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Bioinorganic Chemistry and Applications
Volume 2018, Article ID 3805654, 9 pages
https://doi.org/10.1155/2018/3805654
Research Article

Adsorption Characteristics of Bixin on Acid- and Alkali-Treated Kaolinite in Aprotic Solvents

1Université de Toulouse, INP-ENSIACET, Laboratoire de Chimie Agro-industrielle (LCA), 4 Allée Monso, 31030 Toulouse, France
2Department of Chemistry, Mathematics and Natural Science, Tanjungpura University, Jl. Ahmad Yani, Pontianak 78124, West Kalimantan, Indonesia
3INRA, UMR 1010 CAI, 31030 Toulouse, France

Correspondence should be addressed to Zéphirin Mouloungui; rf.tecaisne@iugnuoluom.nirihpez

Received 29 August 2017; Accepted 31 October 2017; Published 18 January 2018

Academic Editor: Spyros P. Perlepes

Copyright © 2018 Winda Rahmalia 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

The adsorption of bixin in aprotic solvents onto acid- and alkali-treated kaolinite was investigated. Kaolinite was treated three times, for 6 h each, with 8 M HCl or 5 M KOH. The adsorbents were characterized by XRD, FT-IR, EDS, and BET-N2. The effects of contact time and dye concentration on adsorption capacity and kinetics, electronic transition of bixin before and after adsorption, and also mechanism of bixin-kaolinite adsorption were investigated. Dye adsorption followed pseudo-second order kinetics and was faster in acetone than in dimethyl carbonate. The best adsorption results were obtained for KOH-treated kaolinite. In both of the solvents, the adsorption isotherm followed the Langmuir model and adsorption capacity was higher in dimethyl carbonate (qm = 0.43 mg/g) than in acetone (0.29 mg/g). The adsorption capacity and kinetics of KOH-treated kaolinite (qm = 0.43 mg/g, k2 = 3.27 g/mg·min) were better than those of HCl-treated kaolinite (qm = 0.21 mg/g, k2 = 0.25 g/mg·min) and natural kaolinite (qm = 0.18 mg/g, k2 = 0.32 g/mg·min). There are shift in the band position of maximum intensity of bixin after adsorption on this adsorbent. Adsorption in this system seemed to be based essentially on chemisorption due to the electrostatic interaction of bixin with the strong basic and reducing sites of kaolinite.