Solute adsorption and enzyme immobilization on chitosan beads prepared from shrimp shell wastes

The equilibrium and kinetics of adsorption of reactive dye RR222 and Cu2+, and the activity of immobilization of acid phosphatase, on highly swollen c hitosan beads were examined at 30 degreesC. The chitosan was prepared from shrimp shell wastes and was cross-linked with different dosages of glutaral dehyde or glyoxal (100-80,000 mg/l). It was shown that the amounts of solut e adsorption and the immobilization capacity of acid phosphatase on cross-l inked chitosan beads were substantially affected by their degree of cross-l inking. The cross-linking rate of chitosan with glutaraldehyde could be des cribed by a pseudo-second-order equation and the cross-linking equilibrium by the Freundlich equation. This provided an experimental method to control the degree of cross-linking of chitosan beads. Finally, the activity and l ifetime of the immobilized enzyme were measured to evaluate the application potential. (C) 2001 Elsevier Science Ltd. All rights reserved.