scholarly journals Use of Microwaves to Activate Bentonite in the Processes of Sorption of Nickel Ions from Concentrated Aqueous Solutions

2019 ◽  
Vol 19 (2) ◽  
pp. 191-196 ◽  
Author(s):  
A. Kontsur ◽  
L. Sysa ◽  
L. Shevchuk
Keyword(s):  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
Nickel Ion ◽  
Near Surface ◽  
Nickel Ions ◽  
Absorption Isotherm ◽  
Scanning Electronmicroscopy ◽  
Free Hydroxyl ◽  
Static Conditions ◽  
Partial Destruction

The physicochemical parameters of the process of sorption water purification from compounds of Nickelwith clay sorbent in static conditions are studied. The absorption isotherm of ions of this metal from concentratedaqueous solutions on samples of bentonite using ultrahigh-frequency irradiation (microwave) is analyzed. Mostcorrectly, it is described by the linear equation of Langmuir. It is shown that irradiation of this sorbent bymicrowaves in the process of nickel ion sorting almost 2 times increases the value of the marginal sorptioncapacity for this metal (in comparison with the method of "stimulation" - preliminary washing of bentonite withpure water under the action of microwaves). The results of the study of spent bentonite by scanning electronmicroscopy, energy dispersion and X-ray diffraction analysis indicate that the metal under action of themicrowave is deposited on the surface of the bentonite not only in the form of an adsorbed monolayer of ions, butalso in the form of a separate crystalline phase, nickel silicate. Changes in the acidity of the medium duringsorption purification under the action of microwave are observed: from pH ≈ 5.7 ... 6.5 (before exposure) to pH ≈6.7 ... 7.1 (after irradiation). Confirmed assumption about that under the action of microwaves in the aqueousmedium there is a partial destruction of the silicate framework of clay sorbents with the release of silicon ionsSiO32-. These ions undergo hydrolysis, as a result of which the pH of the solution increases. Also, the directdiscontinuity of the Si-O bonds in the near-surface groups ≡Si-OH is not excluded, which leads to an increase inthe number of "free" hydroxyl groups.

STUDY ON CHEMICAL CONSTITUENTS OF THE LICHEN PARMOTREMA TINCTORUM (NYL.) HALE (PARMELIACEAE)

2018 ◽  
Vol 56 (4) ◽  
pp. 434 ◽  
Author(s):  
Nguyen Thi Thu Tram ◽  
Vu Thi Huyen ◽  
Retailleau Pascal
Keyword(s):  
Chemical Constituents ◽  
Chemical Constituent ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
Meta Position ◽  
Phytochemical Investigation ◽  
Lichen Substances ◽  
Free Hydroxyl ◽  
Deep Yellow ◽  
Parmotrema Tinctorum

A phytochemical investigation was conducted on a foliose lichen, Parmotrema tinctorum (Nyl.) Hale, collected in Lam Dong province, Vietnam. Colour reactions for identification of lichen substances (+K deep yellow, +C red, +KC red, + P pale yellow) suggested the presence of atranorin, lecanoric acid, quinones, depsides, and xanthones containing two free hydroxyl groups in meta-position. Chemical constituent study led to the isolation of six compounds, including atranol (1), methyl haematomate (2), divaricatinic acid (3), methyl divaricatinate (4), atranorin (5) and lecanoric acid (6). Their structures were confirmed unambiguously by X-ray diffraction, spectroscopic data and compared with those in references.

Synthesis and Characterization of Zn Nanoparticles by Using Hetero-Bicyclic Compound

2014 ◽  
Vol 938 ◽  
pp. 3-8
Author(s):  
V. Pushpanathan ◽  
D. Suresh Kumar
Keyword(s):  
Condensation Reaction ◽  
Energy Dispersive Spectrum ◽  
Hydroxyl Groups ◽  
Bicyclic Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Free Hydroxyl ◽  
Ft Ir ◽  
Esi Mass Spectrometry

The 1:1 condensation reaction between benzil and tris (hydroxymethyl) aminomethane in methanol yields a hetero bicyclic compound 5-(hydroxymethyl)-1,2-diphenyl-3,7-dioxa-8-aza-bicyclo [3.2.octan-2-ol. It was characterized by FT-IR, NMR (1H and 13C) spectroscopy and ESI mass spectrometry. The structure was conclusively determined by X-ray diffractrometric analysis. The structure shows a hetero bicyclic ring system. It consists of six membered morpholine and five membered oxazolidine rings with free hydroxyl groups. This bicyclic compound was used as a reducing and stabilizing agent to prepare zinc nanoparticles. The morphology and structure were characterized by field emission scanning electron microscope (FE-SEM), powder X-ray diffraction (XRD), and energy dispersive spectrum analysis (EDS).

