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The influence of the presence of inorganic and organic matter during the catalytic reduction of nitrate in a local groundwater over a Pd-Cu catalyst supported on carbon nanotubes was investigated. It was observed that the catalyst performance was affected by the groundwater composition. The nitrate conversion attained was higher in the experiment using only deionized water as solvent than in the case of simulated or real groundwater. With exception of sulphate ions, all the other solutes evaluated (chloride and phosphate ions and natural organic matter) had a negative influence on the catalytic activity and selectivity to nitrogen. [ABSTRACT FROM AUTHOR]

Abstract: Screening tests were carried out in order to study the influence of the support in the performance of Pd monometallic and Pd–Cu bimetallic catalysts for the reduction of nitrate in water. Several metal oxides, as well as metal oxides and activated carbon or carbon nanotube composites were assessed as supports. The catalysts were prepared and tested under the same operation conditions. It was observed that supports play an important role in the catalytic performance and in some cases are directly involved in the reaction mechanism. The Pd–Cu catalysts supported on titanium dioxide and on the composite containing carbon nanotubes and titanium dioxide present the highest conversions, while those supported on ceria materials are the most selective to nitrogen. [Copyright &y& Elsevier]