Low-temperature SCR of NOx with NH3 over Nomex (TM) rejects-based activated carbon fibre composite-supported manganese oxides Part II. Effect of procedures for impregnation and active phase formation
G. Marban et Ab. Fuertes, Low-temperature SCR of NOx with NH3 over Nomex (TM) rejects-based activated carbon fibre composite-supported manganese oxides Part II. Effect of procedures for impregnation and active phase formation, APP CATAL B, 34(1), 2001, pp. 55-71
Citations number
25
Categorie Soggetti
Physical Chemistry/Chemical Physics","Environmental Engineering & Energy
The first part of this work dealt with the preparation and conditioning of
Nomex (TM) rejects-based activated carbon fibre (ACF) composites to be used
as catalytic supports of manganese oxides for the low-temperature selectiv
e catalytic reduction of nitric oxide with ammonia. In this second part, th
e catalytic results obtained by applying different impregnation procedures,
including the previous exchange of the oxidised support with solutions of
NaOH, are described. Washing the support with deionised water after both th
e Na-exchange and the impregnation steps improved the activity of the resul
ting catalyst. For the active phase formation (manganese oxide) on the supp
ort surface, different treatments were tested. It was determined that a tre
atment of the impregnated catalyst consisting of a stage of NO/O-2/NH3 adso
rption/reaction at 150 degreesC followed by heat treatment up to 400 degree
sC under inert atmosphere, and a final stage of mild oxidation at 200 degre
esC yielded the best catalytic results The final oxidation state of mangane
se was estimated to be between II and III.
This final fabrication procedure yielded catalysts that in conditions of hi
gh spatial velocities (11000-25 000 h(-1)) and negligible pressure drop. sh
owed a high catalytic activity at 150 degreesC, with NOx reduction percenta
ges close to 85%, selectivities above 95% and low gasification rates of the
carbonaceous support. (C) 2001 Elsevier Science B.V All rights reserved.