A versatile liquid-jet/sessile droplet system for operando studies of reactions in liquid dispersions and solutions by X-ray absorption spectroscopy

Abstract

X-ray absorption spectroscopy for operando studies of liquid dispersions and solutions.

X-ray Absorption Spectroscopy as a Process Analytical Technology: Reaction Studies for the Manufacture of Sulfonate-Stabilized Calcium Carbonate Particles

“…The continuous-flow liquid-jet PAT system (Figure 2) integrates the previously described liquid-jet cell in a scaled-down industrial process in a 1 L baffled reactor (Figure 3). 18 The baffled reactor contained a polyphasic dispersion in which the overbasing synthesis process took place (details in Section 2.1). To monitor the chemical state changes of calcium during the overbasing process with XAS in real time with minimal disruption to the synthesis, a sampling loop via the liquid-jet cell was introduced into the baffled reactor (Figure 2).…”

“…We have recently shown how windowless liquid-jet monitoring of suspensions and viscous fluids with a fast flow loop constructed from widely available standard components overcomes these limitations elegantly. 18 We have now used this setup to monitor process chemistry, investigating a scaled-down version of a complex industrial manufacturing process for the synthesis of sulfonate-stabilized calcium carbonate particles (nCaCO 3 •mCa(R−SO 3 ) 2 ) . 19−21 Our study highlights the sensitivity of XAS to the structure of the calcium-containing materials in dilute dispersions, which becomes evident through the operando X-ray absorption nearedge structure (XANES) in the spectra.…”

Droplet-based in situ X-ray absorption spectroscopy cell for studying crystallization processes at the tender X-ray energy range

“…In standard liquid cells, this is oen challenging due to sedimentation of the precipitates at the onset of nucleation resulting in Liquid-jet congurations are attractive alternatives that do not suffer from drawbacks associated with windows; however, they require large sample volumes and are susceptible to clogging due to precipitation in the feeding tubes. 34,54 Compared to other droplet-based methods, the main advantage of this cell is that it is simple to use and can be implemented for standard XAS measurements. While aerodynamic levitation offers a windowless and substrate-free technique of elucidating crystallization processes, it is a highly specialized technique, which requires immense effort to generate and stabilize the droplet hence it is still not feasible as a standard XAS technique.…”

“…55,56 The sessile droplet on the other hand is also challenging to stabilize in vacuum and difficult to set the thermodynamic conditions in the droplet because it is in contact with a solution in the syringe. 54 The cell is limited to reactions that are controllable via the gas phase because the mixing of different liquids in situ is not yet feasible. Continuous refreshing of sample is also not possible, hence beam induced damage on the sample can occur.…”

Soft x-ray spectroscopies in liquids and at solid–liquid interface at BACH beamline at Elettra

“…Several in situ cells have been recently designed for various synchrotron-based X-ray techniques, such as X-ray diffraction (XRD) 3,4 scanning/transmission X-ray microscopy (STXM/TXM) 5,6 , Xray spectroscopies (absorption and photoemission) in the hard X-ray range 7,8 and in the soft X-ray energy range. 9,10,11,12 Among the X-ray spectroscopic techniques, EUV and soft X-ray spectroscopies(SXS) are characterized by intrinsic surface sensitivity which allows studying physical and chemical processes occurring at the material surfaces and interfaces.…”