Preparation and infrared spectroscopic characterization of reduced-charge montmorillonite with various Li contents

Clay Minerals ◽  
1996 ◽  
Vol 31 (2) ◽  
pp. 233-241 ◽  
Author(s):  
J. Madejová ◽  
J. Bujdák ◽  
W. P. Gates ◽  
P. Komadel
Keyword(s):  
Infrared Spectroscopy ◽  
Spectroscopic Characterization ◽  
Layer Charge ◽  
Preparation Temperature ◽  
Oh Groups ◽  
Tetrahedral Sheet ◽  
Increasing Temperature ◽  
Octahedral Cations ◽  
Variable Layer

AbstractA series of reduced-charge montmorillonites (RCMs) was prepared from Li-montmorillonite from Jelšový Potok (Slovakia) by heating at various temperatures (105–210°C for 24 h. The amount of fixed Li, 0.09–0.67 per O20(OH)4, increased with increasing temperature, confirming preparation of a set of samples of variable layer charge from the same parent Li-montmorillonite by varying only the preparation temperature. Infrared spectroscopy revealed that Li was trapped in the hexagonal cavities of the tetrahedral sheet at all temperatures. Partial deprotonation of the samples, reflected in the decrease of the intensities of the OH-bending bands, was observed after treatments above 120°C. Analysis of the OH-stretching region showed Li in the previously vacant octahedra in the samples heated above 150°C. Weak inflections near 660 and 720 cm−1 confirmed development of local trioctahedral character of octahedral cations coordinated with OH groups in the sample heated at 210°C. Gradual decrease of the layer charge due to Li fixation led to a shift of the Si-O stretching band to higher frequencies and to the appearance of new, pyrophyllite-like bands at 1120 and 419 cm−1.

Layer charge of expandable 2:1 phyllosilicates in selected parent materials of some Canadian soils

1994 ◽  
Vol 74 (3) ◽  
pp. 291-299 ◽  
Author(s):  
J. M. Arocena ◽  
S. Pawluk ◽  
M. J. Dudas
Keyword(s):  
Cell Layer ◽  
Glacial Till ◽  
Beach Sand ◽  
The Arctic ◽  
Layer Charge ◽  
Detailed Characterization ◽  
Tetrahedral Sheet ◽  
Parent Materials ◽  
The Mean

We investigated the nature of the layer charge of the different expandable 2:1 phyllosilicates present in glacial till, marine sediment, beach sand, loess, weathered sandstone and acid shale parent materials of selected soils from the arctic, alpine and interior plateau regions of Canada. Detailed characterization of 2:1 clay minerals, using the layer charge, was done by intercalation of the clay fractions with different chains (nc = 6 to 18) of n-alkylammonium cations (AC).Results indicated that AC were able to detect a mixture of smectite and vermiculite that was not detected by previous studies, using the glycerol (GLY) and ethylene glycol (EG) solvation techniques. The mean unit cell layer charge [in mol(+)/Si,Al)4O10)] varies from 0.30 to 0.39 for the smectite and from 0.71 to 0.74 for vermiculite. Vermiculite from the beach sand is trioctahedral in which most of the charge is located in the tetrahedral sheet, while vermiculite in the weathered sandstone is dioctahedral in which part of the charge originates from the octahedral layers. The presence of smectite, associated with the weathering of chlorite and an expanding component associated with the degradation of biotite, was also observed. Key words:n-alkylammonium cations, mean layer charge, 2:1 phyllosilicates

scholarly journals Characterization of Modified and Polymer Coated Alumina Surfaces by Infrared Spectroscopy

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Ashraf Yehia El-Naggar
Keyword(s):  
Infrared Spectroscopy ◽  
Alkali Metal ◽  
Ftir Spectroscopy ◽  
Surface Properties ◽  
Adsorption Properties ◽  
Hydroxyl Groups ◽  
Oh Groups ◽  
Structure Changes ◽  
The Individual

The prepared, modified, and coated alumina surfaces were characterized by infrared spectroscopy (FTIR) to investigate the surface properties of the individual and double modified samples. FTIR helps in reporting the changes occurred in hydroxyl groups as well as the structure changes as a result of thermal treating, hydrothermal treating, silylation treating, alkali metal treating, coating, and bonding with polymer. FTIR spectroscopy represents the strength and abundance of surface acidic OH which determine the adsorption properties of polar and nonpolar sorbents. Generally, all treated samples exhibit decrease of OH groups compared with those of parent ones producing alumina surfaces of different adsorptive powers.

