Equilibrium, Kinetics, and Thermodynamics of the Removal of Nickel(II) from Aqueous Solution Using Cow Hooves

I Osasona,O O Ajayi,A O Adebayo

doi:10.1155/2014/863173

I Osasona, O O Ajayi + Show 1 more

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https://doi.org/10.1155/2014/863173

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Abstract

The feasibility of using powdered cow hooves (CH) for removing Ni2+ from aqueous solution was investigated through batch studies. The study was conducted to determine the effect of pH, adsorbent dosage, contact time, adsorbent particle size, and temperature on the adsorption capacity of CH. Equilibrium studies were conducted using initial concentration of Ni2+ ranging from 15 to 100 mgL−1 at 208, 308, and 318 K, respectively. The results of our investigation at room temperature indicated that maximum adsorption of Ni2+ occurred at pH 7 and contact time of 20 minutes. The thermodynamics of the adsorption of Ni2+ onto CH showed that the process was spontaneous and endothermic. Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models were used to quantitatively analysed the equilibrium data. The equilibrium data were best fitted by Freundlich isotherm model, while the adsorption kinetics was well described by pseudo-second-order kinetic equation. The mean adsorption energy obtained from the D-R isotherm revealed that the adsorption process was dominated by physical adsorption. Powdered cow hooves could be utilized as a low-cost adsorbent at room temperature under the conditions of pH 7 and a contact time of 20 minutes for the removal of Ni(II) from aqueous solution.

Highlights

Heavy metal pollution is a global menace that has threatened the existence of lives for decades
Our results revealed that maximum removal of Ni at room temperature could be achieved within a period of 20 minutes and at pH 7
Thermodynamic parameters evaluated from this study showed that the adsorption process was endothermic and spontaneous at all temperatures considered

Summary

Introduction

Heavy metal pollution is a global menace that has threatened the existence of lives for decades. It has been pointed out that an enzyme (a nickel containing enzyme) called carbon monoxide dehydrogenase (CODH) performs an important role in the global carbon cycle. This is because CODH is involved in the interconversion of the environmental pollutant CO and the greenhouse gas CO2 [6]. Even though nickel plays some important roles as an essential micronutrient/enzyme cofactor and carbon dioxide sequestering agent in the environment, excessive concentrations of Ni in animals might cause serious health challenges like gastrointestinal distress, pulmonary fibrosis, skin dermatitis, cyanosis, nausea, tightness of the chest, dry cough and shortness of breath, rapid respiration, and so forth [4, 7, 8]

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