Laser induced breakdown detection for the assessment of colloid mediated radionuclide migration

Walther, Clemens; Bitea, C.; Haüser, Winfried; Kim, J.I.; Scherbaum, Franz

doi:10.1016/s0168-583x(02)01128-x

Cited by 51 publications

(28 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A dielectric breakdown is produced in the focus region of a pulsed laser beam (Nd: YAG-laser, Frequency: 15 Hz, Wavelength: 532 nm). In the so-called s-curve LIBD or acoustic LIBD the laser pulse energy is varied (Walther et al, 2002(Walther et al, , 2006. The laser pulse energy where the first breakdowns of the colloids can be detected is called breakdown threshold.…”

Section: Asymmetric Flow Field-flow Fractionationmentioning

confidence: 99%

Radionuclide desorption kinetics on synthetic Zn/Ni-labeled montmorillonite nanoparticles

Huber

Heck

Truche

et al. 2015

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

International audienceSorption/desorption kinetics for selected radionuclides (Tc-99(VII), Th-232(IV), U-233(VI), Np-237(V), Pu-242 and Am-243(III)) under Grimsel (Switzerland) ground water conditions (pH 9.7 and ionic strength of similar to 1mM) in the presence of synthetic Zn or Ni containing montmorillonite nanoparticles and granodiorite fracture filling material (FFM) from Grimsel were examined in batch studies. The structurally bound Zn or Ni in the octahedral sheet of the synthetic colloids rendered them suitable as colloid markers. Only a weak interaction of the montmorillonite colloids with the fracture filling material occurs over the experimental duration of 10,000 h (similar to 13 months). The tri- and tetravalent radionuclides are initially strongly associated with nanoparticles in contrast to Tc-99(VII), U-233(VI) and Np-237(V) which showed no sorption to the montmorillonite colloids. Radionuclide desorption of the nanoparticles followed by sorption to the fracture filling material is observed for Th-232(IV), Pu-242 and Am-243(III). Based on the conceptual model that the driving force for the kinetically controlled radionuclide desorption from nanoparticles and subsequent association to the FFM is the excess in surface area offered by the FFM, the observed desorption kinetics are related to the colloid/FFM surface area ratio. The observed decrease in concentration of the redox sensitive elements Tc-99(VII), U-233(VI) and Np-237(V) may be explained by reduction to lower oxidation states in line with Eh-pH conditions prevailing in the experiments and thermodynamic considerations leading to (i) precipitation of a sparingly soluble phase, (ii) sorption to the fracture filling material, (iii) possible formation of eigencolloids and/or (iv) sorption to the montmorillonite colloids. Subsequent to the sorption/ desorption kinetics study, an additional experiment was conducted investigating the potential remobilization of radionuclides/ colloids attached to the FFM used in the sorption/desorption kinetic experiments by contacting this FFM with pure Grimsel groundwater for 7 days. A positive correlation of Pu-242, Th-232(IV) and Np-237 was observed with the Zn and Ni concentrations in the desorption experiments indicating a remobilization of sorbed montmorillonite colloids. The results of the study in hand highlight (i) the novel use of structural labeled colloids to decrease the uncertainties in the determination of nanoparticle attachment providing more confidence in the derived radionuclide desorption rates. Moreover, the data illustrate (ii) the importance of radionuclide colloid desorption to be considered in the analysis and application of colloid facilitated transport both in laboratory or in-situ experiments and numerical model simulations and (iii) a possible remobilization of sorbed colloids and associated radionuclides by desorption from the matrix material (FFM) under non-equilibrium conditions

show abstract

Section: Asymmetric Flow Field-flow Fractionationmentioning

confidence: 99%

Radionuclide desorption kinetics on synthetic Zn/Ni-labeled montmorillonite nanoparticles

Huber

Heck

Truche

et al. 2015

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

show abstract

“…Increasing evidence suggests that colloidal nanoparticles play a significant role in the transport and migration of radioactive contaminants and toxic heavy metals in the subsurface environments [1][2][3][4][5][6][7]. Development of sensitive techniques that provide information about the chemical composition, particle size distribution, bonding and structures of the metal ions are critical for any thermodynamic and reactive transport modeling as well as the development of remediation strategies for these contaminants.…”

Section: Introductionmentioning

confidence: 99%

Observation of aqueous Cm(III)/Eu(III) and UO22+ nanoparticulates at concentrations approaching solubility limit by laser-induced fluorescence spectroscopy

