Since nitrate, which in human body reduces to nitrite, is responsible for the blue baby syndrome (methemoglobinemia) and cancer, there is a growing concern for the presence of nitrate and nitrite in surface and groundwater. Because of the harmful effect of nitrate and nitrite, the World Health Organization regulate the maximum concentration of nitrate and nitrite in drinking water to 10 mg-N/L and 1 mg-N/L, respectively. Catalytic reduction is a promising technology that can sustainably treat nitrate and nitrite to nitrogen using hydrogen as an electron donor. In this study, we have developed Pd-In catalysts supported on two novel carbonaceous materials, hollow carbon spheres(HCSs) and three-dimensional hierarchically porous graphitic carbon(HPG carbon). After HCSs and HPG carbon are each synthesized, Pd and In metals were deposited on the support surface using wetness incipient method. Catalyst activity, selectivity, and longevity of these materials for nitrate and nitrite reduction were investigated. HCS- and HPG-supported catalysts were also characterized using for their structures and catalyst metal dispersion. The reaction pathway for nitrate to nitrogen over ammonia was further explored for these two catalysts where the sorption of intermediate NO and N2O on the support and catalyst surfaces was hypothesized to play a key role in the selectivity. The role of these novel support materials as possible selective sieves for nitrate over other anions and natural organic matter (NOM) was also evaluated.

Development of hollow carbon spheres-supported Pd-based catalysts for efficient sorption and reduction of nitrate and nitrite

256th National Meeting (2018)

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