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The present study developed a multistandard color chart for detecting uranium (U) by arsenazo III using digital cameras with color tool measurements and compared it with conventional methods. The color chart is red to dark red as monochromatic for cameras. The detection limit is 5 ng/mL using a preconcentration factor of 100, which is well below WHO guidelines. The digital cameras showed lower bias and better trueness compared to the conventional methods. This provides an advantage in portability, ease of analysis, and no need for high-end instruments/radiochemical laboratories for U analysis in drinking water. [ABSTRACT FROM AUTHOR]

Background. The main sources of anthropogenic input of heavy metals into the environment, especially lead, are various industrial enterprises, the automotive industry. Purpose: development of a sorption-spectrophotometric technique for the determination of lead ions with an immobilized reagent Arsenazo III on a polymer material. Methodology. Methods of reflection spectrophotometry, as well as sorption-spectrophotometric methods were used. The optimal conditions for immobilization and complexation were studied depending on time, environment, temperature and other factors. Originality. A technique was developed for the sorption-spectrophotometric determination of lead ions using immobilized arsenazo III on a polymer fiber, which made it possible to improve the analytical and metrological parameters of the method for its determination. Findings. The optimal conditions for the immobilization and complexation of lead (II) ions with immobilized arsenazo III on a fibrous sorbent were determined, and when studying the effect of pH on the sorption of lead (II) ions, it was found that the sorbent quantitatively extracts lead (II) up to 90-92% in the pH range from 2.0-4.0. [ABSTRACT FROM AUTHOR]

Recent development of portable three-dimensional printed (3DP) microfluidic-based devices has provided a new horizon for real-time field analysis of environmental pollutants. Smartphones with the possibility of launching different software, sensing, and grading color intensity, as well as capability of sending/receiving data through the internet have made this technology very promising. Here, a novel smartphone-based 3DP microfluidic device is reported that uses an image-based colorimetric detection method for the analysis of uranium in water samples, based on the complex formation of uranyl ions with Arsenazo III. The microfluidic device consists of two horizontal channels, separated by an integrated porous membrane, and was printed in a single run using a transparent photopolymer. It enables the operator to see the internal parts and the color change visually, as well as enables the operator to take images and record the color intensity using a smartphone. In each 3DP run, 220 devices are fabricated in 1.5 h (~ 25 s per device) at an estimated price of $2.5 per device. A Box–Behnken design (BBD) was utilized for the optimization of experimental conditions. The calibration curve was linear within 0.5–100 μg mL−1 (R2 > 0.9925) of uranium analysis. The total time of each experiment was approximately 8 min. The 3DP device was successfully employed for the recovery and determination of uranium in spiked natural water samples. [ABSTRACT FROM AUTHOR]

N -allylthiourea chitosan (ATUCS), a chelating material, was prepared, characterized, and studied for the removal of arsenazo III (As (III)) dye from aqueous solution. Scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and 1H- and 13C-nuclear magnetic resonance (NMR) were used to characterize the prepared adsorbent and to investigate the adsorption mechanism. Furthermore, the adsorption behavior of chitosan (CS) and ATUCS were studied under various conditions. The equilibrium adsorbed amount of As (III) onto ATUCS was found to be 116.3 mg/g, compared to 87.3 mg/g with respect to CS. The regeneration of the loaded CS and ATUCS were studied using 1:1 solution of H 2 O 2 -H 2 SO 4 and reused with certain change in efficiency after the third cycle. The adsorption process was found to fit well with pseudo-second-order kinetic model. The equilibrium data were better described with the Freundlich isotherm. The monolayer adsorption capacity was found to be 204.08 and 90.90 mg/g for the As (III)/ATUCS and As (III)/CS systems, respectively, at 25 °C. The pH of the higher uptake of As (III) onto ATUCS and CS was 4–5 and 8.0, respectively. The results demonstrated improved adsorption of As (III) using ATUCS as compared to the CS. [ABSTRACT FROM AUTHOR]

