Quantification of the toxic hexavalent chromium content in an organic matrix by X-ray photoelectron spectroscopy (XPS) and ultra-low-angle microtomy (ULAM)

2017 ◽  
Vol 396 ◽  
pp. 665-671 ◽  
Author(s):  
Theresia Greunz ◽  
Hubert Duchaczek ◽  
Raffaela Sagl ◽  
Jiri Duchoslav ◽  
Roland Steinberger ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Photoelectron Spectroscopy ◽  
Chromium Content ◽  
Organic Matrix ◽  
X Ray

scholarly journals Removal of hexavalent chromium from wastewater by Cu/Fe bimetallic nanoparticles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jien Ye ◽  
Yi Wang ◽  
Qiao Xu ◽  
Hanxin Wu ◽  
Jianhao Tong ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Removal Efficiency ◽  
Photoelectron Spectroscopy ◽  
Bimetallic Nanoparticles ◽  
Chemical Reduction ◽  
Particle Surface ◽  
Zerovalent Iron ◽  
Order Model ◽  
X Ray ◽  
Nanoscale Zerovalent Iron

AbstractPassivation of nanoscale zerovalent iron hinders its efficiency in water treatment, and loading another catalytic metal has been found to improve the efficiency significantly. In this study, Cu/Fe bimetallic nanoparticles were prepared by liquid-phase chemical reduction for removal of hexavalent chromium (Cr(VI)) from wastewater. Synthesized bimetallic nanoparticles were characterized by transmission electron microscopy, Brunauer–Emmet–Teller isotherm, and X-ray diffraction. The results showed that Cu loading can significantly enhance the removal efficiency of Cr(VI) by 29.3% to 84.0%, and the optimal Cu loading rate was 3% (wt%). The removal efficiency decreased with increasing initial pH and Cr(VI) concentration. The removal of Cr(VI) was better fitted by pseudo-second-order model than pseudo-first-order model. Thermodynamic analysis revealed that the Cr(VI) removal was spontaneous and endothermic, and the increase of reaction temperature facilitated the process. X-ray photoelectron spectroscopy (XPS) analysis indicated that Cr(VI) was completely reduced to Cr(III) and precipitated on the particle surface as hydroxylated Cr(OH)3 and CrxFe1−x(OH)3 coprecipitation. Our work could be beneficial for the application of iron-based nanomaterials in remediation of wastewater.

scholarly journals THE DEGRADATION OF THE PROTECTIVE SCALE ON BINARY FeCr ALLOYS (Fe-2.25Cr, Fe-10Cr, Fe-18Cr AND Fe-25Cr) IN CO2 AND IN CO2 + H2O ENVIRONMENT AT 600oC

2016 ◽  
Vol 39 (1) ◽  
pp. 15-29
Author(s):  
Bagas Pujilaksono
Keyword(s):  
Cross Sections ◽  
Photoelectron Spectroscopy ◽  
Chromium Content ◽  
X Ray Diffraction ◽  
Protective Oxide ◽  
Breakaway Oxidation ◽  
X Ray ◽  
Protective Scale ◽  
Dry Conditions ◽  
Scale Surface

The oxidation behaviour of the binary alloys Fe-2.25, Fe-10Cr, Fe-18Cr and Fe-25Cr in dry and wet O2 at 600oC is investigated by isothermal exposures of carefully polished samples for up to 168 hours. The oxidized samples are investigated gravimetrically and the oxides formed are studied by X-ray diffraction. X-ray photoelectron spectroscopy is used for depth pro􀂿 ling of the thin oxides. The scale surface is imaged by SEM. Cross sections through the scale are analyzed by SEM/EDX for imaging and for measuring the chemical composition. The oxidation behavior of the four FeCr alloys is intermediate between those of iron and chromium. Fe-2.25Cr oxidizes in a way similar to iron in both environments, forming a poorly protective scale consisting of FeCr spinel at the bottom, magnetite in the middle and a hematite cap layer. In dry O2, Fe-10Cr, Fe-18Cr and Fe-25Cr form a thin and protective (Fe,Cr)2O3 oxide similar to the chromia 􀂿 lm formed on pure chromium. In wet O2, Fe-10Cr, Fe-18Cr and Fe-25Cr initially form the same kind of protective oxide 􀂿 lm as in dry conditions. After an incubation time that depends on alloy chromium content, all three alloys go into breakaway oxidation and form thick, poorly protective scales similar to those formed on Fe-2.25Cr. Breakaway oxidation in wet O2 is triggered by the evaporation of CrO2(OH)2 from the protective (Fe,Cr)2O3 oxide.

scholarly journals Efficient Removal of Hexavalent Chromium from an Aquatic System Using Nanoscale Zero-Valent Iron Supported by Ramie Biochar

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2698
Author(s):  
Xiangpeng Tan ◽  
Muhammad Shaaban ◽  
Jianwei Yang ◽  
Yajun Cai ◽  
Buyun Wang ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Photoelectron Spectroscopy ◽  
Interaction Mechanism ◽  
Reduction Reaction ◽  
Zero Valent Iron ◽  
Adsorption Activity ◽  
X Ray ◽  
Nano Zero Valent Iron ◽  
Multiple Interaction ◽  
Co Precipitation

