过硫酸钾消解法测定工业废水中总磷的方法改进

Improvement of potassium persulfate digestion method for the determination of total phosphorus in industrial wastewater

水体中的总磷含量是衡量水质的重要指标之一。但是国家标准GB11893-89推荐的过硫酸钾消解法在某些工业废水总磷检测过程中易出现消解不彻底的现象,因此经常导致测定结果偏低。有鉴于此,本文改进了消解方法,采用硫酸+过硫酸钾混合消解体系以强化总磷氧化,并通过加标回收实验和精密度实验对该方法的有效性进行了评价。结果显示,检测值与参考值的相对误差小于1.07%,相对标准偏差为0.54%~1.37%,加标回收率达到97.9%~102.5%。由此可见,与国家标准法相比,改进后的总磷测定方法准确性与可靠性显著提高,可广泛应用于工业废水的水质监测。

Total phosphorus(TP)in water/wastewater is an important indicator of water quality.However,during some industrial wastewater monitoring process,the potassium persulfate digestion method recommended by the national standard GB11893-89 often provides a relatively low TP content due to its insufficient digestion capacity.Therefore,this study improved the digestion approach,where mixed digestion system of sulfuric acid and potassium persulfate was adopted to enhance the oxidation of total phosphorus.The availability of the improved method was evaluated through the experiments about the recovery of standard addition and relative standard deviation.The results showed that the relative errors between measured values and reference values were less than 1.07%.In addition,the relative standard deviation was between 0.54%and 1.37%,and the recovery rate of standard addition reached 97.9%~102.5%.Consequently,compared with national standard method,the accuracy and reliability of the modified method for total phosphorus determination are significantly improved,which can be widely used for the water quality monitoring of industrial wastewater.