废水中硫化物测定样品预处理方法的改进

对废水中硫化物测定预处理方法——氮气吹气法的实验装置、预处理酸度、温度及反应瓶体积大小等条件均作了研究和改进。以多孔吹球代替单孔吹管、以NaOH+EDTA+三乙醇胺代替ZnAc_2—NaAc为吸收液,并提出了逐步加压的吹气方法。通过对回收率、精密度及6种不同类型工业废水的对比测定,效果提高显著,回收率由原法的40％左右提高到95％以上,吹气时间缩短25％,装置简单,便于推广应用。

Improvement in the Pretreatment Method of Samples for the Determination of Sulfides in Wastewater

The pretreatment method of samples, known as Nz-blowing method , for the determination of sulfides in wastewaer has been further studied and improved. The improvement includes the test apparatus,pretreatment procedure,acidity and temperature used in the pretreatment,and the volume of reaction bottle. Particularly,a multihole blowing ball was used to replace the sigle hole blowing pipet.and a mixture of NaOH,EDTA and TEA was used as the blowing-absorbing solution instead of ZnAc2-NaAc. Then a step-wise pressure procedure has been suggested. The studies on the recovery and precision of the improved method and the comparative determination of six different kinds of industrial wastewater show that the improvement has seen an obvious effectiveness and the recovery increases from 40% for the original method to over 95% for the improved method. The blowing time is shortened by 25%. The apparatus is easy to operate.