Phase Separation Dynamics in Oil–Polyethylene Glycol–Sulfate–Water Based Three-Liquid-Phase Systems

Abstract

Phase separation dynamic processes in Three-Liquid-Phase System 1 (TLPS), composed of organic oil (P507 extractant), water-soluble polymer (PEG2000), 2 ammonium sulfate and water, with the change of mass composition of phase-forming 3 components were investigated. It was found that dynamic separation of three-layered 4 liquid phases in TLPS is in fact a course of dispersive polymer and organic oil droplets 5 aggregated and separated out respectively from continuous salt aqueous bottom phase. 6Formation rate of organic oil phase was controlled mainly by coalescence rate of 7 dispersed oil droplets, however rate-determining process for formation of polymer middle 8 phase may change from drop sedimentation to coalescence or co-determined by both, 9 when mass composition of the TLPS changed along different operation lines. With the 10 formation of organic oil phase, it becomes another continuous phase, from which 11 dispersive polymer droplets separated out and aggregated into a bulk phase gradually. 12 Phase separation equilibrating time of TLPS, t E , depends on formation rate of the 13 polymer middle phase and its equilibrium volume. A quantitative correlation of phase 14 separation rate of TLPS with its physic-chemical properties was given. The present work 15 promotes further understanding about influence from change in mass composition of 16 phase-forming components in TLPS on three-phase separation dynamic processes. three coexisting liquid phases, different target compounds have different partitioning 6 behaviors in different liquid layers. 2 Application of TLPS has been extended towards 7many areas, such as separation and purification of various biochemicals 3,4 , preparation of 8 natural products 5,6 , treatment of polyphenol waste water 7 and grouping separation of 9 multi-metals 8,9 . All of those works advance such a unique separation method gradually to 10 its maturity. However, this technology has not been used in industrial scale, partially due 11 to the limited engineering knowledge and understanding of phase separation behavior in 12 this system. 13Up till now, most of investigations on TLPS focus only on thermodynamics 14 phase-forming conditions and its stabilization mechanism, without considering its phase 15 separation dynamic process. 10-12 The lack of data in the aspect makes a main hinder for 16 further developing three-liquid-phase partition technique toward its future engineering 17 applications. Our previous work suggested a mixer-settler-mixer three-chamber 18 integrated extractor to conduct three-liquid-phase partitioning processes. 13,14 That work 19 provides a feasible equipment for continuous operation and future industrial scale-up.

Continuous in Situ Extraction toward Multiphase Complex Systems Based on Superwettable Membrane with Micro-/Nanostructures

“…Real-time concentrations of PCs (phenol and o -nitrophenol) in EA (Figure c, with the standard curves of PCs in Figure S13) illustrate that EA phase is able to selectively enrich phenol (PC-1, concentration 4.86–5.02 mg/mL), but keep away from o -nitrophenol (PC-2, 0.36–0.37 mg/mL). The two solutes can be concentrated in EA and PEG, respectively, at the end of in situ extraction for different interactions between both solute and solvent molecules. , It is also proved by extraction efficiencies of PC-1 and PC-2 (Figure d) in various liquid phases (PC-1 enriched in EA 88.56 ± 0.07%, while PC-2 enriched in PEG-phase 65.35 ± 0.23%), along with color comparison of the final filtrates (see inset pictures, PC-1-EA is colorless, while PC-2-PEG is orange). Similar high performance is obtained by traditional extraction (Figure S14), and it also consistent with the results in a previous literature, in which multiple procedures of mixing, transferring, centrifuging, and waiting for phase equilibrium are required.…”

Separation of Rare Earths from the Transition Metals Using a Novel Ionic-Liquid-Based Aqueous Two-Phase System: Toward Green and Efficient Recycling of Rare Earths from the NdFeB Magnets

“…In the present system, the ionic-liquid-rich phase was salted out from the aqueous solution through a salting-out agent. According to the previous literature, for such systems, the salting-out phase was suggested to be a dispersed phase, while the aqueous solution was suggested to be a continuous phase . Therefore, it was suggested that the ionic-liquid-rich phase would disperse into the aqueous solution in the form of oil drops during the mixing of the extraction system.…”

“…According to the previous literature, for such systems, the salting-out phase was suggested to be a dispersed phase, while the aqueous solution was suggested to be a continuous phase. 34 Therefore, it was suggested that the ionic-liquid-rich phase would disperse into the aqueous solution in the form of oil drops during the mixing of the extraction system. Figure 9b gives the scheme of mixing of iL-ATPS during the extraction process.…”

Liquid–Liquid–Liquid Aqueous Triple-Phase System Based on DES and Dipotassium Hydrogen Phosphate

“…Separation in ATPS lies in the distribution or dissolution differences between the upper and lower phases. The formation of the multiphase system refers to the traditional multiple solvent system , and the present aqueous multiphase system. , The former system often consists of solvents which are immiscible; the latter one is constructed by miscible aqueous solvents, while under critical concentration, more than two immiscible phases form. Gou et al constructed a three-liquid-phase system based on n -hexane–ethanol–NaH 2 PO 4 –H 2 O for simultaneous extraction and separation of lithospermic acid B and tanshinone IIA .…”