Novel synthesized attapulgite nanoparticles-based hydrophobic monolithic column for in-tube solid-phase microextraction of thiosildenafil, pseudovardenafil, and norneosildenafil in functional foods.

In this study, a novel method which involved in-tube solid-phase microextraction (SPME) using an attapulgite (ATP) nanoparticles-based hydrophobic monolithic column was successfully developed. It was coupled with high-performance liquid chromatography-ultraviolet detection for the determination of three phosphodiesterase-5 (PDE-5) inhibitors, including thiosildenafil, pseudovardenafil, and norneosildenafil, in functional foods. The monolithic column was prepared by one-step polymerization, using 3-trimethoxysilylpropyl methacrylate-modified ATP nanoparticles and 1-butyl-3-vinylimidazolium bromide (VBIMBr) as the functional monomers, and ethylene glycol dimethacrylate (EDMA) as the cross-linker. The obtained poly(ATP-VBIMBr-EDMA) monolith was characterized by scanning electron microscopy equipped with energy-dispersive analysis of X-ray, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction. The adsorption capacity, up to 2.00 µg/cm calculated by the Langmuir isotherm model, was about six times that of the poly(VBIMBr-EDMA) monolith. Crucial factors affecting the extraction efficiency, including sample solvent, elution solvent, flow rates of sampling loading and elution, sample loading volume, and elution volume, were investigated in details. Under the optimal in-tube SPME conditions, the proposed method showed good reproducibility with run-to-run, column-to-column, and batch-to-batch relative standard deviations less than 7.2%, and low limits of detection of 0.5-0.9 ng/mL in real samples. Thiosildenafil was detected in four types of functional foods with the contents of 1.30-4.78 µg/g. This newly proposed in-tube SPME method based on poly(ATP-VBIMBr-EDMA) monolith may provide a simple, efficient, and promising alternative to daily monitoring of PDE-5 inhibitors in functional foods.

Attapulgite suspension mitigates fine particulate matter (PM2.5) emission from coal combustion in fluidized bed.

To reduce fine particulate matter emission from coal burning sources especially fossil fuel fired energy generation facility is critical to improve air quality. Attapulgite suspension was attempted to spray in a 6 kW fluidized bed facility and reduce fine particulate matter emission during coal combustion. The key parameters such as attapulgite mass, flowrate and spraying zone were investigated to determine the optimal and critical conditions that influence fine particulate matter emission. Exciting results indicate that both fine particle number and mass concentrations are largely decreased due to the physical/chemical absorption with the suitable mass ratio of 3 wt%. The spray of attapulgite suspension in both dense bed and dilute bed effectively mitigates fine particle emission based on the agglomeration and absorption. The most excellent result is achieved at a flowrate of 38 ml/min in dense bed with particle number reduction up to 93.5% in PM2.5 (fine particles is equal to/less than 2.5 µm), 93.6% in PM1.0 (fine particles is equal to/less than 1.0 µm) and 93.7% in PM0.1 (fine particles is equal to/less than 0.1 µm), respectively. The work highlights the potential of spraying attapulgite suspension as an effective process to reduce fine particle emission during coal combustion in fluidized bed system.

Real-Time Measurements and Characterization of Airborne Particulate Matter from a Primary Silicon Carbide Production Plant.

Airborne particulate matter in the silicon carbide (SiC) industry is a known health hazard. The aims of this study were to elucidate whether the particulate matter generated inside the Acheson furnace during active operation is representative of the overall particulate matter in the furnace hall, and whether the Acheson furnaces are the main sources of ultrafine particles (UFP) in primary SiC production. The number concentration of ultrafine particles was evaluated using an Electrical Low Pressure Impactor (ELPITM, Dekati Ltd., Tampere, Finland), a Fast Mobility Particle Sizer (FMPSTM, TSI, Shoreview, MN, USA) and a Condensation Particle Counter (CPC, TSI, Shoreview, MN, USA). The results are discussed in terms of particle number concentration, particle size distribution and are also characterized by means of electron microscopy (TEM/SEM). Two locations were investigated; the industrial Acheson process furnace hall and a pilot furnace hall; both of which represent an active operating furnace. The geometric mean of the particle number concentration in the Acheson process furnace hall was 7.7 × 104 particles/cm³ for the UFP fraction and 1.0 × 105 particles/cm³ for the submicrometre fraction. Particulate matter collected at the two sites was analysed by electron microscopy. The PM from the Acheson process furnace hall is dominated by carbonaceous particles while the samples collected near the pilot furnace are primarily rich in silicon.

