scholarly journals Transition Metal Oxodiperoxo Complex Modified Metal-Organic Frameworks as Catalysts for the Selective Oxidation of Cyclohexane

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 829 ◽  
Author(s):  
Yuechao Hong ◽  
Jie Peng ◽  
Zhichao Sun ◽  
Zhiquan Yu ◽  
Anjie Wang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Metal Organic Frameworks ◽  
Atomic Emission ◽  
Cyclohexane Oxidation ◽  
Metal Species ◽  
Emission Spectrometry ◽  
Plasma Atomic Emission Spectrometry ◽  
Metal Organic

In this work, a series of modified metal-organic frameworks (MOFs) have been prepared by pre- and post-treatment with transition metal oxodiperoxo complexes (MoO(O2)2, WO(O2)2, and KVO(O2)2). The obtained materials are characterized by XRD, FTIR, SEM, TEM, inductively coupled plasma atomic emission spectrometry (ICP-AES), and X-ray photoelectron spectroscopy (XPS), as well as by N2 adsorption/desorption measurement. The characterization results show that transition metal oxodiperoxo complexes are uniformly incorporated into the MOF materials without changing the basic structures. The performance of cyclohexane oxidation on metal oxodiperoxo complex modified MOFs are evaluated. UiO-67-KVO(O2)2 shows the best performance for cyclohexane oxidation, with 78% selectivity to KA oil (KA oil refers to a cyclohexanol and cyclohexanone mixture) at 9.4% conversion. The KA selectivity is found to depend on reaction time, while hot-filtration experiments indicates that the catalytic process is heterogeneous with no leaching of metal species.

scholarly journals Fabricating Antibacterial and Antioxidant Electrospun Hydrophilic Polyacrylonitrile Nanofibers Loaded with AgNPs by Lignin-Induced In-Situ Method

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 748
Author(s):  
Md. Kaiser Haider ◽  
Azeem Ullah ◽  
Muhammad Nauman Sarwar ◽  
Takumi Yamaguchi ◽  
Qianyu Wang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Atomic Emission ◽  
Emission Spectrometry ◽  
Burst Release ◽  
Bacterial Strains ◽  
Plasma Atomic Emission Spectrometry ◽  
Water Contact ◽  
X Ray ◽  
E Coli

Concerning the environmental hazards owing to the chemical-based synthesis of silver nanoparticles (AgNPs), this study aimed to investigate the possibility of synthesizing AgNPs on the surface of polyacrylonitrile (PAN) nanofibers utilizing biomacromolecule lignin. SEM observations revealed that the average diameters of the produced nanofibers were slightly increased from ~512 nm to ~673 nm due to several factors like-swellings that happened during the salt treatment process, surface-bound lignin, and the presence of AgNPs. The presence of AgNPs was validated by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. The amount of synthesized AgNPs on PAN nanofibers was found to be dependent on both precursor silver salt and reductant lignin concentration. Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectra confirm the presence of lignin on PAN nanofibers. Although the X-ray diffraction pattern did not show any AgNPs band, the reduced intensity of the stabilized PAN characteristics bands at 2θ = 17.28° and 29.38° demonstrated some misalignment of PAN polymeric chains. The water contact angle (WCA) of hydrophobic PAN nanofibers was reduced from 112.6 ± 4.16° to 21.4 ± 5.03° for the maximum AgNPs coated specimen. The prepared membranes exhibited low thermal stability and good swelling capacity up to 20.1 ± 0.92 g/g and 18.05 ± 0.68 g/g in distilled water and 0.9 wt% NaCl solution, respectively. Coated lignin imparts antioxidant activity up to 78.37 ± 0.12% at 12 h of incubation. The resultant nanofibrous membranes showed a proportional increase in antibacterial efficacy with the rise in AgNPs loading against both Gram-positive S. aureus and Gram-negative E. coli bacterial strains by disc diffusion test (AATCC 147-1998). Halos for maximum AgNPs loading was calculated to 18.89 ± 0.15 mm for S. aureus and 21.38 ± 0.17 mm for E. coli. An initial burst release of silver elements within 24 h was observed in the inductively coupled plasma-atomic emission spectrometry (ICP-AES) test, and the release amounts were proportionally expansive with the increase in Ag contents. Our results demonstrated that such types of composite nanofibers have a strong potential to be used in biomedicine.

