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In this work the distribution coefficients (D) of polonium between 0.1 mol dm−3 TOPO/toluene; TOPO/cyclohexane; TBP/toluene and TBP/cyclohexane and aqueous solutions of inorganic acids (HCl, HNO3, H2SO4 and H3PO4) were determinated. The molarities of inorganic acids were between 0.5 and 12.0 mol dm−3. The activity of extracted Po-209 was measured by means of liquid scintillation counting. The best result was obtained for TOPO/toluene and 2 mol dm−3 H2SO4 system (D = 62 ± 9). The most stable conditions of extraction were found for TOPO/toluene-HCl system. [ABSTRACT FROM AUTHOR]

In an actual economic context, the demand for scandium has grown due to its applications in top technologies. However, further development of new technologies will lead to an increase in the market for Sc related to such technologies. The present study aims to improve and upgrade existing technology in terms of efficient scandium recovery, proposing a new material with selective adsorptive properties for scandium recovery. To highlight the impregnation of Amberlite XAD7HP resin with tri-n-octylphosphine oxide extractant by the solvent-impregnated resin method, the obtained adsorbent material was characterized by physico-chemical techniques. Further, the specific surface of the adsorbent and the zero-point charge of the adsorbent surface have been determined. Different parameters, such as initial concentration, adsorbent amount, contact time, or temperature, have been studied. The initial pH effect was investigated when a maximum adsorption capacity of 31.84 mg g−1 was obtained at pH > 3, using 0.1 g of adsorbent and a contact time of 90 min and 298 K. An attempt was made to discuss and provide a clear representation of the studied adsorption process, proposing a specific mechanism for Sc(III) recovery from aqueous solutions through kinetic, thermodynamic, and equilibrium studies. Adsorption/desorption studies reveal that the prepared adsorbent material can be reused five times. [ABSTRACT FROM AUTHOR]

Due to their toxicity and persistence in the environment, phenolic pollutants pose a serious threat to the ecosystem. In this work, the performance of hydrophobic deep eutectic solvents (HDESs) for phenol removal from aqueous effluents is thoroughly investigated using COSMO-RS screening followed by experimental validation. The screening results of 73 HDESs showed that the efficacy of phenol removal is significantly affected by chain length, functional groups, and aromaticity. Trioctylphosphine oxide (TOPO)-based HDESs were found to be the most effective HDESs for phenol elimination combined either with menthol (Men), 1-hexanol (Hex), Decanoic acid (DecA), or Thymol (Thy) all in 1:1 molar ratios. The better phenol elimination abilities of the selected HDESs were confirmed by experimental LLE data obtained at 298.15 K and 101 kPa. In fact, it has been found that there is a positive correlation between extraction efficiency and phenol content. For instance, at a phenol concentration of 7%, TOPO:Men had the highest extraction efficiency (96%). Moreover, the physicochemical properties of the selected HDESs, such as density, viscosity, FTIR, 1HNMR, and TGA, were also measured. The results showed their high thermal stability and low water solubility, which makes them suitable for phenol extraction applications. This study shows that HDESs are capable of removing phenolic contaminants from aqueous effluents in a sustainable and efficient manner and that the selected TOPO-based HDESs are of particular interest for further research and application in phenol removal. [ABSTRACT FROM AUTHOR]

In an actual economic context, the demand for scandium has grown due to its applications in top technologies. However, further development of new technologies will lead to an increase in the market for Sc related to such technologies. The present study aims to improve and upgrade existing technology in terms of efficient scandium recovery, proposing a new material with selective adsorptive properties for scandium recovery. To highlight the impregnation of Amberlite XAD7HP resin with tri-n-octylphosphine oxide extractant by the solvent-impregnated resin method, the obtained adsorbent material was characterized by physico-chemical techniques. Further, the specific surface of the adsorbent and the zero-point charge of the adsorbent surface have been determined. Different parameters, such as initial concentration, adsorbent amount, contact time, or temperature, have been studied. The initial pH effect was investigated when a maximum adsorption capacity of 31.84 mg g−1 was obtained at pH > 3, using 0.1 g of adsorbent and a contact time of 90 min and 298 K. An attempt was made to discuss and provide a clear representation of the studied adsorption process, proposing a specific mechanism for Sc(III) recovery from aqueous solutions through kinetic, thermodynamic, and equilibrium studies. Adsorption/desorption studies reveal that the prepared adsorbent material can be reused five times.

