Browsing by Author "Okolie, Justus I."

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    Adsorption of cupper (II) ion on heterogeneous surfaces of selected low-cost precursors; an application of isotherm, thermodynamic and kinetic models
    (U. P., 2015-01) Uzoije , Atulegwu .Patrick; Okolie, Justus I.; Njoku, P. C.; Enwereuzo., Uzo
    Cupper ions occur naturally in the environment and also prevalent in the waste from metal smelting industries through which it gets to the environment. Excessive intake of cupper results to adverse health effects on plant, animals and humans. The present study therefore studied the Adsorption of Cupper (II) ion on three activated bio-adsorbents; Unripe plantain peel, pineapple peel and commercial activated carbon. The activated carbons were characterized for surface morphology and functional groups for removal of Cupper (II) ion from aqueous solution. Batch process was adopted to study the time, temperature effect and isotherm equilibrium of Cupper (II) ion on. Adsorption of Cupper (II) ion on the three adsorbents got to equilibrium at between 80-100 minutes. Adsorption capacity of the three adsorbent was in this order at all temperature values; Unripe plantain peel greater than pineapple peel and greater than commercial activated carbon. Adsorption of Cupper ion increased with temperature, adsorption got to its plateau at 45oC and began to decrease. Langumuir-freunlich and Dubini-Radushkevichmodels were applied to analyze the Isotherm data. Langumuir-freunlich described the data better than Dubini-Radushkevich. Also, Pseudo-first order, pseudo-second-order, and intra-particle diffusion models were applied to test the kinetic data, pseudo-second-order fitted the data better than pseudo-first order. Pore-pore particle diffusion was observed to be the controlling step. Endothermic and non- spontaneous processes characterized Cupper ion adsorption on the three adsorbents .
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    Equilibrium, thermodynamic and kinetic studies on adsorption of zinc (II) from solutions using different low-cost adsorbents
    (U. P., 2015) Njoku, Pascal C.; Ayuk, Atu A.; Uzoije, Atulegwu, P.; Okolie, Justus I.
    Many industrial wastewaters contain numerous toxic metals such as zinc, which must be removed before reuse of the water or discharge into the environment. In this present study, unripe plantain peel activated carbon (UPPAC), pineapple peel activated carbon (PPAC) and commercial activated carbon (CAC) were utilized as low cost adsorbents for the removal of Zn (II) from aqueous solutions. Batch adsorption methodology was used to evaluate the effect of solution pH, initial metal ion concentration, adsorbent dose, contact time and temperature on adsorption. Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectrophotometer (FTIR) were used to characterize the adsorbents. The equilibrium isotherm data were analyzed using the Langmuir, Freundlich and Temkin isotherm model. The kinetic data were analyzed using the pseudo-first order, pseudo-second order equations, Elovich equation and intraparticle rate equation. Maximum adsorption of Zn (II) on UPPAC, PPAC and CAC (82.45%, 89.95% and 93.45%) was observed at pH 6 and pH 7. The adsorbed amount of Zn (II) increased with increase in contact time and reached equilibrium within 180 minutes. The maximum adsorption was found to be 200 mg/L in the studied range (200 – 1000 mg/L). The adsorption capacity and percent removal of Zn (II) were found to increase with increase in temperature. The Freundlich isotherm models provided the best fit to the experimental data for Zn (II) as indicated by the regression coefficient values (R2 > 0.97). The pseudo-second order equation gave the best fit to the experimental data for the metal ion (R2 > 0.99). Thermodynamic analysis showed a spontaneous adsorption process as negative values of ∆Go (-1.269 to -5.530) were obtained at all temperatures. The positive enthalpy change ∆Ho, 18.00, 20.46 and 23.45 kJ mol-1 for UPPAC, PPAC and CAC indicated an endothermic process. A highly disordered process was indicated by the positive entropy change ∆So.