The adsorption of methyl orange（MO） on chitosan（CS） beads in aqueous solutions was investigated by a batch equilibration technique. Special emphasis was focused on the effect of sorbent concentration（cs） on the ...The adsorption of methyl orange（MO） on chitosan（CS） beads in aqueous solutions was investigated by a batch equilibration technique. Special emphasis was focused on the effect of sorbent concentration（cs） on the adsorp- tion equilibration of MO on CS beads. An obvious Cs-effect was observed in the adsorption equilibration, i.e., the ad- sorption amount（F） was declined with Cs increase. The classical Langmuir model adequately described the adsorption isotherm for each given cs. However, it could not be used to predict the cs-effect observed. The applicability of the Langmuir-SCA isotherm, a surface component activity（SCA） model equation, to fit the cs-effect data was examined. In the SCA model, the activity coefficient of sorbent surface sites, fsH2O, was assumed to be a function of cs due to the deviation of a real adsorption system from an ideal one, arisen from sorbent particle-particle interactions in real systems. The results show that the Langmuir-SCA isotherm could accurately describe the c：effect observed under the studied conditions. Furthermore, the effects of temperature（t）, pH, and electrolyte（NaNO3） concentration（ CNaNO3 ） on fsH2O were examined. The results show that fsH2O clearly decreased with increasing t（20-35℃） and pH（5-8）, but no obvious change in fsH2O was observed as CNaNO3 varied in a range 0.001-0.010 mol/L. These results give a better understanding of the cs-effect.展开更多
基金Supported by the National Natural Science Foundation of China（Nos.21173135, 51372141） and the Specialized Research Fund for the Doctoral Program of Higher Education of China（No.20110131130008）,
文摘The adsorption of methyl orange（MO） on chitosan（CS） beads in aqueous solutions was investigated by a batch equilibration technique. Special emphasis was focused on the effect of sorbent concentration（cs） on the adsorp- tion equilibration of MO on CS beads. An obvious Cs-effect was observed in the adsorption equilibration, i.e., the ad- sorption amount（F） was declined with Cs increase. The classical Langmuir model adequately described the adsorption isotherm for each given cs. However, it could not be used to predict the cs-effect observed. The applicability of the Langmuir-SCA isotherm, a surface component activity（SCA） model equation, to fit the cs-effect data was examined. In the SCA model, the activity coefficient of sorbent surface sites, fsH2O, was assumed to be a function of cs due to the deviation of a real adsorption system from an ideal one, arisen from sorbent particle-particle interactions in real systems. The results show that the Langmuir-SCA isotherm could accurately describe the c：effect observed under the studied conditions. Furthermore, the effects of temperature（t）, pH, and electrolyte（NaNO3） concentration（ CNaNO3 ） on fsH2O were examined. The results show that fsH2O clearly decreased with increasing t（20-35℃） and pH（5-8）, but no obvious change in fsH2O was observed as CNaNO3 varied in a range 0.001-0.010 mol/L. These results give a better understanding of the cs-effect.
