Nitrate ions present in industrial waste waters should be removed before discharge of the solutions. Uchida as well as Okuwaki [Hydrometallurgy, 49, 297-308 (1998)] have proposed that lead metal can serve as a appropriate reducing agent for nitrate ion:
NO3- + Pb = NO2- + PbO(s)
Get ready a log [N] vs. pe plot for NO3- and NO2- when [N]T = 10-3 M.
Given:
NO3- + 2H+ + 2e- = NO2- + H2O log K = 28.15