scholarly journals Equilibrium and Kinetics Studies of Hexavalent Chromium Biosorption by Luffa Cylindrica using Optimised 1,5-Diphenylcarbazide Method

2020 ◽  
Vol 9 (1) ◽  
pp. 310-317
Keyword(s):  
Hexavalent Chromium ◽  
Chemical Structure ◽  
X Ray Diffraction ◽  
Luffa Cylindrica ◽  
X Ray ◽  
Biosorption Process ◽  
Exothermic Process ◽  
Equilibrium And Kinetics ◽  
Classical Models ◽  
Chromium Adsorption

The Luffa Cylindrica fibers plant have been used as a new biological adsorbent for removal of hexavalent chromium from artificially contaminated aqueous solutions. The experiments took place in the bath mode. The influence of certain parameters on the adsorption of chromuim on the biosorbent, namely the adsorbent-adsorbate contact time, the pH of the solution and adsorbent dose of hexavalent chromium was determined. The kinetic study has shown that the process of adsorption chromuim on luffa cylindrica is a physical process characterized by its reversibility, by the speed of the establishment of equilibrium. The exploitation of adsorption isotherms using different classical models of Langmuir, Freundlich and Temkin has shown that adsorption can be governed by the Langmuir model. The maximum monolayer biosorption capacity of luffa cylindrica was found to be 5.91 mg of chromium /g of LC. The thermodynamic parameters for the adsorption system were determined at 283, 298 and 313°K. The obtained values showed that the chromium adsorption is a spontaneous and exothermic process. Finally, the Luffa cylindrica has been evaluated by FTIR, SEM and x-ray diffraction in order to determine if the biosorption process modifies its chemical structure.

A Two-step Electrodeposition of Pd-Cu/Cu2O Nanocomposite on FTO Substrate for Non-enzymatic Hydrogen Peroxide Sensor

2021 ◽  
Vol 17 ◽  
Author(s):  
Ke Huan ◽  
Li Tang ◽  
Dongmei Deng ◽  
Huan Wang ◽  
Xiaojing Si ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cyclic Voltammetry ◽  
Photoelectron Spectroscopy ◽  
Chemical Structure ◽  
Pd Nanoparticles ◽  
Optimal Conditions ◽  
Potential Oscillation ◽  
X Ray Diffraction ◽  
X Ray

Background: Hydrogen peroxide (H2O2) is a common reagent in the production and living, but excessive H2O2 may enhance the danger to the human body. Consequently, it is very important to develop economical, fast and accurate techniques for detecting H2O2. Methods: A simple two-step electrodeposition process was applied to synthesize Pd-Cu/Cu2O nanocomposite for non-enzymatic H2O2 sensor. Cu/Cu2O nanomaterial was firstly electrodeposited on FTO by potential oscillation technique, and then Pd nanoparticles were electrodeposited on Cu/Cu2O nanomaterial by cyclic voltammetry. The chemical structure, component, and morphology of the synthesized Pd-Cu/Cu2O nanocomposite were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical properties of Pd-Cu/Cu2O nanocomposite were studied by cyclic voltammetry and amperometry. Results: Under optimal conditions, the as-fabricated sensor displayed a broad linear range (5-4000 µM) and low detection limit (1.8 µM) for the determination of H2O2. The proposed sensor showed good selectivity and reproducibility. Meanwhile, the proposed sensor has been successfully applied to detect H2O2 in milk. Conclusion: The Pd-Cu/Cu2O/FTO biosensor exhibits excellent electrochemical activity for H2O2 reduction, which has great potential application in the field of food safety.