The kinetics of U(VI) ion transport from an aqueous donor phase to an aqueous acceptor phase were investigated using a recently designed system, the multi-dropped liquid membrane system (MDLM). Equilibrium and kinetic studies were performed involving the extraction of U(VI) from an aqueous nitrate medium into tri-n-octyl phosphine oxide (TOPO). The influences of temperature, carrier, and donor phase concentrations were investigated. U (VI) was extracted from the donor phase to the acceptor in 45 min with an extraction efficiency of about 99.62% under optimum conditions. The interface reactions' kinetic parameters (k1, k2, C B max , t B max , J d max , J a max ) were estimated on the assumption of two successive, irreversible first-order reactions. This study investigated the conditions of transport by TOPO in the extraction of U(VI) ions in the MDLM system and obtained successful results. [ABSTRACT FROM AUTHOR]

The long-term use is one of the weaknesses of polymeric inclusion membranes. The present study focuses on the identification of the optimal conditions of the membrane and aqueous solutions compositions that will allow long-term use of polymeric inclusion membranes. We tried to find out a way to minimize the loss of the membrane organic phase of a polymer inclusion membrane (PIM). For this purpose, PIMs consisting of cellulose triacetate (CTA) as a base polymer and three different carriers, Aliquat 336 (basic), di-(2-ethylhexyl) phosphoric acid (D2EHPA) (acid) and trioctylphosphine oxide (TOPO) (neutral), were elaborated. The stability of the obtained membranes was studied in detail by determining their mass loss when immersed in aqueous solutions containing various salts or acids. The results showed that the stability of the PIMs is heavily influenced by the various studied parameters. The highest stability was recorded in HNO3 acidic medium (pH1) and 1 M NaNO3 medium where a mass loss < 5% wt. was observed. Besides, the PIM containing TOPO was found to be more stable than that containing Aliquat 336 which is in its turn more stable than that containing D2EHPA. The membranes based on Aliquat 336 and TOPO have excellent stability up to T = 60 °C; however, the membrane containing D2EHPA becomes unstable when the temperature is > 25 °C. One of the most relevant results is that the mass loss also depends on the saturation of the aqueous phase by carrier; a better stability is obtained in the case of a continuous immersion. Thus, the membrane can be kept stable for a period of up to 1 month. Finally, this study shows that it is possible to optimize the conditions that allow to stabilize membranes for extended use by adjusting the aqueous medium and membrane composition. [ABSTRACT FROM AUTHOR]

In this study, a solvometallurgical process for the recovery of Cu from industrial dust by leaching with a lixiviant comprising hydrochloric acid (HCl) and ethylene glycol followed by extraction with trioctylphosphine oxide (TOPO) was developed. Copper, Ni, Mg, and Al contained in the dust were efficiently dissolved by using HCl in ethylene glycol, leaving most of the Ag in the residue. The parameters (concentration of the lixivant, reaction temperature, pulp density) that affect leaching efficiency were extensively investigated and optimized. TOPO was used to selectively extract Cu over other metal ions (Ni, Mg, Al, and Ag) from the obtained leachate. The Cu extraction mechanism was investigated by using the slope method, and 0.1 mol/L sulfuric acid was used to strip Cu from the Cu-loaded TOPO. McCabe–Thiele plots for Cu extraction and stripping were constructed to determine the number of counter-current stages along with the volumetric flow ratio of the two phases. Counter-current Cu extraction and stripping simulation tests were carried out to confirm its feasibility. Finally, a flow diagram of the proposed process for separation and recovery of Cu from industrial dust is provided. [ABSTRACT FROM AUTHOR]

