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The association of chromium (Cr) with colloidal particles transport in contaminated sites can affect hexavalent chromium (Cr(VI)) migration and transformation, which is an important mechanism for Cr pollutants in soil and groundwater systems. Here, we investigated colloid and particle-bound Cr migration and transformation effects on rice Cr accumulation during different rice growth stages and different redox conditions in Cr(VI) contaminated soil by pot experiment. Results showed that 13–29% of soil Cr was water dispersible colloid-bound (100–1000 nm) form during rice growth. Using transmission electron microscopy - energy dispersion spectroscopy and asymmetric flow field - flow separation, we identified colloid-bound organic matter (OM) and iron (Fe), most likely in the form of Fe (hydr)oxides - clay composites, as the primary Cr carrier. Specifically, colloid-bound Cr was mainly associated with 125–350 nm soil particle size. Under different redox conditions, colloid- and nanoparticle-bound Cr concentration decreased with increasing nanoparticles zero-valent iron (nZVI) dose. Soil reoxidation promoted the colloid- and nanoparticle-bound Cr release due to the weakly crystalline Fe-(hydr)oxides reprecipitation. Further quantitative analysis showed that colloid-bound Cr concentrations were positively correlated with colloid-bound Mn concentrations during the whole rice growth soils. Most important of all, Cr content in rice grain was positively correlated with colloid-bound Cr significantly. This study provides a quantitative and size-resolved understanding of particle-bound Cr in paddy soils, highlighting the importance of colloid-bound Cr and Fe interactions in Cr geochemical cycle of paddy soil. [Display omitted] • 13–29% of Cr in soil solution was water dispersible colloid-bound (100–1000 nm) fraction during the rice growth. • Colloid-bound Cr was mainly distributed in 120–350 nm size determined by AF4. • Soil reoxidation promoted colloid-bound Cr release due to weakly crystalline Fe-(hydr)oxides reprecipitation. • Colloid-bound Cr were mainly carried by Fe (hydr)oxides, OM and clay minerals colloids. [ABSTRACT FROM AUTHOR]

The association of chromium (Cr) with colloidal particles transport in contaminated sites can affect hexavalent chromium (Cr(VI)) migration and transformation, which is an important mechanism for Cr pollutants in soil and groundwater systems. Here, we investigated colloid and particle-bound Cr migration and transformation effects on rice Cr accumulation during different rice growth stages and different redox conditions in Cr(VI) contaminated soil by pot experiment. Results showed that 13–29% of soil Cr was water dispersible colloid-bound (100–1000 nm) form during rice growth. Using transmission electron microscopy - energy dispersion spectroscopy and asymmetric flow field - flow separation, we identified colloid-bound organic matter (OM) and iron (Fe), most likely in the form of Fe (hydr)oxides - clay composites, as the primary Cr carrier. Specifically, colloid-bound Cr was mainly associated with 125–350 nm soil particle size. Under different redox conditions, colloid- and nanoparticle-bound Cr concentration decreased with increasing nanoparticles zero-valent iron (nZVI) dose. Soil reoxidation promoted the colloid- and nanoparticle-bound Cr release due to the weakly crystalline Fe-(hydr)oxides reprecipitation. Further quantitative analysis showed that colloid-bound Cr concentrations were positively correlated with colloid-bound Mn concentrations during the whole rice growth soils. Most important of all, Cr content in rice grain was positively correlated with colloid-bound Cr significantly. This study provides a quantitative and size-resolved understanding of particle-bound Cr in paddy soils, highlighting the importance of colloid-bound Cr and Fe interactions in Cr geochemical cycle of paddy soil. [Display omitted] • 13–29% of Cr in soil solution was water dispersible colloid-bound (100–1000 nm) fraction during the rice growth. • Colloid-bound Cr was mainly distributed in 120–350 nm size determined by AF4. • Soil reoxidation promoted colloid-bound Cr release due to weakly crystalline Fe-(hydr)oxides reprecipitation. • Colloid-bound Cr were mainly carried by Fe (hydr)oxides, OM and clay minerals colloids. [ABSTRACT FROM AUTHOR]

