Remediation of actual groundwater polluted with nitrate by the catalytic reduction over copper–palladium supported on active carbon

Abstract

Catalytic reduction of nitrate (NO 3 -) in groundwater over a Cu-Pd catalyst supported on active carbon was investigated in a gas-liquid co-current flow system at 298 K. Although CuPd/active carbon, in which the Cu/Pd molar ratio was more than 0.66, showed high activity, high selectivity for the formation of N 2 and N 2 O (98%), and high durability for the reduction of 100 ppm NO 3 -in distilled water, the catalytic performance decreased during the reduction of NO 3 -in groundwater. The catalyst also irreversibly deactivated during the reaction in groundwater. The organic species in the groundwater caused the decrease in the catalytic performance and the irreversible catalyst deactivation. Ozone-treatment of the groundwater to remove the organic species substantially helped to maintain the catalytic activity and to halt the irreversible deactivation of the catalyst. Chloride ion (Cl -) in the groundwater also caused the decrease in the activity and selectivity, but the effects of Cl -were reversible. Sulfate ion (SO 4 2-) and cations, including Mg 2+ , Ca 2+ and K + , had little or no effect on the catalytic performance of Cu-Pd/active carbon, though they were present in the groundwater sample.More than an allowable level of NH 3 (NH 4 + ) was formed during the catalytic reduction of NO 3 -in the groundwater, but was completely removed by the cation-exchange process using Namordenite.3

The ground water ammonium sorption onto Croatian and Serbian clinoptilolite

“…The observed concentrations were higher than Croatian and European Union standards and therefore this ground water was unsuitable for use as drinking water without appropriate treatment [6][7][8]. Thus, available methods for the efficient treatment of waters polluted with ammonium ions are gaining increased interest [9][10][11]. The biological methods were frequently used for the wastewater treatment, but due to the presence of microorganisms, for the surface and drinking waters, as well as for the ground waters, ion exchange treatment was favourable [12][13][14].…”

Nitrate reduction over a Pd-Cu/MWCNT catalyst: application to a polluted groundwater

“…Most of the studies deal with nitrate solutions prepared using deionized water as solvent; however, groundwater contains various cations, anions and organic species, and because of this a decrease in the performance and stability of catalysts is expected when real groundwater is investigated [20][21][22].…”

Bioremoval of lead and iron from sewage water by mangrove-derived Hypocrea lixii

“…2b, c), which is due to participation of specific functional groups on the adsorbent surface (Mohan and Karthikeyan 1997;Wang et al 2009). The kinetics of the present study revealed that the adsorbent (H. lixii biomass) showed the significant adsorbing capacity of the metals.…”