Removal of Zn(II) from Aqueous Acetate Solution Using Di (2-Ethylhexyl) Phosphoric Acid & Tributylphosphate (original) (raw)
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Dibutylbutyl Phosphonate as an Extractant of Zinc(II) from Hydrochloric Acid Solutions
The extraction of zinc(II) and iron(II) with solutions of dibutylbutyl phosphonate (DBBP) from hydrochloric acid solutions is studied. Iron(II) is slightly extracted by the considered extractant. The isotherms of zinc(II) extraction with DBBP are compared with those for TBP. They indicate that extraction effectiveness of DBBP as an extractant is higher than for tributyl phosphate (TBP). It is found that the extraction ability of zinc(II) chlorocomplexes from hydrochloric acid solutions decreases with decreasing DBBP content. Addition of kerosene increases hydrophobicity of DBBP at the same time slightly decreasing the efficiency of zinc(II) extraction. 80 vol% DBBP is applied successfully to separate zinc(II) from iron(II) in the following stages: extraction with excess of DBBP (o/w = 5:1), scrubbing of loaded extractant with small amount of water (w/o = 1:5) to remove iron(II), stripping with water to remove zinc(II) from loaded DBBP (w/o = 1:1).
Analytical Sciences, 1994
The solvent extraction of zinc(II) in 0.1 mol dm-3 sodium chloride solutions with 1-naphthoic acid (HA) into chloroform was measured in the absence and presence of tetrabutylammonium ions (tba+) or trioctylphosphine oxide (TOPO). The extraction of zinc(II) with 1-naphthoic acid was rather poor and the extracted species were in the form of ZnA2 and ZnA2(HA)2 when the metal concentration in the organic phase was lower than 3X105 mol dm-3. However, the polymerized species, ZnnA2n(HA)m, were also extracted when zinc(II) concentration in the organic phase was higher than that value. The addition of tba+ or TOPO enhanced the extraction of zinc(II) 1-naphthoate. This was explained in terms of the extraction of tba+ZnA3-or ZnA2TOPO species. Thus 1-naphthoic acid was found to be an effective extractant for zinc(II) only in the presence of bulky cations or solvating type extractants. We considered the reason why only the monomeric zinc(II) species of the ternary complex or the TOPO adduct was extracted.
Separation and Purification Technology, 2007
The liquid-liquid extraction of zinc using D2EHPA as extractant has been investigated in this paper in order to recover zinc sulphate from an industrial effluent produced by Votorantim Co. (Brazil) which contains several metallic species such as cadmium, cobalt, iron, lead, calcium, magnesium, manganese and nickel. The study was carried out in two main steps: (1) extraction and stripping laboratory scale tests in order to assess adequate operational conditions for the favourable recovery of zinc from the effluent and (2) continuous pilot scale tests using a mixer-settler battery aiming to reproduce the bench results. In the laboratory scale experiments, operating variables such as the pH of the aqueous effluent (0.5-5.0), concentration of D2EHPA (5-50%,w/w) and aqueous/organic volumetric phase ratio (1/5-5/1) were investigated for the zinc extraction process; for the zinc stripping process, the organic/aqueous volumetric phase ratio (1/1-10/1) was studied by contacting a metal loaded organic phase with an industrial acid solution produced by the company in the electrolysis of zinc. The continuous mixer-settler tests have shown that zinc can be selectively and quantitatively removed from the effluent (around 98%) using 3 extraction stages (pH 2.5, [D2EHPA] = 20% (w/w) and A/O = 1), and other 3 stripping stages (O/A = 4). A final solution containing 125.7 g/L of zinc was obtained that could be sent directly to electrowinning.
The extraction of zinc(II), iron(III) and iron(II) with TBP and its binary mixtures with DEHPA and CYANEX 302 from hydrochloric acid solutions was studied. It was found that the extraction ability of zinc(II) chlorocomplexes from hydrochloric acid solutions decreased in the order: TBP > TBP:HL=3:1 vol/vol > TBP:HL=1:1 vol/vol. Iron(III) was strongly extracted by TBP and its binary mixtures with DEHPA and CYANEX 302, and the extraction fell in the order: binary mixtures with DEHPA or CYANEX 302> TBP> DEHPA >> CYANEX 302. Iron(II) was not extracted by the considered extractants. Zinc(II) could not be selectively extracted in the presence of iron(III). Contrary, iron(III) could be selectively extracted, especially with the binary 1:1 vol/vol mixtures of TBP with DEHPA or CYANEX 302. The stripping of zinc(II) could be accomplished in three successive stages using water and 0.1 M H 2SO4. Iron(III) could be stripped in three stages with 0.1 M H2SO4.
