Highly phosphorylated derivatives of chitin, partially deacetylated chitin and chitosan as new functional polymers: metal binding property of the insolubilized materials

Abstract

Highly phosphorylated derivatives of chitin and deacetylated chitins (DA-chitins) were insolubilized by the cross-linking reaction with adipoyl chloride in methanesulphonic acid, and their metal binding ability to Mg 2+, Ca +, Sr 2+, Ba 2+, Mn 2+, Ni 2+, Cu 2+, Zn 2+ and Cd 2+ was investigated. Generally alkaline-earth metals and Mn 2+ were adsorbed strongly to these derivatives than to original chitin or DA-chitins, while the transition elements except Mn 2+ were adsorbed strongly to DA-chitins than to these derivatives. The pH dependence for the Ca 2+-adsorption to these materials showed that the amount of adsorbed Ca 2+ increased with a rise in pH, suggesting the large contribution of phosphoryl group. However, the differential i.r. spectra of chitin phosphate or DA-chitin phosphate between presence and absence of Ca 2+ suggested that not only the phosphoryl group but also other groups such as hydroxyl group and also acetylamino group concerned cooperatively to the metal binding. Results on the potentiometric titration for these cross-linked derivatives were also discussed comparing with those for non-cross-linked phosphorylated derivatives.