Methane oxidation over zeolite catalysts prepared from geothermal fluids

Colloidal silica extracted from geothermal fluid was used as a reagent to produce zeolite Y with high purity. The characteristics of this sample were compared to a sample prepared with a conventional silica sol, namely Ludox. The two samples were treated with ammonium chloride and calcined to partially convert the samples into an H-form. The Na-FAU and H-FAU zeolites were then loaded with Pd and tested as catalysts in the combustion of methane. X-ray diffraction confirmed the characteristic FAU-type framework in all samples. Experiments showed that after addition of Pd, these zeolites were active catalysts in the complete combustion of methane, where the most active catalysts were those prepared from Na-FAU. These findings support the use of low Si/Al FAU-type frameworks in model studies of engine exhaust emissions abatement. The study further shows that the silica sol extracted from geothermal fluids can be successfully utilised for zeolites synthesis.