UV-visible spectrophotometry with Arsenazo III is used to determine the samarium concentration. The results confirm that the concentration of Sm3+ in the aqueous solution from 2.7 × 10–6 to 10.8 × 10–6 mol/L obeys the Lambert–Beer law. The quantitative relationship between the absorbance and concentrations of Ca2+ and F– in the solution with 2.7 × 10–6 mol/L Sm3+ has been obtained. The absorbance of the solution with 10.8 × 10–6 mol/L Sm3+ is found to be 0.58, which is not affected by the concentrations of Ca2+ and F–. So, if the concentrations of Ca2+ and F– were known, the quantitative relationship between absorbance and Sm3+ concentration can be obtained, which is convenient for determining the Sm3+ concentration in aqueous solution with Ca2+ and F– by UV-visible spectrophotometry. [ABSTRACT FROM AUTHOR]

Vortex assisted in situ ionic liquid dispersive liquid-liquid microextraction method was developed for extraction of U(VI) from aqueous solutions using hydrophilic ionic liquid and ion-exchange reagent. Arsenazo III was used as a complexing agent in microextraction process. Under optimized conditions, the proposed method for uranyl ion exhibited good precision, 5.2% for 1 µg L−1 and 5.1% for 4 µg L−1, low limit of detection, 0.06 µg L−1 and high enrichment factor, 91. The accuracy studies were achieved by spiking of 1 and 5 µg L−1 U(VI) into water samples and the recovery was found in the range of 99-111%. [ABSTRACT FROM AUTHOR]

The complexation of thorium with arsenazo III in perchloric acid was quantitatively investigated with ultraviolet-visible (UV-Vis) absorption spectroscopy. The UV-Vis absorption of both 1:1 and 1:2 (thorium to arsenazo III) complexes in perchloric acid were found to be highly enhanced than the previously reported absorption of the complexes in hydrochloric acid. The stability constants of thorium-arsenazo III complexes were determined via computational analysis, and the SIT (specific ion interaction theory) was employed to evaluate the dependence on ionic strength. This work contributes to a better understanding of the speciation and spectroscopic properties of thorium-arsenazo III complexes at high ionic strength. [ABSTRACT FROM AUTHOR]

Mechanically separated meat (MSM) is a by-product of the poultry industry that requires routine quality assessment. Calcium content is an indirect indicator of bone debris in MSM but is difficult to determine by EDTA titration due to the poor solubility of calcium phosphate. Therefore, 1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid was used instead, which has two orders of magnitude higher affinity for calcium ions. In addition, the auxiliary complexing agents triethanolamine and Arsenazo III, an indicator that is sensitive to low calcium concentrations, were used. Automatic titration endpoint detection was performed using an immersion probe at 660 nm. It has been shown that the color change in Arsenazo III can also be read with an RGB camera. The CDTA titration procedure has been tested on commercial Bologna-type sausages and the results were in line with AAS and ICP reference data. The content of calcium in sausages turned out to be very diverse and weakly correlated with the content of MSM. The tested MSM samples had a wide range of calcium content: from 62 to 2833 ppm. Calcium-rich poultry by-products include fat and skin (115 to 412 ppm), articular cartilage (1069 to 1704 ppm), and tendons (532 to 34,539 ppm). The CDTA titration procedure is fully suitable for small meat processing plants due to its simplicity of use and low cost.

