REMEDIATION OF WATER CONTAMINATED WITH NITRATE. DEVELOPMENT OF A CONTINUOUS ADSORPTION/CATALYSIS SYSTEM

Abstract

The elimination of NO3- from water was studied using PdCu structured catalysts prepared on cordierite monoliths coated with Al2O3. The influence of the source of alumina to coat the nude monoliths and the method of preparation of PdCu catalyst was evaluated. The adherence of the Al2O3 on the monoliths was carried out by washcoating using two different suspensions 1) an alumina suspension prepared in the laboratory, and 2) a commercial bohemite colloidal suspension. With bohemite suspension, higher alumina mass gain and better adherence were obtained. No difference was found in the reduction of NO3- with the catalyst preparation method (PdCu or CuPd). The adsorption of NO3- was studied using the montmorillonite clay modified with hexadecyltetraethylammonium mixed with sea sand in a column filtration system. The NO3- was desorbed from the column and the concentrated NO3- was satisfactory removed using PdCu structured catalyst. The adsorption/catalysis combination system used in this work is a promising technology for the treatment of water contaminated with NO3- because it allows to regenerate the adsorption column and to eliminate NO3-.