Gold and Palladium Nanoparticles as Catalysts for Nitrite Reduction in Drinking Water and Local Water Sources

Overview

Objectives/Goals Nitrite contamination, which can cause birth defects, is a growing dilemma facing the global population today, especially in agricultural communities due to the increased use of nitrate rich fertilizers which can contaminate local water supplies. We tested Gold, Palladium, and Pd-on-Au Nanoparticles' effectiveness as catalysts for nitrite reduction. We also detected of the concentration of nitrites in drinking water or sources of drinking water via High Performance Liquid Chromatography. Methods/Materials Gold, Palladium, and Palladium on Gold Nanoparticles were synthesized from Chloroauric(III) Acid, Tannic Acid, Potassium Carbonate, Trisodium Citrate, Palladium(II) Chloride and Hydrochloric Acid. Hydrogen and Carbon Dioxide gas were bubbled into each nanoparticle catalyst and sodium nitrite solution to induce a reduction reaction. Reduction efficiency as well as water sample nitrite concentrations were analyzed via HPLC (Column: Agilent AN1 Anion Exchange Column; Sample Size: 20 uL; Flow Rate: 1mL/sec; Detection: UV, 210; Solvent: 1.7 mM NaHCO3 Solution; Temperature: 35 degrees C; Run Time: 20 minutes, 2 minute cooldown) Results We determined that 30% sc Pd-on-Au NPs were the most effective in the reduction of nitrite to nitrogen gas, decreasing nitrite concentrations to 88% of its original value (p<0.05). 100% sc Pd-on-Au NPs and pure Au NPs decreased nitrite concentration by 11% and 16% respectively (p<0.05). However, both 300% sc Pd-on-Au and pure Pd NPs failed to produce any significant results. In detecting nitrite concentrations in common water sources, only tap water produced trace amounts of nitrite contamination (0.04356 ppm). Conclusions/Discussion The most effective nanoparticle catalyst was the 30% surface coverage Pd-on-Au nanoparticle, with a bell shaped curve for effectiveness around the 30% sc nanoparticle. Furthermore, HPLC detection proved that no nitrite ions were present in detectable concentrations in bottled water and local area water. However, trace amounts of nitrites were detected in tap water, although much lower than the WHO standard of 0.91 mg/L.

Awards (1)

• Honorable Mention

Competition history

• CSEF 2014 Chemistry · Entry S0609

Resources

• CSEF project summary ↗

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