| Summary: | 碩士 === 國立臺北科技大學 === 化學工程系碩士班 === 89 === n this paper, the separations of zinc(Ⅱ) and copper(Ⅱ) by solvent extraction and supported liquid membranes are studied at 25℃. The acid extractant is di(2-ethylhexyl) phosphoric acid. The extraction equilibria of zinc(Ⅱ) and copper(Ⅱ) between extractant ／kerosene solution and aqueous solution are studied first. Then, a supported liquid membrane containing acid extractant is used to investigatethe transports of zinc(Ⅱ) and copper(Ⅱ) through supported liquid membranes.
The extraction equilibria of zinc(Ⅱ) and copper(Ⅱ) from sulfate solutions with di(2-ethylhexyl) phosphoric acid as an acidic extractant are studied first. The experimental data indicate the distribution ratios for the extraction of zinc(Ⅱ) and copper(Ⅱ) increase with increasing either the concentration of extractant in the organic phase or pH value in the aqueous phase. By graphical treatment, the compositions of zinc-HDEHP complex in the organic phase is ZnA2(HA) and the equilibrium constants is 6.97×10^-2 (kmol／m3)^0.5. Also, the compositions of copper-HDEHP complex in the organic phase are and CuA2(HA)2and CuA2(HA)3， the equilibrium constants are 4.65×10^-4 and 5.74×10^-4 (kmol／m3) ^-0.5, respectively.
The mass transfer and separation of zinc(Ⅱ) and copper(Ⅱ) across supported liquid membranes by using di(2-ethylhexyl) phosphoric acid as a carrier are investigated. When the stirring rate increases , the permeability of zinc(Ⅱ) and copper(Ⅱ) increases first and approachs a finite value .When zinc(Ⅱ) and copper(Ⅱ) concentrations in the feed solution increase , the permeability keep constant at first and then decresaes. When the concentration of carrier is increased , the permeability increases while the membrane separation factor of zinc and copper increas.
|
|---|