Thermotropic behavior of sodium cholesteryl carbonate

2009 ◽  
Vol 24 (1) ◽  
pp. 156-163 ◽  
Author(s):  
Rabkwan Chuealee ◽  
Timothy S. Wiedmann ◽  
Teerapol Srichana
Keyword(s):  
Phase Behavior ◽  
Chemical Structure ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Wave Number ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
C Nmr

Sodium cholesteryl carbonate ester (SCC) was synthesized, and its phase behavior was studied. The chemical structure was assessed by solid-state infrared spectroscopy based on vibration analysis. The wave number at 1705 and 1276 cm−1 corresponds to a carbonyl carbonate and O–C–O stretching of SCC, respectively. Molecular structure of SCC was further investigated with 1H and 13C NMR spectroscopy. The chemical shift, for the carbonyl carbonate resonance appeared at 155.5 ppm. A molecular mass of SCC was at m/z of 452. Differential scanning calorimetry (DSC), video-enhanced microscopy (VEM) together with polarized light microscopy, and small-angle x-ray scattering (SAXS) were used to characterize the phase behavior as a function of temperature of SCC. Liquid crystalline phase was formed with SCC. Based on the thermal properties and x-ray diffraction, it appears that SCC forms a structure analogous to the type II monolayer structure observed with cholesterol esters.

X-Ray Diffraction Study of Particulate Tannery Waste Solidified in Cement

2006 ◽  
Vol 530-531 ◽  
pp. 478-484 ◽  
Author(s):  
Carolina A. Pinto ◽  
Francisco Rolando Valenzuela-Díaz ◽  
John J. Sansalone ◽  
Jo Dweck ◽  
Frank K. Cartledge ◽  
...  
Keyword(s):  
Portland Cement ◽  
Calcium Sulfate ◽  
Type Ii ◽  
X Ray Diffraction ◽  
Leather Industry ◽  
X Ray ◽  
Tannery Waste ◽  
Ettringite Formation ◽  
Chromium Adsorption ◽  
Inorganic Waste

The leather industry creates a large quantity of organic and inorganic waste containing chromium. This research examines stabilization of particulate tannery waste in type II Portland cement. Several clays, Brazilian polycationic smectite modified in laboratory and commercial clays were used as additives with the aim of optimizing chromium adsorption. Tannery waste was added in quantities of 10, 15 and 20% relative to cement mass. The solidification components were analyzed separately and in combination in the solidified mixes using X ray diffraction. The analysis showed that reactions between the waste and the cement occurred, and that the tannery waste modified the final compounds of the system. Calcium sulfate present in the waste increased ettringite formation. Chromium also reacted with cement, since compounds with chromium and calcium were identified. Substitution of aluminum and silicon by chromium was also observed.

scholarly journals The Preparation and Chemical Structure Analysis of Novel POSS-Based Porous Materials

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1954 ◽  
Author(s):  
Xiaomei Yang ◽  
Guangzhong Yin ◽  
Zhiyong Li ◽  
Pengfei Wu ◽  
Xiaopei Jin ◽  
...  
Keyword(s):  
Porous Materials ◽  
Photoelectron Spectroscopy ◽  
Chemical Structure ◽  
Preparation Method ◽  
X Ray Diffraction ◽  
Related Research ◽  
X Ray ◽  
Advantages And Disadvantages ◽  
Solvent Water ◽  
Oligomeric Silsesquioxane

In this work, we reported the preparation and chemical analysis of novel polyhedral oligomeric silsesquioxane (POSS)-based porous materials, which were prepared according to Friedel-Crafts chloromethylation by using aluminum chloride as the catalyst and dichloromethane as the solvent. Through controlling the treatment solvent (water or methanol) and kinds of POSS, several materials with different morphologies were conveniently obtained. The chemical structure of porous materials was systematically characterized by Fourier-transform infrared (FTIR) spectra, 29Si Nuclear Magnetic Resonance (NMR), 13C NMR, and X-ray photoelectron spectroscopy (XPS). The samples were further characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) to study their crystallinity, morphology, and thermal properties, respectively. The work systematically demonstrated the chemical structure of the porous materials. Moreover, the advantages and disadvantages of the preparation method and typical properties of the material were evaluated through a comparative analysis with other related research works.

