Kinetics and Mechanism of Backward Extraction of Mn2+ from Mn2+-Cyanex 272 Complex Dissolved in Kerosene by Acidic Sulfate-Acetato Solution Using the Technique of Single Drop. Issue 10 (2nd October 2016)

• Record Type: Journal Article
• Authors: Biswas, Ranjit Kumar; Karmakar, Aneek Krishna; Rahman, Md. Saidur
• Is Part Of: Chemical engineering communications. Volume 203:Issue 10(2016)
• Page Start: 1308
• Page End: 1316
• Publication Date: 2016-10-02
• Subjects: Acetate -- Mn2+-Cyanex 272 complex -- Single drop -- Stripping -- Sulfate; Chemical engineering -- Periodicals; 660.205
• DOI: 10.1080/00986445.2016.1189415
• Languages: English
• ISSNs: 0098-6445

Abstract

Abstract : The rate of acidic sulfate-acetato solution stripping of Mn 2+ from kerosene solution of Mn 2+ -Cyanex 272 complex (MnA2 ) is investigated using the falling single drop technique. To study the kinetics of this process, the reaction orders and the value of backward extraction rate constant ( k b ) have been determined to get the Mn 2+ -transfer flux equation in backward extraction as: F b = 10 −4.88 [MnA2 ](o) (1 + 0.002 [H + ] −1 ) −1 (1 + 5.13 ). The energy of activation ( E a ), entropy variation on activation (Δ S ‡ ), and the enthalpy variation on activation (Δ H ‡ ) have also been determined. It is noticed that the reaction orders with respect to [H + ] and, and the values of E a, Δ S ‡, and Δ H ‡ depend on the concentration regions of H + and used in stripping. The analysis of flux equation at low-concentration region of H + and points out that the dissociation of A − from MnA + is a rate-controlling chemical reaction step. On the other hand, at high-concentration regions of H + and, the rate determining chemical reaction step is the replacement of A − in MnA + by . In other conditions, the process is either diffusion or intermediate control. High negative Δ S ‡ values indicate that the rate controlling chemical reaction steps occur via SN 2 mechanisms. Rate data have been compared with the equilibrium data for the Mn 2+ -Cyanex 272 extraction system.