Microbiomes of Biofilms on Decorative Siliceous Stone: Drawbacks and Advantages of Next Generation Sequencing.

Next Generation Sequencing (NGS), using the Illumina® metabarcoding system, showed differences between biofilm communities on three degraded siliceous stone church façades in central Rio de Janeiro. Two church biofilms (on granite and augen gneiss) were dominated by Actinobacteria; the third (granite), surrounded by trees and further from intense vehicular traffic, by Gammaproteobacteria. Yeast-like forms of Basidiomycetes and Ascomycetes were major fungi on all facades, but 22.8% of Operational Taxonomic Units could not be assigned to any fungal taxon after DNA amplification with ITS primers and analysis with the UNITE database, indicating the need for more fungal NGS studies. The pipeline used in analysis of the V4 region of rRNA bacterial gene sequences influenced the taxa detected, with two major classes and many genera identified only by the pipeline using the Greengenes, and not the Silva, database. Principal Components Analysis separated façade biofilms into the appropriate three groups and indicated greater dissimilarity of the tree-surrounded church biofilm from the others, confirmed by Jaccard Similarity coefficients, suggesting that local environment influences community composition more than stone type. NGS allows rapid and detailed analysis of microbiomes, but results must be carefully assessed and must not be used as the sole indication of community composition.

Nano-scale elastic-plastic properties and indentation-induced deformation of single crystal 4H-SiC.

The nanoscale elastic-plastic response of single crystal 4H-SiC has been investigated by nanoindentationwith a Berkovich tip. The hardness (H) and elastic modulus (E) determined in the load-independent region were 36±2GPa and 413±8GPa, respectively. The indentation size effect (ISE) of hardness within an indentation depth of 60nm was systematically analyzed by the Nix-Gao model. Pop-in events occurring at a depth of ~23nm with indentation loads of 0.60-0.65mN were confirmed to indicate the elastic-plastic transition of the crystal, on the basis of the Hertzian contact theory and Johnson's cavity model. Theoritically calculated maximum tensile strength (13.5GPa) and cleavage strength (33GPa) also affirms the deformation due to the first pop-in rather than tensile stresses. Further analyses of deformation behavior across the indent was done in 4H-SiC by a combined technique of focused ion beam and transmission electron microscope, revealing that slippage occurred in the (0001) plane after indentation.

Functionalised silicon oxide nanoparticles for fingermark detection.

Over the past decade, the use of nanotechnology for fingermark detection has been attracting a lot of attention. A substantial number of nanoparticle types has thus been studied and applied with varying success. However, despite all efforts, few publications present clear supporting evidence of their superiority over standard and commonly used techniques. This paper focuses on a rarely studied type of nanoparticles that regroups all desired properties for effective fingermark detection: silicon oxide. These nanoparticles offer optical and surface properties that can be tuned to provide optimal detection. This study explores their potential as a new method for fingermark detection. Detection conditions, outer functionalisations and optical properties were optimised and a first evaluation of the technique is presented. Dye-doped silicon oxide nanoparticles were assessed against a one-step luminescent cyanoacrylate. Both techniques were compared on natural fingermarks from three donors collected on four different non-porous substrates. On average, the two techniques performed similarly but silicon oxide detected marks with a better homogeneity and was less affected by donor inter-variability. The technique remains to be further optimised and yet silicon oxide nanoparticles already show great promises for effective fingermark detection.

Study of the carbonaceous aerosol and morphological analysis of fine particles along with their mixing state in Delhi, India: a case study.