The synthesis and structure of silica-supported bis(h5-cyclopentadienyl)dichlorotitanium(IV) complexes

1986 ◽  
Vol 51 (7) ◽  
pp. 1430-1438 ◽  
Author(s):  
Alena Reissová ◽  
Zdeněk Bastl ◽  
Martin Čapka
Keyword(s):  
Free Surface ◽  
Hydroxyl Groups ◽  
Titanium Complex ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Free Hydroxyl ◽  
Cyclopentadienyl Anion

The title complexes have been obtained by functionalization of silica with cyclopentadienylsilanes of the type Rx(CH3)3 - xSi(CH2)nC5H5 (x = 1-3, n = 0, 1, 3), trimethylsilylation of free surface hydroxyl groups, transformation of the bonded cyclopentadienyl group to the cyclopentadienyl anion, followed by coordination of (h5-cyclopentadienyl)trichlorotitanium. The effects of single steps of the above immobilization on texture of the support, the number of free hydroxyl groups, the coverage of the surface by cyclopentadienyl groups and the degree of their utilization in anchoring the titanium complex have been investigated. ESCA study has shown that the above anchoring leads to formation of the silica-supported bis(h5-cyclopentadienyl)dichlorotitanium(IV) complex.

A Method for Evaluating Intensity of Water Cavitation Peening Processing

2011 ◽  
Vol 675-677 ◽  
pp. 747-750
Author(s):  
B. Han ◽  
Dong Ying Ju ◽  
Xiao Guang Yu
Keyword(s):  
Residual Stress ◽  
Process Capability ◽  
Diffraction Method ◽  
Spring Steel ◽  
Bubble Collapse ◽  
Plastic Layer ◽  
Process Conditions ◽  
X Ray Diffraction ◽  
Near Surface ◽  
The Impact

Water cavitation peening (WCP) with aeration, namely, a new ventilation nozzle with aeration is adopted to improve the process capability of WCP by increasing the impact pressure induced by the bubble collapse on the surface of components. In this study, in order to investigate the process capability of the WCP with aeration a standard N-type almen strips of spring steel SAE 1070 was treated byWCP with various process conditions, and the arc height value and the residual stress in the superficial layers were measured by means of the Almen-scale and X-ray diffraction method, respectively. The optimal fluxes of aeration and the optimal standoff distances were achieved. The maximum of arc height value reach around 150μm. The depth of plastic layer observed from the results of residual stresses is up to 150μm. The results verify the existence of macro-plastic strain in WCP processing. The distributions of residual stress in near-surface under different peening intensity can provide a reference for engineers to decide the optimal process conditions of WCP processing.

Substitutional and solvation effects on conformational equilibria. Effects on the interaction between opposing axial oxygen atoms

1969 ◽  
Vol 47 (23) ◽  
pp. 4441-4446 ◽  
Author(s):  
R. U. Lemieux ◽  
A. A. Pavia
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Magnetic Resonance ◽  
Hydroxyl Groups ◽  
Evidence Based ◽  
Electrostatic Repulsion ◽  
Hydrogen Bridge ◽  
Conformational Equilibria ◽  
Free Hydroxyl ◽  
Oxygen Atoms

Evidence based both on nuclear magnetic resonance and rotation data primarily obtained from methyl 3-deoxy-β-L-erythro-pentopyranoside and a number of its derivatives is interpreted to show that the electrostatic repulsion between the oxygen atoms at the 2 and 4 positions is substantially less when these oxygens are linked to acyl groups than when in the form of either methyl ethers or as hydroxyl groups hydrogen bonded to solvent. Also, experimental evidence is presented which requires the hydrogen bridge between two axially disposed hydroxyl groups to be substantially strengthened by hydrogen bonding of the free hydroxyl by solvent.

Physical Properties of Saltstone: Physical Properties of Saltstone: A Savannah River Plant Waste Form

1984 ◽  
Vol 44 ◽  
Author(s):  
Christine A. Langton
Keyword(s):  
Compressive Strength ◽  
Physical Properties ◽  
Field Tests ◽  
Waste Form ◽  
Savannah River ◽  
X Ray Diffraction ◽  
Near Surface ◽  
Leach Rate ◽  
Savannah River Plant ◽  
Water To Cement Ratio

AbstractA cement-based waste form, “saltstone,” has been designed for disposal of Savannah River Plant low-level radioactive salt waste. Laboratory and field tests indicate that this stabilization process greatly reduces the mobility of all of the waste constituents in the surface and near-surface environment. Bulk properties of this material have been tailored with respect to salt leach rate, permeability, and compressive strength. Microstructure and mineralogy were characterized by SEM and x-ray diffraction analyses.Compressive strength was found to increase as the water to cement ratio decreased. Porosity and mean pore size increased with increasing water to cement ratios. Bulk diffusivities of the various ions dissolved in the pore solutions were also found to increase as water to cement ratios increased.

