scholarly journals Adsorption of cupric, cadmium and cobalt ions from the aqueous stream using the composite of iron(II,III) oxide and zeolitic imidazole framework-8

2021 ◽  
Author(s):  
Pushpmala Kuwer ◽  
Anshul Yadav ◽  
Pawan Kumar Labhasetwar
Keyword(s):  
Thermal Stability ◽  
Toxic Metals ◽  
Photoelectron Spectroscopy ◽  
Structural Integrity ◽  
Toxic Metal ◽  
Mechanism Analysis ◽  
Potentially Toxic Metals ◽  
Cobalt Ions ◽  
X Ray ◽  
Adsorption Processes

Abstract In recent research, the composite of Fe3O4 and metal-organic frameworks have shown great potential in removing potentially toxic metals from water. We conducted the adsorption studies of potentially toxic metal ions (Cu2+, Co2+ and Cd2+) using the composite of Fe3O4 and zeolitic imidazole framework-8 (Fe3O4@ZIF-8) for the first time. The solvothermal technique was used to synthesize the Fe3O4. The magnetic ZIF-8 offers high thermal stability, greater adsorption surface, good removability, and high chemical and thermal stability. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the synthesized samples. The SEM and XRD results revealed the high purity and structural integrity of ZIF-8 crystallites. To remove potentially toxic metals (Cu2+, Co2+ and Cd2+), the influence of adsorbent dosage, contact time, pH, and adsorbate concentration on the adsorption performance of Fe3O4@ZIF-8 was investigated. Langmuir isotherm accurately represented the adsorption processes, with absorption magnitudes of Fe3O4@ZIF-8 determined to be 46.82 mg g−1, 71.29 mg g−1 and 54.49 mg g−1 for Cu2+, Co2+ and Cd2+, respectively. According to the adsorption mechanism analysis, the primary Cu2+, Co2+ and Cd2+ removal methods of Fe3O4@ZIF-8 were ion exchange and coordination bonds. The uptake capacity of Cu2+, Co2+ and Cd2+ solution by Fe3O4@ZIF-8 were not significantly affected by the presence of counter ions. The material exhibited superior regenerative properties for Cu2+, Co2+ and Cd2+ ions from the water up to three cycles. This study concluded that the Fe3O4@ZIF-8 could be a viable candidate for eliminating potentially toxic metals (Cu2+, Co2+ and Cd2+).

scholarly journals X-ray Photoelectron Spectroscopy Analysis of Chitosan–Graphene Oxide-Based Composite Thin Films for Potential Optical Sensing Applications

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 478
Author(s):  
Wan Mohd Ebtisyam Mustaqim Mohd Daniyal ◽  
Yap Wing Fen ◽  
Silvan Saleviter ◽  
Narong Chanlek ◽  
Hideki Nakajima ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Functional Group ◽  
Optical Sensing ◽  
Composite Thin Films ◽  
Cobalt Ions ◽  
X Ray ◽  
Sensing Applications

In this study, X-ray photoelectron spectroscopy (XPS) was used to study chitosan–graphene oxide (chitosan–GO) incorporated with 4-(2-pyridylazo)resorcinol (PAR) and cadmium sulfide quantum dot (CdS QD) composite thin films for the potential optical sensing of cobalt ions (Co2+). From the XPS results, it was confirmed that carbon, oxygen, and nitrogen elements existed on the PAR–chitosan–GO thin film, while for CdS QD–chitosan–GO, the existence of carbon, oxygen, cadmium, nitrogen, and sulfur were confirmed. Further deconvolution of each element using the Gaussian–Lorentzian curve fitting program revealed the sub-peak component of each element and hence the corresponding functional group was identified. Next, investigation using surface plasmon resonance (SPR) optical sensor proved that both chitosan–GO-based thin films were able to detect Co2+ as low as 0.01 ppm for both composite thin films, while the PAR had the higher binding affinity. The interaction of the Co2+ with the thin films was characterized again using XPS to confirm the functional group involved during the reaction. The XPS results proved that primary amino in the PAR–chitosan–GO thin film contributed more important role for the reaction with Co2+, as in agreement with the SPR results.

