Removal of Cu(II) from aqueous solution using coconut (Cocos nucifera L.) coir dust
By Aniekemeabasi Israel, Regina Ogali, Onyewuchi Akaranta, Ime .B. Obot
The objective of this study is to assess the removal of Cu (II) from aqueous solution onto coconut Cocos nucifera L. (coir dust). The effect of various parameters has been investigated by batch adsorption techniques. The various variables studied include agitation time, pH, and particle size. The optimal time, pH, and particle size was found to be 60 mins, 7.5-8, and 50 μm respectively. The maximum uptake of copper (II) was found to be 111.11 mg of copper (II) per grams of coir dust. The equilibrium data was analyzed using Langmiur, Freundlich, Flory-Huggins and Dubinin-Radushkevich (D-R) isotherm models. Analysis of the data shows that Freundlich and Flory-Huggins described the data more appropriately than the Langmiur and Dubinin-Radushkevich isotherms. Adsorption kinetics data was tested using Pseudo-first-order, pseudo-second-order, Elovich equation and intra-particle diffusion models. Kinetic studies showed that the adsorption followed a pseudo-second-order model. Studies revealed that the intra-particle diffusion played an important role in the mechanism of Copper (II) adsorption while the Elovich equation suggests a chemisorption-ion-exchange mechanism for the adsorbate onto the coir dust.
Keywords: Adsorption, Adsorption isotherm, Coir dust, Copper (II), Ion-exchange, Kinetics