg/L, 400 mg/L, 1600 mg/L and 900 mg/L for samples W1, W2, W3, W4, W5, W6, and W7, respectively while for total dissolved solids (TDS) the values are 50 mg/L, 70 mg/L, 40 mg/L, 830 mg/L 10 mg/L, 110 mg/L and 160 mg/L for samples W1, W2, W3, W4, W5, W6, and W7, respectively. There is need for pre-treatment to be carried out on industrial effluent before discharge into water bodies, without this, there is tendency of these pollutants to persist in the water and its uptake may cause long term health problems to living things.
Physico-Chemical Properties of Wastewater within Agbara and Impact on Ologe Lagoon, Lagos.
(The Pacific Journal of Science and Technology, 2017-05) Folawewo Abayomi David; Madu Alexander Nnamdi; Faboyede Adekemi Omolayo; Muyideen Olaitan Bamidele
The physico-chemical analysis of effluents from diverse factories in Agbara and the fresh water bodies receiving these effluents in Ogun State, Nigeria was carried out to establish the effect of the effluents. The study analyzed the effect of industrial effluent discharge on Ologe Lagoon. Sampling points; W3, W4, W5, W6, and W7 were effluents discharged directly from the factories located within Agbara industrial estate. Sampling points W1 to W7 were chosen along the water body before and after discharged of these effluents to reflect the contribution and the effect of the industrial and domestic effluents. The study revealed that BOD values were 13.04, 75.99, 13.04, 16.48, 14.92, 14.37 and 14.82 for sample W1, W2, W3, W4, W5, W6, and W7, respectively. Except for sample W7, all pH values were all in the basic region with conductivity ranging from 64 μs/cm to as high as 631 μs/cm. The total hardness value ranges from 1.83 to as high as 6.50 whereas the calcium hardness ranges from 0.25 to 1.63. The mean concentration of heavy metals ranges from 2.01ppm – 7.60 ppm, 0.45-1.42 ppm, and 3.0-8.0 ppm for Cu2+, Fe2+, Pb2+, Cr2+ and Zn2+ respectively. With the exception of zinc and iron, the discharge of copper exceeded the maximum permissible limit given by the Federal Environmental Protection Agency of Nigeria (FEPA) and WHO. Similarly, mean level of total suspended solids (TSS), values are 700 mg/L, 1700 mg/L, 2200 mg/L, 200 mg/L, 400 mg/L, 1600 mg/L and 900 mg/L for samples W1, W2, W3, W4, W5, W6, and W7, respectively while for total dissolved solids (TDS) the values are 50 mg/L, 70 mg/L, 40 mg/L, 830 mg/L 10 mg/L, 110 mg/L and 160 mg/L for samples W1, W2, W3, W4, W5, W6, and W7, respectively. There is need for pre-treatment to be carried out on industrial effluent before discharge into water bodies, without this, there is tendency of these pollutants to persist in the water and its uptake may cause long term health problems to living things.
Phytochemical Screening and Antibacterial Activities of the Root Bark Extracts of Hippocratea africana (Willd.) Loes. ex Engl
(European Journal of Medicinal Plants, 2017) Agbaje-Daniels Folashade; Folawewo Abayomi David; Madu Alexander Nnamdi; Faboyede Adekemi Omolayo; Coker A. R.
The root of Hippocratea africana (Celastraceae) is used in ethnomedicine in South-Western Nigeria to treat infectious and parasitic diseases. This study aimed at identifying the compound(s) that are responsible for the antimicrobial activities of the roots and also to contribute to the chemistry of the plant species. Investigation of the phytochemical constituents and antimicrobial activity of the nhexane and methanol root bark extracts of Hippocratea africana was carried out. These extracts were subjected to screening of preliminary phytochemical test, which showed the presence of alkaloids, flavonoids, glycosides, phytosterols, phlobatanins and diterpenes. The crude methanol extract exhibited the largest zone of inhibition (16 mm in diameter with 700 mg/mL extract) against Morganella morganii and the largest zone of inhibition of the n-hexane crude extract (8 mm in diameter with 700 mg/mL) against E. coli. The methanol extract was subjected to column chromatography. Four isolates (A, B C & D) were obtained. Isolates C exhibited largest zone of inhibition (21 mm in diameter at 15 mg/mL) against Escherichia coli while isolate D exhibited the lowest zone of inhibition (3.7 mm in diameter at 15 mg/mL) against Klebsiella neumoniae.
Surface Adsorption of some Heavy Metal Ions in Waste and Underground Waters in Agbara Industrial Estate using Sodium Metasilicate
(International Journal of Scientific Research in Chemistry, 2017) Folawewo Abayomi David; Madu Alexander Nnamdi; Adebanjo M. G.
The surface adsorption of some heavy metals ions in waste and underground waters in Agbara industrial estate using sodium silicate has been investigated and results show that the percentage of metal ions adsorbed by the sodium metasilicate from prepared salts were least in iron Fe 0.0382 % (38.20 ppm), followed by copper Cu 0.0583 % (58.20 ppm). This was closely followed by zinc Zn 0.0590 % (57.70 ppm), nickel Ni 0.0663 % (59.91 ppm) and finally cadmium Cd 0.0698 % (68.765 ppm). Results of the adsorbed concentration and adsorption coefficient of the metasilicate on the watse and underground water samples showed tha zinc ranged from 0.354 ppm amounting to adsorption coefficient of 0.334 to 0.550 ppm amounting to an adsorption coefficient of 0.316, copper ranged from 0.420 ppm equivalent to a coefficient of 0.241 ppm to 0.505 ppm equivalent to a coefficient of 0.246. The values for cadmium ranged from 0.326 ppm to 0.446 ppm equivalent to adsorption coefficient of 0.337 and 0.357 respectively. Nickel had values ranging from 0.248 ppm to 0.380 ppm equivalent to adsorption coefficient of 0.242 and 0.393 respectively while iron had the highest values ranging from 0.664 ppm to 0.878 ppm equivalent of an adsorption coefficient of 0.270 and 0.283 respectively.
Visible light treatment of azo dye-contaminated water by Ni- and Co-doped-ZnO nanoparticles supported on carbon-covered alumina
(Water Practice & Technology, 2023) Folawewo Abayomi David; Bala Muhammad D.
Metal-ion (Co and Ni)-doped-zinc oxide (ZnO) nanocatalysts were successfully embedded onto carbon-covered alumina (CCA) supports via a simple, green sol–gel technique. The nanocatalysts were characterised by various analytical, microscopic, and spectroscopic techniques. The CCA-embedded nanocatalysts were crystalline with high surface areas and pore volume compared to the free metal-ion–doped-ZnO nanocatalysts while retaining the wurtzite phase of the core ZnO. The influences of the dopant content and the CCA on the optical and dye removal activities of the ZnO were investigated. The materials were photocatalytically active under visible light irradiation. Congo red and methyl orange dyes were used as model pollutants, and the reactivity followed a pseudo-first-order reaction kinetics. The reaction rate of the CCA-supported nanocatalysts showed doping with Co.Ni. The CCA/metal-ion-doped-ZnO was found to have photocatalytic activities better than the CCA-supported ZnO.

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