Application of modified cellulose for Pb2+ and Cu2+ removal from aqueous solutions: Kinetic and isotherms studies

Abstract

In this work, acrylamide grafted Kolanut Pod Husk cellulose adsorbents were successfully prepared via chemical modification of Kola nut pod husk  cellulose with acrylamide and N, N’- methylenebisacrylamide. The modified adsorbents were successfully applied for the adsorptive removal of Pb²⁺ and  Cu²⁺ ions from aqueous solutions at different parameters, such as pH of the solution, adsorbent dosage, contact time, and initial metal ion  concentrations were optimized. Qualitative analysis of the modified adsorbents was performed by Fourier Transformed Infra-Red Spectroscopy and  Scanning Electron Microscopy. Characterization analyses portrayed the surface of adsorbents as being short elongated shaped with dispersed pores and  composed of hydroxyl and carbonyl groups as the main binding sites. The optimum conditions for adsorption of Pb²⁺ and Cu²⁺ were found to be: pH; 5,  adsorbent dosage; 3.5 and 4 g L^-1 , concentration; 60 mg L^-1 and contact time; 160 min. Adsorption data were fully fitted with the Freundlich, Langmuir  isotherm model, and a pseudo-second order, Elovich kinetic model. The adsorption of metal ion was heterogenous in nature with qmax of 55.14 mg g^-1 and 62.09 mg g^-1 for Pb²⁺, 54.82 mg g^-1 , and 60.43 mg gfor Cu²⁺ respectively. These results showed that the modified adsorbents were able to  efficiently remove Pb²⁺ and Cu²⁺ from aqueous solutions.