Preparation of Cellulose Derivatives Selectively Adsorbing Metal Ions

点击翻译按钮获取中文摘要

Cellulose derivatives such as hydrazinodeoxycellulose (HDC), carboxyalkyl hydrazinodeoxycellulose (alpha- and beta-CAHDC), alkylaminodeoxycellulose (AADC) and carboxymethylaminodeoxycellulose (CNADC) were prepared from 6-chloro-deoxycellulose (CDC). They have metal ion-adsorbing groups. The preparation conditions and their adsorbing behavior of divalent heavy metal ions from aqueous dilute solutions were examined in detail. In strongly acidic solutions, these adsorbents are highly swollen because of protonation of their amino groups, and do not adsorb heavy metal ions. However, metal ions are adsorbed rapidly from weakly acidic solutions and the amount of adsorption increases with increasing pH.The adsorption of metal ions occurs in the order of Cu^<2+>>Cd^<2+>>Co^<2+>>Ni^<2+> irrespective of adsorbents and Cu^<2+> ions are selectively adsorbed from solutions containing metal ion mixtures irrespective of adsorbents.The reaction conditions of bromination of cellulose and methyl beta-D-glucopyranoside were also examined in homogeneous systems in order to establish the preparation conditions of bromodeoxycellulose which is more reactive as an intermediate. The resulting bromodeoxycellulose was reacted with 8 thiols and it was found that the products with higher degree of substitution was obtained in homogeneous systems than in heterogeneous systems.