EDTA间接滴定法快速测定造纸废水中硫化物

Rapid Determination of Sulphide in Paper Making Waste Water by EDTA Indirect Titration Method

提出了快速测定造纸废水中硫化物的EDTA间接滴定新方法。先将水样酸化，使其水中的HS^-及S^2-离子全部转化为H2S，然后加入过量的金属锌，反应产生的大量H2作为载气，与一并选出的H2S气体通入热的NH3-NH4Cl缓冲溶液及已知量且过量的Zn^2＋标准吸收液中，当ZnS沉淀完全后，以EBT为指示剂，用EDTA标准溶液滴定剩余的Zn^2＋至终点。结果表明，改进后的方法简单、快捷、干扰小,测定结果的相对标准偏差〈3.0％，回收率为93.4％～96．8％。利用t检验法对测定结果进行了显著性检验，它与标准法之间未见有显著性差异。

A new method EDTA indirect titration method for rapid determination of sulphide in paper-making waste water was proposed. At first, the sample of waste water was acidification and the HS^- and S^2- was transformed into H2S, and then the known quantity and excessive Zn was put into the waster water to produce hydrogen （H2）, the H2 and H2S escaped fiom the waster water. They reacted with the hot standard absorb solution of Zn^2＋ in NH3-NH4Cl buffer solution. When the ZnS was deposited, with EBT as the indicator and EDTA as the standardized solution, the residual Zn^2＋ was titrated to end point. The result showed it was an easy-operating way with fast determination and less disturbed. The relative standard deviation was less than 3.0% and the recovery, was between 93.4% and 96.8 %. It was checked up the significance of determination results by the t-test and the result showed there was no significance difference between this way and standard method.