Because of high emissions of anthropogenic as well as natural particles over the Indo-Gangetic Plains (IGP), it is important to study the characteristics of fine (PM2.5) and inhalable particles (PM10), including their morphology, physical and chemical characteristics, etc., in Delhi during winter 2013. The mean mass concentrations of fine (PM2.5) and inhalable (PM10) (continuous) was 117.6 ± 79.1 and 191.0 ± 127.6 µg m(-3), respectively, whereas the coarse mode (PM10-2.5) particle PM mass was 73.38 ± 28.5 µg m(-3). During the same period, offline gravimetric monitoring of PM2.5 was conducted for morphological analysis, and its concentration was ~37 % higher compared to the continuous measurement. Carbonaceous PM such as organic carbon (OC) and elemental carbon (EC) were analyzed on the collected filters, and their mean concentration was respectively 33.8 and 4.0 µg m(-3) during the daytime, while at night it was 41.2 and 10.1 µg m(-3), respectively. The average OC/EC ratio was 8.97 and 3.96 during the day and night, respectively, indicating the formation of secondary organic aerosols during daytime. Effective carbon ratio was studied to see the effect of aerosols on climate, and its mean value was 0.52 and 1.79 during night and day, indicating the dominance of absorbing and scattering types of aerosols respectively into the atmosphere over the study region. Elemental analysis of individual particles indicates that Si is the most abundant element (~37-90 %), followed by O (oxide) and Al. Circularity and aspect ratio was studied, which indicates that particles are not perfectly spherical and not elongated in any direction. Trajectory analysis indicated that in the months of February and March, air masses appear to be transported from the Middle Eastern part along with neighboring countries and over Thar Desert region, while in January it was from the northeast direction which resulted in high concentrations of fine particles.

Nuevos biomateriales: estudio in vivo del carburo de silicio como material osteointegrador / New biomaterials: in vivo study of silicon carbide as boneintegration material

Objetivo: Evaluar, mediante ensayos in vivo, la biocompatibilidad y el grado de penetración ósea en la microestructura porosa del carburo de silicio (SiC). Material y métodos: se implantaron en cóndilos femorales de conejos cilindros de SiC obtenidos a partir de maderas de pino y sapeli. Como material de referencia fueron utilizados cilindros de titanio. El sacrificio de los animales se realizó a las 12 semanas de implantación y se procedió al examen histológico de las muestras. Resultados: Comprobamos un crecimiento de trabéculas óseas, tanto en la superficie del implante como a través de su estructura porosa, sin apreciarse signos de inflamación ni aparición de tejido fibroso alrededor de la muestra. Estos resultados son confirmados mediante microscopía electrónica de barrido (SEM) y análisis de rayos X por dispersión de energías. Conclusión: El carburo de silicio biomórfico es una cerámica con excelentes propiedades mecánicas y porosidad interconectada que le confiere un especial atractivo de cara a sus aplicaciones biomédicas en implantes ortopédicos (AU)

Objective: To evaluate, using in vivo tests, the biocompatibility and the degree of bone penetration into the porous microstructure of silicon carbide (SiC). Material and methods: For this purpose cylindres of SiC obatained from wood of pine and sapeli were implanted in femoral condyles of rabbits. As reference material we used titanium cylinders. The slaughter of animals was performed at 12 weeks of implantation and proceeded to the histological examination of the samples. Results: We see a growth of bone trabeculae, both on the surface of the implant and through its porous structure, without signs of inflammation or appearance of fibrous tissue around the samples. These results are confirmed by scanning electron microscopy scanning (SEM) and X-ray analysis by dispersion of energies (EDS). Conclusion: Biomorphic silicon carbide (SiC) is a ceramic with excellent mechanical properties and interconnected porosity which gives a special attraction for their biomedical applications in orthopaedic implants (AU)

Volatile organic silicon compounds in biogases: development of sampling and analytical methods for total silicon quantification by ICP-OES.

Current waste management policies favor biogases (digester gases (DGs) and landfill gases (LFGs)) valorization as it becomes a way for energy politics. However, volatile organic silicon compounds (VOSiCs) contained into DGs/LFGs severely damage combustion engines and endanger the conversion into electricity by power plants, resulting in a high purification level requirement. Assessing treatment efficiency is still difficult. No consensus has been reached to provide a standardized sampling and quantification of VOSiCs into gases because of their diversity, their physicochemical properties, and the omnipresence of silicon in analytical chains. Usually, samplings are done by adsorption or absorption and quantification made by gas chromatography-mass spectrometry (GC-MS) or inductively coupled plasma-optical emission spectrometry (ICP-OES). In this objective, this paper presents and discusses the optimization of a patented method consisting in VOSiCs sampling by absorption of 100% ethanol and quantification of total Si by ICP-OES.

