Fabrication of green one-part geopolymer from silica-rich vanadium tailing via thermal activation and modification

2022 ◽  
Vol 29 (1) ◽  
pp. 177-184
Author(s):  
Shenxu Bao ◽  
Yongpeng Luo ◽  
Yimin Zhang
Keyword(s):  
2019 ◽  
Vol 15 (34) ◽  
pp. 1-14
Author(s):  
Bushra A. Hasan

Lead selenide PbSe thin films of different thicknesses (300, 500, and 700 nm) were deposited under vacuum using thermal evaporation method on glass substrates. X-ray diffraction measurements showed that increasing of thickness lead to well crystallize the prepared samples, such that the crystallite size increases while the dislocation density decreases with thickness increasing. A.C conductivity, dielectric constants, and loss tangent are studied as function to thickness, frequency (10kHz-10MHz) and temperatures (293K-493K). The conductivity measurements confirm confirmed that hopping is the mechanism responsible for the conduction process. Increasing of thickness decreases the thermal activation energy estimated from Arhinus equation is found to decrease with thickness increasing. The increase of thickness lead to reduce the polarizability α while the increasing of temperature lead to increase α.


Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 338-359
Author(s):  
Magdalena Bonarowska ◽  
Zbigniew Kaszkur ◽  
Krzysztof Matus ◽  
Alicja Drelinkiewicz ◽  
Tomasz Szumełda ◽  
...  

We present an efficient strategy for synthesising the PdAu catalysts with a homogeneous PdAu alloy phase for environmentally important hydrodechlorination of tetrachloromethane in the gas phase. The synthesis of carbon-supported catalysts involved two major steps: (i) incorporation of palladium and gold nanoparticles into carbon support and (ii) activation of the catalysts. The critical part of this work was to find the optimal conditions for both steps. Thus, the incorporation of the nanoparticles was carried out in two ways, by impregnation and direct redox reaction method using acetone solutions of metal precursor salts. The activation was performed either by a conventional thermal reduction in hydrogen or flash irradiation in a microwave oven. The homogeneity and structure of the PdAu alloy were found to depend on the catalyst activation method critically. In all cases, we observed better homogeneity for catalysts that were subject to microwave irradiation. Moreover, the flash microwave irradiation of prepared catalysts provided catalysts of better stability and selectivity towards the desired products (hydrocarbons) in the hydrodechlorination of tetrachloromethane as compared to the catalyst obtained by conventional thermal activation in hydrogen.


1985 ◽  
Vol 260 (30) ◽  
pp. 16255-16262 ◽  
Author(s):  
T J Schmidt ◽  
A Miller-Diener ◽  
M L Webb ◽  
G Litwack

2021 ◽  
Vol 267 ◽  
pp. 124657
Author(s):  
Zhaofeng Li ◽  
Yifan Gao ◽  
Jian Zhang ◽  
Chen Zhang ◽  
Jingpeng Chen ◽  
...  

2021 ◽  
Vol 292 ◽  
pp. 123455
Author(s):  
Omar M. Abdulkareem ◽  
Amor Ben Fraj ◽  
Marwen Bouasker ◽  
Lahcen Khouchaf ◽  
Abdelhafid Khelidj

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