Activated carbon cloth-supported Pd–Cu catalyst: Application for continuous water denitrification

Pd–Cu catalysts supported on woven fibrous cloths have been tested for continuous nitrate hydrogenation in water. The results demonstrate that activated carbon cloth (ACC) is an adequate support for the Pd–Cu bimetallic catalysts giving better activity and selectivity than that of supports like glass fibers cloth (GFC) and GFCs coated with Al2O3 or SnO2, which were also studied. A series of 2% Pd–Cu/ACC catalysts were prepared by selective deposition of Cu on Pd/ACC and examined at steady state in a continuous three-phase radial flow reactor. The activity and selectivity of the bimetallic catalysts depend on the Cu:Pd ratio and the metal loading. The beneficial effect of copper on nitrate hydrogenation activity with a Pd–Cu/ACC catalyst is probably related to the formation of an active Pd–Cu ensembles working as active sites for nitrate-to-nitrite reduction. The maximal nitrate conversion was achieved with 0.6 wt.% Cu–2 wt.% Pd/ACC catalyst showing a 92% selectivity towards gaseous products.