Water Denitration over a Pd–Sn/Al2O3 Catalyst

Abstract

Bimetallic Pd-Sn catalysts were synthesized by incipient-wetness impregnation of the metals on alumina and employed for the reduction of nitrates from aqueous solutions. The catalysts were characterized by FTIR spectroscopy of adsorbed CO, X-ray diffraction (XRD), transmission electron microscopy (TEM), and H 2 chemisorption. The influence of the metal ratio was evaluated in reaction measurements. The bimetallic Pd-Sn catalysts exhibited high selectivity for nitrate removal forming less NO 2 ) and NH 4 + than the Pd-Cu catalysts.

State-of-the-art and perspectives of the catalytic and electrocatalytic reduction of aqueous nitrates

“…Hörold et al [3,4] reported in 1993 a widely recognized reaction mechanism based on catalytic reduction over bimetallic catalysts using a noble metal (Pd, Pt) and a transition metal (Cu, Sn, In) in the presence of hydrogen as the reductant [5][6][7]. Batch reactors with bimetallic catalysts supported on alumina powder have been mostly used to test the reaction performance [5,[7][8][9][10][11].…”

Mono and bimetallic NaY catalysts with high performance in nitrate reduction in water

“…Since the discovery of the good performance of noble metal-containing bimetallic catalysts for this reaction [3], several studies using bimetallic catalysts, composed of a noble metal (Pd, Pt or Rh) and a promoter metal (Cu, Sn or In) supported on different materials have been carried out, in order to develop a catalytic nitrate reduction process highly active and selective for nitrogen. Various supports have been reported in the literature, such as alumina [4,5], zirconia [6], activated carbon [7][8][9], SnO 2 [10], TiO 2 [11], ceria [12], SiO 2 [13] and zeolites [14,15] and it has been demonstrated that the nature of the support significantly affects the catalytic activity and selectivity of the catalysts [16].…”

Nitrate Reduction Catalyzed by Pd–Cu and Pt–Cu Supported on Different Carbon Materials

“…The formation of ammonium as by-product is the critical problem of this process. Since the discovery by Vorlop and Tacke [4], several studies have been carried out using bimetallic catalysts, such as Pd-Cu [5][6][7], Pt-Cu [5,8], Pd-Sn [9][10][11][12] supported on different materials such as activated carbon [13][14][15][16], cationic resin [17], alumina [18,19], titania [20,21], and other metal oxides [22][23][24][25]; however, the selectivities are not yet satisfactory. The activity and selectivity of the bimetallic catalysts in nitrate reduction have shown to be highly dependent on the preparation method, mode of noble metal promoting, metal-promoter ratio as well as the operation conditions.…”