Abstract
Electrochemical removal of nitrate and its intermediates, ammonia and nitrite, by use of a bipolar electrode connection, was investigated under different experimental conditions (initial pH (4, 7, or 10) current density (5, 10, or 15 mA/cm2), nitrate concentration (25, 50, or 75 mg/L NO3 −-N), with or without NaCl as supporting electrolyte). The results showed that nitrate and intermediates were significantly removed in the presence of NaCl as supporting electrolyte; ammonia and nitrite were not removed in the absence of NaCl. Nitrate was reduced from 50 to 8.65 mg/L NO3 −-N in 150 min; under these conditions final ammonia and nitrite concentrations were 3.36 mg/L NH3 and 0.01 mg/L NO2 −-N, respectively. Denitrification times required to reduce nitrate concentration to the recommended standard for drinking water of 10 mg/L NO3 −-N were 180, 120, and 60 min at current densities of 5, 10, and 15 mA/cm2, respectively; initial nitrate concentration is 50 mg/L NO3 −-N. The rate of reduction of nitrate at pH 7 and 10 was greater than at pH 4. With increasing initial nitrate concentration the time required to achieve the recommended standard for drinking water was increased.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have