Novel series of amidines were synthesized via the interaction between alicyclic amines, cyclic ketones, and a highly electrophilic 4-azidoquinolin-2(1H)-ones without any catalyst or additive. All the obtained products were elucidated based on NMR spectroscopy, mass spectrometry, and elemental analysis. The reaction conditions were optimized using cyclohexanone (2), piperidine (3a), and 4-azido-quinolin-2(1H)-one (1a) under an air atmosphere. The new compounds 4a-l and 5a-c were tested for antiproliferative activity against four cancer cell lines using doxorubicin as a reference drug. The most potent derivatives were compounds 4b, 4d, 4e, 4i, and 5c, with GI50 ranging from 1.00 µM to 1.50 µM. Compound 5c was the most effective derivative against the four cancer cell lines, outperforming doxorubicin. The compounds 4b, 4d, 4e, 4i, and 5c were studied further as topoisomerase I and IIα inhibitors. The compounds tested showed selective inhibition of topo I over topo IIα. Finally, docking studies explain why these compounds prefer topo I over topo IIα.

In the present work, the experimental investigation and modeling of Th(IV) metal ions recovery have been carried out by using the recycling mode of the multi-dropped liquid membrane (MDLM) technique. Experiments were done at operational conditions: studies of the MDLM system with single and double reactor column (continuous system). The optimum condition for the extraction of Th(IV) was a 0.50 M HNO3 solution as donor phase, 0.10 molL-1 TOPO as a carrier, and 0.10 M H2SO4 as acceptor phase. The transport percentage of Th(IV) was increased up to >98% and the calculated activation energy which is 6.52 kcalmol-1 indicated that the process was diffusion controlled by Th(IV) ions. The reuptake efficiencies of the extraction of Th(IV) ions in the presence of Cd(II), Cu(II), Ni(II), and Pb(II) separately under optimized experimental conditions were investigated. Therefore, the MDLM system might be useful for the design and the optimization of the recovery of Th(IV) in the recycling mode.

The solvent extraction of Cr(VI) using trioctylphosphine oxide (TOPO), 2,4,4-trimethylpentyl phosphinic acid (Cyanex 272) and their mixture in cyclohexane was investigated. From the pH variation study, the extraction is found to be decreased with increase in pH and maximum extraction was noticed around pH 1.0. Maximum percentage extraction of Cr(VI) with 0.1 M concentration of TOPO, Cyanex 272, and their mixture were found to be 96.7, 46.5, and 97.3%, respectively. Highest loading capacity of 586 mg/L was reported using 0.05 M of TOPO + Cyanex 272. Synergism was observed for each set of experiment. TOPO was found to be better synergist than Cyanex 272. The order of extraction when investigating the different extraction parameters were TOPO + Cyanex 272 > TOPO > Cyanex 272. [ABSTRACT FROM AUTHOR]

A search is initiated for new solvents for liquid–liquid extraction (LLE) chemistry of actinides for future separations. Of late, reports on deep eutectic solvents (DES), which resemble ionic liquids, are on the rise. Two hydrophobic DES based on tri–n-octylphosphine oxide (TOPO) and simple dicarboxylic acids, namely, oxalic acid and its higher homologue, malonic acid are prepared and characterized by FT-IR, UV–Vis, water content, density and viscosity measurements. The LLE chemistry of U(VI) and Am(III) is carried out using the above DES as a function of a few parameters and UV–Vis and IR spectra of the extracted phases were also recorded. The results are discussed with appropriate explanations in this report. [ABSTRACT FROM AUTHOR]

In this study, a solvometallurgical process for the recovery of Cu from industrial dust by leaching with a lixiviant comprising hydrochloric acid (HCl) and ethylene glycol followed by extraction with trioctylphosphine oxide (TOPO) was developed. Copper, Ni, Mg, and Al contained in the dust were efficiently dissolved by using HCl in ethylene glycol, leaving most of the Ag in the residue. The parameters (concentration of the lixivant, reaction temperature, pulp density) that affect leaching efficiency were extensively investigated and optimized. TOPO was used to selectively extract Cu over other metal ions (Ni, Mg, Al, and Ag) from the obtained leachate. The Cu extraction mechanism was investigated by using the slope method, and 0.1 mol/L sulfuric acid was used to strip Cu from the Cu-loaded TOPO. McCabe–Thiele plots for Cu extraction and stripping were constructed to determine the number of counter-current stages along with the volumetric flow ratio of the two phases. Counter-current Cu extraction and stripping simulation tests were carried out to confirm its feasibility. Finally, a flow diagram of the proposed process for separation and recovery of Cu from industrial dust is provided.

