Choi Sung-Yong, Yoshida Zenko, Ohashi Kousaburo
Department of Environmental Sciences, Faculty of Science, Ibaraki University, Mito 310-8512, Japan.
Talanta. 2002 Mar 11;56(4):689-97. doi: 10.1016/s0039-9140(01)00626-9.
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(4)Q) into supercritical carbon dioxide (SF-CO(2)) from a weakly acidic solution. The distribution constants of HMO(4)Q between aqueous and SF-CO(2) phases were determined at 45 degrees C, 8.6-20.4 MPa and I=0.1 M (H, Na)NO(3) (M=mol dm(-3)). At 45 degrees C and 15.7 MPa, gallium(III) was hardly extracted with HMQ into SF-CO(2), but was quantitatively extracted with HMO(4)Q in the pH range of 2.20-2.84. The extraction constant, K(ex, SF-CO(2)) (=Ga(OH)(MO(4)Q)(2)H(+)Ga(3+)HMO(4)Q(-2)), of gallium(III) with HMO(4)Q was determined to be 10(-2.6+/-0.1) at 45 degrees C, 15.7 MPa and I=0.1 M (H, Na)NO(3), which was 63 times larger than that in heptane at 45 degrees C 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(4)Q into SF-CO(2).
本工作开展了基础研究，以研究用2-甲基-8-羟基喹啉（HMQ）和2-甲基-5-丁氧基甲基-8-羟基喹啉（HMO(4)Q）从弱酸性溶液中向超临界二氧化碳（SF-CO₂）中萃取镓（III）。在45℃、8.6 - 20.4MPa以及I = 0.1M（H，Na）NO₃（M = mol dm⁻³）条件下，测定了HMO(4)Q在水相和SF-CO₂相之间的分配常数。在45℃和15.7MPa时，镓（III）很难被HMQ萃取到SF-CO₂中，但在pH值为2.20 - 2.84范围内，能被HMO(4)Q定量萃取。在45℃、15.7MPa以及I = 0.1M（H，Na）NO₃条件下，镓（III）与HMO(4)Q的萃取常数K(ex, SF-CO₂)（=Ga(OH)(MO(4)Q)₂[H⁺]³[Ga³⁺]⁻¹HMO(4)Q⁻²）被测定为10⁻².⁶⁺⁻⁰.¹，这比在45℃和0.10MPa下在庚烷中的萃取常数大63倍。还发现添加3,5 - 二氯苯酚作为协同剂可增强镓（III）被HMO(4)Q萃取到SF-CO₂中的萃取能力。
