The stability of formed CaF2 and its influence on the thermal behavior of C–S–H in CaO–silica gel waste-H2O system

The purpose of this research was to synthesize zeolite-A (Ze-A) and zeolite-Y (Ze-Y) using silica sources from silica gel waste, and also improving adsorption capacity with Fe which was trapped in the synthesized zeolites: Ze-Fe-A and Ze-Fe-Y. All synthesized zeolites were tested with lead solution of 40 mg/L at pH 5. For BET specific surface area, the parent Ze-A and Ze-Y presented surface area of 27.02 and 211.42 m2/g, respectively, whereas Ze-Fe-A and Ze-Fe-Y presented a lower surface area of 10.90 and 28.22 m2/g, respectively. SEM and TEM image demonstrated the cubic and polygon shapes for Ze-A and Ze-Y, respectively, while their modification with Fe presented more round shape. Additionally, both modified zeolites with Fe presented higher adsorption efficiency than their parents. Although the modified zeolites gave lower surface area, the efficiency removal of lead showed higher capacity than zeolite without Fe. It could be concluded that the adsorption mechanism of modified zeolites did not only rely on physical adsorption, but also on chemical adsorption.

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The Effect of Various Hydroxide and Salt Additives on the Reduction of Fluoride Ion Mobility in Industrial Waste

Sustainability ◽

10.3390/su13031554 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1554

Author(s):

Tadas Dambrauskas ◽

Kestutis Baltakys ◽

Agne Grineviciene ◽

Valdas Rudelis

Keyword(s):

Liquid Medium ◽

Silica Gel ◽

Ion Mobility ◽

Fluoride Removal ◽

Dynamic Conditions ◽

Treatment Conditions ◽

Medium Flow ◽

Silica Gel Waste ◽

Fluorine Ions ◽

Static Conditions

In this work, the influence of various hydroxide and salt additives on the removal of F− ions from silica gel waste, which is obtained during the production of AlF3, was examined. The leaching of the mentioned ions from silica gel waste to the liquid medium was achieved by the application of different techniques: (1) leaching under static conditions; (2) leaching under dynamic conditions by the use of continuous liquid medium flow; and (3) leaching in cycles under dynamic conditions. It was determined that the efficiency of the fluoride removal from this waste depends on the w/s ratio, the leaching conditions, and the additives used. It was proven that it is possible to reduce the concentration of fluorine ions from 10% to <5% by changing the treatment conditions and by adding alkaline compounds. The silica gel obtained after the leaching is a promising silicon dioxide source.

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New molecular insights into the stability of Ni–Pd hollow nanoparticles

Inorganic Chemistry Frontiers ◽

10.1039/c7qi00370f ◽

2017 ◽

Vol 4 (10) ◽

pp. 1679-1690 ◽

Cited By ~ 10

Author(s):

Hamed Akbarzadeh ◽

Esmat Mehrjouei ◽

Amir Nasser Shamkhali ◽

Mohsen Abbaspour ◽

Sirous Salemi ◽

...

Keyword(s):

Molecular Dynamics ◽

Thermal Behavior ◽

Molecular Dynamics Simulations ◽

Structural Evolution ◽

Hollow Nanoparticles ◽

The Stability ◽

Dynamics Simulations

Molecular dynamics simulations were used to investigate the structural evolution and thermal behavior of Ni–Pd hollow nanoparticles.

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The influence of the nature and textural properties of different supports on the thermal behavior of Keggin type heteropolyacids

Journal of the Serbian Chemical Society ◽

10.2298/jsc0603235p ◽

2006 ◽

Vol 71 (3) ◽

pp. 235-249 ◽

Cited By ~ 23

Author(s):

Alexandru Popa ◽

Viorel Sasca ◽

Mircea Stefanescu ◽

Erne Kis ◽

Radmila Marinkovic-Neducin

Keyword(s):

Thermal Stability ◽

Thermal Decomposition ◽

Thermal Behavior ◽

Solid Phase ◽

Textural Properties ◽

Nitrogen Adsorption ◽

Active Phase ◽

Support Surface ◽

Sem Images ◽

The Stability

In order to obtain highly dispersed heteropolyacids (HPAs) species, H3PMo12O40 and H4PVMo11O40 were supported on various supports: silica (Aerosil - Degussa and Romsil types) and TiO2. The structure and thermal decomposition of supported and unsupported HPAs were followed by different techniques (TGA-DTA, FTIR, XRD, low temperature nitrogen adsorption, scanning electron microscopy). All the supported HPAs were prepared by impregnation using the incipient wetness technique with a 1:1 mixture of water-ethanol. Samples were prepared with different concentrations to examine the effect of loading on the thermal behavior of the supported acid catalysts. The thermal stability was evaluated with reference to the bulk solid acids and mechanical mixtures. After deposition on silica types supports, an important decrease in thermal stability was observed on the Romsil types and a small decrease on the Aerosil type. The stability of the heteropolyacids supported on titania increased due to an anion-support interaction, as the thermal decomposition proceeded in two steps. The structure of the HPAs was not totally destroyed at 450 ?C as some IR bands were still preserved. A relatively uniform distribution of HPAs on the support surface was observed for all compositions of the active phase. No separate crystallites of solid phase HPAs were found in the SEM images.