Epidemiological evidence has indicated a closely link between PM 0.1 exposure and the incidence rate of cardiovascular diseases. This study explores the underlying communication roles of platelet-derived extracellular vesicles (PEVs) heterogeneous subpopulations in cardiovascular injury. PEVs and PMEVs which were extracted from platelet-rich plasma (PRP) un-exposure or exposure to PM 0.1 by TIM4 affinity beads. By optimizing separation conditions, replacing pipelines, and resetting injection procedures, Asymmetric flow field-flow fractionation (AF4) was employed to separate, purify, characterize, and enrich PEVs and PMEVs heterogeneous subpopulations (small PEVs, PEVs-S/PMEVs-S: <100 nm; medium PEVs, PEVs-M/PMEVs-M: 100–200 nm; and large PEVs, PEVs-L/PMEVs-L: >200 nm). The results showed that the cargoes of PMEVs heterogeneous subpopulations which were released by PRP stimulated by PM 0.1 were changed obviously. Moreover, compared with PEVs, PMEVs can lead to a decrease in the survival rate of Human Umbilical Vein Endothelial Cells (HUVECs). In PMEVs-S subpopulations, the alterations of lipids associated with membrane fusion and cell signaling transport (such as PC, Cer), as well as miRNAs related to inflammation, angiogenesis, and migration (miR-223, miR-22, miR-126, and miR-150), are similar to those in PMEVs-M subpopulations but distinct from PMEVs-L subpopulations. This study revealed the diverse communication mechanisms underlying PM 0.1 -induced cardiovascular injury, thereby offering potential avenues for the development of new biomarkers and therapeutic targets. [Display omitted] • AF4 is a strong tool to isolate and enrich EVs heterogeneous subpopulations. • Exposure to PM 0.1 can cause changes in cargo of PEVs heterogeneous subpopulations. • Lipid and miRNA changes in PEVs are vital for PM 0.1 -induced cardiovascular injury. [ABSTRACT FROM AUTHOR]

The foundation of separation science is the division or deconvolution of a mixture into constituent parts. To do so greatly informs our understanding of complex systems. Equally important is consideration of the behavior of a mixture as a whole—to consider if the whole is the sum of the parts or if individual components interact synergistically or antagonistically when combined. Application of separation science has seldom assumed greater importance than in consideration of the controversy surrounding the traditional and emergent views of the complex chemical system of natural organic matter (NOM). Analyses of simulated and actual environmental water samples using noninvasive separation techniques including flow field‐flow fractionation (flow FFF), excitation–emission matrix (EEM) fluorescence spectroscopy with parallel factor (PARAFAC) analyses, and dynamic light scattering (DLS) are discussed. The data are used to explore whether a distinct chemical category of humic (diagenetic) substances exists in NOM; whether separation of organic matter into fulvic and humic extracts has relevant meaning translatable to actual environmental water samples; whether extraction procedures alter the chemistry of NOM extracts; and, if humic and fulvic acids exist, what physicochemical property or properties make humic substances unique among other forms of NOM. A fluorescence‐based nonoperational definition of humic substances is introduced. The underexplored role of supramolecular, self‐assembled aggregation is presented as a NOM conceptual model. Responses are provided to questions raised in the great NOM debate within a supramolecular context. Core Ideas: A new supramolecular conceptual model invokes strong near‐covalent hydrogen bonding.A nonoperational definition of diagenetic (humic) substances is proposed.Alkali extracts are valid, though imperfect, organic matter proxies.A mechanism for intrinsic chemical recalcitrance of natural organic matter exists.Protection is a "function" of the supramolecular "form." [ABSTRACT FROM AUTHOR]

