摘要
通过加入过量的氢氧化钠标液,使铁铬电解液中的金属离子均形成水解沉淀状态,采用返滴定法测试及计算铁铬电解液中的游离酸,同时和电位滴定法进行比对。加入KF络合掩蔽电解液中存在的Fe^(3+),能准确测试含Fe^(3+)的铁铬电解液中的游离酸。简述了返滴定法测试方法的原理,考查了样品取样量、氢氧化钠用量、酚酞指示剂用量对游离酸测试结果的影响,通过精密度试验和加标回收率试验,准确度较高。简述了电位滴定法的测试原理,考查了滴定终点pH值对游离酸测试结果的影响,通过精密度试验和加标回收率试验,准确度较高,同时改进含Fe3+的电解液电位滴定法,经和返滴定法做比对,两种方法测试结果接近,均能应用于铁铬电解液中游离酸的测试。
By adding excessive sodium hydroxide standard solution,all metal ions in iron-chromium electrolyte form hydrolytic precipitation state.The free acid in iron-chromium electrolyte is measured and calculated by backtitration method,and compared with potentiometric titration method,and the free acid in iron-chromium electrolyte containing Fe3+can be accurately measured by adding KF complex to mask the existing Fe3+.The principle of backtitration method is described.The influence of sample size,sodium hydroxide and phenolphthalein indicator on free acid test results is investigated.The accuracy is high through precision test and standard recovery test.The test principle of potentiometric titration was described,and the influence of pH value of titration endpoint on the test results of free acid was investigated.The accuracy was high through precision test and standard recovery test.Meanwhile,the electrolytic potentiometric titration method containing Fe3+was improved,and the test results of the two methods were similar to that of the backtitration method.
作者
车莹
华蔓
杨合雄
宋德生
肖晋宜
CHE Ying;HUA Man;YANG Hexiong;SONG Desheng;XIAO Jinyi(R Environmental Technology Co.,Ltd.,Huizhou 516267,China)
出处
《化工管理》
2023年第34期148-153,共6页
Chemical Engineering Management
关键词
铁铬电解液
游离酸
返滴定
电位滴定
iron chromium electrolyte
free acid
back titration
potentiometric titration
