Bimetallic Nanocatalysts for Reductive Treatment of Water Contaminated with Chlorinated Priority Pollutants

Preliminary SEM image of hydrophilic PDMS particles.

The superior catalytic efficiency of Pd-coated Au (Pd/Au) NP catalysts was discovered for trichloroethene hydrodechlorination (TCE HDC), a water-phase, room-temperature reaction with important implications for groundwater treatment. In this reporting year, the Project team has studied in detail the interesting observation that gold causes the Pd metal to be more durable against sulfide and chloride poisoning (led by Heck, paper to be submitted). Other work involved the flow-reactor investigation of resin-supported Pd/Au NPs (led by Fang, paper published); the study of the reaction kinetic differences between Pd/Au and Pd-only catalysts for TCE HDC (led by Fang, paper to be submitted); and the spectroscopic analysis of the HDC reaction under reaction conditions (led by Heck, paper published). Supported Pd-Au catalysts were studied for chloroform (CF) HDC, though the synthesis route towards Pd/Au catalyst structure remains to be developed. As an example of inter-university collaborations and industrial outreach, a new project with Martin Reinhard (Stanford) to design and develop a pilot-scale flow reactor for CF HDC was established. Based on a three-phase trickle-bed design, the reactor will eventually be sited at a DuPont facility and operated and test by DuPont personnel. Besides their dissolved form, organic solvents can also exist as sub-surface, dense non-aqueous phase liquids (DNAPLs). New work was initiated to explore their ultimate catalytic removal through the development of an elastomeric support particles based on polydimethylsiloxane (PDMS), which can absorb DNAPLs into its bulk.

Participating Researchers:

• Michael Wong
  
• Pedro Alvarez
• Vicki Colvin