PURPOSE: To obtain an adsorbent having high metal adsorptivity which can adsorb ions from liquid of rather low pH by substituting carboxymethyl groups for hydrogen of aimino groups in chitosan.
CONSTITUTION: The chitosan is obtained by heating chitin contained in shells of Crustacea such as lobster, crab in an alkali soln. Chemically modified units expressed by formula I (n=1 or 2) in which carboxymethyl groups are substituted for hydrogen in the amino group of chitosan are formed in the polymer skeleton of the chitosan. By forming carboxymethyl groups, pKa changes so that the obtd. material has higher coupling ability with metal ions than chitosan itself and can act in a soln. of lower pH than compared to chitosan. The obtd. adsorbent is a low-cost one since the starting material is obtd. from biomass waste, and has high metal adsorptivity which can act even in a low pH soln.
YOSHIZUKA KAZUHARU
IWASAKI MINETO
OWATARI KEISUKE
BABA YOSHINARI
TAZAKI MASATO
| JPH03262531A | 1991-11-22 |