Ion Product of Pure Water Characterized by Physics-Based Water Model

We report a water model, Bind3P (Version 0.1), which was obtained by using sensitivity analysis to readjust the Lennard-Jones parameters of the TIP3P model against experimental binding free energies for six host-guest systems, along with pure liquid properties. Tests of Bind3P against >100 experimental binding free energies and enthalpies for host-guest systems distinct from the training set show a consistent drop in the mean signed error, relative to matched calculations with TIP3P. Importantly, Bind3P preserves the accuracy of bulk water properties, such as density and heat of vaporization. The same approach can be applied to more sophisticated water models that can better represent pure water properties. These results lend further support to concept of integrating host-guest binding data into force field parameterization.

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The Effectiveness Of Glycine Max L Extracts As Coagulant In Peat Water Treatment

Khazanah ◽

10.20885/khazanah.vol12.iss2.art25 ◽

2020 ◽

Vol 12 (2) ◽

Author(s):

Nanda Maulidya ◽

◽

Rudy Syah Putra ◽

Keyword(s):

Glycine Max ◽

Humic Acid ◽

Acid Solution ◽

Pure Water ◽

Water Model ◽

Optimum Dose ◽

Clean Water ◽

Cationic Protein ◽

Glycine Max L ◽

Prior Processing

Peat water is water that has the potential to be used as a source of clean water in the peatland area like in Kalimantan island. However, it was still required prior processing before used as clean water for hygiene and sanitation purposes. Several coagulants have been extensively studied for their potential to remove the color from water and turbidity using natural coagulant. Glycine max L contained a cationic protein that could act as a coagulant. The main objective of this study was to evaluate the effectiveness of Glycine max L extract to reduce the color and turbidity in peat water. In this study, an artificially humic acid solution was prepared as a peat water model. Glycine max L was extracted by using 1.0 M NaCl (NaCl-EX) and pure water (DW-EX). The results showed that the NaCl-EX solution with an optimum dose of 4 mL/500 mL could be used to reduce the color and turbidity effectively.

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Bind3P: Optimization of a Water Model with Host-Guest Binding Data

10.26434/chemrxiv.5848113.v2 ◽

2018 ◽

Author(s):

Jian Yin ◽

Niel M. Henriksen ◽

Hari S. Muddana ◽

Michael K. Gilson

Keyword(s):

Pure Water ◽

Bulk Water ◽

Water Model ◽

Pure Liquid ◽

Free Energies ◽

Water Properties ◽

Binding Data ◽

Guest Binding ◽

The Mean ◽

Binding Free Energies

We report a water model, Bind3P (Version 0.1), which was obtained by using sensitivity analysis to readjust the Lennard-Jones parameters of the TIP3P model against experimental binding free energies for six host-guest systems, along with pure liquid properties. Tests of Bind3P against >100 experimental binding free energies and enthalpies for host-guest systems distinct from the training set show a consistent drop in the mean signed error, relative to matched calculations with TIP3P. Importantly, Bind3P also yields some improvement in the hydration free energies of small organic molecules, and preserves the accuracy of bulk water properties, such as density and the heat of vaporization. The same approach can be applied to more sophisticated water models that can better represent pure water properties. These results lend further support to concept of integrating host-guest binding data into force field parameterization.

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Pressure dependence of solvation of non-polar solute in simple model of water

Condensed Matter Physics ◽

10.5488/cmp.24.33604 ◽

2021 ◽

Vol 24 (3) ◽

pp. 33604

Author(s):

T. Urbic

Keyword(s):

Heat Capacity ◽

Monte Carlo ◽

Free Energy ◽

Pressure Dependence ◽

Size Dependence ◽

Pure Water ◽

Water Model ◽

Two Dimensional ◽

Aqueous Solvation ◽

Temperature And Pressure

We modelled the aqueous solvation of a nonpolar solute as a function of the radius, temperature and pressure. In this study a simple two-dimensional Mercedes-Benz (MB) water model was used in NPT Monte Carlo simulations. This model has previously been shown to qualitatively predict the volume anomalies of pure water and the free energy, enthalpy, entropy, heat capacity, and volume change in order to insert a nonpolar solute into water. Here, we extended the studies of solvation of nonpolar solute to examine the pressure dependence and broader range of temperature and size dependence. The model shows two different mechanisms, one for the solvation of large nonpolar solutes bigger than water and the second for smaller solutes.