Wang

Felmy

Xia

et al. 2006

Journal of Alloys and Compounds

View full text Add to dashboard Cite

“…Suspended particles are normally present in natural waters and they decrease the breakdown threshold [12]. This also alters the plasma shape and its parameters, and must be taken into account for in situ LIBS analysis.…”

Section: Analysis Of Bulk Liquidsmentioning

confidence: 99%

“…Among the application of LIBS on a liquid surface there are: rapid analysis of the pharmaceutical formulation [6] and water contamination [7,8]; studies for medicine [9], and chemical analysis of very limited sample volumes [10,11], particularly important for bio-medical and forensic applications. LIBS measurements of bulk liquids might be employed for in situ detection of leakages in industrial and power plants [1,12,13], other kinds of water contamination [14,15], geothermal winds in deep oceans [16], and direct analysis of liquids inside transparent containers [6]. Detection of submerged materials could be exploited also for feedback control in laser surgery [17], usually performed with liquid coverage, then for recognition of underwater building materials and archeological objects [18,19], and determination of recent pollution and bioactivity in waters [20].…”

mentioning

confidence: 99%

LIBS Analysis of Liquids and of Materials Inside Liquids

Lazic

2014

Springer Series in Optical Sciences

View full text Add to dashboard Cite

Abbreviations and Symbols CILaser induced plasma formation on or inside liquids is characterized by large energy losses due to liquid evaporation. Ablation of a liquid surface is followed by hydro-dynamical instabilities and splashing. Plasma generation inside bulk liquids is affected by the light absorption and scattering, and it is accompanied by intense pressure waves and successive vapor cavitation. Efficient LIBS analyses in presence of liquids require different considerations; the examples are reported and discussed in following. IntroductionLaser induced plasma formation has the irradiance threshold dependent on the sample density, and generally it progressively reduces when passing from gases, to liquids and then to solids. Excluding the losses along the beam path, this means that less laser energy is required for ablation of dry or submerged solid materials than for ablation of a liquid or for generating breakdown inside liquids. Plasma formation in presence of liquids is not efficient because a great portion of the laser energy is expended for the liquid vaporization; this strongly reduces the energy available for the plasma excitation. It has been estimated that about 75 % of the input radiation is consumed for vaporization during laser induced breakdown (LIB) inside water [1]. Furthermore, both water and organic solutions contain hydrogen, which contributes to a rapid thermalization and cooling of the formed plasma. Once the plasma is created in liquids, the high density and nearly incompressible medium strongly confines the plume; the corresponding effects on the plasma evolution and LIBS signal are recently reviewed [2]. Laser ablation (LA) of liquids by short, intense pulses is a complex process where the liquid surface is no longer in equilibrium with the surrounding vapor; this results in a very high net mass flux from the sample surface to the surrounding [3 and references therein]. The high mass flux increases the pressure at the target surface and so raises the boiling temperature. Once the normal boiling is established, the presence of volumetric energy densities slightly higher than that equivalent to the saturation temperature causes the formation and growth of a vapor bubble. If the deposition rate of volumetric energy density by a laser pulse exceeds the energy consumed by vaporization, the liquid is driven to a metastable state until the spinoidal temperature is reached. At this temperature, the liquid undergoes so called ''spinoidal decomposition'' where the entire superheated liquid volume separates into saturated liquid and vapor, which are ejected into atmosphere. This process occurs normally during LIBS sampling of a liquid surface. In case of water ablation it has been estimated that less than 50 % of the deposited energy transforms into vapor while the remaining part is consumed for ejection of droplets [3]. The energy loss on droplet expulsion i.e. splashing further degrades the LIBS signal.LIBS measurements are often performed on water solutions or inside the same. Laser intera...

show abstract

Laser induced breakdown detection for the assessment of colloid mediated radionuclide migration

Cited by 51 publications

References 21 publications

Radionuclide desorption kinetics on synthetic Zn/Ni-labeled montmorillonite nanoparticles

Radionuclide desorption kinetics on synthetic Zn/Ni-labeled montmorillonite nanoparticles

Observation of aqueous Cm(III)/Eu(III) and UO22+ nanoparticulates at concentrations approaching solubility limit by laser-induced fluorescence spectroscopy

LIBS Analysis of Liquids and of Materials Inside Liquids

Contact Info

Product

Resources

About