Synchrotron X-ray fluorescence analysis in environmental and earth sciences

Abstract

Abstract. Compared to other microscopic analytical tools X-ray microscopy techniques have the advantage that the large penetration depth of X-rays in matter allows one to investigate the interior of an object without destructive sample preparation. In combination with X-ray fluorescence tomography, analytical information from inside of a specimen can be obtained. Different X-ray analytical techniques can be used to produce contrast, X-ray absorption, fluorescence, and diffraction, to yield chemical, elemental, and structural information about the sample. Scanning microscopy on the basis of various lens systems in synchrotron radiation sources provides a routine spatial resolution of now about 100 nanometer but in the foreseeable future a 10-20 nanometer spatial resolution can be expected. X-ray absorption spectrometry can also provide chemical (speciation) information on the sample. All this makes X-ray microscopy attractive to many fields of science. In this paper the techniques are briefly reviewed and a number of applications in the earth, planetary and cosmos sciences are illustrated with state-of-the art examples, while applications in the environmental sciences and biology are also briefly discussed.

X-ray Absorption Spectroscopy Reveals Mechanisms of Calcium and Silicon Fouling on Reverse Osmosis Membranes Used in Wastewater Reclamation

“…Two-dimensional X-ray fluorescence (μ-XRF) maps were collected at beamline 14–3 at the Stanford Synchrotron Radiation Lightsource (SSRL). μ-XRF exhibits several characteristics that make it well-suited for investigation of fouling layer composition that complement commonly used elemental-mapping methods, such as SEM–EDS: (1) it has a low detection limit (on the order of fg/μm 2 ) . (2) Signal can be obtained from the entire depth of the fouling layer as the penetration depth ranges from ∼5 to 15 μm for Si fluorescence and ∼15 to 100 μm for Ca fluorescence (dense materials, like calcite, result in the shorter penetration depths; light materials, like polysulfone or OM, result in the longer penetration depths).…”

The value of synchrotron radiation X‐ray techniques to explore microscale chemistry for ecology and evolution research

“…Finally, we demonstrate how SR techniques can be integrated into future ecological and environmental research by analyzing the integral role that synchrotron X‐ray techniques, and their differing associated sample preparation routes, may have on the success or challenges documented by previous example studies with biological specimens. While the application of SR techniques within aspects of environmental science and geoscience research has been previously reviewed (Adams, 2010; Burke et al, 2015; Kopittke et al, 2018; Lombi & Susini, 2009; Majumdar et al, 2012), there still remains a clear knowledge gap surrounding the potential applications of SR X‐ray techniques within the ecological, evolutionary, and zoology research communities. This synthesis will uncover the existing trends observed in current analyses performed by SR X‐ray users within these underrepresented communities, alongside highlighting opportunities and future directions where new users could add value within ecological and evolutionary science.…”

Qualitative and Semiquantitative Determination of the Atomic and Molecular Tungsten Distributions in Hybrid Hydroxyurethanes–Poly(dimethylsiloxane) Films Containing Phosphotungstates ([PW12O40]3–)

“…Synchrotron radiation (generated in storage rings from high energetic electrons) is a very intense source of X-rays. 22 Synchrotron has a much higher brilliance (number of photons emitted/energy interval/second)/(unit of solid angle 5 (unit of size source) than produced by laboratory-based sources (X-ray tubes); therefore, they are more suitable for producing microbeams. Indeed, in the last four decades, there has been an increase in the brilliance of synchrotron radiation to conventional sources by a factor of 10 14 , resulting in intensities 10 4 –10 5 times greater than the intensities produced in laboratory spectrometers.…”

“…For SR-mXRF, an important property is the high degree of polarization of synchrotron radiation, which improves the signal-to-noise ratio significantly and the sensitivity is improved by orders of magnitude. 19,22 Synchrotron radiation-assisted spectroscopy include regions range from infrared to X-rays, covering energies from some eV to dozens of KeV, respectively. This spectroscopy constitutes one of the most powerful tools in experiments involving imaging or microscopy in physics, biology, medicine, nanotechnology, catalysis, among others.…”