Femtogram-scale photothermal spectroscopy of explosive molecules on nanostrings.

We demonstrate detection of femtogram-scale quantities of the explosive molecule 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) via combined nanomechanical photothermal spectroscopy and mass desorption. Photothermal spectroscopy provides a spectroscopic fingerprint of the molecule, which is unavailable using mass adsorption/desorption alone. Our measurement, based on thermomechanical measurement of silicon nitride nanostrings, represents the highest mass resolution ever demonstrated via nanomechanical photothermal spectroscopy. This detection scheme is quick, label-free, and is compatible with parallelized molecular analysis of multicomponent targets.

Ultrasonic sensor based defect detection and characterisation of ceramics.

Ceramic tiles, used in body armour systems, are currently inspected visually offline using an X-ray technique that is both time consuming and very expensive. The aim of this research is to develop a methodology to detect, locate and classify various manufacturing defects in Reaction Sintered Silicon Carbide (RSSC) ceramic tiles, using an ultrasonic sensing technique. Defects such as free silicon, un-sintered silicon carbide material and conventional porosity are often difficult to detect using conventional X-radiography. An alternative inspection system was developed to detect defects in ceramic components using an Artificial Neural Network (ANN) based signal processing technique. The inspection methodology proposed focuses on pre-processing of signals, de-noising, wavelet decomposition, feature extraction and post-processing of the signals for classification purposes. This research contributes to developing an on-line inspection system that would be far more cost effective than present methods and, moreover, assist manufacturers in checking the location of high density areas, defects and enable real time quality control, including the implementation of accept/reject criteria.

Mineralogy of a mudstone at Yellowknife Bay, Gale crater, Mars.

Sedimentary rocks at Yellowknife Bay (Gale crater) on Mars include mudstone sampled by the Curiosity rover. The samples, John Klein and Cumberland, contain detrital basaltic minerals, calcium sulfates, iron oxide or hydroxides, iron sulfides, amorphous material, and trioctahedral smectites. The John Klein smectite has basal spacing of ~10 angstroms, indicating little interlayer hydration. The Cumberland smectite has basal spacing at both ~13.2 and ~10 angstroms. The larger spacing suggests a partially chloritized interlayer or interlayer magnesium or calcium facilitating H2O retention. Basaltic minerals in the mudstone are similar to those in nearby eolian deposits. However, the mudstone has far less Fe-forsterite, possibly lost with formation of smectite plus magnetite. Late Noachian/Early Hesperian or younger age indicates that clay mineral formation on Mars extended beyond Noachian time.

Mechanical and tribological behavior of silicon nitride and silicon carbon nitride coatings for total joint replacements.

Total joint replacements currently have relatively high success rates at 10-15 years; however, increasing ageing and an active population places higher demands on the longevity of the implants. A wear resistant configuration with wear particles that resorb in vivo can potentially increase the lifetime of an implant. In this study, silicon nitride (SixNy) and silicon carbon nitride (SixCyNz) coatings were produced for this purpose using reactive high power impulse magnetron sputtering (HiPIMS). The coatings are intended for hard bearing surfaces on implants. Hardness and elastic modulus of the coatings were evaluated by nanoindentation, cohesive, and adhesive properties were assessed by micro-scratching and the tribological performance was investigated in a ball-on-disc setup run in a serum solution. The majority of the SixNy coatings showed a hardness close to that of sintered silicon nitride (~18 GPa), and an elastic modulus close to that of cobalt chromium (~200 GPa). Furthermore, all except one of the SixNy coatings offered a wear resistance similar to that of bulk silicon nitride and significantly higher than that of cobalt chromium. In contrast, the SixCyNz coatings did not show as high level of wear resistance.

Determinants of exposure to dust and dust constituents in the Norwegian silicon carbide industry.