Spectroscopic characterization of silica aerogels prepared using several precursors – effect on the formation of molecular clusters

2017 ◽  
Vol 41 (14) ◽  
pp. 6742-6759 ◽  
Author(s):  
A. Borba ◽  
J. P. Vareda ◽  
L. Durães ◽  
A. Portugal ◽  
P. N. Simões
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Spectroscopic Characterization ◽  
Spectroscopic Properties ◽  
Silica Aerogels ◽  
Molecular Clusters

The structural and spectroscopic properties of silica aerogels were studied using complementary approaches, such as Fourier transform infrared spectroscopy and solid-state NMR spectroscopy.

scholarly journals Infrared Spectroscopic Characterization of Photoluminescent Polymer Nanocomposites

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Kyle Gipson ◽  
Kathryn Stevens ◽  
Phil Brown ◽  
John Ballato
Keyword(s):  
Infrared Spectroscopy ◽  
Polymer Nanocomposites ◽  
Picolinic Acid ◽  
Spectroscopic Characterization ◽  
Optically Active ◽  
Inorganic Nanoparticles ◽  
Organic Ligands ◽  
Organic System ◽  
X Ray

Organicallycoated inorganic nanoparticles were synthesized to produce photoluminescent nanocomposites based on a polymethyl methacrylate (PMMA) matrix. The nanoparticles comprised organic ligands (acetylsalicylic acid, ASA, and 2-picolinic acid, PA) attached to the lanthanum trifluoride (LaF3) host crystals that were doped with optically active terbium III (Tb3+) and synthesized using solution-based methods. The ligands were employed to functionalize the surface of Tb3+:LaF3nanocrystals to aid in dispersing the nanoparticles. In order to confirm the presence of the constituents within the inorganic-organic system, the nanoparticles were characterized by infrared spectroscopy and energy-dispersive X-ray spectroscopy. Absorption peaks observed from infrared spectroscopy for all the polymer nanocomposites loaded with organic surface treated nanocrystals exhibited peaks that were not present in undoped PMMA but were characteristic of the dopant and the ligand.

Spectroscopic characterization of halogen- and cyano-substituted pyridinevinylenes synthesized without catalyst or solvent

2010 ◽  
Vol 64 (3) ◽  
Author(s):  
M. Percino ◽  
Víctor Chapela ◽  
Ling-Fa Montiel ◽  
Enrique Pérez-Gutiérrez ◽  
José Maldonado
Keyword(s):  
Infrared Spectroscopy ◽  
1H Nmr Spectroscopy ◽  
Cyano Group ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Spectroscopic Characterization ◽  
Aromatic Rings ◽  
Fluorescence Emission Spectra ◽  
Conjugated Compounds

AbstractAn efficient Knoevenagel route using green chemistry conditions was applied for the synthesis of halogen- and cyano- substituted pyridinevinylene compounds. Absorption and fluorescence emission spectra of these conjugated compounds were recorded and compared in order to evaluate the effect of substituents on the electronic properties of pyridinevinylene compounds. The substituents studied were terminal Cl and F, two or three aromatic rings, as well as a cyano group attached to a C=C double bond. The compounds synthesized are: (E)-2-(4-fluorostyryl)pyridine, (E)-2-(4-chlorostyryl)pyridine, (E)-4-(4-chlorostyryl)pyridine, 2,3-diphenylacrylonitrile, 3-phenyl-2-(pyridin-2-yl)acrylonitrile, 3-phenyl-2-(pyridin-3-yl)acrylonitrile, 2-phenyl-3-(pyridin-2-yl)acrylonitrile, 3,3′-(1,4-phenylene)bis(2-phenylacrylonitrile), 3,3′-(1,4-phenylene)bis(2-(pyridin-2-yl)acrylonitrile), and 3,3′-(1,4-phenylene)bis(2-(pyridin-3-yl)acrylonitrile). The solvent-free method used in this work allows obtaining each compound by controlling the reaction temperature. The compounds were characterized by infrared spectroscopy and 1H-NMR spectroscopy.

scholarly journals Synthesis and Reactivity of Poly(propyleneimine) Dendrimers Functionalized with Cyclopentadienone N-Heterocyclic-Carbene Ruthenium(0) Complexes

