Accelerated fractionation of heavy metals in contaminated soils and sediments using rotating coiled columns

Fedotov, Petr S.; Заварзина, А. Г.; Spivakov, B. Ya.; Wennrich, Rainer; Mattusch, Jürgen; Titze, K. de P. C.; Демин, В. В.

doi:10.1039/b111263e

Cited by 58 publications

(49 citation statements)

References 25 publications

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“…(1) When L < 0, particles in the rotating column move against the carrier liquid flow, hence (12) or (13) (2) When L = 0, particles are retained in the flow (14) (3) When L > 0, particles move in the column along the carrier liquid flow (15) It may be supposed that, during the quasistationary motion of a particle in the direction of the carrier liquid flow, the tangential centrifugal force is balanced by the force of resistance to the particle motion; hence, F t ≈ F g . Then, with regard to (4) and (5), we have (16) Thus, the velocity of particle motion along the column wall with respect to the carrier liquid flow (v rel ) is proportional to the squared particle radius.…”

Section: Assessment Of Different Modes Of Particle Motionmentioning

confidence: 99%

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Simulation of the motion of solid particles in the carrier liquid flow in a rotating coiled column

2005

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Rotating coiled columns have been successfully used in countercurrent chromatography (CCC) for several decades [1][2][3]. The main distinction of CCC from other chromatographic techniques is the absence of a solid carrier. A liquid stationary phase is retained in a coiled separation column by the field of centrifugal forces due to the rotation of the column around its axis and its revolution around the central axis of the device; a mobile liquid phase is continuously pumped through the column [1].Different devices with the synchronous and asynchronous rotation of the column were proposed [4,5]. The best choice is planet centrifuge. The column module can rotate in the same direction as it revolves around the central axis (mode J, according to Ito [5]) and in the opposite direction (mode I), depending on the kinematic scheme of planetary transmission. In CCC, mode J (the axes of rotation and revolution are parallel; the speeds and directions of rotation and revolution coincide) has found wide application; it provides intensive mixing of the two phases and a stable retention of the stationary phase. An asymmetric distribution of the centrifugal force vectors in each column coil is typical for mode J (as opposed to mode I; which does not involve such a force field) [5].The hydrodynamic behavior of two-phase liquid systems in a rotating column is very complex. A number of hypotheses have been proposed to explain the retention of the stationary phase in the column, and plausible mechanisms for the mixing of two phases have been considered [6][7][8][9][10][11][12]. However, many problems remain unsolved.In spite of problems arising in the development of the theoretical fundamentals of CCC, the scope of the application of rotating coiled columns is expanding steadily. It has been shown that coiled columns are suitable not only for the separation of solutes in liquid-liquid, liquid-solid [13,14], and liquid-solid-liquid systems [15], but also for particle fractionation [16,17]. In the last case, there is no liquid phase at all. The force field in which colloidal and solid particles occur is responsible for the difference in the migration velocities of mixture components along the column in the mobile phase (carrier liquid) flow.Note that particle fractionation is necessary to solve problems related to the determination of impurity speciation of natural waters and other environmental materials, because toxic organic compounds and trace elements occur in ecosystems not only as ions and dissolved low-molecular compounds, but they can also be bound to macromolecules (including humic substances) and colloidal and solid particles.Rotating columns used for field-flow fractionation in a transverse centrifugal field can offer some advantages. The planet centrifuge involves no rotary joints; restrictions are therefore not imposed on the pressure in the system. Restrictions for the weight of sample particles are also removed, because column volume can be varied by varying the number of coils and their layers. In addition, the asymme...

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Section: Assessment Of Different Modes Of Particle Motionmentioning

confidence: 99%

“…It has been shown that coiled columns are suitable not only for the separation of solutes in liquid-liquid, liquid-solid [13,14], and liquid-solid-liquid systems [15], but also for particle fractionation [16,17]. In the last case, there is no liquid phase at all.…”

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Simulation of the motion of solid particles in the carrier liquid flow in a rotating coiled column

2005

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“…A new effective method for the direct recovery of toxic organic substances (polycyclic aromatic hydrocarbons, PAHs) from liquid sewage sludge [134] and soil [135] has been proposed. A new continuous-flow method has been also developed that enables not only the fast and efficient fractionation of TE species in soils and sediments to be achieved but allows time-resolved (kinetic) studies on the mobilization of trace and major elements in different forms to be made [136][137][138]. The method is time-saving and requires only 4-5 h instead of the several days needed for routine sequential extraction (traditionally used for the fractionation of TEs to assess their mobility and potential bioavailability).…”