Demand for scandium (Sc) has been increasing in recent years. However, there are almost no ores containing Sc, and the supply is insufficient because the separation and recovery of Sc as a byproduct from oxide minerals such as ilmenite ore, bauxite, and laterite are difficult. In this study, extraction and separation of Sc3+ from acidic chloride or acidic nitrate solutions containing transition metals such as Fe3+, Co2+, Ni2+, Zn2+, and Pd2+ were studied using N-lauroylsarcosine (NLS) and tri-n-octylphosphine oxide (TOPO), which together create a "deep eutectic solvent" (DES). Owing to the respective selectivity of NLS and TOPO by different extractive interactions between metal ions and the two extractants in toluene, Sc3+ was effectively and selectively separated even from Fe3+ in the aqueous ammonium nitrate solution, the mutual separation of which is difficult with NLS alone. The mutual separation of Sc3+ and Fe3+ in acidic chloride solution is in general very difficult, while the mutual separation of these metals from acidic nitrate solution is successful. This is due to either anions forming complexes with Sc3+ in the aqueous phase (chloride) or not (nitrate). The potential use of the combination of the NLS with TOPO for selective recovery of Sc3+ from Fe3+ in a refining process is demonstrated. [ABSTRACT FROM AUTHOR]

The extraction of Terbium (III)from aqueous nitrate solutions with a supported liquid membrane was investigated using a mixture of di-(2-ethylhexyl phosphoric acid (D2EHPA) and tri-octyl phosphine oxide (TOPO) with a molar ratio 1/0.4. The Hydrophobic Polyvinylidene Fluoride (PVDF) membrane was used as solid support. The sorption process followed pseudo-second-order kinetics. The quantity of 8.29 mg/g was extracted using a Supported Liquid Membrane (SLM). The influence of the ionic strength, stirring rate, extraction time, and the interactions between them on the extraction yield of Terbium (III) ions was investigated using the factorial designs. The analysis of variance was used to show the relative importance of the extraction process parameters.

O uso do solo no maciço residual de Uruburetama, associado ao aspecto agrícola e ambiental é possivel graças as características ambientais. As Serras de Uruburetama, abrange 973,43 km² estando localizada na região norte do Estado do Ceará. Como procedimento metodológico, foi realizado uma revisão literária para fundamentar o aspecto do relevo, e de suas características. Os resultados permitiem estabelecer, duas áreas denominadas de quadrante I e II, adequadas a compartimentação geomorfológica de (Topo, Vertente e Vale). Como considerações finais observou-se na relação entre os tipos de vertentes nas formas de cultivo repercutindo na alteração da paisagem associada a degradação agrícola, em razão da ausência de manejo adequado do solo e da água.

The recovery of iron from Electric Arc Furnace (EAF) smelter slags via hydrochloric acid leaching and solvent extraction was investigated with a view to developing a simple hydrometallurgical route for the recovery of iron from secondary sources such as smelter slags. Slag samples obtained from a scrap iron processing plant in Ile-Ife, Nigeria was used in this study. Results from leaching tests indicated that the dissolution is chemical reaction controlled. Solvent extraction of Fe (III) from the leachate using trioctyl phosphine oxide indicated that the extraction of iron from chloride media depends on the chloride concentration and the media's pH. [ABSTRACT FROM AUTHOR]

The extraction of terbium (III) from aqueous nitrate solutions with a supported liquid membrane was investigated using a mixture of di-(2-ethylhexyl phosphoric acid (D2EHPA) and tri-octyl phosphine oxide (TOPO) with a molar ratio 1/0.4. The mixture was dissolved in diethyl ether which served as a carrier. The hydrophobic polyvinylidene fluoride (PVDF) membrane was used as a solid support. SEM images and FTIR spectra showed that the PVDF membrane was modified after impregnation. The sorption process followed a pseudo-second-order kinetics. 8.29 mg∙g-1 was extracted using a supported liquid membrane (SLM). The mixture D2EHPA / TOPO (1/0.4) presented a synergistic effect. The influence of the ionic strength, stirring rate, extraction time, and the interactions between them on the extraction yield of terbium (III) ions was investigated using the factorial designs. The analysis of variance (ANOVA) was used to show the relative importance of the extraction process parameters. Student’s t-test to the results of the factorial plane 33, with 30 runs for terbium (III) extraction, showed that the stirring rate in the studied ranges was statistically important. The amount of Tb (III) extracted after 12 cycles was 73.624 mg∙g-1.

