REE redistributions during granite weathering: Implications for Ce anomaly as a proxy for paleoredox states

2020 ◽  
Vol 105 (6) ◽  
pp. 848-859 ◽  
Author(s):  
Koji Ichimura ◽  
Kenzo Sanematsu ◽  
Yoshiaki Kon ◽  
Tetsuichi Takagi ◽  
Takashi Murakami
Keyword(s):  
Field Emission ◽  
Inductively Coupled Plasma ◽  
Atmospheric Oxygen ◽  
Fluorescence Analysis ◽  
Significant Loss ◽  
Formation Mechanisms ◽  
Weathering Profile ◽  
X Ray ◽  
Ce Anomaly ◽  
Topmost Layer

Abstract Different responses of Ce to the redox state from those of the other light rare earth elements (LREEs) can be used to understand paleoredox states. To establish the possibility of using the Ce anomaly as a proxy for paleo-environments, we examined the mineralogical and chemical characteristics of bulk samples and REE-bearing minerals of a modern weathering profile developed on granite, by X-ray fluorescence analysis, laser-ablation inductively coupled plasma mass spectrometry, field emission electron microprobe analysis, field emission scanning electron microscopy, and X-ray diffractometry. Bulk samples showed no significant Ce-anomalies except for the topmost layer that had a positive Ce-anomaly reflecting significant loss of LREEs except for Ce. Allanite-(Ce), primary REE-bearing mineral, contributed to ~100% of La, Ce, Pr, and Nd in the parent rock, and gradually decreased in amount toward the topmost layer. Secondary cerianite-(Ce) [Ce(IV)O2] was observed in the weathering profile, especially at shallower depths. Secondary rhabdophane-(La), -(Ce), -(Nd), and -(Y) were also observed in the weathering profile but in less amounts in the topmost layer. The occurrences of rhabdophane-(La) and -(Nd) in contact with halloysite, a secondary clay mineral, suggest probable adsorption of REEs onto halloysite prior to their formation. Similar formation mechanisms are likely for rhabdophane-(Ce) that commonly occurred in grain boundaries and was usually formed in contact with halloysite. Rhabdophane-(Y) occurred in association with fluorapatite. The ratios of La, Pr, and Nd of rhabdophane-(La), -(Ce), and -(Nd) were similar to that of allanite-(Ce), suggesting that these LREEs are inherited from allanite-(Ce) and behave similarly before the formation of rhabdophane. Different negative Ce-anomaly values of rhabdophane [i.e., ~0.03–0.34 for rhabdophane-(La), -(Nd), and -(Y), and ~0.6 for rhabdophane-(Ce)] can result from a difference in intensity of the formation of cerianite-(Ce) prior to the precipitation of rhabdophane. We have classified LREE redistributions in both secondary minerals and bulk weathered samples during oxic weathering and suggested that Ce anomaly can provide useful information on anoxic weathering and thus atmospheric oxygen evolution in the Precambrian if Ce anomalies of both bulk samples and secondary REE-bearing minerals are determined.

Sorption of Se (IV) from aqueous solutions with subsequent determination by X-ray fluorescence analysis

2020 ◽  
Vol 86 (10) ◽  
pp. 5-9
Author(s):  
D. G. Filatova ◽  
A. A. Arkhipenko ◽  
M. A. Statkus ◽  
V. V. Es’kina ◽  
V. B. Baranovskaya ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Fluorescence Analysis ◽  
Standard Samples ◽  
Phase Contact Time ◽  
Sorbent Phase ◽  
X Ray ◽  
Fundamental Parameters ◽  
Inductively Coupled ◽  
Subsequent Determination