INTRODUCTION: The aim of this study was to identify important determinants of dust exposure in the Norwegian silicon carbide (SiC) industry and to suggest possible control measures. METHODS: Exposure to total dust, respirable dust, quartz, cristobalite, SiC, and fiber was assessed in three Norwegian SiC plants together with information on potential determinants of exposure. Mixed-effect models were constructed with natural log-transformed exposure as the dependent variable. RESULTS: The exposure assessment resulted in about 700 measurements of each of the sampled agents. Geometric mean (GM) exposure for total dust, respirable dust, fibers, and SiC for all workers was 1.6mg m(-3) [geometric standard deviation (GSD) = 3.2], 0.30mg m(-3) (GSD = 2.5), 0.033 fibers cm(-3) (GSD = 5.2), and 0.069mg m(-3) (GSD = 3.1), respectively. Due to a large portion of quartz and cristobalite measurements below the limit of detection in the processing and maintenance departments (>58%), GM for all workers was not calculated. Work in the furnace department was associated with the highest exposure to fibers, quartz, and cristobalite, while work in the processing department was associated with the highest total dust, respirable dust, and SiC exposure. Job group was a strong determinant of exposure for all agents, explaining 43-82% of the between-worker variance. Determinants associated with increased exposure in the furnace department were location of the sorting area inside the furnace hall, cleaning tasks, building and filling furnaces, and manual sorting. Filling and changing pallet boxes were important tasks related to increased exposure to total dust, respirable dust, and SiC in the processing department. For maintenance workers, increased exposure to fibers was associated with maintenance work in the furnace department and increased exposure to SiC was related to maintenance work in the processing department. CONCLUSION: Job group was a strong determinant of exposure for all agents. Several tasks were associated with increased exposure, indicating possibilities for exposure control measures. Recommendations for exposure reduction based on this study are (i) to separate the sorting area from the furnace hall, (ii) minimize manual work on furnaces and in the sorting process, (iii) use remote controlled sanders/grinders with ventilated cabins, (iv) use closed systems for filling pallet boxes, and (v) improve cleaning procedures by using methods that minimize dust generation.

Tide- and rainfall-induced variations of physical and chemical parameters in a mangrove-depleted estuary of East Hainan (South China Sea).

The estuarine dynamics favoring the coexistence of mangroves, seagrass and corals at small river mouths are often poorly understood. We characterize the tidal, day/night and rainfall-induced short-term dynamics in salinity, pH, dissolved oxygen (DO), chlorophyll a (chl a), total suspended matter (TSM), water transparency, surface currents and dissolved nutrients (NO(x)(-), NH(4)(+), PO(4)(3)(-), Si(OH)(4)) of the Wenchang/Wenjiao Estuary (East Hainan, tropical China). Samples were taken at three fixed sites along the estuary during 24 h spring tide cycles in different seasons. Salinity, DO, water transparency and pH generally increased seawards while nutrients decreased. All parameters varied with the tidal cycle, partially in interaction with the diel cycle. Nutrients, chl a and TSM usually fluctuated inversely with water level. Stratification was strong. Inflowing bottom water was of higher salinity, DO and pH and lower temperature and nutrient concentrations than the surface water. Tidal mixing provided regular ventilation of the estuary and limited eutrophication effects of nutrients from aquaculture, agriculture and urban effluents. Under dry weather conditions, the brackish-water lagoon functioned as a sink of nutrients due to efficient uptake by phytoplankton. Presently, the runoff from common intense rains in the watershed affects the estuary with little time delay due to terrestrial deforestation, channelization and loss of mangrove area. The frequency, strength and duration of intermittent estuarization of the back-reef areas have likely increased in the past and deteriorate present seagrass and coral health.

Effect of the cathode material on the removal of nitrates by electrolysis in non-chloride media.

In this work, the effect of the cathode material (conductive diamond, stainless steel, silicon carbide, graphite or lead) and the current density (150-1400 A m(-2)) on the removal of nitrates from aqueous solutions is studied by electrolysis in non-divided electrochemical cells equipped with conductive diamond anodes, using sodium sulphate as the electrolyte. The results show that the cathode material very strongly influences both the process performance and the product distribution. The main products obtained are gaseous nitrogen (NO, N(2)O and NO(2)) and ammonium ions. Nitrate removal follows first order kinetics, which indicates that the electrolysis process is controlled by mass transfer. Furthermore, the stainless steel and graphite cathodes show a great selectivity towards the production of ammonium ions, whereas the silicon carbide cathode leads to the highest formation of gaseous nitrogen, which production is promoted at low current densities.

A novel strategy for retrospective exposure assessment in the Norwegian silicon carbide industry.

