EFFECT OF CATION ON PERFORMANCE OF ZSM-5 FOAM CATALYSTS IN THE SCR OF NOX WITH NH3

Self-supporting ZSM-5 foam catalysts were successfully synthesized by immersing a polyurethane scaffold in a clear solution containing zeolite precursors and then calcining at 600°C after a hydrothermal treatment. Zeolite foams have a good mechanical resistance and high surface area and crystallinity. The catalysts were exchanged with copper or iron ions and tested for the NOx Selective Catalytic Reduction (SCR) in the temperature range 100 - 400°C. Monolith foams provided better performance compared to powder catalysts due to their higher amount of active phase per unit reactor volume coupled to the enhanced mass transfer.Cu-ZSM-5 foam catalyst showed better activity at low temperature, whilst Fe-ZSM-5 foam, although providing a lower NO conversion than the Cu-zeolite counterpart, showed a very high N2 selectivity over a wider temperature range.