Vanadium(IV) ions extraction in the aqueous two-phase system based on poly(ethylene glycol)

Vanadium has found wide applications in various industries: metallurgy, electronics, batteries, and others. This element, being dispersed, does not form its minerals and, therefore, is mined along the way. An alternative approach of vanadium extraction is to separate it from heavy oil, by flushing the oil with strong acids solutions and further hydrometallurgical processing. The existing methods of oil dehydration solutions processing for the vanadium extraction are not perfect - they do not meet the “green” chemistry principles. Thus, we investigated V(IV) ions extraction in the aqueous two-phase system (ATPS) based on poly(ethylene glycol) 1500 (16.3wt%) – NaNO3 (36wt%) – H2O. The dependences of V(IV) extraction efficiency on phases time contact, and dependences V(IV) distribution coefficients on salt phase acidity have been obtained. This system is shown to be a prospective solution for the vanadium(IV) recovery from acidic waste steams problem as it is possible to extract vanadium with an efficiency of more than 81.6% per one extraction step (the distribution coefficient of vanadium (IV) was 4.84).

Study of caffeine and coumarin extraction kinetics in an aqueous two-phase system based on polyethylene glycol 1500

Caffeine and coumarin are organic compounds of plant origin, which have biological activity and have found wide application in medicine, pharmaceutical, perfumery and food industries. Recovery of caffeine and coumarin from aqueous solutions using liquid-liquid extraction is the most effective method. In the present work the kinetic dependences of caffeine and coumarin in the aqueous two-phase system (ATPS) of PEG 1500 - Na2SO4 - H2O were experimentally obtained. It was established that equilibrium in the system is achieved after 17 minutes for caffeine and after 12 minutes for coumarin. The effect of ultrasound on the extraction rate of caffeine and coumarin in an aqueous two-phase system was also studied.

Extraction of Zn (II) ions in an polypropylene glycol 425 - sodium chloride - water aqueous two-phase system

Liquid-liquid extraction is one of the most used separation methods in chemical technology for recovery and separation of metal ions, other inorganic and organic substances. It is known that for extraction of Zn(II) the most frequently used extractants are D2EHPA, Aliquat 336, etc., diluted in an organic solvent. The use of these reagents does not meet the principles of “green” chemistry. Thus, in the present work, the extraction system based on polypropylene glycol 425 and sodium chloride for the extraction of Zn(II) ions from aqueous solutions is proposed. Equilibrium values of the distribution coefficient in the proposed aqueous two-phase system have been determined. Dependence of metal distribution coefficient on time of phase contact is obtained, time to reach equilibrium was 10 minutes. The isotherm of Zn(II) extraction obtained in the proposed system is a straight line, which indicates the independence of the distribution coefficient from the initial concentration of metal in the solution. The received experimental data can be used at the creation of “green” schemes of processing of Ni-MH batteries.