scholarly journals Improvement of the thermal stability of dendritic silver-coated copper microparticles by surface modification based on molecular self-assembly

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Tae Hyeong Kim ◽  
Hyeji Kim ◽  
Hyo Jun Jang ◽  
Nara Lee ◽  
Kwang Hyun Nam ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Electrically Conductive ◽  
X Ray ◽  
Alkyl Chains ◽  
Conductive Film ◽  
Initial Resistance ◽  
Thermal Stability Of ◽  
Scanning Electron

AbstractIn the study reported herein, silver-coated copper (Ag/Cu) powder was modified with alkanethiols featuring alkyl chains of different lengths, namely butyl, octyl, and dodecyl, to improve its thermal stability. The modification of the Ag/Cu powders with adsorbed alkanethiols was confirmed by scanning electron microscopy with energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Each powder was combined with an epoxy resin to prepare an electrically conductive film. The results confirmed that the thermal stability of the films containing alkanethiol-modified Ag/Cu powders is superior to that of the film containing untreated Ag/Cu powder. The longer the alkyl group in the alkanethiol-modified Ag/Cu powder, the higher the initial resistance of the corresponding electrically conductive film and the lower the increase in resistance induced by heat treatment.

scholarly journals Thermal Stability of Octadecyltrichlorosilane and Perfluorooctyltriethoxysilane Monolayers on SiO2

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 210
Author(s):  
Xiangdong Yang ◽  
Haitao Wang ◽  
Peng Wang ◽  
Xuxin Yang ◽  
Hongying Mao
Keyword(s):  
Thermal Stability ◽  
Thermal Behavior ◽  
Work Function ◽  
Photoelectron Spectroscopy ◽  
Vacuum Annealing ◽  
Moderate Temperature ◽  
Ultraviolet Photoelectron Spectroscopy ◽  
X Ray ◽  
Thermal Stability Of

Using in situ ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) measurements, the thermal behavior of octadecyltrichlorosilane (OTS) and 1H, 1H, 2H, and 2H-perfluorooctyltriethoxysilane (PTES) monolayers on SiO2 substrates has been investigated. OTS is thermally stable up to 573 K with vacuum annealing, whereas PTES starts decomposing at a moderate temperature between 373 K and 423 K. Vacuum annealing results in the decomposition of CF3 and CF2 species rather than desorption of the entire PTES molecule. In addition, our UPS results reveal that the work function (WF)of OTS remains the same after annealing; however WF of PTES decreases from ~5.62 eV to ~5.16 eV after annealing at 573 K.

Pd/SiO2 Organic-Inorganic Hybrid Materials by Sol-Gel Method: Preparation and Thermal Stability under H2 Atmosphere

2015 ◽  
Vol 1118 ◽  
pp. 20-27
Author(s):  
Jing Yang ◽  
Bao Song Li ◽  
Xiang Huo ◽  
Hao Xu ◽  
Hai Yun Hou
Keyword(s):  
Thermal Stability ◽  
Calcination Temperature ◽  
Hybrid Materials ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Inorganic Hybrid ◽  
X Ray ◽  
Good Thermal Stability ◽  
Pd Doping

Pd/SiO2 organic-inorganic hybrid materials were prepared by adding PdCl2 into methyl-modified silica sol. The Pd/SiO2 hybrid materials were characterized by X-ray diffraction (XRD), fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The effects of calcination temperature and Pd-doping on the phase transition of Pd element and the thermal stability of CH3 group in the Pd/SiO2 organic-inorganic hybrid materials were investigated. The results showed that the reduced metallic Pd0 exhibits good thermal stability under H2 atmosphere in the calcination process. Pd element in noncalcined Pd/SiO2 materials exists in PdCl2 form, calcination at 200 °C in a H2 atmosphere produces some metallic Pd0 and calcinations at 350 °C results in the complete transformation of Pd2+ to metallic Pd0. With the increase of calcination temperature, the Pd0 particle sizes increase and the hydrophobic Si−CH3 bands decrease in intensity. As the calcination temperature is greater than or equal to 350 °C, the loading of metallic Pd0 nearly has no influence on the chemical structure but, with the increase of Pd content, the formed Pd0 particle size increases. To keep the hydrophobicity of Pd/SiO2 membrane materials, the optimal calcination temperature is about 350 °C under H2 atmosphere.

