离子选择性电极法快速测定强酸废水中的氯离子

Rapid determination of chloride ion in strong acid wastewater by ion selective electrode method

针对现有强酸废水中氯离子(Cl^(-))浓度检测方法中预处理及检测步骤复杂繁琐、浓度范围窄、受基体干扰大的缺点,开发出利用Cl^(-)选择性电极采用一次标准加入法测定强酸废水中Cl^(-)浓度的方法。首先,根据Nernst方程推导出加标前后电位变化值ΔE与Cl^(-)浓度的相关关系c_(x)=35.46/(10^(ΔE/S)-1),然后,通过测定电极斜率S,绘制ΔE-[Cl^(-)]函数表,根据ΔE查表即可快速获得待测样品中Cl^(-)浓度。该方法线性范围宽,可以准确测定10^(-5)~10^(-1)mol·L^(-1)范围的Cl^(-)浓度;方法精密度高,相对标准偏差仅为1.260%~3.373%;方法准确度高,实际强酸废水中加标回收率为98.9%~103%;方法基本不受复杂的水质干扰;不仅可以用作实验室内检测,还可以用于现场Cl^(-)浓度的应急检测。

In view of the shortcomings of the existing detection methods of chloride ion(Cl^(-))concentration in strong acid wastewater,such as complex pretreatment and detection steps,narrow detection concentration range and large interference by the matrix,this study selects the chloride ion selective electrode to determine the Cl^(-)concentration in strong acid wastewater by standard addition method.Firstly,the correlation(c_(x)=35.46/(10^(ΔE/S)-1)between the potential change value before and after standard addition(ΔE)and the chloride ion concentration([Cl^(-)])is deduced according to the Nernst equation.Then,theΔE-[Cl^(-)]function table is drawn by measuring the electrode slope S.According to the table,the Cl^(-)concentration in the sample to be measured can be quickly obtained.This method can accurately determine the Cl^(-)concentration in the range of 10^(-5)~10^(-1)mol·L^(-1);The method has high precision,and the relative standard deviation is only 0.1260%~0.3373%;The method has high accuracy,and the recovery rate of standard addition in actual strong acid wastewater is 98.9%~103%;The method is basically free from complex water quality interference;It can be used not only for indoor detection,but also for on-site Cl^(-)emergency detection.