Recently, methanotrophic and methylotrophic bacteria were found to utilize rare earth elements (REEs). To monitor the REE content in culture media of these bacteria, we have developed a rapid screening method using the Arsenazo III (AS III) dye for spectrophotometric REE detection in the low μM (0.1 to 10 μM) range. We designed this assay to follow LaIII and EuIII depletion from the culture medium by the acidophilic verrucomicrobial methanotroph Methylacidiphilum fumariolicum strain SolV. The assay can also be modified to screen the uptake of other REEs, such as PrIII, or to monitor the depletion of LaIII from growth media in neutrophilic methylotrophs such as Methylobacterium extorquens strain AM1. The AS III assay presents a convenient and fast detection method for REE levels in culture media and is a sensitive alternative to inductively coupled plasma mass spectrometry (ICP-MS) or atomic absorption spectroscopy (AAS). IMPORTANCE REE-dependent bacterial metabolism is a quickly emerging field, and while the importance of REEs for both methanotrophic and methylotrophic bacteria is now firmly established, many important questions, such as how these insoluble elements are taken up into cells, are still unanswered. Here, an Arsenazo III dye-based assay has been developed for fast, specific, and sensitive determination of REE content in different culture media. This assay presents a useful tool for optimizing cultivation protocols, as well as for routine REE monitoring during bacterial growth without the need for specialized analytical instrumentation. Furthermore, this assay has the potential to promote the discovery of other REE-dependent microorganisms and can help to elucidate the mechanisms for acquisition of REEs by methanotrophic and methylotrophic bacteria. [ABSTRACT FROM AUTHOR]

This work describes the liquid-liquid extraction of uranium (U) from 3 mole L-1 nitric acid media by N, N-di(2-ethyl hexyl) hexanamide (DOHA) in dodecane and subsequent determination of uranium using arsenazo III as a chromogenic reagent. Different factors (nitric acid, DOHA, metal ion concentration, salting out effect, temperature and shaking time) affecting the extraction /stripping process, were investigated. The investigation showed that the extraction is independent of the conc. of metal ions in the range of 5 to 300 μg mL-1 and inversely dependent upon the temperature. The desired species so extracted were found to have a stoichiometric composition as UO2(NO3)2.DOHA and UO2(NO3)2.2DOHA at lower and higher concentration of extractant respectively. Uranium could be stripped back from organic phase by using 0.1 mole L-1 ammonium hydroxide (NH4OH) and the extraction was found to be quantitative. [ABSTRACT FROM AUTHOR]

Two-phase aqueous systems, polyethylene glycol PEG-3000 (C3H7OH)-NaNO3 (NaNO3 + KSCN)-H2O, are proposed for the selective extraction of scandium nitrate and thiocyanate complexes followed by the complexometric and spectrophotometric determination of scandium. Conditions for analyte separation from rare-earth and concomitant elements are optimized. The procedures are tested on samples of rare-earth metals, concentrates, and an aluminum alloy. The relative standard deviation is not more than 0.8% for complexometric determination and 4.6% for spectrophotometric determination. The time of analysis is not longer than 30 min. [ABSTRACT FROM AUTHOR]

The present study devoted to description of efficient removal of radioactive UO 2 2+ ions (U(IV)) via complexation with Arsenazo III (ARS III) accelerated by ultrasound-assisted adsorption onto the Au-NPs supported on carbon nanotubes (Au-NPs-CNTs), which were characterized by conventional techniques such as FESEM, EDS and XRD. Central composite design (CCD) employed to model contribution of parameters viz. pH (2.5–8.5), adsorbent mass (5–25 mg), UO 2 2+ concentration (5–25 mg L −1 ) and sonication time (1–5 min) onto response. The predicted results optimum conditions corresponding achievement of maximum UO 2 2+ removal efficiency are pH 5.5, 20 mg of Au-NPs-CNTs, is highly applicability for removal of more than 98% of 25 mg L −1 of UO 2 2+ following 5 min sonication. Through analysis of corresponding results based on evaluation according to UO 2 2+ concentration were found significantly affect responds. ANOVA analysis revealed a high R 2 (0.9950) & AP (51.79) and low SD (0.6078) & CV% (0.6703) values of regression model equation which completely ensure accuracy of the quadratic model. Langmuir isotherm model was applicable for description of adsorption data with maximum monolayer adsorption capacity of 133.3 mg g −1 at 25 °C and pH 5.5. Dubinin–Radushkevich (D–R) isotherm model based on mean sorption energy (E) reveal high contribution of physisorption (1.17–3.78 kJ mol −1 ) on adsorption process. Moreover, Pseudo-second-order kinetic model delivered a better correlation for the experimental data in comparison to the pseudo-first-order kinetic model and intraparticle diffusion mechanism. [ABSTRACT FROM AUTHOR]

