摘要
采用重铬酸钾法、快速消解-分光光度法、完全氧化法对含有不同Cl^-浓度(500、1000、1500mg/L)的2种不同ρCOD(300、700mg/L)的标准水样进行测定,比较分析了Cl^-干扰对3种方法准确性的影响。研究结果表明,通过绘制ρ_(CODCr),Cl^-^-ρ_(Cl^-)浓度标准曲线,扣除氯离子干扰的完全氧化法测定结果与标准值基本符合,说明该方法能较为有效地消除Cl^-干扰,但该方法耗时较长;重铬酸钾法对300mg/L的COD水样的测定结果与标准值偏差不大,但对700mg/L的COD水样时与标准值偏差均在10%以上,说明高COD水样有机物的消解过程明显被Cl^-(500~1500mg/L)干扰,测定结果显著偏高;快速消解-分光光度法测定结果受Cl^-干扰最大,对300mg/L的COD水样的偏差即达到52%,进一步分析表明ρ_(Cl^-)/ρ_(COD)(浓度比)是影响该方法偏差的主要因素,考虑到快速消解法操作效率高,在实际含Cl^-水样测定时可设参数进行校正。
300,700 mg/L COD standard water samples containing different concentrations of chloride ions(500,1000,1500 mg/L)are determined by potassium dichromate method,rapid digestionspectrophotometry and complete oxidation method.The effects of Cl^-interference on the accuracy of the three methods are compared and analyzed.The results of the study show that the results of the complete oxidation method for deducting chloride interference by plotting theρCODCr,Cl^--ρCl^-chlorine ion curves are basically consistent with the standard values,indicating that this method can effectively eliminate Cl^-interference,but this method takes a long time.The results of the potassium dichromate method of 300 mg/L COD water sample show there exists little deviation from the standard value,but the deviation at 700 mg/L COD is more than 10% from the standard value,indicating that the organic matter removal process of the high COD water sample is obvious.The result of determination by Cl^-(500～1500 mg/L)is significantly higher.The result of rapid digestion-spectrophotometry is the most interfered by Cl^-,and the deviation of 300 mg/L COD water sample reaches 52%.Further analysis shows that the concentration ratio of ρCl^-/ρ_(COD) is the main factor influencing the COD deviation of the method.In consideration of the high efficiency of the rapid digestion method,it may be possible to set a parameter to correct the actual chlorine-containing water sample.
出处
《长江大学学报（自然科学版）》
CAS
2018年第13期40-43,共4页
Journal of Yangtze University(Natural Science Edition)
