کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
643181 | 884359 | 2008 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Pt recovery using Cyphos IL-101 immobilized in biopolymer capsules
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
تصفیه و جداسازی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Cyphos® IL-101, a tetraalkylphosphonium chloride salt (ionic liquid, IL) has been immobilized in capsules prepared by ionotropic gelation in calcium chloride solutions. The IL content was varied in the resin between 0.29 and 1.28 mmol IL gâ1. These resins have been tested for Pt recovery from HCl solutions. The equilibrium was very slightly affected by the concentration of HCl and chloride ions. The sorption isotherms were modeled using the Langmuir equation: the maximum sorption capacity was influenced by the drying of the resin but remained close to 177 mg Pt gâ1 for wet resin (i.e. 0.9 mmol Pt gâ1, dry weight basis, or 0.7 mol Pt molâ1 Cyphos) and 142 mg Pt gâ1 for dry resin (i.e. 0.73 mmol Pt gâ1, or 0.57 mol Pt molâ1 Cyphos). The presence of nitrates, nickel or copper ions (added under the form of chloride salts) did not significantly decrease sorption capacity even at concentrations as high as 5 g Lâ1. Conversely, zinc at the concentration of 5 g Lâ1, significantly decreased Pt sorption, probably due to the competition effect of chloro-anionic Zn species. This is another evidence of the ion exchange mechanism involved in the binding of hexachloroplatinate species. The kinetics are weakly affected by the agitation speed (in the range 150-350 rpm) indicating that the resistance to film diffusion is not the limiting step. The kinetics are affected by the IL content, metal concentration and more specifically the drying of the resin: intraparticle diffusion sounds to be the controlling kinetic step: the intraparticle diffusion coefficient varied between 2 Ã 10â12 and 18 Ã 10â11 m2 minâ1, depending on experimental conditions. Platinum can be desorbed from loaded resin using either nitric acid (5 M) or thiourea (0.1 M in 0.1 M HCl acid solution). The resin was efficiently used for three sorption/desorption cycles using nitric acid: a decrease in sorption capacity and desorption efficiency was observed beginning with the third cycle, probably due to a progressive degradation of the resin.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Separation and Purification Technology - Volume 62, Issue 2, 1 September 2008, Pages 470-479
Journal: Separation and Purification Technology - Volume 62, Issue 2, 1 September 2008, Pages 470-479
نویسندگان
Thierry Vincent, Aurély Parodi, Eric Guibal,