The complexation characteristics of thorium-arsenazo III in the range of 1-6 mol·L hydrochloric acid media were investigated by UV-Vis absorption spectroscopy and computational analysis. The chemical equilibrium model of thorium-arsenazo III complexation was established including the species distribution of arsenazo III, the formation of thorium chloride species, and the release of protons from thorium-arsenazo III complexes. In the spectra of thorium-arsenazo III complexes, two characteristic absorption peaks were observed at 610 and 660 nm, and the latter peak showed a tendency to shift about 4 nm to higher wavelength as the acidity of the hydrochloric acid media increased from 1 to 6 mol·L. Analysis of the experimental data indicates that the molar absorptivities of both 1:1 and 1:2 complexes (thorium to arsenazo III) steadily increase as the acidity of medium increases. The determined stability constants of 1:1 and 1:2 complexes at various concentrations of hydrochloric acid were extrapolated to zero ionic strength, based on the specific ion interaction theory (SIT) approach. The limiting stability constants were determined to be $$ { \log }_{10} \beta_{11}^{\text{o}} $$ = 8.56 ± 0.13 and $$ {\log}_{10} \beta_{12}^{\text{o}} $$ = 15.17 ± 0.18 with ion interaction coefficients of Δ ε = -0.57 ± 0.02 kg·mol and Δ ε = -0.60 ± 0.04 kg·mol, respectively. [ABSTRACT FROM AUTHOR]

A modified PVC (polyvinyl chloride) membrane with clinoptilolite nanoparticles/hexadecyltrimethyl ammonium bromide surfactant (HDTMABr)/Arsenazo III: (NSMZ-ARS), was used for construction of Al(III) –selective electrode. The raw and modified samples were characterized by XRD, FTIR, SEM and TEM methods. Among the different tested membranes constructed by raw and modified samples, only, the membrane electrode containing NSMZ-ARS showed a suitable Nernstian response to aluminum in the concentration range of 2.04 × 10 −5 to 1.99 × 10 −1 M ( r = 0.9987), with a detection limit of 1.0 × 10 −5 mol L −1 and a Nernstian slope of 19.6 ± 0.5 mV per decade of aluminum concentration. The electrode response to aluminum remained constant in the pH range of 2–4. The sensor was selective for aluminum over a wide variety of other ions and exhibited. The electrode had a rapid response time and its response reached to steady potential at 5 s. The electrode had also satisfactory long term stability and held its activity at least 3 months. [ABSTRACT FROM AUTHOR]

Clinoptilolite nanoparticles (NClin) modified with hexadecyltrimethyl ammonium bromide surfactant (HDTMABr) and Arsenazo III (ARS) was used for the modification of carbon paste electrode. The modified electrode was used for voltammetric determination of Cesium. The peak current of semi-reversible electrochemical peaks of Arsenazo III was decreased by adding cesium to the solution and hence this decrease was used for the determination of cesium in solution. The electrode response can be controlled by diffusion of cesium to the surface of the modified electrode. The modified electrode showed a suitable linear calibration graph in the concentration ranges of 8.4 × 10 −8 –1.0 × 10 −3 , 9.6 × 10 −9 –1.0 × 10 −3 and 8.0 × 10 −9 –1.0 × 10 −3 mol L −1 cesium with detection limits of 3.6 × 10 −8 , 3.0 × 10 −9 and 2.4 × 10 −9 mol L −1 of Cs + for CV, SqW and chronoamperometric methods, respectively. The proposed electrode showed high selectivity for cesium among the tested cations and good recovery results confirmed applicability of the sensor for Cs determination in real samples. [ABSTRACT FROM AUTHOR]