The nanoscale size of plastic debris makes them potential efficient vectors of many pollutants and more especially of metals. In order to evaluate this ability, nanoplastics were produced from microplastics collected on a beach exposed to the North Atlantic Gyre. The nanoplastics were characterized using multi-dimensional methods: asymmetrical flow field flow fractionation and dynamic light scattering coupled to several detectors. Lead (II) adsorption kinetics, isotherm and pH-edge were then carried out. The sorption reached a steady state after around 200 min. The maximum sorption capacity varied between 97% and 78.5% for both tested Pb concentrations. Lead (II) adsorption kinetics is controlled by chemical reactions with the nanoplastics surface and to a lesser extent by intraparticle diffusion. Adsorption isotherm modeling using Freundlich model demonstrated that NPG are strong adsorbents equivalent to hydrous ferric oxides such as ferrihydrite (log K a d s f r e u n d l i c h = 8.36 against 11.76 for NPG and ferrihydrite, respectively). The adsorption is dependent upon pH, in response to the Pb(II) adsorption by the oxygenated binding sites developed on account of the surface UV oxidation under environmental conditions. They could be able to compete with Fe or humic colloids for Pb binding regards to their amount and specific areas. Nanoplastics could therefore be efficient vectors of Pb and probably of many other metals as well in the environment. Image 1 • Pb(II) binding experiments onto nanoplastics extracted from environmental micro-plastics were performed. • Pb(II) was largely bound onto nanoplastics by specific adsorption and intraparticle diffusion. • Nanoplastics could be significant vectors of metals in the environment. [ABSTRACT FROM AUTHOR]

This work present aims to evaluate the effect of a conventional wastewater treatment process on the number of nanoparticles, and the role of nanoparticles as a carrier of antibiotics. A set of methods based on asymmetrical flow field flow fractionation coupled with multi-angle light scattering to separate and quantify nanoparticles in real wastewater was established. The characterization of nanoparticles was conducted by transmission electron microscopy, energy dispersive spectrometer, UV–visible spectrophotometer and three-dimensional excitation-emission matrix fluorescence spectroscopy. The adsorption of different sizes of nanoparticles separated from the real wastewater for four targeted antibiotics (sulfadiazine, ofloxacin, tylosin and tetracycline) was studied. The results show that the number of nanoparticles were increased in the wastewater treatment process and the size range between 60 and 80 nm was predominant in wastewater samples. The nanoparticles were mainly composed of O, Si, Al and Ca elements and organic components were in the size range of 0–10 nm. Targeted antibiotics were dominantly adsorbed onto nanoparticles with 60–80 nm size range at each stage. The concentrations of tetracycline adsorbed on nanoparticles were surprisingly increased in the end of the treatment process, while ofloxacin and tylosin had the completely opposite phenomenon to tetracycline. The pH and ionic strength definitely affected the aggregation of nanoparticles and interaction with the antibiotics. It is of great significance to give insights into nanoparticle-antibiotic assemblages for the effective treatment and avoiding the water risks due to nanoparticles' ubiquitous and their risks of carrying antibiotics. Image 1 • Nanoparticle numbers were increased in a field-scale WWTP. • NPs composed by O, Si, Ca and Al, aromatic proteins and microbial by-products. • Targeted antibiotics were predominantly adsorbed on NPs within 60–80 nm size range. • Ionic strength, pH and DOM are the important factors of adsorption capacity of NPs for antibiotics. [ABSTRACT FROM AUTHOR]

Secondary micro(nano)plastics generated from the degradation of plastics pose a major threat to environmental and human health. Amid the growing research on microplastics to date, the detection of secondary micro(nano)plastics is hampered by inadequate analytical instrumentation in terms of accuracy, validation, and repeatability. Given that, the current review provides a critical evaluation of the research trends in instrumental methods developed so far for the qualitative and quantitative determination of micro(nano)plastics with an emphasis on the evolution, new trends, missing links, and future directions. We conducted a meta-analysis of the growing literature surveying over 800 journal articles published from 2004 to 2022 based on the Web of Science database. The significance of this review is associated with the proposed novel classification framework to identify three main research trends, viz. (i) preliminary investigations, (ii) current progression, and (iii) novel advances in sampling, characterization, and quantification targeting both micro- and nano-sized plastics. Field Flow Fractionation (FFF) and Hydrodynamic Chromatography (HDC) were found to be the latest techniques for sampling and extraction of microplastics. Fluorescent Molecular Rotor (FMR) and Thermal Desorption-Proton Transfer Reaction-Mass Spectrometry (TD-PTR-MS) were recognized as the modern developments in the identification and quantification of polymer units in micro(nano)plastics. Powerful imaging techniques, viz. Digital Holographic Imaging (DHI) and Fluorescence Lifetime Imaging Microscopy (FLIM) offered nanoscale analysis of the surface topography of nanoplastics. Machine learning provided fast and less labor-intensive analytical protocols for accurate classification of plastic types in environmental samples. Although the existing analytical methods are justifiable merely for microplastics, they are not fully standardized for nanoplastics. Future research needs to be more inclined towards secondary nanoplastics for their effective and selective analysis targeting a broad range of environmental and biological matrices. [Display omitted] • A new classification framework was established to assess overall research trends • FFF and HDC are the latest techniques for sampling and extraction of microplastics • FMR and TD-PTR-MS are modern advances for polymer analysis in micro(nano)plastics • Machine learning methods offer fast classification of secondary micro(nano)plastics • DHI and FLIM techniques provide a powerful imaging of the surface of nanoplastics [ABSTRACT FROM AUTHOR]