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The Effect of AlI3 Nanoadditive on the Thermal Behavior of PMMA Subjected to Thermoanalytical Py-GC-MS Technique

Materials ◽

10.3390/ma14227036 ◽

2021 ◽

Vol 14 (22) ◽

pp. 7036

Author(s):

Muhammad Adnan ◽

Taj Ur Rahman ◽

Ali Bahadur ◽

Muhammad Aurang Zeb ◽

Wajiha Liaqat ◽

...

Keyword(s):

Thermal Degradation ◽

Thermal Behavior ◽

Inorganic Salt ◽

Molecular Level ◽

Sem Analysis ◽

Pure Pmma ◽

Environment Friendly ◽

The Stability ◽

Chemical Association ◽

Pmma Polymer

Thermal degradation of polymethylmethacrylate (PMMA) was studied by using inorganic salt of aluminum triiodide (AlI3). The composites of PMMA were prepared with AlI3 by changing the concentration of the AlI3 additive from 2% to 10% (w/w). The PMMA composites with AlI3 were characterized by TGA, DTG, SEM, FTIR, HBT, and Py-GC-MS techniques. The FTIR peaks of PMMA composite at 1316, 786, and 693 cm−1 justify the chemical association between PMMA and AlI3. TGA study shows that the stability of PMMA is enhanced by the addition of the AlI3 additive. SEM analysis represented that there is a relationship between polymer and additive when they are mixed at the molecular level. The horizontal burning test (HBT) also confirmed that the AlI3 additive produced the flame retarding properties in PMMA polymer. The burning rate of composite with 10% of AlI3 additive decreases five times as much as compared to pure PMMA polymer. Py-GC-MS analysis deduced that PMMA composite produced less toxic and environment-friendly substances (CO2) by the influence of AlI3 additive as compared to neat PMMA.

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The Prospective Approach for the Reduction of Fluoride Ions Mobility in Industrial Waste by Creating Products of Commercial Value

Sustainability ◽

10.3390/su11030634 ◽

2019 ◽

Vol 11 (3) ◽

pp. 634 ◽

Cited By ~ 1

Author(s):

Valdas Rudelis ◽

Tadas Dambrauskas ◽

Agne Grineviciene ◽

Kestutis Baltakys

Keyword(s):

Liquid Medium ◽

Silica Gel ◽

Reaction Temperature ◽

Industrial Waste ◽

Adsorption Properties ◽

Raw Material ◽

Fluoride Ions ◽

Dynamic Conditions ◽

Stable Compound ◽

Silica Gel Waste

In this work, we present the possibility to reduce the amount of fluoride ions in silica gelwaste by using different techniques or to immobilize these ions by creating products ofcommercial value. The leaching of fluoride ions from silica gel waste to the liquid medium wasdone under static and dynamic conditions. It was determined that the removal of fluoride ionsfrom this compound depends on various factors, such as dissociation, solubility, the w/s ratio,reaction temperature, leaching conditions, the adsorption properties of silica gel waste, and others.The obtained results showed that, by applying different techniques, the quantity of fluoride ionscan be reduced by 60%, while obtained water was neutralized by calcium hydroxide.Additionally, it was determined that silica gel waste is a promising raw material for thehydrothermal synthesis of a stable compound containing fluoride ions – cuspidine.

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Alkali-Activated Material Based on Red Clay and Silica Gel Waste

Waste and Biomass Valorization ◽

10.1007/s12649-018-00559-9 ◽

2019 ◽

Vol 11 (6) ◽

pp. 2973-2982

Author(s):

Ruben Paul Borg ◽

Danute Vaičiukynienė ◽

Vincas Gurskis ◽

Dalia Nizevičienė ◽

Rytis Skominas ◽

...

Keyword(s):

Silica Gel ◽

Red Clay ◽

Silica Gel Waste ◽

Alkali Activated

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Some analytic models of plane symmetric radiating collapse

Canadian Journal of Physics ◽

10.1139/cjp-2016-0518 ◽

2017 ◽

Vol 95 (1) ◽

pp. 65-68 ◽

Cited By ~ 1

Author(s):

G. Abbas ◽

Hassan Shah ◽

Zahid Ahmad

Keyword(s):

Thermal Behavior ◽

Analytical Solutions ◽

Adiabatic Index ◽

Junction Conditions ◽

Matter Distribution ◽

Field Equations ◽

Plane Symmetric ◽

Symmetric Source ◽

The Stability ◽

Analytic Models

This paper deals with the analytical solutions of the field equations in the presence of radiating plane symmetric source. For this purpose we have solved the field equations as well as junction conditions by imposing the conformal flatness conditions. The effective adiabatic index (that determines the stability of the system) has been calculated for the present radiating source. It has been found that effective adiabatic index remains invariant throughout the matter distribution. To study the thermal behavior of the source, we have discussed the thermal profile of the source and found that in the absence of dissipation from the system the temperature of the system remains constant.

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