Sorption of phenols on hexadecyltrimethylammonium- modified bentonite: Application of Polanyi−Manes potential theory

2020 ◽  
pp. 0958305X2097728
Author(s):  
Jiyeon Choi ◽  
Dong-Ik Slong ◽  
Won Sik Shin
Keyword(s):  
Molar Volume ◽  
Potential Theory ◽  
Characteristic Curve ◽  
Chemical Compositions ◽  
Pore Filling ◽  
Sorption Data ◽  
Similar Chemical ◽  
Competitive Model ◽  
Sorption Potential ◽  
Sorption Systems

This study investigated the sorption of phenol and 4-chlorophenol (4-CP) on natural bentonite modified with hexadecyltrimethylammonium (HDTMA) cation. The Freundlich, Langmuir, Dubinin−Radushkevich (DR), Sips, and Polanyi−Dubinin−Manes (PDM) models fitted the sorption data well (R2 > 0.92). The Freundlich coefficient and the maximum sorbed amount of the Langmuir and PDM models of 4-CP were higher than phenol because of higher hydrophobicity (log Kow = 2.39 for 4-CP and 1.46 for phenol). The PDM model that includes solubility and molar volume was highly useful in predicting the sorption of phenols having widely different hydrophobicity and solubility. The characteristic curves, the plot of sorbed volume ( qv) versus the sorption potential per molar volume ( ε/ Vm) of 4-CP and phenol were distinctly different although they have similar chemical compositions. The selectivity of 4-CP (3.72) was higher than that of phenol (0.27) in binary sorption systems. The sorbed volume ( qv) in the binary sorption was remarkably reduced and the characteristic curve had wider distribution owing to competition in pore-filling. The sorption behaviors were elucidated by partitioning and pore-filling mechanisms. Among the tested binary sorption models, the modified Langmuir competitive model was the best in the prediction of the binary sorption (R2 > 0.98).

Nanoscale control of internal inhomogeneity enhances water transport in desalination membranes

Science ◽  
2020 ◽  
Vol 371 (6524) ◽  
pp. 72-75 ◽  
Author(s):  
Tyler E. Culp ◽  
Biswajit Khara ◽  
Kaitlyn P. Brickey ◽  
Michael Geitner ◽  
Tawanda J. Zimudzi ◽  
...  
Keyword(s):  
Water Transport ◽  
Water Permeability ◽  
Three Dimensional ◽  
Density Fluctuations ◽  
Active Layer Thickness ◽  
Chemical Compositions ◽  
Design Strategies ◽  
Nanoscale Structures ◽  
Density Maps ◽  
Similar Chemical

Biological membranes can achieve remarkably high permeabilities, while maintaining ideal selectivities, by relying on well-defined internal nanoscale structures in the form of membrane proteins. Here, we apply such design strategies to desalination membranes. A series of polyamide desalination membranes—which were synthesized in an industrial-scale manufacturing line and varied in processing conditions but retained similar chemical compositions—show increasing water permeability and active layer thickness with constant sodium chloride selectivity. Transmission electron microscopy measurements enabled us to determine nanoscale three-dimensional polyamide density maps and predict water permeability with zero adjustable parameters. Density fluctuations are detrimental to water transport, which makes systematic control over nanoscale polyamide inhomogeneity a key route to maximizing water permeability without sacrificing salt selectivity in desalination membranes.

Neotethyan evolution of eastern Greece (Pagondas Mélange, Evia island) inferred from radiolarian biostratigraphy and the geochemistry of associated extrusive rocks

2001 ◽  
Vol 138 (3) ◽  
pp. 345-363 ◽  
Author(s):  
TANIEL DANELIAN ◽  
ALASTAIR H. F. ROBERTSON
Keyword(s):  
Shallow Water ◽  
Carbonate Platform ◽  
Ocean Basin ◽  
Passive Margin ◽  
Late Triassic ◽  
Geochemical Data ◽  
Chemical Compositions ◽  
Similar Chemical ◽  
Thrust Sheets ◽  
Age Range

