Ion exchange of Fe3+ in ZSM-5

The ion exchange of Fe 3+ with sodium in NaZSM-5 was performed with a maximum exchange level of 90% at 25°C. Subsequent exchange of the sodium for NH + 4 ions was made with no loss of iron, but the thermal decomposition necessary for conversion of these ammonium ions to protons leads to reduction of Fe 3+ to Fe 2+ . These phenomena were monitored by e.s.c.a., Mossbauer, i.r. of adsorbed pyridine, and temperature-programmed reduction.