国产过硫酸钾不能用于水样总氮测定的原因解析和对策  

Analysis and Countermeasure of Total Nitrogen Determination Failure in Water Sample with Domestic Potassium Persulfate

作　　者：罗琼 刘则华 尹华[1,2,3] 党志 

机构地区：[1]华南理工大学环境与能源学院,广东广州510006 [2]华南理工大学工业聚集区污染控制与生态修复教育部重点实验室,广东广州510006 [3]华南理工大学污染控制与生态修复广东普通高等学校重点实验室,广东广州510006

出　　处：《中国给水排水》2018年第4期110-113,共4页China Water & Wastewater

基　　金：国家自然科学基金重点项目(41330639);国家自然科学基金和广东省联合基金重点项目(U1501234);国家自然科学基金资助项目(21577040;21107025);广东省公益研究与能力建设项目(B2153210)

摘　　要：碱性过硫酸钾消解-紫外分光光度法是测定总氮的国家标准方法,然而国产过硫酸钾试剂因纯度不够而无法满足分析要求,但具体原因尚未解明。采用各种参数对国产过硫酸钾试剂进行了详细分析,结果表明过硫酸钾的总氮含量为0.103%~0.236%,是其标注浓度的20.6~47.2倍,表明产品总氮超标严重是其不能用于分析的主要原因。在此基础上,用重结晶法对国产过硫酸钾进行了提纯,第一次重结晶后,总氮去除率高达95.6%~97.0%。随着重结晶次数的增加,国产过硫酸钾的总氮含量进一步降低。将重结晶后的过硫酸钾产品应用于水样总氮的分析表明,经重结晶1次或以上的国产过硫酸钾产品可满足水样总氮分析要求。The Chinese national standard method for total nitrogen is the alkaline potassium persul- fate digestion plus UV spectrophotometry. However, apart from the reason that the purity of domestic po- tassium persulfate cannot meet the quality standard, specific reason remains unknown. Therefore, the quality of several domestic potassium persulfate products was examined with total nitrogen, ammonia and blank absorbance values. Results showed that the total actual nitrogen contents were 0. 103% - 0. 236%, which was 20.6 -47.2 times of label contents in domestic potassium persulfate product. Our results clearly indicated that the excessive content of total nitrogenin domestic potassium persulfate prod- ucts was the main reason which led to the failure of total nitrogen measurement. To purify the domestic potassium persulfate, recrystallization was used remove the excessive nitrogen. After once recrystalliza- tion, the total nitrogen removals were as high as 95.6% -97%. With the increase of the recrystallization times, the total nitrogen contents in domestic potassium persulfate were further reduced. With application of recrystallization potassium persulfate for determination of nitrogen in campus lake water sample, it is indicated that recrystallization for one or more times could greatly improve product quality and the purified products were proven to be appropriate for the total nitrogen measurement in real water sample.

关 键 词：国产过硫酸钾 总氮 重结晶 

分 类 号：X832[环境科学与工程—环境工程]