Sorption of radionuclides onto clay minerals and soils.

by John Kam Keung Chow

Publisher: University of Salford in Salford

Written in English
Published: Downloads: 785
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Edition Notes

PhD thesis, Chemistry.

ID Numbers
Open LibraryOL20310577M

Contaminant−soil interaction studies have indicated that physical conformation of organic matter at the solid−aqueous interface is important in governing hydrophobic organic compound (HOC) sorption. To test this, organo-clay complexes were constructed by coating montmorillonite and kaolinite with peat humic acid (PHA) in Na+ or Ca2+ dominated solutions with varying pH and ionic strength. Cesium adsorption on the clay minerals vermiculite and montmorillonite is described as a function of surface coverage using extended X-ray adsorption fine structure spectroscopy (EXAFS). Cesium (Cs) possessed a variable coordination environment consisting of Cs−O distances between and Å; however, disorder typical of the Cs coordination environments prevented the resolution of all. The steady state of Nb sorption was observed in the mineral soil samples already after one week of equilibration, and sorption decreased with depth from a very high value of mL/g at m.   Sorption of Sr on five Slovak bentonites of deposits has been studied with the use of batch technique. In the experiments there have been used natural, chemically modified and irradiated samples, in three different kinds of grain size. The pH influence on sorption of strontium on bentonites, pH change after sorption and influence of competitive ions have been studied.

In particular, a relationship between metal sorption sites, iron bearing minerals, and pore-space distribution can be derived to help evaluate the mechanisms of sorption processes. Sorption onto clays and iron oxyhydroxide phases is an important process in the retardation of certain solutes in the subsurface environment (Jenne, ). Clay mineral - Clay mineral - Chemical and physical properties: Depending on deficiency in the positive or negative charge balance (locally or overall) of mineral structures, clay minerals are able to adsorb certain cations and anions and retain them around the outside of the structural unit in an exchangeable state, generally without affecting the basic silicate structure. Prediction of fate and behavior of radionuclides in the environment is largely governed by sorption processes. Radionuclides physico-chemical species interacting with prevailing abiotic properties of the environment vary widely among varying constituting environmental components. Herein, this work discussed the most significant aspects of sorption processes and properties at the solid-water. Abstract. Understanding sorption and desorption processes is essential to predicting the mobility of radionuclides in the environment. In this study, we investigate adsorption/desorption of cesium in both binary (Cs + one mineral) and ternary (Cs + two minerals) experiments to study component additivity and sorption reversibility over long time periods ( days).

During the past decade, the sorption of radiocaesium ions onto all kinds of minerals and oxides has been studied extensively (Kim et al. ; Kozaki et al. , ). Rectorite is an uncommon natural clay possessing regular inter-stratifications of di-octahedral mica and di-octahedral smectite layers. Studies of the sorption of metal. Results and discussion. The sorption behavior showed large differences between differently aged soils; Freundlich and linear sorption model fits (with sorption constants K f, 1/n exponents, and K d values, respectively) were given for pH = 3 and the unbuffered pH of ∼7. The largest extent of sorption from diluted solutions was found on the surfaces with a pre-incubation time of 3 months. @article{osti_, title = {Initial sorption of aromatic amines to surface soils}, author = {Lee, L S and Nyman, A K and Li, H and Nyman, M C and Jafvert, C}, abstractNote = {Sorption of aniline, {alpha}-naphthylamine, and benzidine to three silty clay loams was measured from CaCl{sub 2} electrolyte solutions in single and binary solute systems after a 1-d residence time.   The use of clay minerals for the decontamination of liquid radioactive waste generated during the work of nuclear energy enterprises remains currently relevant. The effect of the surface hydration of a montmorillonite nanocrystal on the adsorption of cesium and strontium ions from dilute solutions was studied. As opposed to the generally accepted mechanism of the adsorption of cesium .

Sorption of radionuclides onto clay minerals and soils. by John Kam Keung Chow Download PDF EPUB FB2

Clay minerals are ubiquitous in the environment as well as being the most important component of aerosol, soil, sediment, and bedrock.

Therefore, the sorption of radionuclides (RNs) at the clay mineral-water interface is one of the most important reactions controlling their geochemical behaviors, such as speciation, diffusion, migration, transportation, and bioavailability in the by: 3.

