CO2 Sorption-Enhanced Processes by Hydrotalcite-Like Compounds at Different Temperature Levels

2015 ◽  
Vol 13 (2) ◽  
pp. 143-152 ◽  
Author(s):  
K. Gallucci ◽  
F. Micheli ◽  
D. Barisano ◽  
A. Villone ◽  
P.U. Foscolo ◽  
...  

Abstract The aim of this work is to identify solid sorbents for CO2 capture for coal and biomass syngas conditioning and cleaning by means of a sorption-enhanced reaction process. Hydrotalcite-like compounds (HTlcs) were synthesized with and without K2CO3 impregnation. Samples were characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) porosimetry after synthesis and after capture tests, respectively. Sorption and desorption tests were performed in a fluidized bed reactor, under cyclic conditions, at two different temperature levels: 350/450°C and 600/700°C. At low temperature only the Mg–Al HTlcs K promoted samples showed stability and sorption capacity comparable with literature values. On the other hand, results at high temperature indicate that the mixed Mg-Ca-Al HTlcs samples exhibit the best behavior with the highest sorption capacity (1.7 mmolCO2/g) almost stable over 5 sorption/regeneration cycles; furthermore, addition of steam allowed increasing their reactivity by 70% compared to the dry value. This type of sorbent could be a promising candidate to prepare a bifunctional sorbent–catalyst for sorption-enhanced processes, taking place directly in the fluidized bed gasifier, or downstream the reactor for adjustment of gas composition before further conversion in gaseous energy carriers.

2021 ◽  
Author(s):  
Isam M. Arafa ◽  
Mazin Y. Shatnawi ◽  
Yousef N. Obeidallah ◽  
Ahmed K. Hijazi ◽  
Yaser A . Yousef

Abstract Four transition metal borohydrides (MTBHs, MT = Ni, Fe, Co, and Cu) were prepared by sonicating a mixture of the desired MT salt with excess NaBH4 in a nonaqueous DMF/CH3OH media. The process afforded bimetallic (Ni-BH4), trimetallic (Fe-BH4, Co-BH4), and mixed-valence (Cu-H, Cu-BH4) amorphous, ferromagnetic nanoparticles as identified by thermal, ATR-IR, X-Ray diffraction, and magnetic susceptibility techniques. The electrical conductivity (σ) of cold-pressed discs of these MTBHs shows a nonlinear increase while their thermal conductivity (κ) decreases in the temperature range of 303 ≤ T ≤ 373 K. The thermal energy transport occurs through phonon lattice dynamics rather than electronic. The σ/κ ratio shows a nonlinear steep increase from 9.4 to 270 KV-2 in Ni-BH4, while a moderate-weak increase is observed for Fe-BH4, Co-BH4, and Cu-BH4. Accordingly, the corresponding thermoelectric (TE) parameters S, PF, ZT, and η were evaluated. All TE data shows that the bimetallic Ni-BH4 (S, 80 μVK-1; PF, 259 μWm-1K-2; ZT 0.64; η, 2.56%) is a better TE semiconductor than the other three MT-BHs investigated in this study. Our findings show that Ni-BH4 is a promising candidate to exploit low-temperature waste heat from body heat, sunshine, and small domestic devices for small-scale TE applications.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
YiChao Yan ◽  
Wei Shi ◽  
HongChuan Jiang ◽  
Jie Xiong ◽  
WanLi Zhang ◽  
...  

The redox reaction between Al and metallic oxide has its advantage compared with intermetallic reaction and Al/NiO nanomutlilayers are a promising candidate for enhancing the performance of energetic igniter. Al/NiO nanomutlilayers with different modulation periods are prepared on alumina substrate by direct current (DC) magnetron sputtering. The thicknesses of each period are 250 nm, 500 nm, 750 nm, 1000 nm, and 1500 nm, respectively, and the total thickness is 3 μm. The X-ray diffraction (XRD) and scanning electron microscope (SEM) results of the as-deposited Al/NiO nanomutlilayers show that the NiO films are amorphous and the layered structures are clearly distinguished. The X-ray photoelectron spectroscopy (XPS) demonstrates that the thickness of Al2O3increases on the side of Al monolayer after annealing at 450°C. The thermal diffusion time becomes greater significantly as the amount of thermal boundary conductance across the interfaces increases with relatively smaller modulation period. Differential scanning calorimeter (DSC) curve suggests that the energy release per unit mass is below the theoretical heat of the reaction due to the nonstoichiometric ratio between Al and NiO and the presence of impurities.


