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

Abstract

The activities and selectivities of Pd-Cu and Pt-Cu bimetallic catalysts supported on different carbon materials (activated carbons with different surface chemistries, multiwalled carbon nanotubes and carbon xerogels) were studied in the catalytic reduction of nitrate in water. The surface chemistry of the support has an important role in the catalyst activity and selectivity, being its influence more pronounced when Pt-Cu catalysts are used. Generally, catalysts supported on basic carbon materials are more active and selective.

Catalytic Nitrate Removal in a Trickle Bed Reactor: Direct Drinking Water Treatment

“…Favorable catalyst properties include closer spacing of Pd and indium (In), which may facilitate H 2 spill‐over and increase probability of having adjacent nitrogen species that can react to form N 2 (Barrabés & Sá 2011, Sá et al 2005, Epron et al 2001). Different catalyst supports for Pd and In can also affect selectivity, and better N 2 selectivity on activated carbon (AC) was found compared with silica, titania, zirconia, or alumina (Soares et al 2010, Wang et al 2007, Matatov‐Meytal & Sheintuch 2005). Operating conditions that favor N 2 over NH 4 + include lower pH (Prüsse & Vorlop 2001), which decreases hydroxide (OH – ) concentration and competition with NO 3 – for surface sites, and increases the likelihood of having adjacent nitrogen species that can react to form N 2 .…”

Direct conversion of cellulose to sorbitol over ruthenium catalysts: Influence of the support

“…HY is the most acidic support studied, while the remaining supports are almost neutral [31]; therefore, the lower activity and selectivity to sorbitol achieved when using Ru/HY as catalyst could be due to the acid properties of the support or to the deactivation of the zeolite, as mentioned above. Comparing alumina to the carbon supported catalysts, it could be noticed that for Ru/Al 2 O 3 , although presenting the lowest metal dispersion (36%), which lowers its performance, the selectivity to sorbitol achieved after 5 h of reaction was not very different from that achieved when using carbon catalysts, as Ru/P80 and Ru/XG.…”

Adsorption of Paraquat Dichloride to Kaolin Particles and to Mixtures of Kaolin and Hematite Particles in Aqueous Suspensions

“…Textural characterization of the samples was based on the analysis of nitrogen sorption isotherms measured at 77 K in a Quantachrome NOVA 4200e apparatus (Soares et al, 2010). BET 1 surface area and micropore volume were calculated using the BET equation and the tmethod, respectively (Villacañas et al, 2006).…”