Behaviour of Mesoporous Silica (MCM-41) Supported Catalysts in Degradation Reactions

摘要

A dissolution experiment indicated that Pd/MCM-41 is more stable in contact with deionized water at 25±0.1°C than MCM-41 and the stability increased with increasing mass loading of Pd. A long term dissolution experiment showed that MCM-41 retained its characteristic hexagonal structure and high surface area after 1,174 days of contact with deionized water. Samples of Pd/MCM-41 absorbed 0.85±0.18 moles of hydrogen per mole of Pd present in a series of experiments in pressure cells at 25±0.1°C and approximately 101.3 kPa. Pd/MCM-41 exhibited substantial longevity while degrading at least 91% of inflow trichloroethylene (TCE) concentrations in hydrogen-saturated deionized water over 5,036 pore volumes during a column experiment. The dominant breakdown product of TCE degradation in the presence of Pd/MCM-41 was ethane. Minimal concentrations of intermediate degradation products were detected, suggesting that TCE degraded to ethane before desorbing from the Pd/MCM-41 surface.