Acid-base properties of modified aluminas

1982 ◽  
Vol 47 (8) ◽  
pp. 2044-2060 ◽  
Author(s):  
E. A. Paukshtis ◽  
P. I. Soltanov ◽  
E. N. Yurchenko ◽  
Květa Jirátová
Keyword(s):  
Carbon Monoxide ◽  
Ir Spectroscopy ◽  
Relative Proportion ◽  
Total Acidity ◽  
Acid Base ◽  
Pure Alumina ◽  
Oh Groups ◽  
Concentration Of Ions ◽  
Ir Spectroscopic ◽  
Base Properties

Acid-base properties of the pure alumina and aluminas modified by addition of various ions were determined by IR spectroscopic and Benesi method. The quality and concentration of OH groups of alumina samples containing SO42-, F-, Cl-, Na+, Zn2+ and Mg2+ ions were determined by IR spectroscopy, Pyridine, benzonitrile and carbon monoxide were used to determine the concentration and strength of aprotic centres and deuteriochloroform was used to determine the concentration and strength of basic centres. The results allowed to evaluate changes in the above properties caused by changes in the concentration of ions in alumina. It was found that the total acidity of modified aluminas determined by Benesi method correlates well with the relative proportion of acidic OH groups in the total spectrum of OH groups.

Ion-Exchange Separation and Concentration of Ions of Rare-Earth Elements on Fibrous Sorbents

2015 ◽  
Vol 670 ◽  
pp. 270-275
Author(s):  
Lyudmila A. Bobkova ◽  
Lidiya N. Skvortsova ◽  
Ludmila B. Naumova ◽  
Galina V. Kashkan
Keyword(s):  
Rare Earth ◽  
Ion Exchange ◽  
Rare Earth Elements ◽  
Alkaline Treatment ◽  
Acid Base ◽  
Ionic Force ◽  
Concentration Of Ions ◽  
Ion Exchange Separation ◽  
Definition Of ◽  
Base Properties

Acid-base properties and selectivity of absorption such ions as REE (Eu3+, Gd3+, Nd3+, Yb3+) from solutions with various ionic force by the fibrous ampholytes PAN-FOSPAN and PAN-IDUC are investigated. PAN-FOSPAN shows the greatest selectivity to ions of REE. This fact can be used for division and the subsequent definition of ions. PAN-IDUC as a high selective fibrous sorbent after alkaline treatment is perspective one for absorption of the REE sum.

scholarly journals Surface Functionality Features of Porous Silicon Prepared and Treated in Different Conditions

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yu. M. Spivak ◽  
S. V. Mjakin ◽  
V. A. Moshnikov ◽  
M. F. Panov ◽  
A. O. Belorus ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Ir Spectroscopy ◽  
Ir Spectra ◽  
Current Density ◽  
Functional Composition ◽  
Acid Base ◽  
Oh Groups ◽  
Surface Functionality ◽  
Lewis Acidic Sites ◽  
Acidic Sites

Hydrophilic layers of porous silicon are prepared by single- or two-step anodization and characterized by evaluating their surface hydrophilicity and contents of functional groups using IR spectroscopy and adsorption of acid-base indicators with differentpKavalues. The surface functional composition of the synthesized samples is shown to be adjustable depending on the anodization current density. The surface of samples obtained at anodization current density 30 mA/cm2is predominantly occupied withpKa2.5 corresponding to ≡Si–OH groups. The increase of current density to 80 mA/cm2results in the increase of surface functional nonuniformity with the formation of versatile centers, primarily Lewis acidic sites corresponding to Si atoms, as indicated by selective indicator adsorption in agreement with the disappearance of Si–H bonds in IR spectra and overall surface disordering according to SEM and AFM data.

Acid-base properties of 1,3-diphenyl-5-(1H-tetrazol-2-yl)formazan and 1,3-diphenyl-5-(2H-1,2,4-triazol-3-yl)formazan

1982 ◽  
Vol 47 (11) ◽  
pp. 2882-2889
Author(s):  
Nadezhda Likhareva ◽  
Ladislav Šůcha ◽  
Miloslav Suchánek
Keyword(s):  
Computer Program ◽  
Dissociation Constants ◽  
Acid Base ◽  
New Compounds ◽  
Base Properties

Two new compounds from the formazan series, viz. 1,3-diphenyl-5-(1H-tetrazol-2-yl)formazan and 1,3-diphenyl-5-(2H-1,2,4-triazol-3-yl)formazan, were prepared, and the dissociation constants and molar absorptivities of all of their acid-base species were determined spectrophotometrically employing the SPEKTFOT computer program.

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