In this study, ramie biochar (RBC) was used to activate nano zero-valent iron (nZVI) to enhance hexavalent chromium (Cr(VI)) removal. The best results were obtained at a pyrolysis temperature of 600 °C, a biochar particle size of < 150 μm, and an iron to carbon ratio = 1:1. Under the optimal conditions, the removal of Cr(VI) by RBC600-nZVI (98.69%) was much greater than that of RBC600 (12.42%) and nZVI (58.26%). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) revealed that the reaction mechanism at the Fe and Cr interface was a multiple interaction mechanism with reduction dominated, adsorption, and co-precipitation simultaneously. The enhanced performance of RBC600-nZVI resulted from the effective dispersion of nZVI on the surface of RBC600, therefore increasing the adsorption activity sites. At the same time, RBC600 and nZVI exerted a synergistic influence on the composite structure, which jointly promoted the reduction reaction of Cr(VI) and removed more Cr(VI). This study shows that RBC-nZVI is a potentially valuable remediation material that not only provides a new idea for the utilization of ramie waste, but also effectively overcomes the limitations of nZVI, thus, achieving efficient and rapid remediation of Cr(VI).

scholarly journals Preparation and characterization of block copolymers containing cinnamate groups with end-capped ZnO

2013 ◽  
Vol 11 (9) ◽  
pp. 1492-1504 ◽  
Author(s):  
Florentina Jitaru ◽  
Tinca Buruiana ◽  
Gabriela Hitruc ◽  
Emil Buruiana
Keyword(s):  
Photoelectron Spectroscopy ◽  
Uv Spectroscopy ◽  
Organic Matrix ◽  
Proton Nuclear Magnetic Resonance ◽  
Broad Emission Band ◽  
Zno Nanoparticle ◽  
Resonance Fluorescence ◽  
X Ray ◽  
Transmission Electron ◽  
Poly Ethylene

AbstractAbstract ZnO-poly(2-cinnamoyloxyethyl methacrylate) and ZnO-poly(2-cinnamoyloxyethyl methacrylate)-b-poly[(poly(ethylene glycol) methyl ether methacrylate] have been prepared by atom transfer polymerization initiated through a 2-bromoisobutyryl or bromoethyl group linked onto the ZnO nanoparticle surface (ZnO-BIBB, ZnO-BEI). The structure and morphology of the hybrids were characterized using Fourier transform infrared, proton nuclear magnetic resonance, fluorescence and UV spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron (TEM) and atomic force microscopy. The existence of nanoparticles with diameters varying between 40 and 100 nm was evident in the TEM images of the pure ZnO, ZnO-PCEMA-Br-2 and the diblock copolymer. Under an excitation of 340 nm, these materials exhibit a broad emission band at around 390 nm, which was associated with the presence of ZnO in the organic matrix. Graphical abstract

Electron Microscopy and X-Ray Photoelectron Spectroscopy of Oxygen Plasmaetched Bacterial Spores and Cells

1976 ◽  
Vol 34 ◽  
pp. 134-135
Author(s):  
Richard S. Thomas ◽  
Merle M. Millard ◽  
René Scherrer
Keyword(s):  
Photoelectron Spectroscopy ◽  
Organic Matrix ◽  
Structural Features ◽  
Mineral Elements ◽  
Bacterial Spores ◽  
Electron Microscopic ◽  
X Ray ◽  
Culture Cells ◽  
Combined Application ◽  
Morphological Studies

Low-temperature, oxygen plasma etching (OPE) is a useful technique in electron-microscopic (EM) morphological studies of mineral-containing organic polymers and biological structures. OPE gently and cleanly etches away the organic matrix at the surface of the specimen, leaving behind oxides and salts of exposed mineral elements. X-ray photoelectron spectroscopy (XPS) is widely used for macroscopic chemical analysis of the surfaces of polymers and inorganic specimens. The XPS signal originates from a surface depth of less than 100 Å. Combined application of the three techniques, OPE, EM and XPS to dispersible, macroscopic specimens which are microscopically homogeneous should allow correlation of fine structural features with surface and subsurface chemical composition. The present, preliminary study explores this possibility on bacterial spores and cells. Further details, and similar studies on tissue culture cells will be reported elsewhere.

In situ Synthesis of Nickel Ferrite Nanoparticle/organic Hybrid

2005 ◽  
Vol 20 (6) ◽  
pp. 1590-1596 ◽  
Author(s):  
Satoshi Nakamura ◽  
Wataru Sakamoto ◽  
Toshinobu Yogo
Keyword(s):  
Photoelectron Spectroscopy ◽  
Nickel Ferrite ◽  
Oxide Particle ◽  
Organic Matrix ◽  
X Ray ◽  
Organic Hybrid ◽  
Ferrite Particle ◽  
Ferrite Nanoparticle ◽  
Hydrolysis Conditions

A NiFe2O4 particle/organic hybrid was synthesized in situ from iron-organic and nickel organic compounds below 100 °C. A mixture of nickel (II) acetylacetonate (NA) and iron (III) 3-allylacetylacetonate (IAA) was hydrolyzed and polymerized yielding spinel oxide particle/oligomer hybrid. X-ray diffraction analysis revealed that the crystallinity of spinel particles was dependent upon the hydrolysis conditions of NA-IAA. Nanocrystalline nickel ferrite particles around 10 nm were uniformly dispersed in the organic matrix. The formation of nickel ferrite was confirmed by energy-dispersive x-ray and x-ray photoelectron spectroscopy. The saturation magnetization of hybrid increased with increasing water amount for hydrolysis. Nano-sized nickel ferrite particle/organic hybrid showed a BH curve with no remanence above 75 K. The magnetization versus H/T curves at 300, 200, and 75 K were superimposed on the same curve and satisfied the Langevin equation. The remanent magnetization and coercive field of the hybrid were 7.4 emu/g and 460 Oe, respectively, at 5 K.

Sign in / Sign up

Export Citation Format

Share Document