(14f) Degrading Organic Compounds in Simulated Produced Water By Creating Hydroxyl Radicals Catalytically

Authors: 
Yin, Y., Rice University
Heck, K. N., Rice University
Powell, C., Rice University
Coonrod, C. L., Rice University
Guo, S., Rice University
Wong, M. S., Rice University
Currently, most produced water is disposed of by downhole injection, however, there is limited availability of disposal wells and growing concern over potential environmental contamination from produced water to groundwater wells. Few treatment technologies address the removal of organic compounds present in produced water which promote hazardous bacterial growth. In this work, we explored the potential application of alumina-supported palladium catalysts to degrade organic compounds using low-cost chemical additives. We find that a 1 wt% Pd supported on Al2O3 ("Pd/Al2O3") catalyst can degrade phenol in DI water at room temperature and atmospheric pressure when in the presence of oxygen and formic acid or hydroxylamine. To understand this result, we carried out control experiments using formic acid or hydroxylamine, O2, and catalyst in DI water without phenol. We observed hydrogen peroxide (H2O2) generation rates of 3360 and 8745 mmol-H2O2­ gmetal-1 h-1 using formic acid and hydroxylamine, respectively. Additionally, another control experiment showed no degradation of phenol with added H2O2 and Pd/Al2O3, and we further hypothesized that radicals directly generated O2 and hydroxylamine or formic acid over the Pd/Al2O3 were key to phenol degradation. Using a terephthalic acid-based fluorescence assay, we monitored •OH radical production and estimated its generation rate to be 5.3 mmol gmetal-1 h-1.