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A study on the removal of urea from aqueous solution with immobilized urease and electrodialysis

1992; Wiley; Volume: 55; Issue: 2 Linguagem: Inglês

10.1002/jctb.280550214

1097-4660

Ting‐Chia Huang, Dong‐Hwang Chen,

Anaerobic Digestion and Biogas Production

Abstract A five‐compartment electrodialyzer with immobilized urease was developed for the removal of urea from aqueous solution. The immobilized urease, supported on polyurethane foam, was placed in the central (dilute) compartment, where urea was hydrolyzed and the products NH 4 + and CO 3 2‐ /HCO 3 − were removed simultaneously by electrodialysis. The system was studied both under constant current and under constant voltage. The effects of urea concentration and applied current or voltage on the removal of urea and ammonium ions from the dilute solution were investigated. The variations of the pH of dilute solution, the current or voltage of system, and current efficiency were also examined during reaction‐electrodialysis. The removal of urea by enzymic reaction was not affected significantly by the applied electric field. The current effieiencies for removing ammonium ions from dilute solution were mostly within 40‐80%, and the removal percentage of ammonium ions was dependent on current density and current efficiency.