Catalytic activity and characterization of Pt/calcined CuZnAl hydrotalcites in nitrate reduction reaction in water

Groundwater pollution with high nitrate concentration has become an important environmental and health issue. Catalytic reduction of nitrates emerged as a promising technique to remove nitrate in water. In the present study, Pt supported on CuZnAl calcined hydrotalcite catalysts with different Cu/Zn ratios (0.5, 1 and 2) were tested in a continuous reactor for the catalytic reduction of nitrates. These materials were characterized by different techniques such as: BET, TPR, XRD, HRTEM, XPS, FTIR. According to the results, the Cu/Zn atomic ratio in the active support has a strong influence in the nitrate conversion and in the nitrogen selectivity, indicating that the interaction of copper in the support plays an important role. The highest nitrogen yield is achieved with a Cu/Zn ratio 1. Also, the incidence of the Pt metal loading was studied in the range of 0.5–2%. This variable does not present a significant influence in the catalytic activity compared to the Cu/Zn ratio, within the range studied. Furthermore, catalysts are stable for this reaction.

.Figure optionsDownload high-quality image (110 K)Download as PowerPoint slideHighlights
► Catalytic reduction of nitrates using Cu hydrotalcite-like materials in continuous reactor.
► Pt supported over CuZnAl mixed oxides are active and stable catalysts for nitrate reduction in water.
► Effect of Pt addition on the surface properties of Cu-containing calcined hydrotalcites
► Conversion and nitrogen selectivity strongly depend on the Cu/Zn atomic ratio
► Sample with a Cu/Zn ratio 1 presented the highest nitrogen yield.