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Thermal Design of Supercritical Water Oxidation Reactors

Heat Transfer, Volume 3 ◽

10.1115/imece2002-33853 ◽

2002 ◽

Cited By ~ 1

Author(s):

S. N. Rogak ◽

M. S. Khan ◽

I. Vera-Pe´rez

Keyword(s):

Heat Transfer ◽

Supercritical Water ◽

Water Oxidation ◽

Flow Reactor ◽

Inorganic Compounds ◽

Pure Water ◽

Thermal Design ◽

Water Model ◽

Supercritical Water Oxidation ◽

Treated Effluent

Waste destruction using supercritical water oxidation (SCWO) was demonstrated in laboratories in the early 1980’s and in full-size facilities by the early 1990’s. The process offers thorough destruction of toxins in a compact facility without supplementary energy. Early estimates that SCWO could auto-thermally treat wastewaters with as little as 2% weight organic ignored some practical factors, such as corrosion, fouling, heat transfer limitations. In this paper, a thermal model for a SCWO system based on pure water properties and heat transfer correlations is used to estimate heat exchanger size and frictional pressure losses. Information on real mixtures at SCWO conditions is not established to the point needed for rigorous thermal modeling, but the pure-water model can be interpreted using real-fluid properties and experience from operating SCWO systems. It is shown that the waste composition has a direct influence on the SCWO design. Auto-thermal treatment of dilute streams (2% organic) is economic only if inorganic compounds are absent from the waste stream or treated effluent, and the plant is of moderate size. For more corrosive wastes, or those with fouling agents, it becomes very expensive to preheat the feed beyond the critical temperature. Without preheating to supercritical temperatures, some back-mixing of hot products is needed to stabilize reaction, so that plug-flow reactor designs become inappropriate.

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Bind3P: Optimization of a Water Model with Host-Guest Binding Data

10.26434/chemrxiv.5848113 ◽

2018 ◽

Author(s):

Jian Yin ◽

Niel M. Henriksen ◽

Hari S. Muddana ◽

Michael K. Gilson

Keyword(s):

Pure Water ◽

Bulk Water ◽

Water Model ◽

Pure Liquid ◽

Free Energies ◽

Water Properties ◽

Binding Data ◽

Guest Binding ◽

The Mean ◽

Binding Free Energies

We report a water model, Bind3P (Version 0.1), which was obtained by using sensitivity analysis to readjust the Lennard-Jones parameters of the TIP3P model against experimental binding free energies for six host-guest systems, along with pure liquid properties. Tests of Bind3P against >100 experimental binding free energies and enthalpies for host-guest systems distinct from the training set show a consistent drop in the mean signed error, relative to matched calculations with TIP3P. Importantly, Bind3P also yields some improvement in the hydration free energies of small organic molecules, and preserves the accuracy of bulk water properties, such as density and the heat of vaporization. The same approach can be applied to more sophisticated water models that can better represent pure water properties. These results lend further support to concept of integrating host-guest binding data into force field parameterization.

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The role of latent heat in heterogeneous ice nucleation

10.5194/egusphere-egu21-16164 ◽

2021 ◽

Author(s):

Olli Pakarinen ◽

Cintia Pulido Lamas ◽

Golnaz Roudsari ◽

Bernhard Reischl ◽

Hanna Vehkamäki

Keyword(s):

