α-Ketoglutaric Acid-Modified Chitosan Resin as Sorbent for Enhancing Methylene Blue Removal from Aqueous Solutions

In this study, cross linked chitosan resin (CCR) was prepared by cross linking chitosan with glutaraldehyde, and then α-ketoglutaric acid-modified chitosan resin (KCR) was obtained by modifying CCR with α-ketoglutaric acid. The sorption behavior of methylene blue (MB) on KCR and CCR from aqueous solution was investigated. The effect of various experimental parameters (e.g. initial pH, sorbent dose, dye concentration, contact time, and temperature) was examined. The maximal MB sorption ratio on KCR and CCR was respectively reached beyond pH 8 and at pH 8. The MB removal ratio on KCR and CCR increased with increasing sorbent dose but decreased with increasing dye concentration. The isothermal data of MB sorbed on KCR and CCR followed the Langmuir model. The MB sorption process could be described by the pseudo-second-order kinetic model. The thermodynamic study indicated that the MB sorption process was spontaneous and exothermic.

Keywords
Methylene blue, Sorption, α-Ketoglutaric acid-modified chitosan resin, Kinetics, Thermodynamics