Extractive separation of metal ions with inorganic ligands such as halide ion into supercritical carbon dioxide

金属离子与卤离子等无机配体萃取分离成超临界二氧化碳

基本信息

批准号：
12640579
负责人：
OHASHI Kousaburo
金额：
$ 2.3万
依托单位：
IBARAKI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

A supercritical fluid extraction (SFE) by a supercritical fluid instead of a conventional organic solvent has recently been focused on the advanced method to remove the metal ions from aqueous solutions and solid materials. Among the supercritical fluids used in SFE, a carbon dioxide has been widely used because of its desirable properties, i.e. relatively low critical temperature and pressure, non-toxicity, non-flammability and high purity, although its solvating power is lower than those of organic solvents, such as chloroform.Extraction of most metal ions into supercritical fluid carbon dioxide (SF-CO_2), which is highly nonpolar as a solvent, from liquid and solid samples is difficult due to the requirement of charge neutralization of metal ions. The formation, however, of an uncharged complex enabled the extraction of metal ions into SF-CO_2, as well as a conventional solvent extraction. To select a suitable chelating extractants, therefore, is essential in the SF-CO_2 extraction.This work performed fundamental studies for the extraction of gallium(III) with 2-methyl-8-quinolinol (HMQ) and 2-methyl-5-butyloxymethyl-8-quinolinol (HMO_4Q) into supercritical fluid carbon dioxide from a weakly acidic solution. The distribution constants of HMO_4Q between aqueous and SF-CO_2 phases were determined at 45℃, 8.6-20.4 MPa and I = 0.1 M (H, Na)NO_3. At 45℃ and 15.3 MPa, gallium(III) was hardly extracted with HMQ into SF-CO_2, but was quantitatively extracted with HMO_4Q in the pH range of 2.20-2.84. The extraction constant, K_<ex-co2> ( [Ga(OH)(MO_4Q)_2]_<SF-CO_2>[H^+]^3[Ga^<3+>]^<-1> [HMO_4Q])^<-2>_<SF-CO2>), of gallium(III) with HMO_4Q was determined to be 10^<-2.6> at 45℃, 15.7 MPa and I = 0.1 M(H, Na)NO_3, which was 63 times larger than that in heptane at 45℃ and 0.10 MPa. It was also found that the addition of 3 ,5-dichlorophenol as a synergist enhanced the extractability of gallium(III) with HMO_4Q into SF-CO_2.

超临界流体提取（SFE）是通过超临界流体而不是常规有机溶液的，最近已集中在先进的方法上，以从水溶液和固体材料中去除金属离子。在SFE中使用的超临界液中，由于其理想的特性，即相对低的临界温度和压力，无毒性，无毒性，非粘液性和高纯度，尽管其求解功率低于其氯于氯于氯于cobon carbon dioxiide，但其求解功率低于氯仿的相对较低，但二氧化碳的求解功率低于有机溶液的相对低临界温度和压力，非毒性，无污染物和高纯度，尽管其相对低的临界温度和压力，二氧化碳。由于需要对金属离子进行电荷中和，因此很难从液体和固体样品中产生偿付能力。然而，未充电的复合物的形成使金属离子可以提取SF-CO_2，以及常规的溶解度提取。因此，在SF-CO_2提取中，必须选择合适的螯合提取物。这项工作对用2-甲基-8-喹诺醇（HMQ）和2-甲基-5-甲基-5-二甲基氧甲基甲基-8-甲基-8- Quinolinolinolinolinolinolinolinolinol（HMO_4Q）提取凝固剂（iii）进行了基本研究，从在45℃，8.6-20.4 MPa和i = 0.1 m（H，Na）NO_3下确定水和SF-CO_2相之间HMO_4Q的分布常数。在45℃和15.3 MPa时，几乎不将HMQ提取到SF-CO_2中，但用HMO_4Q定量提取的pH范围为2.20-2.84。提取常数，k_ <ex-co2>（[[ga（oh）（mo_4q）_2] _ <sf-co_2> [h^+]^3 [ga^<3+>]^<-1> [hmo_4q]^<-2> _2> _2> _ <sf-co2>），与HMO_4 q eg at Gallium（iii）的<sf-co2>），45^at 45。 MPA和I = 0.1 m（H，Na）NO_3，比在45℃和0.10 MPa的heptane大的63倍。还发现，将3,5-二氯苯酚作为协同作用增强了凝胶（III）的可萃取性（III），将HMO_4Q用HMO_4Q提高到SF-CO_2中。