Section: Other Applications Of Hydrodynamic CCC Columnsmentioning

confidence: 99%

Countercurrent chromatography in analytical chemistry (IUPAC Technical Report)

Berthod

Maryutina

Spivakov

et al. 2009

Pure and Applied Chemistry

137

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Countercurrent chromatography (CCC) is a generic term covering all forms of liquid-liquid chromatography that use a support-free liquid stationary phase held in place by a simple centrifugal or complex centrifugal force field. Biphasic liquid systems are used with one liquid phase being the stationary phase and the other being the mobile phase. Although initiated almost 30 years ago, CCC lacked reliable columns. This is changing now, and the newly designed centrifuges appearing on the market make excellent CCC columns. This review focuses on the advantages of a liquid stationary phase and addresses the chromatographic theory of CCC. The main difference with classical liquid chromatography (LC) is the variable volume of the stationary phase. There are mainly two different ways to obtain a liquid stationary phase using centrifugal forces, the hydrostatic way and the hydrodynamic way. These two kinds of CCC columns are described and compared. The reported applications of CCC in analytical chemistry and comparison with other separation and enrichment methods show that the technique can be successfully used in the analysis of plants and other natural products, for the separation of biochemicals and pharmaceuticals, for the separation of alkaloids from medical herbs, in food analysis, etc. On the basis of the studies of the last two decades, recommendations are also given for the application of CCC in trace inorganic analysis and in radioanalytical chemistry.

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“…The main assets of dynamic fractionation are as follows: (1) accurate monitoring of the ongoing leaching of trace and major elements; (2) simplification of the overall procedure (from days to hours); (3) minimization of risks of sample contamination and straightforward manipulation of leaching agents; and (4) evaluation of the efficiency and selectivity of the extractants as well as the maximum pool of available fractions [9]. Among the dynamic approaches suited for the fractionation of trace elements in environmental substrates, the so-called rotating coiled column (RCC) extraction [10], microcolumn (MC) extraction [11][12][13], and stirred flow cell extraction [14,15] should be mentioned. In RCC, the particulate sample (usually 500 mg) is retained by centrifugal forces, whereas different eluents are continuously pumped through.…”

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confidence: 99%

Fractionation of Sb and As in soil and sludge samples using different continuous-flow extraction techniques

2012

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The fractionation of Sb and As in soil and sludge samples had been comparably studied using two continuous-flow systems: a microcolumn (MC) and a rotating coiled column (RCC). The leachants were applied in correspondence with a five-step sequential extraction scheme addressing water-soluble, non-specifically sorbed, specifically sorbed, and bound to amorphous and crystalline Fe/Al oxide fractions of Sb and As. Inductively coupled plasma atomic emission spectroscopy was applied to determine antimony, arsenic, and major elements in the effluent and in the residual fractions after their digestion. Resemblances and discrepancies of the two methods were evaluated by the fractionation of Sb and As in forest soil, river sludge, and dumped waste (soil) samples. For the forest soil sample, which is very poor in organic matter, RCC and MC extractions yielded similar quantitative values of As and Sb contents in individual leachable fractions. However, for the river sludge sample with a moderate concentration of C (org) (3.3 %), the results obtained by both continuous-flow methods are in satisfactory agreement. RCC extraction enabled water-soluble and non-specifically sorbed As fractions to be recovered, whereas after MC leaching, these environmentally relevant forms of As were not detected. For the soil rich in organic matter (C(org) = 11.5 %), the discrepancy between the data of RCC and MC fractionations is significant. RCC extraction provides about six times higher recoveries of As and Sb bound to amorphous Fe/Al oxides. More efficient leaching of As and Sb in RCC may be attributed to the migration of organic-rich particles with low density inside the column that might enhance the mixing of the solid and liquid phases.

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Accelerated fractionation of heavy metals in contaminated soils and sediments using rotating coiled columns

Cited by 58 publications

References 25 publications

Simulation of the motion of solid particles in the carrier liquid flow in a rotating coiled column

Simulation of the motion of solid particles in the carrier liquid flow in a rotating coiled column

Countercurrent chromatography in analytical chemistry (IUPAC Technical Report)

Fractionation of Sb and As in soil and sludge samples using different continuous-flow extraction techniques

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