Kim HS  Kim YH

Vol. 28,  No. 4, pp. 309-315, Dec.  2022
10.7464/ksct.2022.28.4.309

Electro-chemical method Nitrate total nitrogen DSA Optimal cathode

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Research was conducted to derive the optimal operation conditions and the optimal cathode for using a DSA electrode as an anode to minimize electrode consumption during the removal of nitrogen from wastewater by the electro-chemical method. Of the various electrodes tested as cathodes, brass was determined to be the optimal electrode. It had the highest NO3-N removal rate and the lowest concentration of residual NH3-N, a by-product when Cl is present in the solution. Investigating the effect of current density found that when the initial concentration of NO3-N was 50 mg L-1, the optimal current density was 15 mA cm-2. In addition, current densities above 15 mA cm-2 did not significantly affect the NO3-N removal rate. The effect of electrolytes on removing NO3-N and minimizing NH3-N was investigated by using Na2SO4 and NaCl as electrolytes and varying the reaction times. When Na2SO4 and NaCl are mixed at a ratio of 1.0 g L-1 to 0.5 g L-1 and reacted for 90 min at a current density of 15 mA cm-2 and an initial NO3-N concentration of 50 mg L-1, the removal rate of NO3-N was about 48% and there was no residual NH3-N. On the other hand, when using only 1.5 g L-1 of NaCl as an electrolyte, the removal rate of NO3-N was the highest at about 55% and there was no residual NH3-N.