Sorption of Radionuclides onto Natural Clay Rocks: Authors: HARTMANN sorption overestimates experimental data for the natural rock. Complete sorption to natural clay rock and the synthetic clay/calcite mixture is observed for Eu(III) at pH > 7 for the conditions studied. (III). We conclude that the clay minerals in the multiphasic clay.

The study reveals that chemical constituents of the soil and their amount present in the soil also control the sorption of radionuclides. The study indicates that soil that has some clay minerals (montmorillonite) has comparatively higher distribution coefficient (K d) and attains dynamic equilibrium early compared to soil with lower clay Cited by: 1.

Desorption includes extraction of sorbed radionuclides from soil to water system giving The mobility of Cs in temperate soils is primarily controlled by sorption onto clay minerals. Abstract Time course and the processes in the sorption of cesium from dilute solutions by illite, Kinetics of Cesium Sorption by Clay Minerals Molecular Models of Radionuclide Interaction with Soil Minerals, Geochemistry of Soil Radionuclides, undefined, (), ().Cited by:   Sorption of heavy metals plays a vital role in controlling environmental pollution.

Here, we reviewed the sorption of heavy metals such as Ni, Co, Cu, Zn, V, Pb, Hg, In, As, Cd, Cr, Ga, Cs, Mn, V, Eu, Mo, Th, TI and Cr on metal oxides and clay minerals.

The mechanism of association between these ions and the host minerals, and the factors controlling their sorption are discussed in detail. Sorption of Heavy Metals on Clay Minerals and Oxides_A both natural and synthetic metal oxides and clay minerals for soil and water reme- The sorption of Zn onto hydrous Mn-oxide.

In this chapter the wide range of soil/sediment sorption data of organic contaminants as solutes or vapors is analyzed for consistency with conceptual models.

The chapter starts with the postulated roles of soil minerals (as an adsorbent) and soil organic matter (SOM) (as a partition medium), as deduced from extensive studies, and extends the.

Soil clay mineral and organic components have been shown to be responsible for sorption of many pesticides. This study assessed the influence of the different components of the clay fraction of five soils and model sorbents (montmorillonite, Fe oxide, and humic acid) and their binary and ternary associations on sorption of the insecticide imidacloprid (1‐[(6‐chloro‐3‐pyridinyl.

Violante A, Pigna M () Competitive sorption of arsenate and phosphate on different clay minerals and soils. Soil Sci Soc Am J – Google Scholar Violante A, Ricciardella M, Pigna M, Capasso R (a) Effects of organic ligands on the sorption of trace elements onto metal oxides and organo-mineral complexes.

Velde B, Meunier A () The origin of clay minerals in soils and weathered rocks. Springer, Berlin/Heidelberg, p CrossRef Google Scholar Verma PK, Semenkova AS, Krupskaya VV, Zakusin SV, Mohapatra PK, Romanchuk AY, Kalmykov SN () Eu(III) sorption onto various montmorillonites: experiments and modeling.

Siderophores are released by microorganisms to ensure their iron nutrition through the dissolution of iron(III) oxides. These compounds can also chelate divalent heavy metal ions and may therefore affect heavy metal sorption and mobility in soils.

Using model systems, we studied the influence of the hydroxamate siderophore desferrioxamine B (DFOB) on the adsorption of Cu, Zn, and Cd on Na. Sorption and fixation of microquantities of Cs by six minerals, as affected by the saturating cations, were studied.

Micas and vermiculite sorbed more Cs in the presence of Ca and similar divalent cations than in the presence of K and similar monovalent cations.

Experimental results indicate that hydrophobic sorption onto oven-dry clay minerals with negligible soil organic matter is controlled by rates of inter-particle Fickian diffusion mechanisms, intra-particle Fickian diffusion mechanisms, and sorption kinetics.

Using an analytical solution to Fick's Second Law where sorption is partitioned into. All C i values calculated from Fig. 2 were greater than 0, with the exception of PFOS sorption onto JS soil in stage 1. It suggests that more than one mechanism are involved in the sorption of PFOS sorption, e.g., film diffusion.

In other words, both film diffusion and intraparticle diffusion are the rate-limiting steps in PFOS sorption onto. The partition coefficient of radiocesium sorbed on soil showed the following order: Cl soil ≫ Kt soil > Tml soil > Lt soil. It was due to clay minerals. The second-order kinetic model was applied to the Cs and Sr sorption data.

The rate constant of Cs or Sr sorption on the four soils was substantiality increased with increasing temperature. Sorption–adsorption of pesticides was affected by a number of soil properties including organic matter, pH, clay minerals and soil texture.

