Effective and selective conversion of nitrate from aqueous solutions to nitrogen gas under neutral pH condition using Al/Cu bimetal-sulfamic acid reduction method

To expand the working pH range of NO 3 – -N reduction from aqueous solution, a two-step method including the Al/Cu bimetal and sulfamic acid reduction was developed. In this process, Al/Cu bimetallic materials were prepared by chemical deposition method and characterized by EDS, SEM, XRD and XPS. The NO 3 – -N reduction batch experiment showed that 100% of NO 3 – -N was reduced and converted to N 2 at pH of 7, Al/Cu dosage of 30 g/L and EDTA-2Na concentration of 6 mmol/L. When the pH value was adjusted to 3, 5 and 9, NO 3 – -N reduction efficiencies ca. 80–97% were also obtained in the first step, and 100% N 2 selectivity was further obtained with the second reduction step at pH of 3, 7 and 9. The kinetics study indicated that the Al/Cu reduction process was in accordance with the pseudo-second order kinetics model.