Adsorption of anionic dyes on chitosan beads. 1. The influence of the chemical structures of dyes and temperature on the adsorption kinetics

• Published in: Journal of colloid and interface science Vol. 280; no. 2; pp. 380 - 386
• Main Authors: Cestari, Antonio R., Vieira, Eunice F.S., dos Santos, Aline G.P., Mota, Jackeline A., de Almeida, Vanessa P.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 15-12-2004; Elsevier
• Subjects: Adsorption; Adsorption kinetics; Anions - chemistry; Avrami kinetic model; Biocompatible Materials - chemistry; Chemistry; Chitin - chemistry; Chitosan - chemistry; Chitosan beads; Coloring Agents - chemistry; Cross-Linking Reagents; Exact sciences and technology; General and physical chemistry; Glutaral - chemistry; Hydrogen-Ion Concentration; Kinetics; Molecular Conformation; Reactive dyes; Solutions; Surface physical chemistry; Temperature; X-Ray Diffraction; Adsorption kinetics; Avrami kinetic model; Chitosan beads; Reactive dyes; Kinetic model; Dyes; Adsorption; Crosslinked state; Reactive dye; Chemical structure; Chitosan; Kinetics
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2004.08.007

In this work, chitosan beads were synthesized in acidic medium and cross-linked in 1% glutaraldehyde solution. The characterization of the materials using TG/DTG, XRD, and BET surface areas showed that the beads did not modify their characteristics after the cross-linking reaction. The cross-linked beads were utilized as adsorbents for the removal of the yellow-, blue-, and red-anionic reactive dyes from aqueous solutions at pH 2.0. Adsorption of the yellow-dye increased from 25 to 50 °C. However, adsorption of the blue-dye decreased from 25 to 50 °C. Interestingly, the adsorption of the red-dye decreased from 25 to 35 °C and increased from 45 to 50 °C. The kinetic data were evaluated using an Avrami kinetic model, where the parameter
n was related to the determination of changes in the adsorption mechanisms. Adsorption data of the dyes in relation to the contact time, the chemical structures of the dyes, and temperature were presented and were discussed.