An approach to sorptive separation of Se (IV) from solutions on a novel S,N-containing sorbent with subsequent determination of the analyte in the sorbent phase by micro-x-ray fluorescence method is presented. The sorbent copolymethylenesulfide-N-alkyl-methylenamine (CMA) was synthesized using «snake in the cage» procedure and proven to be stable in acid solutions. Conditions for quantitative extraction of Se (IV) were determined: sorption in 5 M HCl or 0.05 M HNO3 solutions when heated to 60°C, phase contact time being 1 h. The residual selenium content in the solution was determined by inductively coupled plasma mass spectrometry (ICP-MS) using 82Se isotope. The absence of selenium losses is proved and the mechanism of sorption interaction under specified conditions is proposed. The method of micro-x-ray fluorescence analysis (micro-RFA) with mapping revealed a uniform distribution of selenium on the sorbent surface. The possibility of determining selenium in the sorbent phase by micro-RFA is shown. When comparing the obtained results with the results of calculations by the method of fundamental parameters, it is shown the necessity of using standard samples of sorbates to obtain correct results of RFA determination of selenium in the sorbent phase.

scholarly journals Oil-based mud waste reclamation and utilisation in low-density polyethylene composites

2020 ◽  
Vol 38 (12) ◽  
pp. 1331-1344
Author(s):  
Shohel Siddique ◽  
Kyari Yates ◽  
Kerr Matthews ◽  
Laszlo J Csetenyi ◽  
James Njuguna
Keyword(s):  
Inductively Coupled Plasma ◽  
Oil And Gas ◽  
Microscopic Analysis ◽  
Optical Emission ◽  
Fluorescence Analysis ◽  
Xrd Analysis ◽  
Low Density Polyethylene ◽  
Emission Spectrometry ◽  
Low Density ◽  
X Ray

Oil-based mud (OBM) waste from the oil and gas exploration industry can be valorised to tailor-made reclaimed clay-reinforced low-density polyethylene (LDPE) nanocomposites. This study aims to fill the information gap in the literature and to provide opportunities to explore the effective recovery and recycling techniques of the resources present in the OBM waste stream. Elemental analysis using inductively coupled plasma–optical emission spectrometry (ICP-OES) and X-ray fluorescence analysis, chemical structural analysis by Fourier transform infrared (FTIR) spectroscopy, and morphological analysis of LDPE/organo-modified montmorillonite (LDPE/MMT) and LDPE/OBM slurry nanocomposites by scanning electron microscopy (SEM) have been conducted. Further analysis including calorimetry, thermogravimetry, spectroscopy, microscopy, energy dispersive X-ray analysis and X-ray diffraction (XRD) was carried out to evaluate the thermo-chemical characteristics of OBM waste and OBM clay-reinforced LDPE nanocomposites, confirming the presence of different clay minerals including inorganic salts in OBM slurry powder. The microscopic analysis revealed that the distance between polymer matrix and OBM slurry filler is less than that of MMT, which suggests better interfacial adhesion of OBM slurry compared with the adhesion between MMT and LDPE matrix. This was also confirmed by XRD analysis, which showed the superior delamination structure OBM slurry compared with the structure of MMT. There is a trend noticeable for both of these fillers that the nanocomposites with higher percentage filler contents (7.5 and 10.0 wt% in this case) were indicated to act as a thermal conductive material. The heat capacity values of nanocomposites decreased about 33% in LDPE with 7.5 wt% MMT and about 17% in LDPE with 10.0 wt% OBM slurry. It was also noted, for both nanocomposites, that the residue remaining after 1000°C increases with the incremental wt% of fillers in the nanocomposites. There is a big difference in residue amount (in %) left after thermogravimetric analysis in the two nanocomposites, indicating that OBM slurry may have significant influence in decomposing LDPE matrix; this might be an interesting area to explore in the future. The results provide insight and opportunity to manufacture waste-derived renewable nanocomposites with enhanced structural and thermal properties.

