Modified Vermiculites Study by Various Physicochemical Methods

2015 ◽  
Vol 752-753 ◽  
pp. 257-262 ◽  
Author(s):  
N.P. Shapkin ◽  
V.I. Razov ◽  
I.G. Khalchenko ◽  
V.I. Mayorov ◽  
A.L. Shkuratov ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Acid Concentration ◽  
Apparent Density ◽  
Brilliant Green ◽  
Dye Adsorption ◽  
Nitrogen Adsorption ◽  
Positron Annihilation Lifetime ◽  
Maximum Sorption ◽  
Physicochemical Methods ◽  
Internal Volume

Kovdor (Karelia) deposite vermiculites modified by acid of different concentrations and chitosan were studied using positron annihilation lifetime spectroscopy, measuring apparent density, dye adsorption, nitrogen adsorption by BET and porometry. It has been shown that after acidizing vermiculite density changes comparing to the samples’ density depending on the acid concentration. The density increases with the increasing acid concentration. Internal volume of the micropores and the value of maximum sorption of brilliant green change directly proportional to the density of the modified vermiculite.

scholarly journals Convenient Preparation of Graphene Oxide from Expandable Graphite and Its Characterization by Positron Annihilation Lifetime Spectroscopy

2019 ◽  
Vol 5 (1) ◽  
pp. 6 ◽  
Author(s):  
Guido Panzarasa ◽  
Giovanni Consolati ◽  
Marco Scavini ◽  
Mariangela Longhi ◽  
Fiorenza Quasso
Keyword(s):  
Graphene Oxide ◽  
Positron Annihilation ◽  
Nitrogen Adsorption ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Expandable Graphite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Positron Annihilation Lifetime ◽  
Convenient Preparation ◽  
Extract Information

Graphene oxide (GO) is conveniently prepared from expandable graphite using a simplified Hummers’ method. The product is thoroughly characterized by usual techniques (UV-vis, Fourier-transform infrared (FTIR) and Raman spectroscopies, zeta potential, electron microscopy, X-ray diffraction, nitrogen adsorption) to confirm the success of synthesis. Positron annihilation lifetime spectroscopy (PALS) is then used to extract information on the microenvironment in between the layers of graphene oxide.

Seeking the Good Fitting Procedure of PALS Polymer Spectra

2008 ◽  
Vol 607 ◽  
pp. 64-66
Author(s):  
Nicolas Laforest ◽  
Jérémie De Baerdemaeker ◽  
Corine Bas ◽  
Charles Dauwe
Keyword(s):  
Experimental Data ◽  
Low Temperature ◽  
Positron Annihilation ◽  
Physical Meaning ◽  
Lifetime Measurements ◽  
Positron Annihilation Lifetime ◽  
Fitting Procedure ◽  
Fitting Procedures ◽  
Blob Model

Positron annihilation lifetime measurements on polymethylmethacrylate (PMMA) at low temperature were performed. Different discrete fitting procedures have been used to analyze the experimental data. It shows that the extracted parameters depend strongly on the fitting procedure. The physical meaning of the results is discussed. The blob model seems to give the best annihilation parameters.

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