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-li...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 ofpH, 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.展开更多
The potential of base treated Shorea dasyphylla（BTSD） sawdust for Acid Blue 25（AB 25） adsorption was investigated in a batch adsorption process.Various physiochemical parameters such as pH,stirring rate,dosage,con...The potential of base treated Shorea dasyphylla（BTSD） sawdust for Acid Blue 25（AB 25） adsorption was investigated in a batch adsorption process.Various physiochemical parameters such as pH,stirring rate,dosage,concentration,contact time and temperature were studied.The adsorbent was characterized with Fourier transform infrared spectrophotometer,scanning electron microscope and Brunauer,Emmett and Teller analysis.The optimum conditions for AB 25 adsorption were pH 2,stirring rate 500 r/min,adsorbent dosage 0.10 g and contact time 60 min.The pseudo second-order model showed the best conformity to the kinetic data.The equilibrium adsorption of AB 25 was described by Freundlich and Langmuir,with the latter found to agree well with the isotherm model.The maximum monolayer adsorption capacity of BTSD was 24.39 mg/g at 300 K,estimated from the Langmuir model.Thermodynamic parameters such as Gibbs free energy,enthalpy and entropy were determined.It was found that AB 25 adsorption was spontaneous and exothermic.展开更多
基金supported by the UniversitiSains Malaysia, under Short Term Research Grant (GrantNo. 304/PKIMIA/636065)
文摘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 ofpH, 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.
基金the Universiti Sains Malaysia for the financial support (No. 304/PKIMIA/638056)
文摘The potential of base treated Shorea dasyphylla（BTSD） sawdust for Acid Blue 25（AB 25） adsorption was investigated in a batch adsorption process.Various physiochemical parameters such as pH,stirring rate,dosage,concentration,contact time and temperature were studied.The adsorbent was characterized with Fourier transform infrared spectrophotometer,scanning electron microscope and Brunauer,Emmett and Teller analysis.The optimum conditions for AB 25 adsorption were pH 2,stirring rate 500 r/min,adsorbent dosage 0.10 g and contact time 60 min.The pseudo second-order model showed the best conformity to the kinetic data.The equilibrium adsorption of AB 25 was described by Freundlich and Langmuir,with the latter found to agree well with the isotherm model.The maximum monolayer adsorption capacity of BTSD was 24.39 mg/g at 300 K,estimated from the Langmuir model.Thermodynamic parameters such as Gibbs free energy,enthalpy and entropy were determined.It was found that AB 25 adsorption was spontaneous and exothermic.