This paper presents new radiolarian biostratigraphic and igneous/metamorphic geochemical data for a Mesozoic volcanic–sedimentary mélange on the island of Evia (Euboea or Evvoia), eastern Greece. This mélange includes dismembered thrust sheets and blocks of radiolarian chert and basalt. Biostratigraphic age data show that radiolarites interbedded with basalt-derived, coarse clastic sediments near the base of a coherent succession were deposited in Middle and Late Triassic time (Late Ladinian–Carnian, Norian?). Geochemical evidence shows that associated extrusive rocks, of inferred Triassic age, range from ‘enriched’ alkaline basalts, to ‘transitional’ basalts, and more ‘depleted’ mid-ocean ridge-type basalts. Amphibolite facies meta-basalts from the metamorphic sole of the over-riding Evia ophiolite exhibit similar chemical compositions. Both the basalts and the meta-basalts commonly show an apparent subduction-related influence (e.g. relative Nb depletion) that may have been inherited from a previous subduction event in the region. The basalts are interpreted to have erupted during Middle–Late Triassic time (Late Ladinian–Carnian), related to initial opening of a Neotethyan ocean basin adjacent to a rifted continental margin. Radiolarites located stratigraphically higher in the coherent succession studied are dated as Middle Jurassic (Late Bathonian–Early Callovian). Similar-aged radiolarites are depositionally associated with ophiolitic rocks (including boninites), in some other areas of Greece and Albania. During initial ocean basin closure (Bajocian–Bathonian) the adjacent shallow-water carbonate platform (Pelagonian zone) disintegrated to form basins in which siliceous sediments were deposited and highs on which shallow-water carbonates continued to accumulate. This facies differentiation is seen as a response to crustal flexure as the Neotethyan ocean began to close. The over-riding Pagondas Mélange and other similar units in the region are interpreted as accretionary prisms related to subduction of Neotethyan oceanic crust in Middle–Late Jurassic time. These mélanges were emplaced, probably diachronously during Oxfordian–Kimmeridgian time, when the passive margin collapsed, creating a foredeep ahead of advancing thrust sheets of mélange and ophiolites.

scholarly journals Study of the Origin of the Unexpected Pearlite during the Cooling Stage of Two Cast High-Speed Steels

2011 ◽  
Vol 172-174 ◽  
pp. 803-808 ◽  
Author(s):  
Jérôme Tchoufang Tchuindjang ◽  
Jacqueline Lecomte-Beckers
Keyword(s):  
Retained Austenite ◽  
High Speed ◽  
Solid Phase ◽  
Casting Process ◽  
Eutectic Phase ◽  
Chemical Compositions ◽  
Spin Casting ◽  
Eutectic Carbides ◽  
Similar Chemical ◽  
The Matrix

Two HSS grades (A and B) belonging to the complex system Fe-Cr-C-Si-X, where X is a strong carbide-forming element such as V, Mb or W, were studied. Samples in the as-received conditions came from an industrial spin casting process, with a varying cooling rate during processing. Chemical compositions of both alloys were closed to each other and were chosen to enhance their hardenability and to avoid less resistant phases such as pearlite and ferrite. Differential Thermal Analysis was performed on both alloys, in order to increase their crystallization behaviour. Light microscopy and SEM associated with EDS analyses were done to characterize the microstructure of both alloys in the as-received conditions and after DTA trials. The matrix of both HSS grades was composed of eutectic carbides, martensite and retained austenite, these phases exhibiting similar chemical compositions in both alloys. Unexpected pearlite was found in the as-cast HSS alloy B without W, this grade containing more Mo, more V and less Cr than the HSS grade A. It appeared from DTA tests that pearlite found in the alloy B arose more from the destabilisation of the Cr-rich retained austenite associated with the plate-like M2C carbide, than from the matrix itself. In fact, pearlite zones located in the vicinity of M2C are due to related isothermal solid phase transformations form the previous austenitic eutectic phase that is enriched with Cr and Mo.

First-principles investigation on the transport properties of quaternary CoFeRGa (R = Ti, V, Cr, Mn, Cu, and Nb) Heusler compounds

2020 ◽  
Vol 22 (40) ◽  
pp. 23185-23194
Author(s):  
Beibei Shi ◽  
Jingyu Li ◽  
Chi Zhang ◽  
Wenya Zhai ◽  
Shujuan Jiang ◽  
...  
Keyword(s):  
Transport Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Heusler Alloys ◽  
Chemical Compositions ◽  
Heusler Compounds ◽  
Similar Chemical

The Heusler alloys CoFeRGa (R = Ti, V, Cr, Mn, Cu, and Nb) have similar chemical compositions, but exhibit remarkably distinct electronic structures, magnetism and transport properties.

X-ray study of the pseudopolymorphism of the azithromycin monohydrate

2003 ◽  
Vol 218 (10) ◽  
Author(s):  
J. M. Montejo-Bernardo ◽  
Santiago García-Grande ◽  
M. S. Bayod-Jasanada ◽  
L. Lavona-Díaz ◽  
I. Llorente
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Single Crystal ◽  
Powder Diffraction ◽  
Chemical Compositions ◽  
X Ray ◽  
Large Size ◽  
Similar Chemical ◽  
Solid State Conformation ◽  
State Composition

AbstractA combination of X-ray powder diffraction and single crystal studies on azithomycin pseudopolymorphs give the precise solid state composition of all monohydrate pseudopolymorphs reported. According to the X-ray results the four monohydrates of azithromycin studied have the same crystallographic parameters. Furthermore, the analysis of the relative intensities from the powder patterns points to very similar chemical compositions and crystal structures. This result has been confirmed by the single crystal studies. The single crystal studies show that the solid state conformation of the azithromycin molecules is affected by the presence of solvents. The solvent methanol molecules were found disordered probably due to the existence of many positions where the hydrogen bonding is favoured and the large size of the available space to host the solvents.

