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Journal of Chemistry
Volume 2016 (2016), Article ID 6436039, 11 pages
http://dx.doi.org/10.1155/2016/6436039
Research Article

Biosorption of Acid Dye in Single and Multidye Systems onto Sawdust of Locust Bean (Parkia biglobosa) Tree

1Department of Chemistry, Cape Peninsula University of Technology, P.O. Box 1906, Bellville 7535, South Africa
2Department of Pure and Applied Chemistry, Ladoke Akintola University of Technology, PMB 4000, Ogbomoso 210214, Nigeria

Received 27 October 2015; Revised 12 January 2016; Accepted 17 February 2016

Academic Editor: Marisol Belmonte

Copyright © 2016 Abdur-Rahim Adebisi Giwa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Properties of raw sawdust of Parkia biglobosa, as a biosorbent for the removal of Acid Blue 161 dye in single, binary, and ternary dye systems with Rhodamine B and Methylene Blue dyes in aqueous solution, were investigated. The sawdust was characterized using Scanning Electron Microscopy, Fourier Transform Infrared spectrophotometry, X-ray diffraction, and pH point of zero charge. Batch adsorption experiments were carried out to determine the equilibrium characteristics, thermodynamics, and kinetics of the sorption processes. The data obtained were subjected to various isotherm and kinetics equations. The results showed that the adsorption processes were described by different isotherm models depending on the composition of the system; they were all spontaneous ( ranges from −0.72 to −5.36 kJ/mol) and endothermic (range of is 11.37–26.31 kJ/mol) and with increased randomness with values of 55.55 and 98.78 J·mol/K for single and ternary systems, respectively. Pseudo-second-order kinetics model gave better fit for all the sorption systems studied irrespective of the differences in composition, with the initial and overall rate constants higher for the mixtures than for the single system (6.76 g·mg−1min−1). The presence of Rhodamine B and Methylene Blue had a synergetic effect on the maximum monolayer capacity of the adsorbent for Acid Blue 161 dye.