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 264
Author(s):  
Cristiana Cesari ◽  
Riccardo Conti ◽  
Andrea Cingolani ◽  
Valerio Zanotti ◽  
Maria Cristina Cassani ◽  
...  
Keyword(s):  
Hydrogen Transfer ◽  
Spectroscopic Characterization ◽  
Transfer Hydrogenation ◽  
Cerium Ammonium Nitrate ◽  
Oh Groups ◽  
Mononuclear Complexes ◽  
Synthetic Procedure ◽  
Cerium Ammonium ◽  
Specific Reactivity

Ligand design in metal chemistry is a fundamental step when pursuing compounds with specific reactivity. In this paper, the functionalization of the OH group in the lateral chain of the N-heterocyclic-carbene (NHC) ligand bound to a bis-carbonyl cyclopentadienone NHC ruthenium(0) complex allowed the decoration of five generations of poly(propyleneimine) (PPIs) dendrimers with up to 64 organometallic moieties. The coupling was achieved by employing carbonyldiimidazole and the formation of carbamate linkages between dendritic peripheral NH2 and lateral OH groups on ruthenium complexes. The synthetic procedure, chemical purification, and spectroscopic characterization of the five generations of dendrimers (3g1–5) are here described. The ruthenium-modified dendrimers were activated as catalysts in the transfer hydrogenation of the model compound 4-fluoroacetophenone in the presence of cerium ammonium nitrate as their mononuclear congeners. The catalytic activity, being similar for the five generations, shows a decrease if compared to mononuclear complexes. This detrimental effect might be ascribed to the –CH2NH– functionalization, largely present in dendrimer skeleton and that can compete with the hydrogen transfer mechanism, but also partially to a dendritic effect caused by steric encumbrance.

scholarly journals Infrared spectroscopy of exoplanets: observational constraints

2014 ◽  
Vol 372 (2014) ◽  
pp. 20130083 ◽  
Author(s):  
Thérèse Encrenaz
Keyword(s):  
Infrared Spectroscopy ◽  
Extrasolar Planets ◽  
Spectroscopic Characterization ◽  
Research Area ◽  
Research Field ◽  
Resolving Power ◽  
Observational Constraints ◽  
Different Types ◽  
New Research

The exploration of transiting extrasolar planets is an exploding research area in astronomy. With more than 400 transiting exoplanets identified so far, these discoveries have made possible the development of a new research field, the spectroscopic characterization of exoplanets' atmospheres, using both primary and secondary transits. However, these observations have been so far limited to a small number of targets. In this paper, we first review the advantages and limitations of both primary and secondary transit methods. Then, we analyse what kind of infrared spectra can be expected for different types of planets and discuss how to optimize the spectral range and the resolving power of the observations. Finally, we propose a list of favourable targets for present and future ground-based observations.

scholarly journals Preparation and characterization of cornstalk microspheric hydrochar and adsorption mechanism of mesotrione

2021 ◽  
Vol 8 (6) ◽  
pp. 202209
Author(s):  
Zhongqing Zhang ◽  
Mengmeng Zhou ◽  
Jinhua Liu ◽  
Jiahao Li ◽  
Jingmin Yang ◽  
...  
Keyword(s):  
Underlying Mechanism ◽  
Order Kinetic ◽  
Aromatic Rings ◽  
Preparation Temperature ◽  
Oh Groups ◽  
Adsorption Mechanisms ◽  
Monolayer Adsorption ◽  
Langmuir Isotherm Model ◽  
Ft Ir

In this study, cornstalk was pyrolysed to obtain hydrochar (HC), which was used to remove mesotrione from aqueous solutions. HC characterization and batch experiments were conducted to investigate mesotrione adsorption and the underlying mechanism. The characterization revealed microspheres on the HC surface. FT-IR spectra showed that the HC contained a large number of –OH groups, C=C bonds of aromatic rings, C–H groups in aromatic rings and phenolic C–O bonds. The adsorption results showed that the mesotrione adsorption ability gradually increased as the HC preparation temperature increased. The quasi-second-order kinetic equation ( R 2 ≥ 0.9860, p < 0.05) agreed well with the mesotrione adsorption process. The maximum monolayer adsorption capacity, which was obtained at pH 7 and 45°C with HC prepared at 240°C, was 3181.7 mg kg −1 with the Langmuir isotherm model ( R 2 ≥ 0.9491, p < 0.05). Van der Waals and dipole forces and hydrogen bonds were inferred as the main adsorption mechanisms. HC has potential as an effective and energy-saving adsorbent for mesotrione to reduce environmental pollution.

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