A simple, rapid, accurate and precise spectrophotometric method is proposed for determining sulphadiazine (SDA) in pure from and in its pharmaceutical and veterinary preparations. The method is based on oxidation-reduction reaction between SDA and cerium(IV) ion (ceric ion), then the subsequent reaction of cerium(III) with arsenazo III reagent in acidic medium to produce a green-blue complex which is stable, water soluble and has a maximum absorption at 654 nm with a molar absorptivity of 1.22*10^5 l.mol^-1. cm^-1. beer's law is obeyed in the concntration range from 1 to 10mg SDA in a final volume of 25 ml. The proposed method has been applied successfully to determine SDA in pharmaceutical and veterinary preparations.

A new solvent-impregnated resin (SIR) was constructed using Amberlite XAD-2 and 3-hydroxy-2-naphthoic acid (3H2NA). The SIR was applied for stepwise extraction of Th(IV) and U(VI) from the coexistence ions dissolved in aqueous media at pHs of 3.0 and 7.0, respectively. The U(VI) and Th(IV) ions adsorbed on the minicolumn were consecutively eluted with 0.5 M and 4 M HCl solutions. They were then measured by Arsenazo III at their maximum absorption wavelengths. The characteristic parameters for the successful separation of these ions from the aqueous media were investigated. The SIR showed excellent reproducibility during the 800 subsequent extraction cycles. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) were functionalized with the indicator dye Arsenazo III via reductive synthesis of AuNPs in the presence of arsenazo III. The indicator dye is shown to be immobilized on the AuNPs via interaction between gold and sulfo groups. The functionalized AuNPs undergo aggregation in the presence of uranyl ion due to the coordination interaction between arsenazo III and uranyl ion. This is accompanied by a longwave shift of the surface plasmon resonance absorption band (from 535 nm to 548 nm) and an up to 46.8 % increase in absorbance. This finding forms the basis for a photometric assay for uranyl ion. It shows good selectivity and has a 0.5 μM detection limit. Applied to the determination of uranyl ion in spiked environmental water samples, the recoveries were between 97 and 106 %. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A new Th(IV) ion-imprinted polymer (IIP) was synthesized for the separation and recovery of trace Th(IV) ion from river water sample. Th(IV) IIP was prepared by copolymerization of methyl methacrylate (monomer) and ethylene glycol dimethacrylate (cross-linker) in the presence of Th(IV)-thiosemicarbazide-4-vinyl pyridine ternary complex wherein Th(IV) ion is the imprint ion and is used to form the imprinted polymer. Thorium(IV) ion was eluted with 10 mL of 1 M HCl. The polymers have been characterized by surface area measurements, fourier transform infrared spectroscopy, microanalysis and scanning electron microscopy analysis. The adsorption capacity of the imprinted polymer was found to be 0.290 mmol g−1, which is much higher than most of the reported IIPs. The optimum pH for quantitative enrichment is 4.0. The relative selectivity coefficient values of the imprinted polymer for Th(IV)/Pb(II), Th(IV)/Zn(II), Th(IV)/Cu(II), Th(IV)/Ni(II), Th(IV)/Cd(II) and Th(IV)/Co(II) are 37.13, 37.40, 30.34, 35.69, 37.63 and 36.28, respectively. The lowest concentration that could be determined by Arsenazo III spectrophotometric method below which the recovery becomes non-quantitative is 5 μg L−1. [ABSTRACT FROM AUTHOR]

