Knowledge Bank

Groundwater contamination of chlorinated compounds has been a major concern because of the carcinogenic consequences in affecting drinking water. The catalytic hydrodechlorination of chlorinated compounds like trichloroethylene (TCE) to less toxic hydrocarbons offers a sustainable, efficient, and cost effective method for decontaminating groundwater. In groundwater, catalyst deactivation from ionic species is an on-going problem. Therefore, a newly developed swellable organically-modified silica (SOMS) support has been used for hydrodechlorination of TCE to protect the active sites from anions through the hydrophobic and swellable nature of SOMS. In addition, the effects of heat treatment on the catalytic performance and poison-resistant nature of SOMS have been investigated. Catalytic activity experiments were performed in an aqueous phase batch reactor operating at 50 bar and 30°C for pristine and sulfide ion poisoned palladium catalysts using SOMS support. Characterization experiments for the temperature treated SOMS support were performed through nitrogen physisorption to analyze textural properties of the catalysts and Infrared Spectroscopy to examine the surface functional groups. The catalytic activity and characterization results for different heat-treated catalysts are analyzed in this study to determine the catalyst’s degree of protection from anions, while maintaining activity of Pd metal. The hydrodechlorination activity is quantified by percent of conversion of trichloroethylene and was determined that heat-treated pristine SOMS achieved more activity and similar deactivation of poisoned SOMS when compared to commercial catalyst 1% Pd/Al2O3. In addition, the material characteristics changed with heat treatment, including textural, chemical, and physical properties. The results of this research project are expected to ultimately contribute to the design of cheaper, better, and deactivation-resistant catalysts, greatly benefiting the catalytic groundwater remediation technologies.