Patent ID: RE39553

Claim:
A method for removing NO x and SO x contaminants from a gaseous stream comprising the steps of: (1) heat treating a catalyst precursor to form a catalyst composite; (2) ( 1 ) in a sorbing period, passing a lean gaseous stream comprising NO x and SO x within a sorbing temperature range through the a catalyst composite to sorb at least some of the SO x contaminants and thereby provide a SO x depleted gaseous stream exiting the catalyst composite and to sorb and abate at least some of the NO x contaminants in the gaseous stream and thereby provide a NO x depleted gaseous stream exiting the catalyst composite; (3) ( 2 ) in a SO x desorbing period, converting the lean gaseous stream to a rich gaseous stream and raising the temperature of the gaseous stream to within a desorbing temperature range to thereby reduce and desorb at least some of the SO x contaminants from the catalyst composite and thereby provide a SO x enriched gaseous stream exiting the catalyst composite; and (4) ( 3 ) in a NO x desorbing period, converting the lean gaseous stream to a rich gaseous stream to thereby reduce and desorb at least some of the NO x contaminants from the catalyst composite and thereby provide a NO x enriched gaseous stream exiting the catalyst composite; wherein the catalyst precursor composite comprises: (a) a platinum component; (b) a support; (c) a NOx sorbent component; and (d) a spinet material prepared by calcining an anionic clay material represented by the formula M m N n (OH) (2m+2n) A a .bH 2 O , wherein M is Co 2+ ; N is a trivalent metal cation; A is a mono-, di-, or trivalent anion which decomposes when heated to a temperature sufficient to form a volatile gas; m and n are such that m/n has values from about 0.5 to about 6; a is a number with the proviso that when A is a monovalent anion, a=n, when A is a divalent anion, a=1/2n, and when A is a trivalent anion, a=1/3n; and b is an integer having a value from 1 to about 10.