Study on the Identification of Adulteration of Polycarbonate Drinking Bottles with Postconsumer Recycled Plastics

2016 ◽  
Vol 848 ◽  
pp. 184-188 ◽  
Author(s):  
Xiao Xiao Wei ◽  
Wei Li Liu ◽  
Mei Zhang ◽  
Xia Gao
Keyword(s):  
Analytical Method ◽  
Chemical Compositions ◽  
Recycled Materials ◽  
Ms Analysis ◽  
Similar Chemical ◽  
Vis Spectroscopy ◽  
Recycled Plastics

Adulteration of polycarbonate (PC) drinking bottles with postconsumer recycled PC materials was considerably difficult to identify due to similar chemical compositions and minute differences between virgin and recycled PC materials. In the present study, UV/Vis spectroscopy coupled with GC-MS analysis was carried out to identify the adulteration with recycled materials in PC drinking bottles. The minimum adulterating level which could be detected was 20 %. This strategy represents a rapid and promising analytical method for screening the adulteration of PC drinking bottles with postconsumer recycled plastics.

Transmission electron microscopy study of the epitaxial association of hedenbergite whiskers with babingtonite

2018 ◽  
Vol 82 (1) ◽  
pp. 23-33
Author(s):  
Mariko Nagashima ◽  
Daisuke Nishio-Hamane
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Solid State Reactions ◽  
Chemical Compositions ◽  
Transmission Electron ◽  
Structural Relationships ◽  
Diffusion Controlled ◽  
Similar Chemical

ABSTRACTOvergrowths of whiskers of hedenbergite (Ca(Fe2+,Mg)Si2O6) on the hydrous pyroxenoid babingtonite (Ca2Fe2+Fe3+[Si5O14(OH)]) have been observed at Arvigo in Switzerland and Kreimbach/Kaulbach in Germany, and we have studied them with transmission electron microscopy in order to understand their structural relationships and formation. The boundaries between babingtonite and hedenbergite are sharply defined, and the two minerals are in direct contact with no additional phases present. The relationships of babingtonite (Bab) and hedenbergite (Hd) were determined as Bab[100]//Hd[112] in the Arvigo specimen and Bab[$\bar 1$00]//Hd[1$\bar 1$2] in the Kreimbach/Kaulbach specimen. Diffraction derived from Bab(031) and Hd(02$\bar 1$) in the Arvigo samples and Bab(031) and Hd(021) in the Kreimbach/Kaulbach samples were observed in identical positions. The reciprocity between the babingtonite and hedenbergite structures is governed by the direction of the SiO4-tetrahedral chains, and the related configuration of octahedra. Thus, hedenbergite is apparently an epitaxial phase grown on a base of {010} plates of babingtonite. The defined orientation relationship is also consistent with that shown in topotaxial intergrowths of other clinopyroxenes and pyroxenoids. The topotaxial intergrowths may result from diffusion-controlled solid-state reactions, whereas rapid whisker growth is characteristic of supersaturated solutions or a vapour medium. The epitaxial growth of hedenbergite whiskers on babingtonite with an abrupt but coherent change of structure at the interface represents an ideal example where the similar chemical compositions of host and guest contribute strongly to the close structural relationship.

Mineralogy and Petrology of Serpentine

2007 ◽  
Author(s):  
Earl B. Alexander ◽  
Roger G. Coleman ◽  
Todd Keeler-Wolfe ◽  
Susan P. Harrison
Keyword(s):  
Ultramafic Rock ◽  
Magnesium Silicate ◽  
Ultramafic Rocks ◽  
Chemical Compositions ◽  
Silicate Minerals ◽  
Excess Iron ◽  
Serpentine Minerals ◽  
Similar Chemical ◽  
Serpentine Mineral ◽  
Mineralogical Compositions