Nanocarriers that are used for targeted drug delivery come in contact with biological liquids and subsequently proteins will adsorb to the nanocarriers’ surface to form the so called ‘protein corona’. The protein corona defines the biological identity and determines the biological response towards the nanocarriers in the body. To make nanomedicine safe and reliable it is required to get a better insight into this protein corona and, therefore, the adsorbed proteins have to be characterized. Currently, centrifugation is the common method to isolate the protein corona for further investigations. However, with this method it is only possible to investigate the strongly bound proteins, also referred to as ‘hard protein corona’. Therefore, we want to introduce a new separation technique to separate nanoparticles including the soft protein corona containing also loosely bound proteins for further characterization. The used separation technique is the asymmetric flow field-flow fractionation (AF4). We were able to separate the nanoparticles with proteins forming the soft protein corona and were able to show that in our system only the hard protein corona directly influenced the cell uptake behavior. Statement of Significance Currently, there is an ongoing debate whether only strongly bound proteins (hard corona) or also loosely bound proteins (soft corona) contribute to the biological identity of nanocarriers, because up to now isolation of the soft corona was not possible. Here, asymmetric flow field-flow fractionation was used to isolate nanoparticles with a preserved soft corona from the biological medium. This enabled the characterization of the soft corona composition and to evaluate its influence on cellular uptake. For our system we found that only the strongly bound proteins (hard corona) determined cell internalization. This method can now be used to evaluate the impact of the soft corona further and to characterize nanomaterials that cannot be separated from blood plasma by other means. [ABSTRACT FROM AUTHOR]

Shaped film cooling holes have become a standard geometry for protecting gas turbine components. Few studies, however, have reported flowfield measurements for moderately expanded shaped holes and even fewer have reported on the effects of high freestream turbulence intensity relevant to gas turbine airfoils. This study presents detailed flowfield and adiabatic effectiveness measurements for a shaped hole at freestream turbulence intensities of 0.5% and 13%. Test conditions included blowing ratios of 1.5 and 3 at a density ratio of 1.5. Measured flowfields revealed a counter-rotating vortex pair (CRVP) and high jet penetration into the mainstream at the blowing ratio of 3. Elevated freestream turbulence had a minimal effect on mean velocities and rather acted by increasing turbulence intensity around the coolant jet, resulting in increased lateral spreading of coolant. [ABSTRACT FROM AUTHOR]

