Phase Equilibrium and Partition of Iodide in an Aqueous Biphasic System Formed by (NH4)2SO4 + PEG + H2O at 25 °C

Graber, Teófilo A.; Medina, H. Ochoa; Galleguillos, and Héctor R.; Taboada, María E.

doi:10.1021/je600593c

Cited by 23 publications

(16 citation statements)

References 19 publications

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“…Figure A1. Experimental LLE tie-line data for the aqueous PEG10000-AS system at 298.15 K by Graber et al (2007), shown as the mole fraction of water (x(water)) in the ternary PEG10000-AS-water liquid bulk mixture vs. the mole fraction of AS (x (electrolyte)) of the PEG10000-AS mixture on a water-free basis. The dashed blue line indicates the dry PEG10000 : AS mass ratio of 2 : 1 studied in the DASH-SP experiments.…”

Section: Data Availabilitymentioning

confidence: 99%

Discontinuities in hygroscopic growth below and above water saturation for laboratory surrogates of oligomers in organic atmospheric aerosols

et al. 2016

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Abstract. Discontinuities in apparent hygroscopicity below and above water saturation have been observed for organic and mixed organic-inorganic aerosol particles in both laboratory studies and in the ambient atmosphere. However, uncertainty remains regarding the factors that contribute to observations of low hygroscopic growth below water saturation but enhanced cloud condensation nuclei (CCN) activity for a given aerosol population. Utilizing laboratory surrogates for oligomers in atmospheric aerosols, we explore the extent to which such discontinuities are influenced by organic component molecular mass and viscosity, non-ideal thermodynamic interactions between aerosol components, and the combination of these factors. Measurements of hygroscopic growth under subsaturated conditions and the CCN activity of aerosols comprised of polyethylene glycol (PEG) with average molecular masses ranging from 200 to 10 000 g mol −1 and mixtures of PEG with ammonium sulfate (AS) were conducted. Experimental results are compared to calculations of hygroscopic growth at thermodynamic equilibrium conducted with the Aerosol Inorganic Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model, and the potential influence of kinetic limitations on observed water uptake was further explored through estimations of water diffusivity in the PEG oligomers. Particle-phase behavior, including the prevalence of liquid-liquid phase separation (LLPS), was also modeled with AIOMFAC. Under subsaturated relative humidity (RH) conditions, we observed little variability in hygroscopic growth across PEG systems with different molecular masses; however, an increase in CCN activity with increasing PEG molecular mass was observed. This effect is most pronounced for PEG-AS mixtures, and, in fact, an enhancement in CCN activity was observed for the PEG10000-AS mixture as compared to pure AS, as evidenced by a 15 % reduction in critical activation diameter at a supersaturation of 0.8 %. We also observed a marked increase in apparent hygroscopicity for mixtures of higher molecular mass PEG and AS under supersaturated conditions as compared to subsaturated hygroscopic growth. AIOMFAC-based predictions and estimations of water diffusivity in PEG suggest that such discontinuities in apparent hygroscopicity above and below water saturation can be attributed, at least in part, to differences in the sensitivity of water uptake behavior to surface tension effects. There is no evidence that kinetic limitations to water uptake due to the presence of viscous aerosol components influenced hygroscopic growth. For the systems that display an enhancement in apparent hygroscopicity above water saturation, LLPS is predicted to persist to high RH. This indicates a miscibilityPublished by Copernicus Publications on behalf of the European Geosciences Union. 12768 N. Hodas et al.: Discontinuities in the hygroscopicity of oligomers gap and is likely to influence bulk-to-surface partitioning of PEG at high RH, impacting droplet surface tension and CCN activity....

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Section: Data Availabilitymentioning

confidence: 99%

Discontinuities in hygroscopic growth below and above water saturation for laboratory surrogates of oligomers in organic atmospheric aerosols

et al. 2016

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“…Particularly, ATPS formed by PEG + (NH 4 ) 2 SO 4 + H 2 O has been studied for a long time [14,15]. These ATPS have been used in the extraction of various analytes, such as ionic species [16,17], small molecules [18], and also in the partition proteins [19]. These ATPS in general, have physicochemical properties which vary considerably with molecular weight PEG.…”

Section: Introductionmentioning

confidence: 99%

Phase diagrams of aqueous two-phase systems formed by polyethylene glycol+ammonium sulfate+water: equilibrium data and thermodynamic modeling

Murari

Penido

Machado

et al. 2015

Fluid Phase Equilibria

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“…Iodine is an important ingredient in the generation of thyroid hormones, which regulates several biochemical reactions associated with growth and developments of reproductive systems, immune defense systems and many more biological processes. 18,20 However, use of the phase forming component of ABS itself in speciation is still unexplored. [15][16][17] Different iodine species are responsible for their varied applications.…”

Section: Introductionmentioning

confidence: 99%

Block copolymer as a novel functional phase in an aqueous biphasic system for species selective iodine extraction

2015

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This article describes a newly designed block copolymer based aqueous biphasic system (ABS, composed of two immiscible aqueous phases) which is further utilized to study extraction behavior of three iodine species viz., I 2 , I À , and IO 4 À . Phase diagram and tie line data reveals the potential working range of this new biphasic system. Fluorescence, dynamic light scattering, transmission electron microscopy (TEM) and conductance data establish the micellar arrangement in solutions of this particular block copolymer.Elemental iodine is easily soluble in copolymer solution due to charge transfer complexation. Polymer phase of the ABS is found to have species dependent selectivity of extraction for the three different iodine species. Two non toxic, non flammable dyes 3,6-diamino-10-phenylphenazinium chloride (DPC) and haematoxylin are introduced for the first time to detect iodide and periodate species respectively in the copolymer medium.

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Phase Equilibrium and Partition of Iodide in an Aqueous Biphasic System Formed by (NH₄)₂SO₄ + PEG + H₂O at 25 °C

Cited by 23 publications

References 19 publications

Discontinuities in hygroscopic growth below and above water saturation for laboratory surrogates of oligomers in organic atmospheric aerosols

Discontinuities in hygroscopic growth below and above water saturation for laboratory surrogates of oligomers in organic atmospheric aerosols

Phase diagrams of aqueous two-phase systems formed by polyethylene glycol+ammonium sulfate+water: equilibrium data and thermodynamic modeling

Block copolymer as a novel functional phase in an aqueous biphasic system for species selective iodine extraction

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