Sorption of rhenium on alumina under dynamic conditions

• Published in: Journal of the Serbian Chemical Society 2007, Vol.72 (6), p.555-562
• Main Authors: Lukic, Dragoljub, Vucina, Jurij, Milonjic, Slobodan
• Format: Article
• Language: English
• Subjects: alumina; rhenium; sorption; sorption capacity; sorption isotherm
• ISSN: 0352-5139; 1820-7421
• DOI: 10.2298/JSC0706555L

The sorption of perrhenate anion on alumina from aqueous solutions of sodium chloride was investigated under dynamic conditions. The initial concentrations of rhenium were in the range of 2.7x10-2-2.7 mmol/dm3. The breakthrough curves as the function of Re and NaCl concentrations (0.12-0.20 mol/dm3), pH 2-6 and flow rate 3-10 ml/min were determined. According to the experimental results, it was concluded that the breakthrough capacities, the capacities at c/c0 = 0.5, the total column capacities and the utilization degrees (column efficiency) increase with increasing Re and NaCl concentrations and decreasing pH. The optimal flow rate was found to be 3 ml/min. At pH2 and c0 = 2.7 mmol Re/dm3, the total capacity was found to be Q 0.9 max = 2.1x10-2 mmol Re/g Al2O3. The data for perrhenate anions fit with a Henry-type isotherm. It was found that, under the above mentioned conditions, the value of the Henry constant K H was 7.8x10-3 dm3/g and the Gibbs energy change, ?G was -0.5 kJ/mol. Ispitivana je sorpcija perenatnog anjona iz rastvora NaCl na Al2O3 u dinamickim uslovima. Pocetne koncentracije renijuma su bile u opsegu 2,7x10-2-2,7 mmol/dm3. Probojne krive odredjene su u zavisnosti od koncentracija renijuma i NaCl (0,12 - 0,20 mol/dm 3 , pH 2-6 i brzine protoka rastvora 3-10 ml/min. Na osnovu dobijenih rezultata zakljuceno je da vrednosti probojnih kapaciteta, kapaciteta pri c/c 0 = 0,5, ukupnog kapaciteta kolone i efikasnosti kolone rastu sa porastom koncentracija Re i NaCl i opadanjem vrednosti pH. Nadjeno je da je optimalna brzina protoka 3 ml/min. Ukupni kapacitet na pH 2 i c 0 = 2,7 mmol Re/dm3 iznosi Q0,9 max = 2,1x10-2 mmol Re/g Al2O3. Dobijeni podaci odgovaraju Henrijevom tipu izoterme. Nadjeno je da je, pod gore navedenim uslovima, vrednost Henrijeve konstante K H = 7,8x10-3 dm3/g, a vrednost promene Gibsove energije procesa sorpcije, ?G=-5,0 kJ/mol. .