Decomposition of nitrate by in situ buff abrasion of lead plate

A new approach to the decomposition of nitrate ion using Pb metal has been developed. Removal of the oxide layer formed on the surface of Pb plate and the production of Pb powder have been achieved by in situ abrasion of Pb plate in NH₄NO₃ solution with an abrasive buff. NO^-₃ was reduced to NO^-₂ at initial concentrations of NH₄NO₃ in the range 0.01-0.2 M, rotational speed of buff, 100-800 rpm and temperature, 25-80°C. Complete reduction of NO^-₃ in 0.05-0.2 M NH₄NO₃ solution was achieved at 80°C within 4 h. As the temperature increases, the reduction rate of NO^-₃ to NO^-₂ increases abruptly. The reduction rate increases gradually with rotational speed. The formation of NO^-₂ is almost independent of the initial NO^-₃ concentration. Reduction of NO^-₃ to NO^-₂ is related to corrosion of Pb in NH₄NO₃ solution.