[Display omitted] • TOPO/PAN capsules are facile synthesis and low cost; • U(VI) has fast kinetic adsorption rate (about 1 h) and large adsorption capacity(161.8 mg/g) on TOPO/PAN capsules in the acidic solution; • TOPO/PAN capsules exhibited good selectivity for U(VI) in the acidic solution and excellent reusability. The adsorption capacity and adsorption rate of most adsorbents for U (VI) are maximum in the pH value range of 5 ∼ 9. However, uranium-containing wastewater produced during uranium mining is usually highly acidic. Therefore, it is of great significance to prepare adsorbents suitable for the separation and enrichment of U(VI) ions from strongly acidic solutions. PAN capsules were synthesized by phase transformation method, and then impregnated TOPO in PAN capsules by impregnation method. TOPO/PAN has good morphology and higher adsorption capacity for U(VI) under acidic conditions. The effects of time, solid–liquid ratio, pH and ionic strength on TOPO/PAN adsorption of U(VI) were studied. The experimental results showed that the pseudo-second-order kinetic model and Langmuir model well described the kinetic and equilibrium data of adsorption process. The capsules have fast adsorption rate, good adsorption capacity and good ion selectivity in highly acidic solutions. After 5 cycles, the adsorption rate of TOPO/PAN is still above 96 % and the adsorption rate decreases by 1.2 %, which indicate that TOPO/PAN has good reusability. The research shows that TOPO/PAN has good practical application value. [ABSTRACT FROM AUTHOR]

Novel methods of separation and purification are envisaged for natural uranium, containing 0.7% of fissile 235U, a precious resource that fuels nuclear power plants. The present study demonstrates Solid phase extraction (SPE) of uranium as a sustainable alternative to conventional liquid-liquid extraction, leading to minimisation of organic inventory and enhancement of ease of operation concerning usage of viscous eutectic solvent. Overcoming the issue of the low solubility of organophosphorus extractant tri-octyl phosphine oxide (TOPO) in a hydrocarbon diluent, the aqueous insoluble, non-ionic eutectic solvent could be prepared with biodegradable menthol having TOPO: menthol mole ratio of 1:2 (MT2), 1:3 (MT3) and 1:4 (MT4). Eutectic solvents were sorbed on radio chemically stable Chromosorb W resin as solid support (MTC2, MTC3, MTC4), with loading of 45% for MTC2 and 40% for both MTC3 and MTC4, confirmed by weight difference and thermogravimetry. Batch sorption studies of U(VI) from nitric acid medium revealed attainment of equilibrium at 60 min., following a pseudo-second-order rate equation, Langmuir adsorption isotherm and a static capacity of 19 mg g−1. The U(VI) uptake was found to increase with the increase in acid molarity indicating solvating mechanism of extraction (K D = 1240 ± 4, 4 M HNO 3). Recyclability was established and stripping was effective with 0.5 M HNO 3. Column operation was also successfully demonstrated (breakthrough capacity = 18.9 mg g−1). The U(VI) uptake of >98% was indicated for nitric acid-digested crude yellow cake matrices viz. sodium diuranate (SDU), magnesium diuranate (MDU) and heat-treated uranium peroxide (HTUP). For higher matrix content, near complete uranium uptake and suppression of extraction of representative impurities (Fe, Mn, Ni, Ce) was revealed indicating facile uranium separation and purification from matrices relevant to the front end of the nuclear fuel cycle. • Bulk uranium SPE scheme, from matrices relevant to front-end, with TOPO and biodegradable menthol sorbed Chromosorb W • Reusable stationary phase simplifying process and minimising oragnic inventory • Batch and column operation reveal high U(VI) uptake (K D = 1240 ± 4) and capacity (19 mg g−1) • Chemisorption of uranyl, confirmed by UV–Vis spectrophotometry, IR and electrometry, onto TOPO in stationary phase • Demonstrated U(VI) uptake (> 98%) and suppression of extraction of representative impurities (Fe, Mn, Ni, Ce) [ABSTRACT FROM AUTHOR]

