Copello G J, Varela F, Vivot R Martínez, Díaz L E
Cátedra de Química Analítica Instrumental, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina.
Bioresour Technol. 2008 Sep;99(14):6538-44. doi: 10.1016/j.biortech.2007.11.055. Epub 2007 Dec 31.
The generation of layer-by-layer silicate-chitosan composite biosorbent was studied. The films were evaluated on its stability regarding the polymer leakage and its capability in the removal of Cd(II), Cr(III) and Cr(VI) from an aqueous solution. SEM, EDAX and ATR-IR techniques were applied for material characterization. Silicate-chitosan films with a final layer of silicate demonstrated chitosan retention and had better sorption capacities than those without it. For metal species, such as Cd(II) and Cr(III), the greatest adsorption was obtained when the pH of the solution was 7. When Cr(VI) was evaluated, pH 4 was the optimal for its adsorption. Langmuir and Freundlich isotherms were modeled for the equilibrium data. An 80% of the adsorbed metal was recovered by HNO(3) incubation. This non-covalent immobilization method allowed chitosan surface retention and did not affect its adsorption properties. The use of a coated surface would facilitate sorbent removal from medium after adsorption.
研究了逐层硅酸盐-壳聚糖复合生物吸附剂的制备。对薄膜的聚合物泄漏稳定性及其从水溶液中去除Cd(II)、Cr(III)和Cr(VI)的能力进行了评估。采用扫描电子显微镜（SEM）、能量散射X射线光谱（EDAX）和衰减全反射红外光谱（ATR-IR）技术对材料进行表征。具有硅酸盐终层的硅酸盐-壳聚糖薄膜表现出壳聚糖保留能力，并且比没有该终层的薄膜具有更好的吸附容量。对于金属物种，如Cd(II)和Cr(III)，当溶液pH值为7时吸附量最大。评估Cr(VI)时，pH 4是其吸附的最佳值。对平衡数据建立了朗缪尔等温线和弗伦德利希等温线模型。通过硝酸孵育回收了80%的吸附金属。这种非共价固定方法使壳聚糖保留在表面，且不影响其吸附性能。使用涂层表面将便于吸附后从介质中去除吸附剂。