A hybrid imprinted polymer was synthesized using 3-(trimethoxysilyl) propylmethacrylate 4 vinylpyridine as the inorganic monomer, metacrilic acid as the organic monomer, and the uranile ion as the template. The synthesis was performed via a sol-gel technique. The polymer was sieved and introduced into a minicolumn, which was coupled in a flow injection system with spectrophotometric detection to preconcentrate uranium and allow its determination at low concentration. The method had a linear dynamic range between 2.0–100 µg L−1, a detection limit of 0.40 µg L−1, a preconcentration factor of 97, a concentration efficiency of 19.4 min−1, a consumptive index of 0.227 mL, and a sampling frequency of 10 analyzes h−1. The imprinted polymer had an adsorptive capacity of 1.77 mg g−1. The method was employed for the determination of uranium in effluent and river water. The precision, expressed as the relative standard deviation, was lower than 5.5%. The accuracy was investigated by comparison with alpha spectrometry; the results were statistically the same. The speed of the process is an advantage compared to the traditional alpha spectrometry. In addition, the present method is green because of the low consumption of sample and reagents and is a useful alternative for uranium determination. [ABSTRACT FROM AUTHOR]

A new study has been conducted to quantify lanthanide(III) ions using Arsenazo III–polyaminocarboxylic acid (PACA) system. The study disclosed two different analytically important information: (i) λ max of lanthanide–Arsenazo III complexes for lighter lanthanides like Ce(III) and Nd(III) did not shift from its original position on addition of PACA and (ii) for heavier lanthanides like Dy(III), Tm(III) and Lu(III) a new λ max at 538 nm was observed, while wavelengths at 610 nm and 654 nm were disappeared in presence of ethylenediaminetertracetic acid (EDTA) and trans -1,2-Diaminocyclohexane-N,N,N′,N′-tetraacetic acid (DCTA), further the intensity of peak decreased with increase in lanthanide(III) ion concentration. Effect of ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA) and N-(2-hydroxyethyl) ethylenediamine-N,N′,N′-triacetic acid (EDTA-OH) on Arsenzo(III)–Ln(III) complex is very weak and there is no analytically importance of such interaction. Moreover, this work confirms that Nd(III) and heavy lanthanides can be successfully determined with high accuracy in the working range of concentration of these metal ions. [ABSTRACT FROM AUTHOR]

The possibility of the sequential determination of nickel with dimethylglyoxime and zirconium with arsenazo III from a single aliquot portion using polyacrylonitrile fiber as a solid phase impregnated with a KU-2 cation exchanger is studied. Conditions for the simultaneous adsorption of nickel and zirconium in the dynamic mode from 0.01 M HNO are found as along with the ones for their sequential determination on one disc. The calibration functions are linear in the range 5-50 ng/mL, the detection limits for both elements are 2 ng/mL. In their simultaneous presence, the determination of nickel and zirconium is not affected by 10-fold weight amounts of Fe(III), Cu(II), Co(II), Al, Mn(II), Pb, Zn, Cd, Cr(VI), Mo(VI), and V(V). A method is proposed for determining nickel and zirconium from a single aliquot portion on a single substrate disc at their ratios from 1: 1 to a 5-fold excess of each element. [ABSTRACT FROM AUTHOR]

The use of double J ureteral stents can lead to several adverse effects, as urinary infection. Bacteria tend to colonize the stent surface, leading to the formation of bacterial biofilms. The presence of urease-producing bacteria increase the urine pH leading to the incrustation and blockage of the stent. On the other hand, these large crystalline masses function as niduses, allowing the attachment of even more bacteria and decreasing its exposure to antibiotics. The aim of this in vitro study was to assess the effect of phytate on the attachment of bacteria to the catheter surface under conditions that favor crystallization. Catheter sections were incubated in a synthetic urine medium (pH 6.5) in the presence or absence of Pseudomonas aeruginosa and phytate. Amount of calcium deposits was measured using an Arsenazo III colorimetric method and the number of attached bacteria to the stent was determined. Differences were assessed using an ANOVA with a Bonferroni post hoc test. The formation of calcium phosphate deposits (brushite and hydroxyapatite) and oxalate crystals (COM), as were as the amount of bacteria decreased when phytate was present. Thus, phytate successfully decreased bacterial adhesion by inhibiting the formation of crystalline deposits., (© 2022. The Author(s).)