Thermal stability of magnetic tunnel junctions studied by x-ray photoelectron spectroscopy

2001 ◽  
Vol 78 (2) ◽  
pp. 234-236 ◽  
Author(s):  
David J. Keavney ◽  
Sungkyun Park ◽  
Charles M. Falco ◽  
J. M. Slaughter
Keyword(s):  
Thermal Stability ◽  
Photoelectron Spectroscopy ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
X Ray ◽  
Thermal Stability Of

scholarly journals Synthesis, characterization and properties of polymers containing simultaneously the imine and amide moieties.

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Christian Sánchez ◽  
Carlos Bustos ◽  
Fabiola Alvarado ◽  
Eduardo Schott ◽  
Nicolas Gatica ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Photoelectron Spectroscopy ◽  
High Thermal Stability ◽  
High Solubility ◽  
Reduced Pressure ◽  
X Ray ◽  
H Nmr ◽  
Polymeric Fraction

Abstract We present the synthesis of polymers by means of self-condensation of ethyl 3-aminophenyl acetate, using HCl as catalyst at high temperature and reduced pressure. This polymer was fractionated by successive precipitation from mixtures of methanol/diethylether of different polarity, yielding three polymeric fractions: Poly A, Poly B and Poly C. Likewise, under the same conditions, 3- aminophenyl acetic acid yields only one polymeric fraction, Poly D. These polymers were characterized by elemental analysis, IR and, in some cases, by 1H-NMR and X-Ray Photoelectron Spectroscopy (XPS). The obtained results show that polymers can be classified as hybrid materials, because in the backbone, they contain simultaneously the amide and imine groups and, at the end of the chain, they have amine and carboxylic acid functions. High solubility of some of these polymers in DMF or methanol has permitted the determination of viscosities and the preparation of films. Poly B and Poly C films exhibit amorphous morphology; and Poly D display spherullitic-type semi-crystallization pattern. The polymers can absorb solvents and they can swell up forming large-sized gels in DMF and methanol. Besides these polymers have high thermal stability that reaches a weight loss of 11.60% at 353 °C.

Thermal stability of carbon nitride thin films

2001 ◽  
Vol 16 (11) ◽  
pp. 3188-3201 ◽  
Author(s):  
Niklas Hellgren ◽  
Nian Lin ◽  
Esteban Broitman ◽  
Virginie Serin ◽  
Stefano E. Grillo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Photoelectron Spectroscopy ◽  
Carbon Nitride ◽  
Amorphous Structure ◽  
X Ray ◽  
Bonding Structure ◽  
Higher Temperature ◽  
Electron Energy Loss ◽  
Thermal Stability Of

The thermal stability of carbon nitride films, deposited by reactive direct current magnetron sputtering in N2 discharge, was studied for postdeposition annealing temperatures TA up to 1000 °C. Films were grown at temperatures of 100 °C (amorphous structure) and 350 and 550 °C (fullerenelike structure) and were analyzed with respect to thickness, composition, microstructure, bonding structure, and mechanical properties as a function of TA and annealing time. All properties investigated were found to be stable for annealing up to 300 °C for long times (>48 h). For higher TA, nitrogen is lost from the films and graphitization takes place. At TA = 500 °C the graphitization process takes up to 48 h while at TA = 900 °C it takes less than 2 min. A comparison on the evolution of x-ray photoelectron spectroscopy, electron energy loss spectroscopy and Raman spectra during annealing shows that for TA > 800 °C, preferentially pyridinelike N and –C≡N is lost from the films, mainly in the form of molecular N2 and C2N2, while N substituted in graphite is preserved the longest in the structure. Films deposited at the higher temperature exhibit better thermal stability, but annealing at temperatures a few hundred degrees Celsius above the deposition temperature for long times is always detrimental for the mechanical properties of the films.

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