Browsing by Author "Enenebeaku, C. K."

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    Adsorption and corrosion-inhibiting effect of dacryodis edulis extract on low-carbon-steel corrosion in acidic media
    (Elsevier Inc, 2010-09-01) Oguzie, E. E.; Enenebeaku, C. K.; Akalezi, C. O.; Okoro, S. C.; Ayuk, A. A.; Ejike, E. N.
    The inhibition of low-carbon-steel corrosion in 1 M HCl and 0.5 M H2SO4 by extracts of Dacryodis edulis (DE) was investigated using gravimetric and electrochemical techniques. DE extract was found to inhibit the uniform and localized corrosion of carbon steel in the acidic media, affecting both the cathodic and anodic partial reactions. The corrosion process was inhibited by adsorption of the extracted organic mat ter onto the steel surface in a concentration-dependent manner and involved both protonated and molec ular species. Molecular dynamics simulations were performed to illustrate the process of adsorption of some specific components of the extract
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    Adsorption and corrosion-inhibiting effect of dacryodis edulis extract on low-carbon-steel corrosion in acidic media
    (Elsevier Inc., 2010) Oguzie, E. E.; Enenebeaku, C. K.; Akalezi, C. O.; Okoro, S. C.; Ayuk, A. A.; Ejike, E. N.
    The inhibition of low-carbon-steel corrosion in 1 M HCl and 0.5 M H2SO4 by extracts of Dacryodis edulis(DE) was investigated using gravimetric and electrochemical techniques. DE extract was found to inhibit the uniform and localized corrosion of carbon steel in the acidic media, affecting both the cathodic and anodic partial reactions. The corrosion process was inhibited by adsorption of the extracted organic mat ter onto the steel surface in a concentration-dependent manner and involved both protonated and molec ular species. Molecular dynamics simulations were performed to illustrate the process of adsorption of some specific components of the extract.
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    Corrosion inhibiting effect of aframomum melegueta extracts and adsorption characteristics of the active constituents on mild steel in acidic media
    (Taylor & Francis Group, LLC, 2013) Oguzie, E. E.; Iheabunike, Z. O.; Oguzie, K. L.; Ogukwe, C. E.; Chidiebere, M. A.; Enenebeaku, C. K.; Akalezi, C. O.
    The extract from the seeds of Aframomum melegueta (AM) was investigated as corrosion inhibitor for mild steel in aerated 1M HCl and 0.5M H2SO4 solutions using gravimetric and electrochemical techniques. AM extract was found to inhibit both the cathodic and anodic partial reactions of the corrosion process, via adsorption of the organic matter on the metal/solution interface, as described by the Langmuir as well as Flory-Huggins adsorption isotherms. Corrosion rates in all systems studied increased with rise in temperature. Increasing the temperature of the system enhanced inhibition efficiency of AM extract in 1M HCl, but decreased efficiency in 0.5M H2SO4. Molecular dynamics simulations were performed to theoretically illustrate the electronic structure and adsorption behaviour of the active constituents of the seeds of Aframomum melegueta; paradol (1-(4-Hydroxy-3-methoxyphenyl)decan-3-one) and shogaol ((E)-1-(4-Hydroxy-3- methoxyphenyl)dec-4-en-3-one) in order to theoretically evaluate their contributions to the corrosion inhibiting action of the extract.
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    Effect of hexamethylpararosaniline chloride (crystal violet) on mild steel corrosion in acidic media
    (Elsevier Ltd, 2008) Oguzie, E. E.; Njoku, V. O.; Enenebeaku, C. K.; Akalezi, C. O.; Obi, C.