Recovery of zinc from an industrial zinc leach residue by solvent extraction using D2EHPA
A hydrometallurgical treatment involving solvent extraction of zinc using di-2-ethylhexyl phosphoric acid (D2EHPA) has been investigated to recover zinc from an industrial leach residue. The residue was leached with sulfuric acid producing leach liquor which was subjected to solvent extraction for enrichment of zinc and removal of impurities. Operating variables, such as pH, D2EHPA concentration, temperature, aqueous/organic (A/O) phase ratio, tri-butyl phosphate (TBP) concentration and sodium sulfate (Na2SO4) concentration in aqueous phase were studied. Practically, all zinc was extracted from the aqueous solution at pH 2.5 with 20% w/w D2EHPA in kerosene. Increasing either TBP concentration up to 5%, or Na2SO4 concentration up to 0.2 M, increased the zinc extraction. Zinc could be extracted at one theoretical stage at A/O of 1/1, as calculated by McCabe–Thiele method.
2020
The presented study describes the solvent extraction process of Zn(II) and Pb(II) from aqueous solutions by a cation exchanger extractant named bis(2-ethylhexyl)phosphoric acid (DEHPA). The results confirm that both of the extraction efficiency and extraction selectivity depend on the employed organic diluent. The applied extractant was selective towards zinc ions; this selectivity did not depend on the employed organic diluent. Keep in mind the possible interaction of the studied metal ions with the polyether compounds (PEGs) dissolved in the aqueous phase, the role of the presence of two PEGs with molecular masses 200 (PEG200) and 2000 (PEG2000) on the selectivity characteristics of the proposed extraction system was appraised. The evaluated PEGs play the role of masking agents by complexing the lead ions in the aqueous phase, while the zinc ions did not interact with them. These interactions result in the transposition of the extraction curves of lead as a function of pH, towards...
Industrial & Engineering Chemistry Research, 2012
The solvent extraction equilibrium of zinc with 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (EHPNA) in an alkane diluent, Shellsol D70, was studied at a constant ionic strength of 1 mol/L from nitrate solutions considering the correction of the extractant nonideality in the organic phase by Alstad's method. On the basis of the slope analysis of the obtained data, a molar ratio of 1:2 for the zinc to the EHPNA dimer in the extracted complex was indicated. Apparent extraction equilibrium constants obtained at each temperature from 283 to 323 K showed the endothermic nature of the extraction reaction and gave the apparent standard enthalpy and entropy changes. These two constants enable the calculation of the zinc distribution ratio at each temperature which correlates the experimental data with good accuracy.
Separation and Purification Technology, 2009
Trihexyl(tetradecyl)phosphonium chloride (Cyphos ® IL 101) and bis(trifluoromethylsulphonyl)imide (Cyphos ® IL 109) -phosphonium ionic liquids -were used as novel reagents mixed with toluene to extract zinc(II) from chloride media. Extraction of zinc(II) was very fast and efficient (E Zn over 95%) for molar ratio of Cyphos ® IL 101/Zn(II) more than 2. It was found that the presence of HCl in the feed enhanced Zn(II) extraction. The reactions of Zn(II) extraction mechanism were proposed. The values of H • were estimated to be 32.93 (standard deviation (s.d.) = 2.81) and 52.85 (s.d. = 1.90) kJ mol −1 and S • amounted to 120.65 (s.d. = 8.84) and 182.13 (s.d. = 6.02) J mol −1 K −1 for reaction without HCl and with 0.58 M acid, respectively. The extraction of zinc(II) with Cyphos ® IL 101/toluene mixture is an endothermic reaction. Successful stripping of zinc(II) from the loaded organic phase was achieved with 1 M sulphuric acid. Cyphos ® IL 101 can be reused at least in 3 cycles of extraction-stripping process. Due to low extraction of Zn(II) Cyphos ® IL 109 cannot be considered as effective extractant in the studied system.