Kinetic Separation of Nickel(II) and Cobalt(II) with 5-Octyloxymethyl-8-quinolinol by Differential Extraction
Kinetic Separation of Nickel(II) and Cobalt(II) with 5-Octyloxymethyl-8-quinolinol by Differential Extraction
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5-辛氧基甲基-8-羟基喹啉差速萃取动力学分离镍(II)和钴(II)
DOI：
10.2116/analsci.4.617
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发表时间：
1988
影响因子：
1.6
通讯作者：
Katsumi Yamamoto
中科院分区：
文献类型：
--
作者：
H. Kokusen;Kimiyuki Suzaki;K. Ohashi;Katsumi Yamamoto
本文研究了5-辛氧基甲基-8-羟基喹啉（HO_8Q）对镍（Ⅱ）和钴（Ⅱ）的萃取速率控制分离及HO_8Q萃取镍和钴的动力学。萃取率对金属离子和HO_8Q均为一级反应，对氢离子为反一级反应。萃取速率可用-d[M^2+]/df = k _HL+ k _L[H^+]^-1 k _aK_DR^-1[M^2+][HO_8Q]表示，其中K _a和k _DR分别为HO_8Q羟基的酸解离常数和HO_8Q在氯仿-水之间的分配常数。在25°C和l =0.1 mol dm^-3（NaClO_4）时，镍（II）和钴（II）的k _HL值分别为4.2×10^3 mol ^-1 dm^3 s ^-1和4.7×10^4 mol^-1 dm^3 s^-1。在上述条件下，镍（II）和钴（II）的k _L分别为7.1×10^8 mol^-1 dm^3s ^-1和6.0× 10^10 mol ^-1 dm^3s^-1。速率控制步骤应为金属离子与HO_8Q的中性和阴离子形式的竞争反应。从钴（II）中控制速率分离镍（II）的方法如下：将10立方厘米含有3.00×10^-5 mol dm^-3金属离子的水溶液和pH 4.6的醋酸盐缓冲液的混合物，与10立方厘米5.0×10^-2 mol dm ^-3 HO_2溶液一起剧烈振荡。分离效率大于95%。
The extraction rate-controlled separation of nickel(II) from cobalt(II) with 5-octyloxymethyl-8-quinolinol (HO_8Q) and the kinetics of the extraction of nickel(II) and cobalt(II) with HO_8Q are described. The extraction rate was first-order regarding metal ions and HO_8Q, and was inverse first-order regarding hydrogen ions. The extraction rates were represented by -d[M^2+]/d f = k _HL+ k _L[H^+]^-1 k _aK_DR^-1[M^2+][HO_8Q], where K _a and k _DR are the acid-dissociation constant of the hydroxy group of HO_8Q and the distribution constant of HO_8Q between chloroform and water, respectively. The values of k _HL were determined to be 4.2×10^3 mol^-1 dm^3 s^-1 and 4.7×10^4 mol^-1 dm^3 s^-1 for nickel(II) and cobalt(II), respectively, at 25°C and l =0.1 mol dm^-3 (NaClO_4). The k _L are to be 7.1×10^8 mol^-1 dm^3s^-1 and 6.0×10^10mol^-1 dm^3s^-1 for nickel(II) and cobalt(II), respectively, under the above-mentioned conditions. The rate-determining steps should be the competitive reactions of metal ions with the neutral and anionic forms of HO_8Q. The procedure for a rate-controlled separation of nickel(II) from cobalt(II) are as follows: A mixture composing ten cm^3 of the aqueous solution containing 3.00×10^-5 mol dm^-3 metal ions and an acetate buffer at pH 4.6 was vigorously shaken with a 10 cm^3 of 5.0×10^-2moldm^-3 HO_8Q chloroform solution for 2 min. The separation efficiency was more than 95%.