工业循环冷却水中钼酸盐类缓蚀剂MoO_4^(2-)测定方法的改进

Determination of MoO_4^(2-) in Industrial Cyclic Cooling Water Using Molybdate as Corrosion Inhibitor

准确调节被测样液的pH值为3.4～3.6,用G4砂芯滤器或慢速滤纸干过滤被测样液,控制样液MoO_4^(2-)待测浓度在3～5μg/mL,取样液体积为5～20mL。给出了适宜的MoO_4^(2-)工作曲线,并对其可靠性和高浓度Ca^(2+)、Mg^(2+)等阳离子对测定的干扰进行了定量评价。结果表明在MoO_4^(2-)浓度为2～5μg/mL时,测定相对误差不超过3.35%。

This paper introduces modifying suggestions for determining the concentration of MoO^2- _4in the test of evaluating the inhibition performance in industrial cyclic cooling water ~according to sulfocyanatespectrophotometry. the pH value of sample liquid was adjusted ~accurately in the range of 3.4～3.6,and the sample liquid is dryfiltered by using G_4 sand filter or paper filtered with fliter paper at a slow rate.The range of 3～5μg/mL and 5～20mL were suitable for the concentration of MoO^2- _4and its volume,respectively.Additionally,the ~favorable working curve of MoO^2- _4 was given and its reliability and the influence of high ~concentration of Ca^2+ and Mg^2+ in the solution on determination of MoO^2- _4 were investigated quantitatively.The results indicated that the relative error in the process of determination was below 3.35% as the concentration of MoO^2- _4 was in the range of 2～5μg/mL.