Effect of Processing Conditions on Properties of KMnO4-Treated PAN Fibers

2013 ◽  
Vol 821-822 ◽  
pp. 23-27
Author(s):  
Xiang Li ◽  
Chun Yi Liu ◽  
Ai Wen Qin ◽  
Xin Zhen Zhao ◽  
Chun Ju He
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Chemical Structure ◽  
Suitable Condition ◽  
Wide Angle ◽  
Processing Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron ◽  
Pan Fibers

Plasticized polyacrylonitrile(PAN) fibers have been chemically impregnated with aqueous solution of KMnO4under varying conditions of temperature and time. The effect of modification conditions on the chemical structure and the mechanical properties of precursor fibers are characterized by wide-angle X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscope. The experimental results show that KMnO4can be used not only as catalyst for cyclization reaction, but also as plasticizer. The chemical modification between KMnO4and PAN can not occur below70°C, the most suitable condition for modification is performed at 80°C for 5 min.

Polyaniline Nanofibers Prepared with Binary Oxidant at the Presence of Para-Phenylenediamine

2017 ◽  
Vol 898 ◽  
pp. 2354-2359
Author(s):  
Peng Fei Qian ◽  
Tao Li ◽  
Bang Lei Liang ◽  
Zong Yi Qin
Keyword(s):  
Chemical Structure ◽  
Ammonium Persulfate ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
Chemical Polymerization ◽  
X Ray ◽  
Polyaniline Nanofibers ◽  
Infrared And Raman Spectroscopy ◽  
Visible Absorption Spectroscopy

Polyaniline nanofibers were facially synthesized by the chemical polymerization with binary oxidant containing ammonium persulfate and ferric chloride at the presence of para-phenylenediamine. For a better comparison, the polymerization with single oxidant was also carried out. The effect of binary oxidant on the morphology and structure was systematically investigated for better understanding the role of oxidant in the formation of nanostructures. The morphology, chemical structure as well as crystalline and thermal property were characterized by field emission scanning electron microscopy, ultraviolet-visible absorption spectroscopy, Fourier transform infrared and Raman spectroscopy, X-ray diffraction and thermogravimetric analysis.

scholarly journals Fabrication of ZnO/CNTs for Application in CO2 Sensor at Room Temperature

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3087
Author(s):  
Rana Saad ◽  
Ahmed Gamal ◽  
Mohamed Zayed ◽  
Ashour M. Ahmed ◽  
Mohamed Shaban ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Chemical Vapor ◽  
Xrd Analysis ◽  
Chemical Vapor Deposition Method ◽  
Spray Pyrolysis Method ◽  
X Ray Diffraction ◽  
Co2 Gas ◽  
X Ray ◽  
Co2 Sensor ◽  
Higher Sensitivity

Thin films of ZnO and ZnO/carbon nanotubes (CNTs) are prepared and used as CO2 gas sensors. The spray pyrolysis method was used to prepare both ZnO and ZnO/CNTs films, with CNTs first prepared using the chemical vapor deposition method (CVD). The chemical structure and optical analyses for all the prepared nanomaterials were performed using X-ray diffraction (XRD), Fourier transformer infrared spectroscopy (FTIR), and UV/Vis spectrophotometer devices, respectively. According to the XRD analysis, the crystal sizes of ZnO and ZnO/CNTs were approximately 50.4 and 65.2 nm, respectively. CNTs have average inner and outer diameters of about 3 and 13 nm respectively, according to the transmitted electron microscope (TEM), and a wall thickness of about 5 nm. The detection of CO2 is accomplished by passing varying rates of the gas from 30 to 150 sccm over the prepared thin-film electrodes. At 150 sccm, the sensitivities of ZnO and ZnO/CNTs sensors are 6.8% and 22.4%, respectively. The ZnO/CNTs sensor has a very stable sensitivity to CO2 gas for 21 days. Moreover, this sensor has a high selectivity to CO2 in comparison with other gases, in which the ZnO/CNTs sensor has a higher sensitivity to CO2 compared to H2 and C2H2.

scholarly journals Research on Coal Tar Pitch Catalytic Oxidation and Its Effect on the Emission of PAHs during Co-Carbonation with Coal

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1428
Author(s):  
Liqing Chen ◽  
Fanhui Guo ◽  
Jianjun Wu ◽  
Ping Li ◽  
Yixin Zhang
Keyword(s):  
Catalytic Oxidation ◽  
Chemical Structure ◽  
Catalytic Mechanism ◽  
Condensation Reaction ◽  
Coal Tar ◽  
Coal Tar Pitch ◽  
Air Oxidation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polycyclic Aromatic

