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采用四苯硼钠电位滴定法测定阳离子褐煤树脂的阳离子度。通过消除测定方法的离子干扰、优化四苯硼钠电位滴定法的测定条件来提高测定方法的准确度。采用5%盐酸溶液提取阳离子腐植酸,去除钾离子和其他水溶性杂质;四苯硼钠电位滴定过程中,提纯后阳离子腐植酸加入量为0.5 g,用0.2%氢氧化钠溶液溶解阳离子腐植酸,在p H 10.0条件下,选用甘汞电极为参比电极,氟硼酸根离子选择性电极为指示电极,用十六烷基三甲基溴化铵标准溶液电位滴定四苯硼钠,电位突变约200~300 m V,加标回收率达95%,满足分析测试的要求。实验结果表明,该方法选择性好、准确性高、易于操作,具有较高的推广应用价值。
Determination of the cationic degree of cationic lignite resin by tetraphenylboron sodium potentiometric titration. By eliminating the interference of the determination method and optimizing the measurement conditions of the tetraphenylboron potential titration method, the accuracy of the determination method is improved. Cationic humic acid was extracted by 5% hydrochloric acid solution to remove potassium ions and other water-soluble impurities. During tetraphenylboron sodium potentiometric titration, the amount of cationic humic acid added was 0.5 g. The cationic humic acid was dissolved in 0.2% sodium hydroxide solution , Under the condition of p H 10.0, calomel electrode was selected as the reference electrode, and the fluoroborate ion selective electrode was used as the indicator electrode. Potentiometric titration of sodium tetraphenylborate was carried out by potentiometric titration with cetyltrimethylammonium bromide standard solution About 200 ~ 300 mV, spiked recovery rate of 95%, to meet the analytical test requirements. Experimental results show that this method has good selectivity, high accuracy, easy to operate, and has a high value of popularization and application.