2020 ◽  
Vol 405 ◽  
pp. 33-39
Author(s):  
Elisabeth Rauchenwald ◽  
Mario Lessiak ◽  
Ronald Weissenbacher ◽  
Sabine Schwarz ◽  
Roland Haubner

Chemical vapour deposited HfN can be utilised as a component of multilayer systems in protective coatings on cutting tools. In this study, related AlHfN coatings were synthesized through a reaction of metallic hafnium and aluminium with HCl gas forming gaseous HfCl4 and AlCl3, which were subsequently transported into a heated coating reactor. Via high temperatures and separately introduced NH3 and N2 as reaction gases, AlHfN coatings were deposited on hardmetal inserts. By varying the ratio between AlCl3 and HfCl4, compositionally different AlHfN coatings were examined. Additionally, surface morphology, composition as well as crystalline phases of the obtained coatings were analysed by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Finally, the microstructure of the cross section of a coating was investigated via transmission electron microscopy. The observations revealed a great impact of the gas composition on the morphology and crystal structures of the coatings. Within the layer, the growth of columnar microstructures was detected. Additionally, the formation of an amorphous HfN intermediate layer between the substrate and the AlHfN with a thickness of approximately 2 nm was found.


2019 ◽  
Vol 43 (9-10) ◽  
pp. 437-442 ◽  
Author(s):  
Shou De Xu ◽  
Xiang Hua Wu

A series of bimetallic dppfM(II) (dppf = 1,1’-bis (diphenyphosphino) ferrocene; M = Pt and Pd) dithiocarbamate complexes is synthesized and characterized by spectroscopic methods and single-crystal X-ray diffraction. Their antitumor activities in vitro are investigated by MTT assays against four cancer cell lines. The anticancer studies indicate most of the complexes display good to excellent antitumor activity. Remarkably, the platinum complex with a pyrrolidinyl substituent (3b) was identified as the most promising candidate due to its high potency and broad spectrum of activity.


2014 ◽  
Vol 521 ◽  
pp. 676-679
Author(s):  
Feng Hai Li ◽  
Jie Jie Huang ◽  
Yi Tian Fang

To optimize operational parameters of fluidized-bed lignite gasification technology. Experiments have been conducted with Huolinhe (HLH) and Xiaolongtan (XLT) lignite ashes to investigate the mineral transformation behaviors under reducing atmosphere by X-ray diffraction (XRD). The results show that the initial melted parts are primarily result from wustite interacted other minerals under reducing atmosphere. Wustite can react with aluminosilicate minerals to form some low-melting eutectic compounds, and lead to its initial melting temperature 200 °C below the deformation temperature. Mullite is formed at 1000 °C or so, and its content increases and then decreases with the temperature increase, and reaches maximum at 1200 °C. Gehlenite and anorthite come from the reaction between calcium oxide and mullite. Owing to the generation of some gases during mineral transformation under weak reducing atmosphere, many holes are formed on the surface of molten ash.


Author(s):  
Chuang Huang ◽  
Hong Shui Wang ◽  
Hai Long Liu ◽  
Chun Yong Liang ◽  
Bao Fa Li ◽  
...  

The controllable deposition of hydroxyapatite (HA) on femtosecond lasers micro-patterned Titanium (Ti) plates was studied in simulated body fluid (SBF). Energy Dispersive Spectrometer analysis and X-ray Diffraction (XRD) analysis show that the hydroxyapatite deposites on the pattened titanium surface in 1.5 SBF and SEM studies show three growth modes of HA (homogeneous hydroxyapatite layer, needle-like structure, and plate-like structure) deposited at different spots of the Ti plate surface. This stereo reticular structure of hydroxyapatite could be regarded as promising candidate material for metal implantation.


