Chemical equilibrium in the complexation of first transition series divalent cations Cu2+, Mn2+ and Zn2+ with chitosan

Journal of the Brazilian Chemical Society

Universidad de Oriente, Santiago de Cuba, Cuba¹  Yola, Oscar Reyes¹  Instituto Superior de Ciencias Médicas, Santiago de Cuba, Cuba¹  Mercê, Ana Lucia Ramalho¹  Hernández, Raúl Bonne¹  Universidade Federal do Paraná, Curitiba, Brazil¹ 

关键词: chitosan;    divalent cations;    pH;    stability constants;    biodegradable and biocompatible polymers;   

DOI  :  10.1590/S0103-50532007000700015

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

This study provided the data for calculating the stability constants formed in the aqueous HCl equilibrium of chitosan and Cu2+, Mn2+ and Zn2+, and determined the species distribution diagrams to show the influence of pH in the complexation systems based on data obtained from potentiometric and spectrophotometric titrations. The solid complexes further obtained from these aqueous HCl systems, were investigated by infrared spectroscopy. It was verified that chitosan coordinated with the cations Cu2+, Mn2+ and Zn2+ at pHs >4 >5 and >2 respectively, in ligand to metal ratio of 1:1. The logarithms of the binding constants for ML species presented the following stability order: Cu2+>Zn2+>Mn2+. Some possible complexed structures were suggested having both N and/or O atoms as binding sites with one or two monomers of the biopolymer studied.

【 授权许可】

Unknown