Removal of Urea from Water Using Urease-Immobilized Fibers

Abstract

Dimethylaminoethyl methacrylate (DMAEMA) was graft-polymerized at a density of 1.7 mmol/g onto a 6-nylon fiber by radiation-induced graft polymerization. Urease was bound to the resultant anion-exchange fiber by electrostatic interaction. After crosslinking with transglutaminase, 80% of the bound urease was immobilized at a density of 41 mg/g of the fiber. Urea in water was quantitatively hydrolyzed during the permeation of a 0.20 mg/L urea solution through the urease-immobilized-fiber-packed bed with a diameter of 5.5 mm and a height of 27 mm in the residence time range of 12–180 s. The activity of immobilized urease did not deteriorate after repeated use of the fiber, i.e., during reaction and storage.