Influence of Pd-Cu on nanoscale zero-valent iron supported for selective reduction of nitrate

Selective reduction of nitrate over nanoscale zero-valent iron (nFe(0)) modified metals (Pd and Cu) was investigated. Parameters of modified metal loading, metallic ratio (Pd:Cu), and H-2 gas supplying were investigated on the influence of nitrate reduction. Metal (Cu, Pd) deposited onto nanoiron was proven to be effective in promoting the formation of nitrogen gas and, on the other hand, suppressing the NH4+ formation. Hydrogen gas feeding appeared to have a synergistic effect on nitrate removal and on nitrogen gas selectivity in all types of catalytic reductants. A catalyst with a loading of 10% of (Pd-Cu)-nFe(0) with a ratio of Pd:Cu of 2:1, and H-2 feeding showed the highest selective to N-2: NH4+ formation (51:42), compared to the others ((Cu-Pd)-nFe(0), Cu-nFe(0), Pd-nFe(0) and nFe(0)). The significant improvement in initiating the formation of N-2, on the other hand suppressing the formation of NH4+, was referred to an indirect electron-transferring process of nFe(0) to Cu and to Pd, consequently. In addition, kinetic evaluations on each catalyst was evaluated and used to postulate the selective reduction of nitrate phenomena. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.