二苯碳酰二肼分光光度法测定实验废水中六价铬含量的研究

Determination of Cr(Ⅵ) by Spectrophotometry with Diphenyl Carbamide in Experimental Wastewater

虽然高校实验室中产生的废水量相对较小、六价铬含量相对较低,但是直接排放,对环境的污染依然很大,因此开展实验室废水监测工作十分必要。文章采用二苯碳酰二肼分光光度法,探讨了不同实验用水、显色温度、不同显色剂体系和保存条件对六价铬含量分析的影响。结果表明,蒸馏水、纯净水、去离子水均可满足实验方法的要求;冷藏条件下,显色剂能保持10天以上;在一定范围内,显色温度越高,达到最大吸光度的时间越短;乙醇体系比丙酮体系更具优势,而且无毒、环保。通过定量限、准确度、精密度及加标回收率实验证明了本实验方法的适用性。

Although the amount of waste water produced in university laboratories is relatively small and the content of Cr(Ⅵ) is relatively low, it will still cause great environmental pollutionif directly discharged. Therefore, it is very necessary to carry out laboratory waste water monitoring. The effects of different experimental water, color developing temperature, colored system and storage conditions of colored system on the determination of Cr were discussed by diphenyl carbamide spectrophotometry. The results show that distilled water, purified water and deionized water have no difference with the experimental method. Compared with room temperature, refrigerated condition is more suitable for storing colored system, which can be maintained for more than 10 days. Within limits, the higher the color temperature, the shorter the time to reach the maximum absorbance. Colored system with Ethanol has more advantages than colored system with acetone, and is nontoxic and environment-friendly. The applicability of the experimental method and optimized conditions was proved by the experiments of quantitative limit, accuracy, precision and standard addition recovery.