This technical note reports for the first time the simultaneous vapor generation of 16 rare-earth elements (REEs) via reaction with sodium tetrahydroborate (THB). Significant improvement in REE vapor generation efficiency was discovered in the presence of arsenazo III (ARS). Subsequent to a critical evaluation on the impacts of various experimental variables, including the concentrations of acids, THB, and ARS, blank-limited (reagent contamination and impurity from ARS) detection limits (LODs) in the range of 0.004-0.15 μg L -1 were achieved based on three times the standard deviation of the method blank by the proposed vapor generation inductively coupled plasma mass spectrometry (ICP-MS). The nature of released REE species was studied by various approaches and identified to be REE nanoparticles and REE-ARS chelates; a dual-route mechanism for the vapor generation of REEs was thereby proposed.

Highlights: [•] Accurate measurement of uranium is with great importance in the nuclear fuel cycle. [•] Fe(II) added to a gamma irradiated U(VI) solution can give rise to Fenton reaction. [•] The induced Fenton reaction can decompose the subsequently added Arsenazo III. [•] With γ radiation and ferrous iron, a new U measurement method needs to be developed. [Copyright &y& Elsevier]

Uranium is a very toxic and radioactive element. Removal of uranium from wastewaters requires remediation technologies. Actual methods are costly and ineffective when uranium concentration is very low. Little is known about the enhancement of sorption of uranyl ions by phosphate ions on aluminosilicates. Here, we studied sorption of uranyl acetate on red clay in the presence of phosphates. The concentration of U(VI) ranged 0.0001-0.001 mol/L, whereas the concentration of PO was constant at 0.0001 mol/L. We designed a new method for the analysis of ternary surface complexes. We observed for the first time a remarkable improvement of U(VI) sorption on red clay under the influence of phosphates. We also found that at least two different ternary surface complexes U(VI)-phosphate-clay are formed in the sorbent phase. The complexation of UO cations by phosphate ligands in the sorbent phase was confirmed by the X-ray photoelectron spectra of U 4f electrons. [ABSTRACT FROM AUTHOR]

A surfactant-functionalized polyacrylonitrile (SFPAN) was synthesized in the present investigation via gamma radiation-induced polymerization and was applied for sorbing two hazardous organics, Thoron (TH) and Arsenazo III (ARIII), from radioactive liquid waste. Efficient removals were achieved for both organics over a wide range of pH. The sorption kinetic studies of TH and ARIII revealed that the equilibrium time is significantly dependent on the solution pH. Among the tested sorption kinetic models, the kinetic data of TH and ARIII fit well to the pseudo-second-order one. The sorption equilibrium data obtained for TH and ARIII were analyzed using Freundlich, Langmuir, Temkin and Dubinin-Radushkevich (D-R) isotherm models. The obtained results demonstrated that the equilibrium data are well described by Freundlich and D-R models. The calculated values of the sorption energy ( E) and the Gibbs free energy change ( ΔG) suggested that the sorption process of TH and ARIII onto SFPAN is governed by physisorption. SFPAN was further tested for the uptake of the concerned organics from radioactive process wastewater. The obtained results suggest its applicability for the treatment of liquid organic radioactive wastes. [ABSTRACT FROM AUTHOR]

An automated method is developed for the spectrophotometric determination of nanoamounts of uranium(VI) with Arsenazo III using online preconcentration by the coprecipitation of the uranium complex of the reagent with organic coprecipitants. The collector was an Arsenazo III ion pair with organic cations poorly soluble in water. The concentrate was separated by filtration through a cellulose fiber membrane and dissolved in a flow of an organic solvent; the analytical signal was recorded as the output peak. The developed method is characterized by simplicity, sufficiently high sensitivity, high throughput and rapidity, and can be used for the selective determination of uranium(VI) in complex liquid matrices. The detection limit is ∼0.01 ng/mL (3 s, n = 5, P = 0.95). The throughput of the method is 150 samples per hour. [ABSTRACT FROM AUTHOR]