X-Ray Fluorescence Analysis of Oxide Magnetic Tape Using Thin Layer Fundamental Parameter Analysis

1991 ◽  
Vol 35 (B) ◽  
pp. 1133-1138
Author(s):  
Ko Kimura ◽  
Hideaki Wakamatsu ◽  
Takeshi Kitamura ◽  
Ryozo Maeda ◽  
Kunthiro Fujiwara
Keyword(s):  
Thin Layer ◽  
Magnetic Tape ◽  
Inductively Coupled Plasma ◽  
Rapid Determination ◽  
Fluorescence Analysis ◽  
Parameter Analysis ◽  
Elemental Content ◽  
Fundamental Parameter ◽  
Standard Samples ◽  
X Ray

In recent years, for the development of magnetic tape, it has become increasingly important that the elemental content be determined accurately and rapidly. In the past, the elemental content of magnetic tape was determined by calibration analysis using a wavelength dispersive X-ray fluorescence spectrometer(WDXRF). For calibration analysis many standard samples and large amount of sample were needed. Preparation of sample for calibration analysis, as well as for inductively coupled plasma emission spectral analysis(ICP) was difficult. On the other hand, for thin layer fundamental parameter analysis(we call TLFP) using a WDXRF, a few standard samples and l.pss sample are needed and preparation of the sample is easy. The superiority of TLFP analysis can be seen In comparison with calibration analysis and IOP analysis in Table 1. For this reason, this study has established a method for accurate and rapid determination of the elemental composition of oxide magnetic tape by TLFP analysis using a WDXRF.

scholarly journals Comparative analysis of X-ray fluorescence methods for elemental composition determination of the archaeological ceramics from low sample quantity

2021 ◽  
Vol 25 (1) ◽  
pp. 20-33
Author(s):  
G. V. Pashkova ◽  
◽  
M. M. Mukhamedova ◽  
V. M. Chubarov ◽  
A. S. Maltsev ◽  
...  
Keyword(s):  
Elemental Composition ◽  
Inductively Coupled Plasma ◽  
Bulk Composition ◽  
Fluorescence Analysis ◽  
Total Reflection ◽  
Late Neolithic ◽  
Burial Site ◽  
Archaeological Ceramics ◽  
X Ray

Wavelength-dispersive X-ray fluorescence analysis (WDXRF) and total-reflection X-ray fluorescence (TXRF) analysis were applied to study the elemental composition of the Late Neolithic ancient ceramics collected at the Popovsky Lug burial site (Kachug, Upper Lena river, Russia). Semi-quantitative non-destructive analysis of ceramic pieces showed that measurements of the upper and lower sides of the ceramic are less informative than the measurement of its cut. Various sample preparation techniques for the low quantity of crushed ceramics such as fusion, pressing and preparation of suspensions were compared to preserve the material. Samples were prepared as 150 mg fused beads and 250 mg pressed pellets for WDXRF, and as suspensions of 20 mg sample based on the aqueous solution of the Triton X-100 surfactant for TXRF. Certified methods were used to validate the obtained contents of rock-forming oxides and inductively coupled plasma mass spectrometry was used to confirm the results of trace elements determination. Based on the carried-out studies, a combination of the wavelength-dispersive X-ray fluorescence analysis (glass) and total-reflection X-ray fluorescence analysis (suspension) methods was chosen to obtain the data on the elemental bulk composition of archaeological ceramics. The proposed combination allowed the quantitative determination of Na, Mg, Al, Si, P, K, Ca, Ti, Mn, Fe, V, Cr, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Pb, and Ba from the sample of crushed ceramics weighing only about 170 mg.

A fusion method for preparing glass samples of peridotitic and picritic rock compositions for bulk analysis

1995 ◽  
Vol 59 (395) ◽  
pp. 267-271 ◽  
Author(s):  
N. W. A. Odling
Keyword(s):  
Bulk Composition ◽  
Fluorescence Analysis ◽  
Significant Loss ◽  
Glass Beads ◽  
Crystalline Material ◽  
Time Analysis ◽  
Bulk Analysis ◽  
X Ray ◽  
Natural Rock ◽  
Microscope Stage