Molecular Dynamics ◽

Latent Heat ◽

Pure Water ◽

Ice Nucleation ◽

Water Model ◽

Heat Of Fusion ◽

Initial Structure ◽

Noticeable Effect ◽

Ice Growth ◽

Heterogeneous Ice Nucleation

Understanding the way in which ice forms is of great importance to many fields of science.&#160;Pure water droplets in the atmosphere can remain in the liquid phase to nearly -40&#186; C. Crystallization of ice in the atmosphere therefore typically occurs in the presence of ice nucleating particles (INPs), such as mineral dust or organic particles, which trigger heterogeneous ice nucleation at clearly higher temperatures. The growth of ice is accompanied by a significant release of latent heat of fusion, which causes supercooled liquid droplets to freeze in two stages [Pruppacher and Klett, 1997].&#160;We are studying these topics by utilizing the monatomic water model [Molinero and Moore, 2009] for unbiased molecular dynamics (MD) simulations, where different surfaces immersed in water are cooled below the melting point over tens of nanoseconds of simulation time and crystallization is followed.&#160;With a combination of finite difference calculations and novel moving-thermostat molecular dynamics simulations we show that the release of latent heat from ice growth has a noticeable effect on both the ice growth rate and the initial structure of the forming ice. However, latent heat is&#160;found not to be as critically important in controlling immersion nucleation as it is in vapor-to-liquid nucleation [Tanaka et al.2017].&#160;This work was supported by the ERC Grant 692891-DAMOCLES, the Academy of Finland Flagship funding (grant no. 337549), and the University of Helsinki, Faculty of Science ATMATH project. Supercomputing resources were provided by CSC&#8211;IT Center for Science, Ltd., Finland.&#160;REFERENCES&#160;Pruppacher, H. R. and J. D. Klett (1997). Microphysics of Clouds and Precipitation. Vol. 18. Kluwer Academic.Molinero, V. and E. B. Moore (2009). J. Phys. Chem. B 113, 4008.Tanaka, K. K et al. (2017). Phys. Rev. E 96, 022804.

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K and Ti metasomatism of the mantle wedge by fluids under sub-arc conditions

10.5194/egusphere-egu2020-17987 ◽

2020 ◽

Author(s):

Dimitri Sverjensky ◽

Simon Matthews

Keyword(s):

Mantle Wedge ◽

Chemical Elements ◽

Pure Water ◽

Water Model ◽

Island Arcs ◽

Silicate Anion ◽

Deep Earth ◽

High Silica ◽

Subducting Slab ◽

Metasomatized Mantle

It is well documented that subducting slabs influence arc volcanics. Slab components are transferred to the mantle wedge by fluids and/or melts. Aqueous fluids released from the slab are thought to trigger partial melting in the mantle wedge and potentially influence the chemistry of the lavas that erupt in island arcs. Both fluids and melts from the slab have been proposed to transfer chemical elements to the mantle wedge. However, exactly how this occurs chemically and physically remains unclear. Recent progress in developing a Deep Earth Water model calibrated with experimental mineral and rock solubility data under sub-arc conditions now enables the chemical mass transfer from slab to mantle wedge to be predicted for comparison with natural samples.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; We report a new aqueous speciation model for Ti-species calibrated with experimental data Kessel and co-workers and Antignano and Manning that includes a neutral Ti-OH species, a Na-Ti-silicate anion, and a Ti-silicate-bicarbonate anion. The Ti-OH species is only important in almost pure water. However, the Na-Ti-silicate anion is important in high-silica fluids (e.g. in equilibrium with quartz or coesite-bearing mafic eclogites) but is overtaken in importance by the Ti-silicate-bicarbonate complex in CO2-bearing fluids.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; In the present study, we modeled the metasomatic reactions when a fluid in equilibrium with a mafic eclogite leaves a subducting slab and encounters lherzolite in the overlying mantle wedge. Initially, the mafic eclogitic fluid was in equilibrium with clinopyroxene, garnet, coesite, diamond, magnesite solid-solution, and rutile at 700&#176;C and 4.0 GPa. Whilst the presence of CO2 enables the modelled fluid to carry 600 mg/kg H2O of nominally immobile Ti from the slab into the wedge, the fluid transports a factor of 30 more K. The fluid was then heated to 950&#176;C and simultaneously reacted irreversibly with lherzolite containing 0.86 wt% K2O and 0.084 wt% TiO2. The resultant metasomatized peridotite consisted of olivine, orthopyroxene, clinopyroxene, and garnet to which phlogopite-rich biotite had been added, and from which the TiO2 component was subtracted. Overall, the metasomatism resulted in K-enrichment and Ti-depletion in the metasomatized part of the mantle wedge. The final fluid was enriched in Ti (2,830 mg/kg H2O) with lowered K (11,600 mg/kg H2O). Both the remaining fluid and metasomatized mantle may serve as sources of the elevated K/Ti ratios in arc volcanics relative to MORB.

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Decoration of specific sites on freeze-fractured membranes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081565 ◽

1978 ◽

Vol 36 (2) ◽

pp. 140-141

Author(s):

H. Gross ◽

H. Moor

Keyword(s):

Pure Water ◽

Freeze Fracture ◽

Chemical Properties ◽

Surface Forces ◽

Sulfate Pentahydrate ◽

Copper Sulfate Pentahydrate ◽

Physico Chemical ◽

Water Of Hydration ◽

Small Container ◽

Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

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