Due to the limited solubility of phosphorus (P) in soil, understanding its binding in fine colloids is vital to better forecast P dynamics and losses in agricultural systems. We hypothesized that water-dispersible P is present as nanoparticles and that iron (Fe) plays a crucial role for P binding to these nanoparticles. To test this, we isolated water-dispersible fine colloids (WDFC) from an arable topsoil (Haplic Luvisol, Germany) and assessed colloidal P forms after asymmetric flow field-flow fractionation coupled with ultraviolet and an inductively coupled plasma mass spectrometer, with and without removal of amorphous and crystalline Fe oxides using oxalate and dithionite, respectively. We found that fine colloidal P was present in two dominant sizes: (i) in associations of organic matter and amorphous Fe (Al) oxides in nanoparticles <20 nm, and (ii) in aggregates of fine clay, organic matter and Fe oxides (more crystalline Fe oxides) with a mean diameter of 170 to 225 nm. Solution 31P-nuclear magnetic resonance spectra indicated that the organically bound P predominantly comprised orthophosphate-monoesters. Approximately 65% of P in the WDFC was liberated after the removal of Fe oxides (especially amorphous Fe oxides). The remaining P was bound to larger-sized WDFC particles and Fe bearing phyllosilicate minerals. Intriguingly, the removal of Fe by dithionite resulted in a disaggregation of the nanoparticles, evident in higher portions of organically bound P in the <20 nm nanoparticle fraction, and a widening of size distribution pattern in larger-sized WDFC fraction. We conclude that the crystalline Fe oxides contributed to soil P sequestration by (i) acting as cementing agents contributing to soil fine colloid aggregation, and (ii) binding not only inorganic but also organic P in larger soil WDFC particles. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A simple and straightforward method for measuring diffusion coefficients using interdigitated array (IDA) electrodes is reported. The method does not require that the exact electrode area be known but depends only the size of the gap between the IDA electrode pairs. Electroactive molecules produced at the generator electrode of the IDA by a voltage step or scan can diffuse to the collector electrode and the time delay before the current for the reverse electrochemical reaction is detected at the collector is used to calculate the diffusion coefficient. The measurement of the diffusion rate of Ru(NH3)62+ in aqueous solution has been used as an example measuring diffusion coefficients using this method. Additionally, a digital simulation of the electrochemical response of the IDA electrodes was used to simulate the entire current/voltage/time behavior of the system and verify the experimentally measured diffusion coefficients. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Veterinary Research / Revue Canadienne de Recherche Vétérinaire is the property of Canadian Veterinary Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Samples from a pristine raised peat bog runoff in Austria, the Tannermoor creek, were analysed for their iron linked to natural organic matter (NOM) content. Dissolved organic carbon<0.45μm (DOC) was 41–64mgL−1, iron 4.4–5.5mgL−1. Samples were analysed applying asymmetric field flow fractionation (AsFlFFF) coupled to UV–vis absorption, fluorescence and inductively coupled plasma mass spectrometry (ICP-MS). The samples showed an iron peak associated with the NOM peak, one sample exhibiting a second peak of iron independent from the NOM peak. As highland peat bogs with similar climatic conditions and vegetation to the Tanner Moor are found throughout the world, including areas adjacent to the sea, we examined the behaviour of NOM and iron in samples brought to euhaline (35‰) conditions with artificial sea salt. The enhanced ionic strength reduced NOM by 53% and iron by 82%. Size exclusion chromatography (SEC) of the samples at sea-like salinity revealed two major fractions of NOM associated with different iron concentrations. The larger one, eluting sharply after the upper exclusion limits of 4000–5000gmol−1, seems to be most important for iron chelating. The results outline the global importance of sub-mountainous and mountainous raised peat bogs as a source of iron chelators to the marine environment at sites where such peat bogs release their run-offs into the sea. [Copyright &y& Elsevier]

Phosphorus transport from agricultural land contributes to eutrophication of surface waters. Pipe drain and trench waters from a grassland field on a heavy clay soil in the Netherlands were sampled before and after manure application. Phosphorus speciation was analyzed by physicochemical P fractionation, and the colloidal P fraction in the dissolved fraction (<0.45 μm) was analyzed by asymmetric flow field-flow fractionation (AF4) coupled to highresolution inductively coupled plasma--mass spectrometry and ultraviolet diode array detector. When no manure was applied for almost 7 mo, total P (TP) concentrations were low (<21 μmol L-1), and TP was almost evenly distributed among dissolved reactive P (DRP), dissolved unreactive P (DUP), and particulate P (PP). Total P concentrations increased by a factor of 60 and 4 when rainfall followed shortly after application of cattle slurry or its solid fraction, respectively. Under these conditions, DRP contributed 50% or more to TP. The P speciation within the DUP and PP fractions varied among the different sampling times. Phosphorus associated with dissolved organic matter, probably via cation bridging, comprised a small fraction of DUP at all sampling times. Colloidal P coeluted with clay particles when P application was withheld for almost 7 mo and after application of the solid cattle slurry fraction. At these sampling times, PP correlated well with particulate Fe, Al, and Si, indicating that P is associated with colloidal clay particles. After cattle slurry application, part of DUP was probably present as phospholipids. Physicochemical fractionation combined with AF4 analysis is a promising tool to unravel the speciation of colloidal P in environmental water samples. [ABSTRACT FROM AUTHOR]

