表面活性剂对稀土与偶氮氯膦-mK显色反应的影响及其应用

Effect of surfactant on color reaction of rare earths with chlorophosphonazo-mK and application

研究了溴化十六烷基三甲基铵、十二烷基磺酸钠、吐温 80、乳化剂OP和聚乙烯醇 5种表面活性剂对稀土与偶氮氯膦 mK显色反应的影响。结果表明 :乳化剂OP、吐温 80和聚乙烯醇对显色反应有增敏作用 ,其中吐温 80效果最为显著。在 0 0 2～ 0 0 8mol/L硫酸介质中和吐温 80存在下 ,Ce 与偶氮氯膦 mK生成稳定的蓝绿色络合物 ,最大吸收波长为 668nm ,表观摩尔吸光系数ε =9 1× 10 4 。用此显色体系测定低合金钢中稀土 。

Influence of five kinds of surfactants, i. e. cetyl trimethyl ammonium bromide, sodium dodecyl sulfonate(SDS), Tween-80,polyvinyl alcohol (PVA),emulsion OP,on the color reaction of rare earths (mainly cerium) with chlorophosphonazo-mK(CPA-mK) is studied.Results show that emulsion OP, Tween-80 and PVA have an effect of increase sensitivity. Among them Tween-80 is the best. In the medium of 0.02-0.08 mol/L H 2SO 4 and in the presence of Tween-80,Ce*$ forms a stable blue-green complex with CPA-mK.The maximum absorption of the complex is at 668 nm. The apparent molar absorptivity ε 668 is 9.1×10 4 L·mol -1·cm -1. The chromogenic system has been applied to determine total rare earths in low-alloyed steel with satisfactory results.