Cloth catalysts for water denitrification

Abstract

The use of glass fibers in the form of woven cloth (GFC), as a new type of catalytic support, was studied for the reduction of aqueous nitrate solutions using a Pd/Cu-GFC catalyst. The activity (per gram Pd) and selectivity to nitrogen were found to be comparable with those found for Pd-Cu catalysts supported on the other carriers. The maximal initial removal activity was found for a catalyst with a Pd/(Pd + Cu) ratio of 0.81. The corresponding activity was 0.7 mmol min −1 (g Pd ) −1 , and the selectivity was 97 mol% at 25 • C and pH 6.5 for initial nitrate concentration of 100 mg l −1 . The selectivity to nitrogen declined at high conversions of nitrate and high pH.

Highly effective photocatalytic system comprising semiconductor photocatalyst and supported bimetallic non-photocatalyst for selective reduction of nitrate to nitrogen in water

“…1) [3], the reaction over supported bimetallic catalysts has been actively investigated as a promising technology to remediate NO 3 --polluted groundwater . Thus far, a few bimetallic Pd and bimetallic Pt catalysts showing high activity and high selectivity to N 2 have been developed [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. However, using gaseous H 2 as a reducing agent is a serious issue because handling the flammable gas at high pressures is difficult.…”

Remediation of actual groundwater polluted with nitrate by the catalytic reduction over copper–palladium supported on active carbon

“…2) is a critical problem, because the allowable level of NH 3 in drinking water is 0.5 ppm. Many studies have been carried out on the catalytic reduction of NO 3 -using bimetallic catalysts, such as Cu-Pd [3][4][5][6][7][8][9][10][11][12][13][14], Sn-Pd [15][16][17], In-Pd [9,18], and Cu-Pt [19,20], since Vorlop and coworkers discovered that Cu-Pd/Al 2 O 3 is an active and selective catalyst [3,4]. [7].…”

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

“…Moreover, clothtype catalysts are preferable to monoliths when rapid fluctuations in the flow regime occur, as often-encountered in applications for environmental protection . Catalytic cloths combine an open macrostructure with mechanical flexibility, allowing new options for the design of catalytic reactors. Recently, we have studied some novel Pd-based catalytic cloths for hydrodechlorination [14] and for nitrite and nitrate hydrogenation [15][16][17] and obtained promising results. In this aspect it is interesting to support Pd-Cu on the activated carbon cloths (ACC), that have been proven to have a great potential as a catalytic support, especially for the expensive noble metals, since a high metal loading and dispersion can be achieved.…”

“…In this work, following a previously reports on use Pd-Cu/glass fiber cloth (GFC) as a catalyst for nitrate hydrogenation [16] and Pd/ACC for nitrite hydrogenation [17], we extend the study of a Pd-Cu catalytic cloths for nitrate removal in a radial-flow reactor operated in steady state with pre-dissolved hydrogen in the water. Most previous studies used batch reactor.…”