Patent ID: 6033640
Filing Date: 2000-03-07
Classification: B01D,B01J

Abstract:
The method of catalytically removing nitrogen oxides from oxygen rich exhaust streams by direct conversion of the nitrogen oxides to nitrogen and oxygen comprising the steps of selecting a catalyst represented by the following stoichiometries(BiO.sub.1.5).sub.1-x-y-z /(B.sub.n O).sub.x /(M.sup.1 O).sub.y /(M.sup.2 O).sub.zwhere B=a basic cation chosen from Ba.sup.2+ or Sr.sup.2+ (n=1) or from the alkali metal cations (n=2: Li.sup.+, Na.sup.+, K.sup.+, Rb.sup.+, or Cs.sup.+); M.sup.1 =a transition metal cation of Co, Fe, or Ni; and M.sup.2 =a transition metal cation of Cu, V, Nb, or W, where the ranges of the subscripts are as follows: 0<x<0.8, 0<y<0.5, and 0<z<0.5, and x+y+z<1, supporting the catalyst on a support structure in the path of the exhaust stream, andcausing the exhaust stream to impinge upon the catalyst where the Lewis base cations provide sites for absorption of the nitrogen oxide molecules and the transition metal cations oxidize the nitrogen oxide molecules so that they can interact in the presence of oxygen to provide N.sub.2 and O.sub.2.