Author(s)

Ranjit Kumar Biswas, Aneek Krishna Karmakar, Muhammad Saidur Rahman

Department of Applied Chemistry and Chemical Engineering, Rajshahi University, Rajshahi, Bangladesh.

The kinetics of extraction of Ni(II) in the Ni²⁺-SO₄ ^2_AC^- (Na⁺, H⁺)-Cyanex 272 (H₂A₂)-kerosene-3% (v/v) octan-1-ol system using the single falling drop technique have been reported. The flux of Ni²⁺ transfer (F) at 303 K in presence of 3% (v/v) octan-1-ol (de-emulsifier) can be represented as:.Depending on reaction parameters, the activation energy (E_a) and enthalpy change in activation (DH^±) varies within 17 - 58 kJ/mol and 17 - 67 kJ/mol, respectively. Entropy change in activation (DS^±) is always negative. Based on the empirical flux equation, E_a and DS^± values, mechanisms of extractions in different parametric conditions are proposed. At low and [Ac^-], and pH, the chemical controlled step is: Ni²⁺ + A^- → NiA⁺; and this reaction occurs via an S_N2 mechanism. But in most parametric conditions, the process is under intermediate control; and at high SO₄^2- and [Ac^-], and pH, the extraction process is under diffusion control.

Kinetics; Cyanex 272; Sulphate; Kerosene; Ni²⁺; Single Drop Technique

Biswas, R. , Karmakar, A. and Rahman, M. (2013) Extraction Kinetics of Ni(II) in the Ni²⁺- SO₄^2--Ac^-(Na⁺, H⁺)-Cyanex 272 (H₂A₂)-Kerosene-3% (v/v) Octan-1-ol System Using Single Drop Technique. International Journal of Nonferrous Metallurgy, 2, 80-88. doi: 10.4236/ijnm.2013.22011.