Catalytic membrane in denitrification of water: a means to facilitate intraporous diffusion of reactants

The series of mono- and bi-metallic catalysts with Pd and/or Cu supported o ver gamma -Al2O3 was investigated with respect to reduction of nitrate and nitrite ions in water by hydrogen. Pronounced limitations of catalytic perf ormance due to intraporous diffusion of the reactants were observed in the reaction. Catalytic membrane containing the Pd-Cu active component supporte d over macroporous ceramic membrane-support was prepared, investigated and applied to facilitate the intraporous mass transfer. Forced flow of the rea cting solution through the membrane was revealed to increase the effective catalytic activity. The approach explored in this study offers a cost-effic ient alternative to the conventional concept of catalytic water denitrifica tion process in a slurry reactor, presuming fixed-bed type operation with m acroporous catalytic membranes at high level of catalytic activity. (C) 200 0 Elsevier Science B.V. All rights reserved.