水中总氮测定方法的经验总结

水中总氮的测定目前多数实验室采用碱性过硫酸钾消解紫外分光光度法(GB11894-89),该方法虽步骤少、成本低,但在测定过程中往往会出现空白值偏高问题,导致测量结果不够准确。作者根据多年工作经验,对该测定方法的实验条件提出一些改进,从而使该种测定方法的空白值达到要求。     

Hg0 absorption in potassium persulfate solution

The aqueous phase oxidation of gaseous elemental mercury （Hg^0） by potassium persulfate （KPS） catalyzed by Ag^＋ was investigated using a glass bubble column reactor. Concentration of gaseous mercury and potassium persulfate were measured by cold vapor atom absorption （CVAA） and ion chromatograph （IC）, respectively. The effects of pH value, concentration of potassium persulfate and silver nitrate （SN）, temperature, Hg^0 concentration in the reactor inlet and tertiary butanol （TBA）, free radical scavenger, on the removal efficiency of Hg^0 were studied. The results showed that the removal efficiency of Hg^0 increased with increasing concentration of potassium persulfate and silver nitrate, while temperature and TBA were negatively effective. Furthermore, the removal efficiency of Hg^0 was much better in neutral solution than in both acidic and alkaline solution. But the influence of pH was almost eliminated by adding AgNO3. High Hg^0 concentration has positive effect. The possible reaction mechanism of gaseous mercury was also discussed.