scholarly journals PHYSICOCHEMICAL CHARACTERISTICS OF RASAMANIKYA-AN AYURVEDIC ARSENICAL FORMULATION

2019 ◽  
pp. 31-36
Author(s):  
Arjun Singh ◽  
Sarada Ota ◽  
Narayanan Srikanth ◽  
Galib R ◽  
Sreedhar Bojja ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Chemical Characterization ◽  
Atomic Emission ◽  
Physicochemical Characteristics ◽  
Energy Dispersive ◽  
Emission Spectrometry ◽  
Plasma Atomic Emission Spectrometry ◽  
Classical Text ◽  
X Ray

Objective: The objective of this study was standardization and Chemical characterization of rasamanikya prepared as per standard operating procedures (SOP) mentioned in the classical text. Methods: Rasamanikya was prepared by putting churnodaka shodhita haratala (Orpiment-As2S3) between two abhraka (white mica) sheets which are heated for a while to obtain a red colored finished product. The Ayurvedic specifications for the analysis of rasamanikya were performed through qualitative and quantitative analysis. Physicochemical analysis, assay of elements by atomic absorption spectrometer (AAS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) were carried out and some other tests such as x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray analyzer (EDAX) were also performed to ensure the quality of the drug. Results: In the finished drug Arsenic and Sulphur are present in the form of As4S4, As2S3, As2S5. On the basis of XPS survey scans, scanning electron microscopy-energy dispersive x-ray analyzer (SEM-EDAX) and carbon, hydrogen, nitrogen, sulphur (CHNS) analysis the Arsenic to Sulphur (As to S) ratio is thus standardized as 39-47: 53-61. In addition to this powder, XRD shows a major conversion into an amorphous phase. Conclusion: The results could be used to lay down a new set of pharmacopoeial standards for the preparation of rasamanikya for getting optimal efficacy of medicine. Therefore, the information will help the Scientists and Researchers to build comprehensive standards, to screen the compounds responsible for different bioactivities, and to elucidate the molecular mechanism of action.

Silicate analysis of carbonated rocks using ICP-AES with calibration by the concentration ratio

2020 ◽  
Vol 86 (5) ◽  
pp. 16-21
Author(s):  
T. A. Karimova ◽  
G. L. Buchbinder ◽  
S. V. Kachin
Keyword(s):  
Inductively Coupled Plasma ◽  
Concentration Ratio ◽  
Total Error ◽  
Atomic Emission ◽  
Emission Spectrometry ◽  
Calibration Error ◽  
Plasma Atomic Emission Spectrometry ◽  
Standard Samples ◽  
Inductively Coupled ◽  
Carbonate Materials

Calibration by the concentration ratio provides better metrological characteristics compared to other calibration modes when using the inductively coupled plasma atomic emission spectrometry (ICP-AES) for analysis of geological samples and technical materials on their base. The main reasons for the observed improvement are: i) elimination of the calibration error of measuring vessels and the error of weighing samples of the analyzed materials from the total error of the analysis; ii) high intensity of the lines of base element; and iii) higher accuracy of measuring the ratio of intensities compared to that of measuring the absolute intensities. Calcium oxide is better suited as a base when using calibration by the concentration ratio in analysis of carbonate rocks, technical materials, slags containing less than 20% SiO2 and more than 20% CaO. An equation is derived to calculate the content of components determined in carbonate materials when using calibration by the concentration ratio. A method of ICP-AES with calibration by the concentration ratio is developed for determination of CaO (in the range of contents 20 – 100%), SiO2 (2.0 – 35%), Al2O3 (0.1 – 30%), MgO (0.1 – 20%), Fe2O3 (0.5 – 40%), Na2O (0.1 – 15%), K2O (0.1 – 5%), P2O5 (0.001 – 2%), MnO (0.01 – 2%), TiO2 (0.01 – 2.0%) in various carbonate materials. Acid decomposition of the samples in closed vessels heated in a HotBlock 200 system is proposed. Correctness of the procedure is confirmed in analysis of standard samples of rocks. The developed procedure was used during the interlaboratory analysis of the standard sample of slag SH17 produced by ZAO ISO (Yekaterinburg, Russia).

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