AbstractA design for a micro furnace and a fusion technique are described by which silicate materials (in particular picritic and peridotitic rock compositions) may be fused and quenched to a homogeneous glass without significant loss of components, for the purposes of bulk analysis. The furnace consists of a Pt wire electrical resistance heater mounted in a furnace assembly which is fitted to a microscope stage. Microscopic examination of the sample during the fusion process allows the sample to be quenched as soon as all crystalline material has been fused and thus minimizes the loss of iron and alkalis due either to over-heating or prolonged fusion time. Analysis of glass beads of a model peridotite composition (analysed independently by X-ray fluorescence analysis) shows that for typical fusion times (5–10 seconds) the bulk composition is preserved at distances of > 25 µm from the margins of the glass beads. Analysis of natural rock powders of known composition shows that the method can be used to analyse whole rock compositions. The furnace is simple to construct and cheap to run and provides a simple and rapid method of producing glass samples for bulk analysis.

An x-ray microprobe based upon a close-coupled focal-spot / glass capillary arrangement

1992 ◽  
Vol 50 (2) ◽  
pp. 1758-1759
Author(s):  
D. A. Carpenter ◽  
M. A. Taylor
Keyword(s):  
Imaging Techniques ◽  
Fluorescence Analysis ◽  
High Sensitivity ◽  
Specimen Preparation ◽  
X Rays ◽  
Glass Capillary ◽  
Close Coupling ◽  
X Ray ◽  
Point To Point ◽  
Beam Damage

The development of intense sources of x rays has led to renewed interest in the use of microbeams of x rays in x-ray fluorescence analysis. Sparks pointed out that the use of x rays as a probe offered the advantages of high sensitivity, low detection limits, low beam damage, and large penetration depths with minimal specimen preparation or perturbation. In addition, the option of air operation provided special advantages for examination of hydrated systems or for nondestructive microanalysis of large specimens.The disadvantages of synchrotron sources prompted the development of laboratory-based instrumentation with various schemes to maximize the beam flux while maintaining small point-to-point resolution. Nichols and Ryon developed a microprobe using a rotating anode source and a modified microdiffractometer. Cross and Wherry showed that by close-coupling the x-ray source, specimen, and detector, good intensities could be obtained for beam sizes between 30 and 100μm. More importantly, both groups combined specimen scanning with modern imaging techniques for rapid element mapping.

XRMF applications of a monolithic, polycapillary, focusing x-ray optic

1996 ◽  
Vol 54 ◽  
pp. 240-241
Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla
Keyword(s):  
Trace Elements ◽  
Point Source ◽  
Focal Spot ◽  
Fluorescence Analysis ◽  
X Rays ◽  
Focal Distance ◽  
Spot Diameter ◽  
X Ray ◽  
Focal Spot Diameter

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.

Comparison of high-angle take-off and low-angle take-off EDX detector geometry of the HF-2000 FE-TEM

1993 ◽  
Vol 51 ◽  
pp. 252-253
Author(s):  
Y. Sato ◽  
T. Hashimoto ◽  
M. Ichihashi ◽  
Y. Ueki ◽  
K. Hirose ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Field Emission ◽  
Solid Angle ◽  
Energy Dispersive ◽  
Objective Lens ◽  
X Rays ◽  
High Angle ◽  
X Ray ◽  
Detector Geometry

Analytical TEMs have two variations in x-ray detector geometry, high and low angle take off. The high take off angle is advantageous for accuracy of quantitative analysis, because the x rays are less absorbed when they go through the sample. The low take off angle geometry enables better sensitivity because of larger detector solid angle.Hitachi HF-2000 cold field emission TEM has two versions; high angle take off and low angle take off. The former allows an energy dispersive x-ray detector above the objective lens. The latter allows the detector beside the objective lens. The x-ray take off angle is 68° for the high take off angle with the specimen held at right angles to the beam, and 22° for the low angle take off. The solid angle is 0.037 sr for the high angle take off, and 0.12 sr for the low angle take off, using a 30 mm2 detector.

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