Iron-loaded small pore aluminosilicate zeolites and method of making metal loaded small pore aluminosilicate zeolites

A method of making a metal-loaded aluminosilicate zeolite having a maximum pore opening defined by eight tetrahedral atoms, wherein the metal is present in a range of from about 0.5 to about 5.0 wt. % based on the total weight of the metal-loaded aluminosilicate zeolite, by treatment of pre-formed crystallites of an aluminosilicate zeolite, which method comprises the steps of:

• (i) introducing mesoporosity into the pre-formed aluminosilicate zeolite crystallites by application of an aqueous alkali treatment to dissolve silica or application of an aqueous acidic treatment to dissolve alumina in the aluminosilicate zeolite crystallites;
• (ii) introducing the metal into the product of step (i) by wet impregnation or wet ion-exchange by contacting the product of step (i) with a mixture of a metal reagent and a structure directing agent for the metal-loaded aluminosilicate zeolite;
• and
• (iii) performing hydrothermal crystallisation on the product of step (ii).