中国有色冶金

The current research and application of Spectrophotometric IPB method is mainly focused on the detection with an ammonia concentration of appr. 1g/mL, while in actual production activities, the ammonia nitrogen concentration in the places involving ammonia nitrogen production and solid waste treatment is relatively high, and errors may occur while using this method for detection. In this paper, the Spectrophotometric IPB method was used to detect the absorbance of ammonia nitrogen in the solutions with different ammonia concentrations, it was found that the absorbance increased first and then decreased in the concentration range of 0-100.00g/mL; when the ammonia concentration was 0-1.00g/mL, there was a linear positive correlation between the ammonia content and the absorbance; when the ammonia concentration was 0-3.00g/mL, the ammonia content had a linear positive relationship with the absorbance, but the slope of the curve decreased; when the ammonia concentration was 3.00-7.00g/mL, the ammonia content and the absorbance were positively correlated, but the slope further reduced; when the ammonia concentration was 7.00-100.00g/mL, the ammonia content was negatively correlated with the absorbance, and with the increase of the concentration, the ammonia reacting dose lessened; furthermore, the reacting dose of ammonia at high ammonia concentration of 100.00g/mL was even lower than that of 0.50g/mL. Through analysis and experimental research, the reasons for such abnormal phenomenon were speculated that when the ammonia concentration was too high, the sodium nitroprusside would bring the reaction conversion rate down, and excess chloramines might react with the cyano group of the sodium nitroprusside, resulting in catalyst deactivation and weakening the activity of catalytic reaction.