There is a high concentration of S2+in ammonia distillation wastewater,which seriously affects the accuracy of the determination results by ion-selective electrode method.Therefore,Nessler's reagent colorimetry is generally employed to detect ammoniacal nitrogen in ammonia distillation wastewater at coking plants,but it has a complicated operation process,needs long determination time and obtains analysis results lagged.Thus,an all-solid ammonium ion selective electrode is developed,and an electrochemical analysis method is established for rapid detection of ammoniacal nitrogen in ammonia distillation wastewater through adding a moderate amount of zinc acetate into wastewater to eliminate the interference of S2-.Adjusting the pH of wastewater sample to 4-7,adding a moderate amount of zinc acetate,then the potential difference between ammonium ion selective electrode and Ag/AgCl reference electrode is measured,and finally the concentration of ammoniacal nitrogen in wastewater sample is obtained by means of standard curve.The linear detection range of ammoniacal nitrogen by this method is 0.14-1 400 mg·L-1,the detection limit is 0.011 mg·L-1,the relative standard deviation RSD is 1.14％-3.02％,and the recovery rate is 99.85％-104.18％.This method is easy to operate,needs a short detection time,can rapidly analyze ammoniacal nitrogen in ammonia distillation wastewater at coking plants,and shows a good application prospect in developing ammoniacal nitrogen online monitoring device.
关键词
蒸氨废水/氨氮快速测定/离子选择性电极/纳氏试剂比色法/硫离子
Key words
ammonia distillation wastewater/rapid determination of ammoniacal nitrogen/ion selective electrode/Nessler's reagent colorimetric/sulfide ion
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