Colloidal Particles at Solid–Liquid Interfaces: Mechanisms of Desorption Kinetics

Weiß, Michael; Lüthi, Yves; Rička, J.; Jörg, Thomas; Bebie, Hans

doi:10.1006/jcis.1998.5636

Cited by 22 publications

(21 citation statements)

References 31 publications

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“…If the desorption rate constant had decreased significantly with each pass (i.e., a higher recovery of Am with each pass), then it would be logical to conclude that Am adsorbed to different types of colloid sorption sites with different effective desorption rate constants. Alternatively, an aging process might be implicated in which Am that is adsorbed to colloids for longer times tends to become more strongly associated with the colloids and thus desorbs more slowly with time (Weiss et al, 1998). The fast desorption process observed also supports the chemical modeling described in Section 2.4, which indicates that under our experimental conditions Am is adsorbed and not precipitated on the surface of the colloids due to oversaturation or chemical instability.…”

Section: Discussionsupporting

confidence: 85%

Laboratory investigation of the role of desorption kinetics on americium transport associated with bentonite colloids

Dittrich

Boukhalfa

Ware

et al. 2015

Journal of Environmental Radioactivity

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Understanding the parameters that control colloid-mediated transport of radionuclides is important for the safe disposal of used nuclear fuel. We report an experimental and reactive transport modeling examination of americium transport in a groundwater-bentonite-fracture fill material system. A series of batch sorption and column transport experiments were conducted to determine the role of desorption kinetics from bentonite colloids in the transport of americium through fracture materials. We used fracture fill material from a shear zone in altered granodiorite collected from the Grimsel Test Site (GTS) in Switzerland and colloidal suspensions generated from FEBEX bentonite, a potential repository backfill material. The colloidal suspension (100 mg L(-1)) was prepared in synthetic groundwater that matched the natural water chemistry at GTS and was spiked with 5.5 × 10(-10) M (241)Am. Batch characterizations indicated that 97% of the americium in the stock suspension was adsorbed to the colloids. Breakthrough experiments conducted by injecting the americium colloidal suspension through three identical columns in series, each with mean residence times of 6 h, show that more than 95% of the bentonite colloids were transported through each of the columns, with modeled colloid filtration rates (k(f)) of 0.01-0.02 h(-1). Am recoveries in each column were 55-60%, and Am desorption rate constants from the colloids, determined from 1-D transport modeling, were 0.96, 0.98, and 0.91 h(-1) in the three columns, respectively. The consistency in Am recoveries and desorption rate constants in each column indicates that the Am was not associated with binding sites of widely-varying strengths on the colloids, as one binding site with fast kinetics represented the system accurately for all three sequential columns. Our data suggest that colloid-mediated transport of Am in a bentonite-fracture fill material system is unlikely to result in transport over long distance scales because of the ability of the fracture materials to rapidly strip Am from the bentonite colloids and the apparent lack of a strong binding site that would keep a fraction of the Am strongly-associated with the colloids.

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Section: Discussionsupporting

confidence: 85%

Laboratory investigation of the role of desorption kinetics on americium transport associated with bentonite colloids

Dittrich

Boukhalfa

Ware

et al. 2015

Journal of Environmental Radioactivity

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“…30 On the other hand, in the case of larger and rigid particles, only surface properties will control the adsorption behavior. 31 In this sense, dendrimers are between particles and polyelectrolytes. ( 1 -r 1 r 1 t 1 2 -r 1 2 )…”

Section: Discussionmentioning

confidence: 99%

Adsorption of Poly(propylene imine) Dendrimers on Glass. An Interplay between Surface and Particle Properties

2000

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The adsorption behavior of positively charged poly(propylene imine) dendrimers on glass has been studied by scanning angle reflectometry as a function of generation, pH, and ionic strength. The results indicate that the adsorption is controlled by properties of both the dendrimers (size and charge) and the surface layer (distribution of glass surface sites). At constant pH and ionic strength the collector properties remain the same, and the adsorption scales with dendrimer size. Because of the limited number of glass surface sites there is only 15% surface coverage at maximum. Adsorption increases with decreasing pH and increasing ionic strength, and the effect of pH is much more pronounced for the smaller dendrimers. To explain the adsorption results, not only the size and charge of the dendrimer have to be taken into account, but also the charge density and the roughness of the surface. This implies that the dendrimer size is comparable to the characteristic length scale of the surface roughness.

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“…Weiss et al [1998] observed that the resistance to desorption of latex particles from a glass surface increases with adhesion duration. They used a two parameter gamma distribution of the potential well depth at the binding sites to calculate the desorption rate distribution causing the observed adhesion time distribution.…”

Section: Majdalani Et Al: Mobilization and Preferential Transport Ofmentioning

confidence: 99%

Mobilization and preferential transport of soil particles during infiltration: A core‐scale modeling approach

Majdalani

Michel

Pietro

et al. 2007

Water Resources Research

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[1] Understanding particle movement in soils is a major concern for both geotechnics and soil physics with regard to environmental protection and water resources management. This paper describes a model for mobilization and preferential transport of soil particles through structured soils. The approach combines a kinematic-dispersive wave model for preferential water flow with a convective-dispersive equation subject to a source/sink term for particle transport and mobilization. Particle detachment from macropore walls is considered during both the steady and transient water flow regimes. It is assumed to follow first-order kinetics with a varying detachment efficiency, which depends on the history of the detachment process. Estimates of model parameters are obtained by comparing simulations with experimental particle breakthrough curves obtained during infiltrations through undisturbed soil columns. Both water flux and particle concentrations are satisfactorily simulated by the model. Particle mobilization parameters favoring both attachment and detachment of particles are related to the incoming solution ionic strength by a Fermi-type function.Citation: Majdalani, S., E. Michel, L. Di Pietro, R. Angulo-Jaramillo, and M. Rousseau (2007), Mobilization and preferential transport of soil particles during infiltration: A core-scale modeling approach, Water Resour. Res., 43, W05401,

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Colloidal Particles at Solid–Liquid Interfaces: Mechanisms of Desorption Kinetics

Cited by 22 publications

References 31 publications

Laboratory investigation of the role of desorption kinetics on americium transport associated with bentonite colloids

Laboratory investigation of the role of desorption kinetics on americium transport associated with bentonite colloids

Adsorption of Poly(propylene imine) Dendrimers on Glass. An Interplay between Surface and Particle Properties

Mobilization and preferential transport of soil particles during infiltration: A core‐scale modeling approach

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