“Serpentine” is used both as the name of a rock and the name of a mineral. Mineralogists use “serpentine” as a group name for serpentine minerals. Petrologists refer to rocks composed mostly of serpentine minerals and minor amounts of talc, chlorite, magnetite, and brucite as serpentinites. The addition of “-ite” to mineral names is common practice in petrologic nomenclature. For instance, quartzite is a name for a rock made up mostly of quartz. Serpentinites are rocks that form as a result of metamorphism or metasomatism of primary magnesium–iron silicate minerals. This entails the replacement of the primary silicate minerals by magnesium silicate serpentine minerals and the concentration of excess iron in magnetite. “Mafic” is a euphonious term derived from magnesium and ferric that is used for dark colored rocks rich in ferromagnesian silicate minerals. “Ultramafic” is used when the magnesium–ferrous silicate minerals compose >90% of the total rock. Olivine, clinopyroxene, and orthopyroxene are the minerals in primary ultramafic rocks, with minor amounts of plagioclase, amphibole, and chromite. Ultrabasic has been used by some geologists in referring to ultramafic rocks. The most common ultramafic rocks are harzburgite, containing <75% olivine and 25% orthopyroxene; dunite, with 100% olivine; and lherzolite, which has 75% olivine, 15% orthopyroxene, and >10% clinopyroxene, with or without plagioclase. Very small amounts of chromite are present in all of the mantle ultramafic rocks (Coleman 1971). The alteration of primary ultramafic rocks to serpentine mineral assemblages is incremental due to episodic invasion of water into the ultramafic rock. It is difficult to distinguish and map the gradations from primary ultramafic rock to serpentinite. Because of this difficulty in distinction, we prefer to use the term ultramafic or serpentinized peridotite for all gradations to serpentinite. Pedologists and botanists commonly group serpentinites with primary ultramafic rocks and refer to these substrates as serpentine because all of them have similar chemical compositions. As will become apparent later, there is great variability in the mineralogical compositions of these rocks and the soils derived from them.

scholarly journals Water Vapor Transport Properties of Polyurethane Films for Packaging of Respiring Foods

2019 ◽  
Author(s):  
Deniz Turan
Keyword(s):  
Steady State ◽  
Water Vapor ◽  
Thermoplastic Polyurethane ◽  
Water Vapor Sorption ◽  
Water Vapor Transport ◽  
Vapor Permeability ◽  
Chemical Compositions ◽  
Sorption Data ◽  
Steady State Method ◽  
State Method

AbstractThermoplastic polyurethane (PU) polymers with different chemical compositions were synthesized and casted to films, and their water vapor barrier properties at different range of relative humidity (RH) were characterized. The water vapor permeability (WVP) of packaging films is one of their most important properties to identify their suitability for use as packaging materials and is rather a complicated phenomena if the polymer has polar nature. The WVPs of PU films are determined both by permeation measurements which are a steady-state method and water vapor sorption measurements which are a non-steady-state method. Effective permeability (Peff), solubility (Seff), and diffusion (Deff) coefficients of PU films were determined at 23 °C within the RH range of 0–97%. It was found that Peff, Seff, and Deff increased with increasing RH gradient due to water vapor and polymer interactions. Microscopic images showed that 1,4-butanediol (BDO) helped to improve porous structure. Castor oil (CO) caused a decrease in the intensity of active absorption sites, namely, the C=O···H-N hydrogen bonds between chains. Results of two methods were yielded in the same magnitude of order. In most cases, the non-steady-state (sorption) method yields higher WVP values than steady state. At 0➔85% RH, the difference was up to 8-fold. Conditioning and equilibrating of films at 50% RH helped to reach sorption data approximate to permeation data. It was suitable to use sorption measurements to estimate the WVP which is a considerable simplification for polar polymers, e.g., developed PU film.

scholarly journals Ethnopharmacological Evaluation ofBreuEssential Oils fromProtiumSpecies Administered by Inhalation

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Eduardo Rodrigues da Silva ◽  
Danilo Ribeiro de Oliveira ◽  
Patrícia Dias Fernandes ◽  
Humberto Ribeiro Bizzo ◽  
Suzana Guimarães Leitão
Keyword(s):  
Essential Oils ◽  
Formalin Test ◽  
Significant Inhibition ◽  
Chemical Compositions ◽  
Static Headspace ◽  
Hot Plate ◽  
Hot Plate Test ◽  
Test Formulation ◽  
Similar Chemical ◽  
Sedative Effects

Background.Breuis an aromatic oleoresin which has been used by Amazonian traditional communities as a remedy for headaches and migraines by burning and inhaling the smoke produced during its combustion. This study evaluated the antinociceptive and sedative activities of formulations containingbreuessential oils administered by inhalation.Methods. Five different formulations (A–E) containingbreuessential oils were evaluated for their sedative and antinociceptive activities in mice. They were delivered for 20 minutes using an inhalation chamber coupled with a nebulizer and the air inside was collected by static headspace and analyzed by GC-FID.Results. All nebulized formulations had similar chemical compositions and major compounds as the original essential oils. None of them resulted in significant increase in response time during the hot plate test. In the formalin test, Formulation E showed a significant inhibition of licking responses in the early (46.8%) and late (60.2%) phases. Formulation B was effective (36.9%) in the first phase and Formulation D (37.9%) in the second. None of the formulations presented sedative effects.Conclusion.Breuessential oils, when inhaled, may present antinociceptive and anti-inflammatory properties without sedation. Additionally, nebulization proved to be an efficient method for administration of formulations containing these essential oils.

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