Light-Mediated Cross-Coupling of Anomeric Trifluoroborates

2021 ◽  
Author(s):  
Eric Miller ◽  
Maciej Walczak
Keyword(s):  
Cross Coupling ◽  
Hydroxyl Groups ◽  
Anomeric Effect ◽  
Computational Studies ◽  
Carbohydrate Chemistry ◽  
New Class ◽  
Free Hydroxyl ◽  
Anomeric Carbon ◽  
Stereoselective Reactions

Stereoselective reactions at the anomeric carbon constitute the cornerstone of preparative carbohydrate chemistry. Here, we report the synthesis of axial C1 trifluoroborates and stereoselective C-arylation and etherification reactions under photoredox conditions. These reactions are characterized by high anomeric selectivities for 2-deoxysugars and broad substrate scope (24 examples), including disaccharides and trifluoroborates with free hydroxyl groups. Computational studies show that high axial selectivities for these reactions originate from a combination of kinetic anomeric effect of the intermediate C1 radical and stereoelectronic stabilization of Ni(III) through the metallo-anomeric effect. Taken together, this new class of carbohydrate reagents adds the palette of anomeric nucleophile reagents suitable for efficient installation C-C and Cheteroatom bonds.

Effect of Yttria-Stabilized Zirconia Concentration in an Electroless Bath on Microstructure and Composition of Ni/Yttria-Stabilized Zirconia Nanocomposite

2021 ◽  
Vol 21 (11) ◽  
pp. 5592-5602
Author(s):  
Samira Almasi ◽  
Ali Mohammad Rashidi
Keyword(s):  
High Performance ◽  
Yttria Stabilized Zirconia ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Nickel Ion ◽  
Nanocomposite Particles ◽  
X Ray ◽  
Ni Content ◽  
Naoh Solution ◽  
Average Size

The effect of the yttria-stabilized zirconia (YSZ) nanoparticle loading in an electro-less bath was considered as one of the vital synthesis variables for control Ni content and microstructure of prepared nanocomposite particles, which are two crucial factors to achieving high-performance SOFC anode. Nanocomposite particles were prepared using a simple electroless method without any expensive pretreatment of sensitizing by Sn2+ ions as well as activating by Pd2+ ions that are usually used to apply nickel coating on the surface of a non-conductive substrate. The process was performed by adding YSZ nanoparticles into NaOH solution, separating them from the solution by the centrifugal method, then providing several water-based nanofluids with different concentrations of activated YSZ nanoparticles, mixing them with NiCI2 solution, followed by adding the hydrazine and then NaOH solution. X-ray diffraction and scanning electron microscopy coupled with energy dispersive X-ray analysis were used to analyze the prepared nanocomposite particles. It is observed that after adding YSZ nanoparticles into the NaOH solution, the pH of the solution varied gradually from a starting pH of 10.2 to 9. Also, by increasing the YSZ nanoparticles loading in the electroless bath from 76 mg/l to 126 mg/l, the grain size of Ni deposits, the Ni content and the average size of the prepared nanocomposite particles decreased. The electrochemical mechanism previously proposed for the nickel ion reduction was modified, and a novel analytical model was proposed for variation of the efficiency of Ni deposition with YSZ nanoparticles loading.

scholarly journals Intercalation of oxalate ions in the interlayer space of a layered double hydroxide for nickel ions adsorption

2016 ◽  
Vol 5 (2) ◽  
pp. 144
Author(s):  
Doungmo Giscard ◽  
Théophile Kamgaing ◽  
Ranil Clément Tonleu Temgoua ◽  
Ervice Ymele ◽  
Francis Merlin Melataguia Tchieno ◽  
...  
Keyword(s):  
Interlayer Space ◽  
X Ray Diffraction ◽  
Batch Mode ◽  
Nickel Ions ◽  
X Ray ◽  
Modified Clay ◽  
Pseudo Second Order ◽  
Oxalate Ions ◽  
Double Hydroxide ◽  
Clay Materials

In this study, sorption properties of a synthesized anionic clay were enhanced by the intercalation of oxalate ions in its interlayer space. The pristine and modified clay materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and thermal analysis. These techniques confirmed the presence of oxalate ions in the interlayer space of the clay. The intercalated clay was then used as a matrix for the sorption in batch mode of nickel ions in aqueous solution. The influence of a number of parameters such as contact time, pH, initial concentration of the analyte and adsorbent dosage were studied. The maximum adsorption of nickel was obtained at pH 6, that is, about 90% Ni2+ removal. The adsorbent/adsorbate equilibrium follows a pseudo-second order kinetics and best matches the Langmuir model. The modified clay was shown to be efficient matrix for the sorption of nickel ions.

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