Coal tar pitch (CTP) is abundant and widely used, but its properties will be affected due to oxidation aging during storage. In this study, CTP was oxidized by simulating the air oxidation process, and the change of chemical structure has been analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and both gas chromatography and mass spectrometry (GCMS). The effects of the oxidized and unoxidized CTP co-carbonization with coal on the polycyclic aromatic hydrocarbons (PAHs) emission were detected by GCMS. The small and medium-molecule aromatic substances were reduced during CTP oxidation, while the intermolecular condensation reaction increased the macromolecules content. The catalytic can effectively facilitate the dehydrogenation and condensation reaction of CTP and the entry of oxygen molecules, which leads to the increase of oxygen-containing groups and the decrease of PAHs. Compared to the raw CTP, the catalytic oxidized CTP significantly reduced the emissions of toxic PAHs during the co-carbonization with coal. A possible catalytic mechanism of CTP catalytic oxidation is proposed.

scholarly journals Bioimmobilization of lead by Bacillus subtilis X3 biomass isolated from lead mine soil under promotion of multiple adsorption mechanisms

2019 ◽  
Vol 6 (2) ◽  
pp. 181701 ◽  
Author(s):  
Weichuan Qiao ◽  
Yunhao Zhang ◽  
Hao Xia ◽  
Yang Luo ◽  
Si Liu ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Photoelectron Spectroscopy ◽  
Extracellular Polymeric Substances ◽  
Exchange Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Mechanisms ◽  
Ion Exchange Process ◽  
Biosorption Process ◽  
Amine Groups

In this study, a lead-resistant bacterium, Bacillus subtilis X3, was used to prepare a lead bioadsorbent for immobilization and removal of lead in lead solution. The lead shot precipitate was analysed by scanning electron microscopy combined with energy dispersive X-ray fluorescence microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The adsorbed lead was mainly mineralized to form Pb 5 (PO 4 ) 3 OH, Pb 10 (PO 4 ) 6 (OH) 2 and Pb 5 (PO 4 ) 3 Cl; however, other mechanisms that can also promote the mineralization of lead should not be ignored. For example, Na + and Ca 2+ on the cell wall surface were exchanged with Pb 2+ in solution, which confirmed that the ion-exchange process occurred before mineralization. Moreover, adsorption bridging caused by extracellular polymeric substances also accelerated the further aggregation of lead, and the biomass was encapsulated by lead gradually. Hydroxyl, carbonyl, carboxyl and amine groups were not observed in lead mineral crystals, but the complexation between lead and these groups still benefited the mineralization of lead. The valence of Pb(II) was not changed after mineralization, which indicated that the biosorption process was not a redox reaction. Finally, biosorption occurred on the outer surface of the cell, but its specific surface area was relatively small, limiting the amount and efficiency of biosorption.

Morphological studies on renewable castor oil-based nanocomposites with modified clay and MWCNTs as fillers

2020 ◽  
pp. 096739112093524
Author(s):  
Anupama Mogha ◽  
Anupama Kaushik
Keyword(s):  
Electron Microscopy ◽  
Castor Oil ◽  
Chemical Structure ◽  
Morphological Analysis ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Morphological Studies ◽  
Transmission Electron ◽  
Commercial Applications

This research presents an analysis of castor oil-based polymer nanocomposites that can be used for numerous commercial applications. Due to the versatile chemical structure of castor oil, it can replace the petrochemical products and hence can be optimized as nontoxic bioresource for the production of nanocomposites with the incorporation of nanofillers in small quantities. It can be directly used as polyol resource without any chemical alteration for synthesis of polyurethane (PU) nanocomposites. The prepared PU nanocomposites were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, wide angle X-ray diffraction, transmission electron microscopy (TEM), and mechanical properties. The compositional and structural studies indicate the formation of PU linkages and well dispersion of clay and multiwalled carbon nanotubes between the polymer–nanofiller phase, as shown by the morphological analysis using TEM. Also, there is an increase in the tensile strength and Young’s modulus values with the increase in the filler content.

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