Kinetics of ultrasound-assisted solvent extraction of vanadium with methyltrioctylammonium chloride (MAC)

Abstract

The ultrasound-assisted extraction process of vanadium from the aqueous phase to the organic phase by methyltrioctylammonium chloride (MAC) was studied. The factors that influence the vanadium extraction rate such as stirring speed, temperature, and ultrasound power were investigated. The rate expression of vanadium extraction with ultrasound was established. The extraction process could consist of diffusion and chemical capturing steps at the aqueous-organic interface. This study demonstrated that the diffusion resistance could be eliminated by increasing the stirring speed and ultrasound power. The vanadium extraction process without diffusion resistance conformed to the first-order kinetic model. The activation energy (Ea) of this extraction process was determined as 36.7 kJ mol−1 along with a pre-exponential factor k0a as 3.27 × 105 s−1, while the ultrasound enhancement factor can be expressed as ε = 1 + 1.40 × 10−2P - 6.61 × 10−5P2. The optimal extraction kinetics are identified by examining the factors affecting the vanadium extraction rate (rextr), which are stirring speed ≥ 200 rpm, ultrasound power (P) = 90 W, extraction temperature (T) = 318.15 K. This study provides a theoretical basis for the extraction process of vanadium and aids the design of ultrasound-assisted extraction applications.