Field-flow fractionation (FFF) is one of the promising alternative separation techniques to size exclusion chromatography (SEC). In this study, water soluble polymers including Bovine Serum Albumin (BSA), pullulan, poly(ethylene oxide) (PEO), sodium poly(styrene sulfonate) (NaPSS), and partially saponified poly(vinyl alcohol) (PVA) have successfully been characterized by a means of the FFF technique, fitted with a multiangle laser light scattering (MALS) detector in 0.1 M Na NO3 as an eluent at 25°C. The factors which affect the retention time, tr, and the separation factor, Rs, of the monomer and dimer of BSA are the thickness of spacer, w, channel flow rate, VCHF, cross-flow rate, VCHF, focusing time, injection volume, and polymer concentration, Cp. We found that the retention time, tr, in the FFF follows the equation of tr~[VCHF]-1.0[VCHF]1.0[w]2.0, in agreement with theory. Several cross-flow rates were examined for the characterization of the water soluble flexible polymers and the polyelectrolyte, and an appropriate gradient method for these polymers is found to be described by the equation of VCHF = A exp (-Btr), where A and B are constant. For the polyelectrolyte, the retention time significantly varies with salt concentration, due to the balance between change in the conformation of polyelectrolyte chains and the electrostatic exclusion from the membrane filter. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the effect of manure phosphorus (P) fractions on P losses from monoammonium phosphate- (MAP), solid cattle manure- (SCM) and liquid swine manure- (LSM) treated soils. Phosphorus fractions in manure were identified with the use of the modified Hedley fractionation scheme. Simulated rainfall was used to quantify P losses in runoff from two soils, such as clay loam and sand. The study shows that the proportion of total labile P ain manure was importantly greater in LSM with 70% compared to SCM with just 44%.

Several multirate separator tests (MRTs) have been undertaken on wells in the Veslefrikk field that are on commingled production from the Brent Group and Intra Dunlin Sand. During these tests, produced-water samples were also collected. Integrated analysis of the results of interpretion of the produced-water analyses and the MRT results have provided a range of information for each production zone including the nature and composition of the produced water, seawater fraction of these produced waters, fraction of total water flow being produced, pressure, productivity index, oil and water rates, and water cut. This information can reduce the need for deploying production-logging tools (PLTs), allows the scaling potential between the deeper and the shallower zones to be evaluated, aids squeeze-treatment design, is beneficial for predicting formation damage from crossflow, and aids watershutoff decisions. In this paper, the methods of interpreting the produced-water analyses are presented through the use of a field example. To aid interpretation, interpretation of other produced-water analyses from the field and reactive-transport modeling have been undertaken to better understand reactions occurring in the reservoir as a result of seawater injection and the effects of these reactions on produced-water compositions. In an accompanying paper (Tjomsland et al. 2011), the integrated MRT-analysis techniques are described and the results and applications of additional field examples are presented. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fractionation of metals (Pb, Cd, Ni, Zn, Cu and Cr) in severely contaminated sediment has been investigated to determine its speciation and eco-toxic potential at the beginning of the experiment and after 18 months of sediment oxidation. Pb, Ni and Zn showed a high risk, while Cu, Cd and Cr showed low to medium risk at the beginning. Oxidation yielded an increased mobility of all metals apart from cadmium. The ratio of the simultaneously extracted metals (SEM) and acid volatile sulfides (AVS) was found to be >1. Semi-dynamic and toxicity characteristic leaching tests were conducted to assess the effectiveness of solidification/stabilization (S/S) thermal treatment with clay and long-term leaching behavior of these metals. A diffusion-based model was used to elucidate the controlling leaching mechanisms. Applied S/S thermal treatment was effective in immobilizing metals, irrespective of their different availability in the untreated samples. The controlling leaching mechanism appeared to be diffusion. [Copyright &y& Elsevier]

Equations were derived for the prediction of the drag coefficient of a collapsing bubble during its flow in liquid. Expressions were obtained analytically for the drag coefficient in terms of Reynolds, Peclet, and Jakob numbers as well as a dimensionless time for the collapse of a thermally controlled bubble. Equations were derived for the drag coefficient and virtual mass coefficient for a collapsing bubble under inertia-controlled and mass-diffusion-controlled processes. The flow and thermal parameters were obtained by solving the viscous dissipation integral around the bubble surface. These new theoretical results showed agreement with previously reported numerical solutions and experimental data. Some avenues for further research were pointed out. [ABSTRACT FROM AUTHOR]

