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ASAIO Renal Abstracts

AMMONIUM REMOVAL WITH A NOVEL ZIRCONIUM SILICATE

Bem, David S.1; Sherman, John D.2; Ash, Stephen R.3; Marte, Julio C.4; Willis, Richard R.4; Braun, Richard4; Muldoon, Brian S.5

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UOP, a leading producer of adsorbents and specialty materials, has developed a novel material which surpasses the alternatives in selectivity for the removal of ammonium. At moderate ammonium concentrations, as in dialysate regeneration for renal dialysis, it has 50% greater capacity than zirconium phosphate for ammonium. These experiments were performed at concentrations representative of ammonium concentrations resulting from the action of urease on urea in renal dialysate. At the lower ammonium concentrations typical of hepatic dialysis, this material retains a high capacity for ammonium where the alternative materials do not.

This new and patented material has been designated UZSiTM ion exchanger, standing for UOP Zirconium Silicate. The material has a discrete microporous crystalline structure which imparts the selectivity for ammonium ion exchange. The chemical family of zirconium silicates has an extended history of safe use in human oral applications.

UOP's UZSi ion exchange material has been evaluated for use in renal and hepatic dialysis. In all cases the UZSi successfully removes ammonium from the dialysis solution via ion exchange.

As an example, in vitro tests of ammonium removal with powdered UZSi were performed in a liver dialysis unit in the presence of physiologic concentrations of ammonium, calcium and magnesium. The UZSi removed 10 times the ammonium compared to other commercial materials. These tests demonstrated that UOP's UZSi ion exchanger created a high clearance of ammonium throughout the 6 hour treatment cycle.

UOP has also prepared a beaded form of the UZSi material with the addition of a binder. This form of the material maintains its capacity and selectivity for ammonium and is suitable for column applications, such as for regeneration of dialysates.

Copyright © 2001 by the American Society for Artificial Internal Organs