Characterization of 'strong-fragile' behaviour of glass-forming aqueous solutions by neutron scattering

2002 ◽  
Vol 74 (0) ◽  
pp. s448-s449
Author(s):  
C. Branca ◽  
A. Faraone ◽  
G. Galli ◽  
S. Magazu' ◽  
G. Maisano ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Neutron Scattering ◽  
Glass Forming

Structural characterization of glass‐forming oil/water microemulsions by neutron scattering

1989 ◽  
Vol 91 (1) ◽  
pp. 395-398 ◽  
Author(s):  
C. Alba‐Simionesco ◽  
J. Teixeira ◽  
C. A. Angell
Keyword(s):  
Neutron Scattering ◽  
Structural Characterization ◽  
Glass Forming ◽  
Oil Water

scholarly journals Preparation and Characterization of the Sulfur-Impregnated Natural Zeolite Clinoptilolite for Hg(II) Removal from Aqueous Solutions

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 217
Author(s):  
Marin Ugrina ◽  
Martin Gaberšek ◽  
Aleksandra Daković ◽  
Ivona Nuić
Keyword(s):  
Chemical Modification ◽  
Aqueous Solutions ◽  
Specific Surface ◽  
Surface Area ◽  
Natural Zeolite ◽  
Contact Time ◽  
Liquid Ratio ◽  
X Ray ◽  
Solid Liquid

Sulfur-impregnated zeolite has been obtained from the natural zeolite clinoptilolite by chemical modification with Na2S at 150 °C. The purpose of zeolite impregnation was to enhance the sorption of Hg(II) from aqueous solutions. Chemical analysis, acid and basic properties determined by Bohem’s method, chemical behavior at different pHo values, zeta potential, cation-exchange capacity (CEC), specific surface area, X-ray powder diffraction (XRPD), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), as well as thermogravimetry with derivative thermogravimetry (TG-DTG) were used for detailed comparative mineralogical and physico-chemical characterization of natural and sulfur-impregnated zeolites. Results revealed that the surface of the natural zeolite was successfully impregnated with sulfur species in the form of FeS and CaS. Chemical modification caused an increase in basicity and the net negative surface charge due to an increase in oxygen-containing functional groups as well as a decrease in specific surface area and crystallinity due to the formation of sulfur-containing clusters at the zeolite surface. The sorption of Hg(II) species onto the sulfur-impregnated zeolite was affected by the pH, solid/liquid ratio, initial Hg(II) concentration, and contact time. The optimal sorption conditions were determined as pH 2, a solid/liquid ratio of 10 g/L, and a contact time of 800 min. The maximum obtained sorption capacity of the sulfur-impregnated zeolite toward Hg(II) was 1.02 mmol/g. The sorption mechanism of Hg(II) onto the sulfur-impregnated zeolite involves electrostatic attraction, ion exchange, and surface complexation, accompanied by co-precipitation of Hg(II) in the form of HgS. It was found that sulfur-impregnation enhanced the sorption of Hg(II) by 3.6 times compared to the natural zeolite. The leaching test indicated the retention of Hg(II) in the zeolite structure over a wide pH range, making this sulfur-impregnated sorbent a promising material for the remediation of a mercury-polluted environment.

Synthesis and Characterization of Chitosan/Fluorapatite Composites for the Removal of Cr (VI) from Aqueous Solutions and Optimized Parameters

2020 ◽  
Vol 231 (4) ◽  
Author(s):  
Rachid El Kaim Billah ◽  
Youness Abdellaoui ◽  
Zakaria Anfar ◽  
Germán Giácoman-Vallejos ◽  
Mahfoud Agunaou ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Synthesis And Characterization
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