2013 ◽  
Vol 805-806 ◽  
pp. 1317-1320
Author(s):  
Feng Hai Li ◽  
Zhen Zhu Li ◽  
Ming Jie Ma ◽  
Jie Jie Huang ◽  
Yi Tian Fang

To investigate fusibility characteristics of slag from Jincheng Anthracite (JC) pressurized ash agglomerate fluidized bed (AFB) gasification of Jincheng Anthracite (JC), the slag samples were examined by an ash fusion temperature (AFT) analyzer, scanning electron microscope (SEM), and X-ray diffraction (XRD). The results show that the AFTs of three kinds of slag are lower than that of JC greatly, and the AFTs of three kinds of slag decrease from the slag formed that on the central tube (SC) to distribution plate (SD) to inner face (SI), as a result of the increase of total base content and the differences in their mineral compositions accordingly. Not all slag during AFB gasification are composed of molten mineral matters. This can be explained that the phenomena that the slag formation during fluidized-bed gasification when the operating temperature is below the AFTs of coal.


2014 ◽  
Vol 1053 ◽  
pp. 181-184 ◽  
Author(s):  
Hui Hui Zhang ◽  
Dan Han ◽  
Peng Song ◽  
Qi Wang

Porous structures represent a unique class of functional nanomaterials with many applications. In this work, porous SnO2 with 3D networks structures were synthesized by a facile Lewis acid catalytic template method. Techniques of X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the structure and morphology of the products. The porous SnO2 posses large macroscopic scale and porous nanostructure with huge pore volume and large surface exposure area. The sensor based on SnO2 with porous structures exhibited high response to acetone gas (CH3COCH3). It suggests that the as-prepared porous SnO2 is promising candidate for good performance acetone sensor.


2012 ◽  
Vol 727-728 ◽  
pp. 727-730 ◽  
Author(s):  
Omayra Ferreiro ◽  
Fatima Yubero ◽  
Roseli Marins Balestra ◽  
Marize Varella ◽  
Magna Monteiro

This work involves the processing of bovine bone for use as biofilter collector of heavy metals in water. Before processing, it was necessary to clean the bone selected for removing the organic material adhered thereto. Drying was done in weathered during 18 days. Then the bones were calcined at a constant temperature of 750°C for 6 hour. The bone grinding was performed by means of an analytical mill in order to obtain a finer grain size. Once processed, the bovine bone powder was characterized by X-ray diffraction and fluorescence analyses. The results showed that the powder phase is less crystalline hydroxyapatite, when compared to highly crystalline synthetic hydroxyapatite, which favors the sorption capacity of lead by bovine bone.


2008 ◽  
Vol 396-398 ◽  
pp. 369-372 ◽  
Author(s):  
Alexandre Mello ◽  
Elena Mavropoulos ◽  
Zhen Hong ◽  
J.B. Ketterson ◽  
Antonella M. Rossi

Hydroxyapatite (HAP) crystalline thin-coatings have been grown using a right angle RF magnetron sputtering approach at room temperature. The surface structural information of these biocompatible coatings at nanometer scales was obtained by glancing-incidence X-ray diffraction (GIXRD) with synchrotron radiation. The GIXRD spectra were obtained by fixed incidence theta angles at 0.5 and 1 degree. Structural profile analyses were performed over these nano-coating layers with reduced substrate interference. The coating thickness was calibrated by specular X-ray reflectivity (XRR) curves. Experiments have been performed on thin-coatings of HAP sputtered on silicon wafers and acid etched titanium discs at room temperature. GIXRD analysis has shown that all the principal peaks are attributed to a crystalline HAP. Previous tests of biocompatibility with osteoblasts cells have been encouraging studies on the surface of hydroxyapatite thin coatings prepared by opposing RF magnetron sputtering approach, as a promising candidate for bioimplant materials.


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