title: Chitosan and chemically modified chitosan beads for acid dyes sorption.
abstract: 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.
authors.affiliation: Department of Chemistry, Faculty of Science and Technology, Universiti Pendidikan Sultan Idris, 35900 Perak, Malaysia. azlkam@yahoo.co.uk
authors.forename: Kamari
authors.initials: K
authors.lastname: Azlan
authors.forename: Wan Ngah
authors.initials: WN
authors.lastname: Wan Saime
authors.forename: Liew
authors.initials: L
authors.lastname: Lai Ken
mesh_terms: D000143:Acids / Q000737:chemistry*; D000327:Adsorption; D000880:Anthraquinones / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D012235:Rhodamines / Q000737:chemistry; D013499:Surface Properties; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000737:chemistry; D018508:Water Purification / Q000379:methods
chemical_list: C542340:1-amino-9,10-dihydro-9,10-dioxo-4-(phenylamino)-2-anthracenesulfonic acid; D000143:Acids; D000880:Anthraquinones; D004396:Coloring Agents; D003432:Cross-Linking Reagents; D012235:Rhodamines; D014874:Water Pollutants, Chemical; C022027:lissamine rhodamine B; D048271:Chitosan