Show abstract Sorption and desorption of the herbicide prometryne in two types of soil subjected to the changes of pH and soil.

In this study, the effects of Mn 2+ on Cd 2+ sorption to two types of clay minerals, a well-crystalline natural kaolinite (KGa-1b) and a synthetic montmorillonite (Syn-1), were investigated. Batch experiments on Mn 2+ and Cd 2+ sorption to Ca-saturated KGa-1b and Syn-1.

[16], soil [17], nickel ferrocyanide [18], and hydrous silica [19], granite [20]. In the scope of this study, the sorption behaviour of Cs. ion on some natural clay minerals and zeolite from Turkey were investigated.

The effet of shaking time, concentration, and the temperature on sorption were investigated. Iso. Preloading Cs and Pb on Clay Minerals After the Cs and Pb sorption maxima on kaolinite and illite were determined, the clay minerals were preloaded with Cs at targets of 5, 20, and percent of their sorption plateaus.

For Cs modification, 20 g of clay minerals and mL of. Soil microorganisms have reportedly played role in determining the sorption of radionuclides within organic soil systems (Parekh et al., ) and biotransformation of alcohol in soil (Liu et al.

portant for the sorption of radionuclides are minerals such as smectite, illite, vermiculite, chlorite, allophone and imogolite as well as the oxides and hydroxides of silica, aluminium, iron and manganese. The adsorption is due to the charge at the surface of these soil constituents and the three-dimensional structure of the adsorbing mineral.

Sorption interactions with montmorillonite and other clay minerals in soils, sediments, and radionuclides from the repository (e.g., Grauer, ). For these reasons, a quantitative 1. knowledge of radionuclide sorption onto clay minerals is desirable.

A convenient representation of sorption data is the distribution coefficient, KD, which. For example, fallout radionuclides are preferentially bound to clay minerals owing to the higher number of potential sorption sites (Fan et al., ; Lomenick and Tamura, ;Tamura, First published on 6th May In submerged soils and sediments, clay minerals are often exposed to anoxic waters containing ferrous iron (Fe 2+).Here, we investigated the sorption of Fe 2+ onto a synthetic montmorillonite (Syn-1) low in structural Fe.

ILLINOISSTATEGEOLOGICALSURVEY • ° a x TimeinMinutes FigWater-sorptioncurvesforsamplesofvariousweights. TestMethod. Prediction of the behavior of soils of arbitrary composition may also be achieved through studying sorption and desorption behavior of these clay minerals (Covelo et al., a).

The clay buffer capacity and by extension, the initial pH play an importance role in the mobility of the heavy metals in the clay. In order to select appropriate amendments for cropping hyperaccumulator or normal plants on contaminated soils and establish the relationship between Cd sorption characteristics of soil amendments and their capacity to reduce Cd uptake by plants, batch sorption experiments with 11 different clay minerals and organic materials and a pot experiment with the same amendments were.

Clay minerals (montmorillonite, vermiculite) are layered aluminosilicates, in which ion-exchange is typically associated with cations situated in clay mineral interlayers. The stabilization of Cs + and Sr 2+ contamination in the sandy soils was tested using different synthetic and natural zeolites [ 91 ].

monovalent and divalent metallic cations onto clay minerals. In particular, the report focuses on the sorption of Cs' and Sr".

The results of these simulations give insights into the basic mechanisms controlling metal sorption onto common soil components such as clay minerals. The information on mechanisms controlling sorption reported here.

Batch experiments were conducted to study the sorption of uranium (U) onto soil in deionised water as a function of its dosage, temperature and humic acid (HA).

Furthermore, soils were characterized for particle sizes in the form of sand (>63 µm), silt (>2–clay (soils were admixture of mainly sand and silt along with a small.

The subject of this chapter is soil chemistry. The chapter is entitled Processes and Factors Affecting Phosphorus (P) Adsorption in Soils.

The chapter aims to give an overview of the major mechanisms responsible for phosphate sorption (i.e., adsorption and absorption of phosphate) in soils, particularly of acid soils. According to studies conducted by some soil scientists, the major soil.Furthermore, the relatively higher sorption of U onto soil might be also affected by high abundances of finer particles in the form of clays.

Results also indicated that sorption is strongly dependent on kind of clay minerals, temperature and presence of HA. The thermodynamic data suggested that the sorption reaction is spontaneous and endothermic.