Baroni P, Vieira R S, Meneghetti E, da Silva M G C, Beppu M M
Departamento de Termofluidodinâmica, Faculdade de Engenharia Química, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz-Caixa Postal 6066 Barão Geraldo, CEP 13083-970, Campinas, SP, Brazil.
J Hazard Mater. 2008 Apr 15;152(3):1155-63. doi: 10.1016/j.jhazmat.2007.07.099. Epub 2007 Aug 3.
Removal of chromium ions from aqueous solutions by using natural and crosslinked chitosan membranes was achieved using batch adsorption experiments. The effect of pH (6.0 and 2.0), concentration of chromium ions and crosslinking agents (glutaraldehyde: GLA and epichlorohydrin: ECH) on the adsorption properties of chitosan membranes was analyzed. The experimental equilibrium data was fitted to Langmuir and Freundlich models. Through the model curves, it was possible to observe that the amount of chromium ions adsorbed was significantly higher for crosslinked membranes compared to non-crosslinked chitosan. The maximum adsorbed amount was about 1400 mg g(-1) for ECH-crosslinked chitosan at pH 6.0. The adsorption rates for crosslinked chitosan membranes with glutaraldehyde and epichlorohydrin were similar for natural chitosan. Desorption study using NaCl (1 mol L(-1)) solution was performed on chitosan membranes, in order to recover chromium ions and to determine the suitable number of cycles for repeated use of these membranes without considerable decrease in their adsorption capacity. The desorption results showed that chromium ions could be more effectively removed at pH 2.0 than pH 6.0, mainly for ECH-crosslinked chitosan.
通过分批吸附实验，利用天然壳聚糖膜和交联壳聚糖膜从水溶液中去除铬离子。分析了pH值（6.0和2.0）、铬离子浓度以及交联剂（戊二醛：GLA和环氧氯丙烷：ECH）对壳聚糖膜吸附性能的影响。将实验平衡数据拟合到朗缪尔模型和弗伦德利希模型。通过模型曲线可以观察到，与未交联的壳聚糖相比，交联膜对铬离子的吸附量显著更高。在pH值为6.0时，环氧氯丙烷交联壳聚糖的最大吸附量约为1400 mg g(-1)。戊二醛和环氧氯丙烷交联壳聚糖膜的吸附速率与天然壳聚糖相似。对壳聚糖膜进行了使用NaCl（1 mol L(-1)）溶液的解吸研究，以回收铬离子并确定这些膜在重复使用时吸附容量无显著下降的合适循环次数。解吸结果表明，在pH值为2.0时比pH值为6.0时能更有效地去除铬离子，主要针对环氧氯丙烷交联壳聚糖。