    The corrosion inhibition of mild steel in 0.5 M H2SO4 and 1 M HCl by hexamethylpararosaniline chloride (HMPC) was investigated using the gravimetric technique in the temperature range 303–333 K. The results indicate that HPMC inhibited the corrosion reaction in both acid media at all temperatures and inhibition efficiency increased with HMPC concentration. The inhibiting action is attributed to general adsorption of protonated and molecular HPMC species on the corroding metal surface. Adsorption followed a modified Langmuir isotherm and the Temkin isotherm, with very high negative values of the free energy of adsorption (DG0ads). An increase in temperature reduced the inhibition efficiency of HPMC in 0.5 M H2SO4 but increased efficiency in 1 M HCl. Activation parameters such as activation energy (Ea), activation enthalpy (DH*) and activation entropy (DS*) as well as the adsorption heat (Qads) were evaluated from the effect of temperature on corrosion and inhibition
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    Establishing risk assessment from reclaimed Nekede Mechanic Village Owerri, Nigeria
    (U. P., 2018-09-14) Nkwoada, A. U.; Alisa, C. O.; Amakom, C. M.; Enenebeaku, C. K.
    The current resettlement of Nekede Auto-Mechanic village by Imo State government of Nigeria created a sparse piece of land awaiting government utilization. Risk assessment was carried out on the land using existing boreholes and soil to determine land utilization potential. Analysis of the physicochemical water parameters showed that there was no contamination of boreholes. The high value of COD correlated with the high levels of Fe in soil and water samples. Heavy metals concentrations showed that Fe was very much present in the soil while Pb, Cd and Cu had reduced concentrations. Risk assessment for the soil samples showed that Fe had the highest mean and median value. The highest mean value for water was Cu metal. Highest variance value was Cu in soil while Pb had the lowest value in water. Hazard quotient of water samples showed that hazards existed for Cd, Cu and Pb but at a moderate level for Fe. Estimated daily/weekly water intake values were all below WHO/FAO standards. The soil enrichment factor showed no enrichment for Pb, minimal enrichment for Cd, moderate enrichment for Cu and significant contamination for Fe. Ecological risk assessments for the heavy metals were at low ecological risk. Potential ecological index depicts Fe and Cd at a considerable level of ecological risk. Likewise, contaminants existed at the nearby Otamiri river due to dredging and nearby waste dumps. The anthropogenic activity at the Otamiri river posed a serious environmental concern if not controlled and reclaimed. Hence, the reclamation of Nekede auto mechanic village will not be suitable for agricultural or recreational purposes.
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    Studies on adsorptive behavior of Cd2+ on graphene oxide: Alternative novel approach
    (U. P., 2018-03-03) Nkwoada, A. U.; Alisa, C. O.; Enenebeaku, C. K.; Oguzie, E, E.
    Certain adsorptive mechanisms and interactions often exist within linearized kinetic functions which are largely unreported. A novel inverse saturation modeling was applied to evaluate the adsorptive behavior of super-saturation, saturation, and desorptive processes on linear kinetic function plots using pseudo 1st order, pseudo 2nd order, Elovich and Intra-particle diffusion. Graphene oxide was prepared by room temperature synthesis and used as adsorbent over Cd2+ adsorbate. Batch adsorption process was conducted and four error functions were utilized. The sum of squares of the errors and Sum of absolute errors identified pseudo 2nd order as having the least deviation at 0.113 and 0.337 respectively. The modelled pseudo 1st order reaction had R2 = 0.985 while the inverse saturation model had R2 value of 0.998, both been a better data fit than non-modelled pseudo 1st order R2 at 0.917. The slower reaction kinetics in pseudo 1st order was due to supersaturation during adsorption as shown by inverse saturation point. The correlation coefficient of modeled kinetic plot of pseudo 2nd order, Intra particle diffusion and Elovich had R2 = 1. The Elovich inverse saturation plot showed that the graph was an L-isotherm type indicating progressive saturation. The rate determining step experienced by Intra-particle diffusion was accommodated by wide range of inverse saturation plots showing adsorption, supersaturation and desorption as points of greatest influence. The inverse saturation plot of pseudo 2nd order plot had absolute slope of 2.656 and large intercept of 24.815 driving it's faster reaction kinetics. Hence, the inverse saturation point modelling provided a much better interpretation of adsorptive behavior of graphene oxide adsorbent over Cd2+ adsorbate.