Adsorption of anionic dyes on chitosan beads. 1. The influence of the chemical structures of dyes and temperature on the adsorption kinetics.
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 degrees C. However, adsorption of the blue-dye decreased from 25 to 50 degrees C. Interestingly, the adsorption of the red-dye decreased from 25 to 35 degrees C and increased from 45 to 50 degrees 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.
Cestari
Antonio R
AR
Laboratory of Materials and Calorimetry, Departamento de Química/CCET, Universidade Federal de Sergipe, CEP 49000-000, São Cristovão, Sergipe, Brazil. cestari@ufs.br
Vieira
Eunice F S
EF
Dos Santos
Aline G P
AG
Mota
Jackeline A
JA
de Almeida
Vanessa P
VP
D000327:Adsorption; D000838:Anions / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D002686:Chitin / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D003432:Cross-Linking Reagents; D005976:Glutaral / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008968:Molecular Conformation; D012996:Solutions; D013696:Temperature; D014961:X-Ray Diffraction
D000838:Anions; D001672:Biocompatible Materials; D004396:Coloring Agents; D003432:Cross-Linking Reagents; D012996:Solutions; D002686:Chitin; D048271:Chitosan; D005976:Glutaral