The effect of electrochemical removal of low concentration ammoniacal nitrogen in wastewater and the oxidation mechanism of ammoniacal nitrogen are studied.The influences of chloride ion concentration,current density and pH on oxidation effect of ammoniacal nitrogen are analyzed.It is found that the removal of low concentration ammoniacal nitrogen by electrochemical method mainly depends on the indirect oxidation of hypochlorite and hydroxyl radicals generated by the anode during the electrolysis process.The concentration of ammoniacal nitrogen decreases from 100 mg·L-1 to 1.7 mg·L-1 after 150 min of electrolysis under the conditions that chloride ion concentration is 400 mg·L-1,current density is 20 mA·cm-2 and raw water pH is not adjusted.The removal rate reaches 98.1％,no by-product nitrites(NO2-N)is produced,and the final by-product nitrates-based nitrogen(NO3--N)concentration is 1.9 mg·L-1,and the selectivity of nitrogen gas is about 97％.
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