电感耦合等离子体原子发射光谱法测定钒电池硫酸氧钒中钒和硫酸根

全钒液流电池是一种应用广泛的新能源技术,固体硫酸氧钒(VOSO₄·nH₂O,n=3~5)则是制备钒电解液的基础原料,钒及硫酸根含量及其比例关系决定着电解液乃至钒电池的品质,因此建立了电感耦合等离子体原子发射光谱法(ICP-AES)测定钒电池硫酸氧钒中钒和硫酸根的方法。优选了待测元素灵敏度适中的分析谱线,满足了同时测定钒电池硫酸氧钒中含量范围变化较大的钒和硫酸根的需要,并且优化了分析谱线的积分区域、同步背景校正区域等仪器检测条件,改善方法检测性能。以钒和硫酸根的混合标准溶液系列绘制校准曲线,使用基体匹配法消除基体效应的影响。方法中钒和硫酸根的测定范围分别为15.0%~30.0%和35.0%~50.0%;校准曲线线性相关系数大于0.9999。实验方法用于测定2个硫酸氧钒样品中钒和硫酸根,结果的相对标准偏差(RSD,n=11)小于0.50%;回收率为96%~104%。分别使用本法测定3个硫酸氧钒样品中钒和硫酸根,并与使用过硫酸铵氧化-硫酸亚铁铵滴定法测定钒、硫酸钡重量法测定硫酸根的结果进行比对,测定结果比较吻合。

Determination of vanadium and sulfate in vanadyl sulfate for vanadium battery by inductively coupled plasma atomic emission spectrometry

The all-vanadium redox flow battery was a widely used new energy technology. The solid vanadyl sulfate (VOSO₄·nH₂O, n=3-5) was the basic raw material for preparing vanadium electrolyte, and the content of vanadium and sulfate as well as their proportional relationship determined the quality of electrolyte and even vanadium battery. Therefore, the determination method of vanadium and sulfate in vanadyl sulfate for vanadium battery by inductively coupled plasma atomic emission spectrometry (ICP-AES) was established. The analytical lines of testing elements with appropriate sensitivity were optimized and selected, which could meet the requirements for the simultaneous determination of vanadium and sulfate in vanadyl sulfate for vanadium battery with large content scope change. Moreover, the instrumental conditions such as integral region of analytical lines and the region of synchronous background correction were optimized to improve the detection performance of this method. The calibration curve was drawn with a series of mixed standard solutions containing vanadium and sulfate to eliminate the influence of matrix effect with matrix matching. The detection range for vanadium and sulfate was 15.0%-30.0% and 35.0%-50.0%, respectively. The linear correlation coefficients of calibration curves were all greater than 0.9999. The experimental method was applied for the determination of vanadium and sulfate in two vanadyl sulfate samples. The relative standard deviations (RSD, n=11) of results were less than 0.50%, and the recoveries were between 96% and 104%. The contents of vanadium and sulfate in three vanadyl sulfate samples were determined according the experimental method, and the results were compared with those obtained by ammonium persulfate oxidation-ammonium ferrous sulfate titration for vanadium and barium sulfate gravimetry for sulfate. The determination results were all in good agreement.