微波消解光度法快速测定炼油污水中COD_(Cr)

RAPID PHOTOMETRIC DETERMINATION OF COD_(Cr) IN REFINERY WASTE WATER WITH MICROWAVE-HEATING SAMPLE DIGESTION

采用微波消解光度法测定炼油污水的化学需氧量,用炼油污水(回流法准确测定其COD值)作为COD的标准溶液制作工作曲线、或求取回归方程的新方法。CODCr的测定范围为90～2000mg·L-1。与用邻苯二甲酸氢钾作为标准的CODCr值求得的回归方程相比,其值更接近回流法。方法具有设备简单、操作方便、分析时间短、精密度高、且快速、成本低、二次污染少等优点,值得在石油化工企业中推广应用。

The accurate value of COD_(Cr) of the refinery waste water was determined preliminarily by the conventional refluxing method, and used as standard instead of the potassium hydrogen o-phthalate standard, in the preparation of standard working curve or in the calculation of the linear regression equation. The absorbance of the sample solution (or the standard solution) after digestion was measured photometrically at 600nm for its trivalent chromium content. The power used in the microwave heating of sample (or standard) solution is 720W and the time taken for the digestion is 12min. The range of determination of COD_(Cr) of this method is from 90 to 2 000mg·L^(-1). It was found that results of COD_(Cr) obtained by this method are more closer to the results obtained by the refluxing method as compared with the method using o-phthalate as standard. It was shown by the results obtained, that the present method is more profitable and feasible to be used in the monitoring of waste water from petro-refinery.