The objective was to construct a retrospective job-exposure matrix (JEM) for the Norwegian silicon carbide industry. More than 3300 historical total dust measurements were available (1967-2005); however, there were few measurements of other agents. Total dust measurements were therefore used as the basis for the JEM, and a novel method was developed to estimate exposure to other agents. Multiple linear regression models were developed to describe historical exposure to total dust. Exposure estimates were extrapolated backward to periods without exposure data by adjustments for process and work-hour related changes. An exposure assessment study was performed where total dust was sampled in parallel with fibers or respirable dust. The respirable dust was analyzed for the content of quartz, cristobalite, and silicon carbide. Mixed-effect models were developed to estimate the exposure to these agents from total dust exposure, plant, and job group. Exposure to asbestos and polycyclic aromatic hydrocarbons was assigned qualitatively. Multiple linear regression models of total dust described historical exposure best in the furnace department (R(2) (adj) = 0.49-0.74). Models in the other departments explained less variance (R(2) (adj) = 0.12-0.32). Exposure determinants and total dust explained a substantial proportion of the between- (70-100%) and within-worker (8.0-54%) variance in the mixed-effect models. The relative bias between available historical measurements and the estimated exposure to dust components varied between -39% (fiber) and 40% (quartz). However, corrections were not considered necessary due to limitations in the historical data. The component-specific metrices were sufficiently different from each other (r(Pearson) < 0.7), with the exception of total and respirable dust (r(Pearson) = 0.84) and total dust and cristobalite (r(Pearson) = 0.72), and will enable component-specific epidemiologic analyses in the future. Improved and less correlated estimates of exposure levels for the different components in the dust were obtained with the updated exposure assessment. Due to limitations in the measurement data, assumptions had to be made, especially in the period before 1967. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a file containing tables outlining multiple linear regression models for prediction of total dust exposure in the processing departments of Norwegian SiC producing plants, evaluation of the predictive abilities of the reduced total dust models, and mixed models for pedicting exposure to fibers and respirable quartz, cristobalite, non-fibrous silicon carbide and respirable dust from total dust exposure.].

Development of a PIXE analysis method for the determination of the biopersistence of SiC and TiC nanoparticles in rat lungs.

With the advent of nanoparticles produced in high quantities and employed in products or processes, the need to evaluate their potential toxicological effects is necessary. For this purpose, biopersistence studies are needed to assess the possible effects of nanoparticles in parallel with a proper characterization. The insoluble character of many nanomaterials makes traditional chemical analytical methods unapplicable for the ex-vivo measurements of their concentration in organs. Ion beam-based techniques such as Particle-Induced X-ray Emission (PIXE) can solve this difficulty. We illustrate that by the measurement of biopersistence of SiC and TiC nanoparticles instilled in rats lungs and investigated over a 60-day time span. The results can be obtained within minutes and the limits of detection are within ppm levels.

Stardust in meteorites.

Primitive meteorites, interplanetary dust particles, and comets contain dust grains that formed around stars that lived their lives before the solar system formed. These remarkable objects have been intensively studied since their discovery a little over twenty years ago and they provide samples of other stars that can be studied in the laboratory in exquisite detail with modern analytical tools. The properties of stardust grains are used to constrain models of nucleosynthesis in red giant stars and supernovae, the dominant sources of dust grains that are recycled into the interstellar medium by stars.

Preparation and application of attapulgite/iron oxide magnetic composites for the removal of U(VI) from aqueous solution.

Recently, magnetic sorbents have received considerable attention because of their excellent segregative features and sorption capacities. Herein, attapulgite/iron oxide magnetic (ATP/IOM) composites were prepared and characterized. The sorption results indicated that ATP/IOM composites were superior to ATP and iron oxides individually for the removal of U(VI) from aqueous solution. Based on X-ray photoelectron spectroscopy (XPS) analysis and surface complexation model, the main sorption species of U(VI) on ATP were==X(2)UO(2)(0) below pH 4.0 and==S(s)OUO(2)(+), ==S(w)OUO(2)CO(3)(-), and==S(w)OUO(2)(CO(3))(2)(3-) above pH 5.0. However the prevalent species on ATP/IOM composites were==S(s)OUO(2)(+) and==S(w)OUO(2)(CO(3))(2)(3-) over the observed pH range. ATP/IOM composites are a promising candidate for pre-concentration and immobilization of radionuclides from large volumes of aqueous solutions, as required for remediation purposes.