The process of recycling lithium (Li) from common coal fly ash using strong acids can release substantial quantities of hazardous low-value residues, and the complex ionic composition of the acidic leaching solution hinders the selective extraction of Li. Accordingly, a green and economical approach was developed for the selective recovery of Li and extraction of valuable Al-rich residues from high-alumina fly ash (HAFA). In HAFA, the glass phase (the main Li-bearing phase) can be selectively dissolved in the mild NaOH solution at 95 °C for 2 h, and valuable mullite phase (the main Al-bearing phase) was retained in the leaching residue (Al 2 O 3 content 49.00 wt%). The leaching efficiencies of Li, Si, and Al were 91.60%, 43.19%, and 3.56%, respectively. Among the primary metallic elements present in HAFA, only Li, Na, K, and Al in the glass phase were readily dissolved in the alkaline solution. Meanwhile, the synergistic extraction system of HBTA and TOPO has good complexing ability with Li + compared to Al3+, K+, and Na+. Therefore, Li+ can be selectively extracted from alkaline leaching solutions using HBTA and TOPO. The Li extraction efficiency reached 99.68% after three consecutive extractions under the optimal conditions. Finally, the used alkali leaching solution and synergistic extractants can be regenerated via Ca(OH) 2 precipitation and HCl reverse extraction. These findings can provide new strategies for the green and overall utilization of HAFA. [ABSTRACT FROM AUTHOR]

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A methodology for separation and purification of 210Po from uranium, thorium and daughters has been studied. Solvent extraction coupled with liquid scintillation analysis using HDEHP (di-(2-ethylhexyl) phosphoric acid) and TOPO (trioctylphosphine oxide) in toluene as extractive scintillator was optimized. About 95% of 210Po was extracted in the organic phase of TOPO as an extracting agent from an aqueous solution in 1 M HCl, compared to 1.6% extraction by HDEHP. The methodology was validated with uranium ore tailing sample, IAEA-385 sediment and IAEA-447 Moss-soil reference materials for application to environmental samples. A minimum detectable activity of 118 mBq kg−1 was achieved. [ABSTRACT FROM AUTHOR]

In this study, the transport and mechanism of Fe(III) ions in acidic solution were investigated by using TOPO as carrier dissolved in kerosene with multi-drop membrane system. The parameters which are important in the transport of Fe(III) ions and their effects on the extraction process have been studied. These parameters are the effects of concentration of HCl solutions of donor phase, concentration of NaCl solutions of acceptor phase, concentration of TOPO solution of organic phase, transfer rate of organic phase, and temperature of the system. The optimum conditions for extraction of Fe(III) ions was conducted as 2.00 M of HCl and 100 mgL-1 Fe(III) ions for donor phase, 1.5x10-2 M of TOPO, 2.00 M NaCl of acceptor phase, 50 mLmin-1 of flux rate at 298.15 K. Over time, the reduction curves of the Fe(III) ions in the donor phase showed good agreement with the experimental data on the organic and acceptor phases. The activation energy was determined as 25.79 kJmol-1 and the extraction of Fe(III) ions was carried out by an intermediated-controlled process. [ABSTRACT FROM AUTHOR]

Graphical abstract Integrated process for the separation and recovery of Ag(I) from the nitrate solution used to leach the solar cell. Highlights • Ag(I) and Al(III) were separated from solar cell nitrate leachate with TOPO. • TOPO selectively extracted Ag(I) over Al(III) in 10 mol/m3 HNO 3 solution. • Selective stripping of Ag(I) was successful with 100 mol/m3 thiourea solution. • TOPO was regenerated by stripping of co-loaded Al(III) with 3000 mol/m3 HNO 3. Abstract For the recovery of Ag(I) from the leachate of silicon solar cells, a nitrate solution containing Ag(I) and Al(III) was subjected to solvent extraction with trioctylphosphine oxide (TOPO). TOPO selectively extracted Ag(I) over Al(III) at low nitric acid concentrations. Most of the Ag(I), along with small amount of Al(III), was extracted from the 10 mol/m3 nitric acid solution using 500 mol/m3 TOPO. HNO 3 stripped both Ag(I) and Al(III) from the metal-loaded TOPO, whereas thiourea could selectively strip Ag(I) from the loaded TOPO. Metal-loaded TOPO could be regenerated after stripping of Ag(I) with thiourea, followed by stripping of Al(III) with HNO 3. A process flow sheet for Ag(I) recovery from the nitrate leachate of silicon solar cells was proposed. [ABSTRACT FROM AUTHOR]