The article provides information on a study that explored the potential of flow field-flow fractionation (FIFFF) as a new and better technique than laser sizing for characterizing soil colloids in drained and undrained field lysimeters from soil cores sampled at different depths. The soil was sampled at the Rowden Experimental site at the Institute of Grassland and Environmental Research in North Wyke, Devon, England. It compares soils from under two grazed grassland plot lysimeters with different hydrological conditions. It discusses laser sizing particle-size distributions and FIFFF colloidal size distributions.

Studies the influence of the steric exclusion mechanism on the dependence of the retention on the thickness of the micro-thermal field-flow fractionation (TFFF) channel. Agreement of theory with experimental data found; Preservation of the use of micro-TFFF within an extended range of molar masses and particle sizes; Importance of considering a possible deterioration of the separation owing to steric exclusion while reducing the channel thickness.

The article presents a study which describes a model that simulates the response of a northern hardwood forest ecosystem to changes in atmospheric sulfur (S) deposition. It explores the simulation of stable S isotopes using fractionation and mineralization of soil organic S to explain the depletion in watersheds. It recommends the need to further research the rates of dry S deposition, the rate of mineral weathering, and the isotopic composition of mineral mass balances.

Suitable methods and fit-for-purpose techniques are required to allow characterization of carbon-based nanomaterials (CB-NMs) in complex matrices. In this study, two methods were developed; a method for extraction and characterization of CB-NMs in biological media and a method for fractionation of natural organic matter (NOM) coated CB-NMs in environmental matrices. The former method was developed by extracting carbon nanotubes (CNTs: sized 0.75 × 3000 nm) and nanoplastics (sized 60, 200 and 600 nm) from eggshells and characterizing the extracted CB-NMs in terms of particle size distribution using asymmetrical flow field-flow fractionation (AF4) coupled with multi-angle light scattering (MALS). The latter method was developed using AF4-MALS to fraction NOM-coated CNT (sized 0.75 × 3000 nm) and nanoplastics (sized 60, 200 and 300 nm) in a simulated natural surface water and provide information about the size distribution of the CB-NM-NOM complexes. The developed AF4-MALS method successfully fractioned the CB-NM-NOM complexes based on hydrodynamic size and provided the size distribution of the complexes. The NOM corona did not shift significantly the median size of the CB-NMs. It influenced however the size distribution of the nanoplastics and CNTs. The sample preparation method failed to extract the CNTs (recovery < 20%) from the matrices of the eggshells while being successful for extracting the nanoplastics (recoveries > 60%). The AF4-MALS fractogram showed that the extraction method did not significantly influence the size distribution of the nanoplastics of 60 and 200 nm size, whereas the peak of 600 nm nanoplastics shifted towards a smaller hydrodynamic size. In conclusion, the developed sample preparation method followed by the developed AF4-MALS method can be applied for extraction, separation and characterization of CB-NMs in biological and environmental matrices. Thus, the methods have a high potential to be methods of choice to investigate CB-NMs in future studies. Image 1 • A method was developed to extract, separate and characterize CB-NMs and CB-NM-NOM complexes in environmental and biological media using AF4-MALS. • We extracted nanoplastics from simulated biological and environmental media. • The AF4-MALS method successfully separated CB-NMs from environmental samples. • The method characterized the CB-NMs in terms of size and size distribution. • NOM corona influences the size distribution of CNTs and nanoplastics. [ABSTRACT FROM AUTHOR]

The article discusses the fundamentals of process simulations of fractionation columns and offers tips on how to use the correct simulator that will result to rate tower internals. Some of the topics include tray ratings, packing ratings and general comments on rating trays or packings. Figures are also presented including one showing Flows to an Individual Tray and another showing Flows to Packed Bed.

Reports on Wyatt Technology Inc.'s launch of a particle-sizing system that integrates two of its macromolecular characterization instruments, the Eclipse field flow fractionation (FFF) device and the DAWN multi-angle light scattering (MALS) detection system. Achievement of absolute particle sizing for samples containing submicron particles without the need for device calibration or sizing standards; Comments of company executive Christoph Johann.