冰冻条件下水中硝基苯的变化

为了解松花江水中硝基苯在自然冰冻情况下的归趋,进行了硝基苯水样的冰冻实验。同时对松花江达连河断面主河道上冰层中硝基苯含量进行了分层检测。冰冻实验结果表明,在水样全部结冰情况下,冰中硝基苯浓度(以融化后水中硝基苯浓度计,下同)与原水样中硝基苯浓度比值与冰冻速度没有明显关系,该比值一般在0.47~0.80间;在水样不完全结冰情况下,结冰速度对硝基苯在冰相与水相中的分配比具有显著影响,快速结冰时分配比为0.21,而慢速结冰时仅为0.050。冰冻过程中水中硝基苯逐渐被浓缩,部分硝基苯挥发到大气中。污染带流经达连河断面时所结冰的各个层位中硝基苯浓度均远远低于国家《地表水环境质量标准》(GB 3838-2002)限值。

Nitrobenzene Changes in Water Under Natural Ice

For understanding nitrobenzene distribution in water under natural ice in Songhua River, nitrobenzene contents of different ice layers of main riverway were examined at Dalianghe in Songhua River. It was shown that nitrobenzene concentrations in ice are not proportional to those of original water samples under entirely icing conditions. The ratio of nitrobenzene concentrations in ice and water is 0.47-0.80. The icing velocity has obvious effects on nitrobenzene distributions in ice and water phases under incompletely icing conditions. When fast icing, the distribution ratio of nitrobenzene concentrations in ice and water was 0.21 ; while slow icing, the distribution ratio was 0. 050. Nitrobenzene was condensed gradually during icing course. Part of nitrobenzene volatilized into air. When nitrobenzene polluted band flowed into Dalianhe sections, nitrobenzene concentrations in different layers of ice were much less than concentrations demanded in the national standard of environmental quality for surface water.