Dowex 1×4-trioctylphosphine oxide powder (DTP) was prepared, characterized, and studied as an adsorbent for the adsorption of Th(IV) from aqueous solutions. The adsorption of Th(IV) strongly depends on pH. The adsorption follows the pseudo-second-order kinetics, and the adsorption isotherms agree well with the Langmuir model with a maximum adsorption capacity of 132.1 mg g−1. [ABSTRACT FROM AUTHOR]

In this study, two novel supported liquid membranes (SLMs) was developed by using Trioctylphosphine oxide (TOPO) and N-(furane-2-iylmethyl)-N'-hydroxy-2-oxo-2-(4-phenylphenyl) eteneimideamide (BKOF) as a carrier that have different functional groups, each dissolved in the organic phase N-N-dimethyl formamide. Hydrophobic polyvinylidene fluoride (PVDF) and polyamide microporous membranes were used as support to prepare these membranes. Developed membranes were characterized with several analytical methods, including scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and thermal gravimetric analysis (TGA). Characterization processes confirm the novelty of membranes due to different surface morphologies of prepared SLMs, compared to the PVDF and polyamide supports. Performance of prepared SLMs were evaluated by rejection tests for Ni(II) and Fe(III)) from aqueous solutions by using Donnan dialysis method. The highest flux values were obtained when the feed phase concentration of 1.0x10-1 M NiCl2.6H2O or 1.0x10-1 M Fe(NO3)3.9H2O, the strip phase concentration of 1.0x10-1 M HCl or 1.0x10-1 M HNO3, respectively. [ABSTRACT FROM AUTHOR]

• The maximum separation factor of ∼ 4418 was achieved between Nb and Ta. • 'Cation exchange' predominates in ionic liquid; while 'solvation' in n -dodecane. • Spontaneous and exothermic liquid–liquid mass transfer. • Formation of outer-sphere complex. • High degree of radiolytic stability and good recyclability. The present investigation demonstrated the mutual separation Nb and Ta from their mixture in hydrochloric acid medium using TOPO in an ionic liquid (C 6 mim•NTf 2). The maximum separation factor achieved was ∼ 4400. In C 6 mim•NTf 2 , the extraction proceeded via 'cation exchange' mechanism with M O C l 2. T O P O I L + as the species; while in n-dodecane the extraction proceeded via neutral 'solvation' mechanism with MO Cl 3. 2 T O P O as the extracted species (where, M = Nb and Ta). The sluggish extraction in C 6 mim•NTf 2 was attributed to the its high viscosity coefficient compared to n-dodecane. The extraction was found to be spontaneous and exothermic in nature with a reduction in overall entropy indicating the formation of outer-sphere complexes. Dilute acid was found to be effective for the back extraction of Nb and Ta from the loaded n-dodecane phase, while EDTA - guanidine carbonate or DTPA - Guanidine carbonate were effective for back extraction from the ionic liquid phase. It was found that 2–3 contacts were sufficient for the quantitative back extraction of the metal ions. The C 6 mim•NTf 2 based solvent systems exhibited better radiolytic stability compared to that of the n-dodecane based solvent system. [ABSTRACT FROM AUTHOR]

