Chitosan and chemically modified chitosan beads for acid dyes sorption
AZLAN Kamari , WAN SAIME Wan Ngah , LAI KEN Liew
DOI:
Received April 01, 2008,Revised June 12, 2008, Accepted , Available online
Volume 21,2009,Pages 296-302
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The capabilities of chitosan and chitosan-EGDE (ethylene glycol diglycidyl ether) beads for removing Acid Red 37 (AR 37) and
Acid Blue 25 (AB 25) from aqueous solution were examined. Chitosan beads were cross-linked with EGDE to enhance its chemical
resistance and mechanical strength. Experiments were performed as a function of pH, agitation period and concentration of AR 37 and
AB 25. It was shown that the adsorption capacities of chitosan for both acid dyes were comparatively higher than those of chitosan-
EGDE. This is mainly because cross-linking using EGDE reduces the major adsorption sites -NH3
+ on chitosan. Langmuir isotherm
model showed the best conformity compared to Freundlich and BET. The kinetic experimental data agreed very well to the pseudo
second-order kinetic model. The desorption study revealed that after three cycles of adsorption and desorption by NaOH and HCl, both
adsorbents retained their promising adsorption abilities. FT-IR analysis proved that the adsorption of acid dyes onto chitosan-based
adsorbents was a physical adsorption. Results also showed that chitosan and chitosan-EGDE beads were favourable adsorbers and
could be employed as low-cost alternatives for the removal of acid dyes in wastewater treatment.