The extraction of thorium oxalate concentrate as processing product of monazite using Tri Octyl Posfine Oxide (TOPO) has been done. The most impurities contained in thorium oxalate concentrate are Ce (cerium) and La (lanthanum). The purpose of this study is to purify Th by separating Ce and La using extraction process. The extraction is done by bacth and multistage. The solution of feed or water phase is 10 grams of Th oxalate concentrate dissolved in 10.08 M HNO3 so that the volume becomes 100 mL and the organic phase is TOPO in kerosene. Stripping in each stage conducted three times, first stripping use water, second stripping use 5 % oxalic acid and the third stripping use water. Extraction time at every stage is 15 minutes and stripping time at every stage is 5 minutes with ratio of aqueous phase to organic phase = 1 : 1 . The parameters were studied % TOPO - kerosene and number of extraction stage. The optimum usage of TOPO in kerosene is 5 %. On extraction I obtained Ce concentrate and on extraction II and III obtained Th concentrates. The extraction II efficiency of Th is 39.76 % and extraction III efficiency of Th is 26.33 % . Coefficient of distribution (Kd) of Th in stage II is 0.7587 and Kd of Th in stage III is 1.0096. Total extraction efficiency of Th is 80.08 %, total extraction efficiency of Ce is 56.12 %, and total extraction efficiency of La is 1.54 %. The separation factor of Th – Ce in extraction I is 1.00 and separation factor of Th – La in extraction I is 92.0, separation factor of Th – Ce in extraction II is 250.24, and separation factor of Th – La in extraction II is ∞. Separation factor of Th – Ce in extraction III is 124.22 and separation factor of Th – La in extraction III is ∞. Total separation factor of Th – Ce is 1.4270 and total separation factor of Th – La is 4.0459. The content of Th oxalate in stripping product from the extraction II is 97.06 % and in stripping product from the extraction III is 98.00%.

PARP-1 could repair the DNA damages induced by Topo inhibitors, therefore inhibiting Topo and PARP-1 simultaneously might be able to overcome resistance and improve outcomes. In this study a series of 4-amidobenzimidazole acridines were designed and synthesized as dual Topo and PARP-1 inhibitors. Compound 11l displayed good inhibitory activities against Topo and PARP-1, as well as significantly inhibited cancer cells proliferation. Further mechanistic evaluations indicated that 11l treatment in MCF-7 cells induced accumulated DNA double-strand breaks, prompted remarkable apoptosis, and caused prominent G0/G1 cell cycle arrest. Moreover, 11l greatly suppressed tumor growth in mice, and displayed favorable metabolic properties in liver microsomes. Our study suggested that single agents inhibiting Topo and PARP concurrently might be an alternative for cancer therapy and 11l represented a potential lead compound for development of antitumor agents. [ABSTRACT FROM AUTHOR]

Quantum dot nanocrystals have particular optical properties due to the quantum confinement effect and the surface effect. This study focuses on the effects of organic materials capping quantum dot on the emission properties of quantum dots. The quantum dots prepared by using 1-hexadecylamine in the synthesis show strong emission, while the quantum dots prepared by using tri-octylphosphine oxide exhibit a suppressed emission and an extra emission related with the surface energy traps. These organic materials cap the quantum dots and make the surface conditions of quantum dots different. TEM images and X-ray diffraction patterns reveal that 1-hexadecylamine constructs a layer on the surface of quantum dot during the synthesis and this surface passivation by a layer of 1-hexadecylamine reduces the surface energy traps. Differently from 1-hexadecylamine, tri-octylphosphine oxide dangles from the surface, which causes a poorly passivated surface. This generates the surface deep trap levels giving rise to a significant and broad emission in the lower energy regime. The optical mechanism is studied by measuring the emission spectra and the time-resolved spectra at various temperatures from 4 K to 300 K. [ABSTRACT FROM AUTHOR]

The synergistic solvent extraction of cobalt (II) from sulfate aqueous solutions with capric acid (HL) and tri-n-octylphosphine oxide (TOPO) intochloroform, has been studied. The experimental data for the capric acid alone reveal the self-adduct formation CoL2(HL)2, in the organic phase. A remarkable enhancement on the extraction of cobalt (II) with capric acid was observed upon the addition TOPO. The synergistic enhancement was ascribed to the adduct formation CoL2(HL)2 n(TOPO) (n=1 or 2). The TOPO-HL interaction strongly influences the synergistic extraction efficiency. The value of the partition, dimerization and equilibrium constants were determined. [ABSTRACT FROM AUTHOR]

The titled system has been investigated using a single drop technique and flux (F) method of data treatment. In calculating fluxes, the time for drop formation and coalescence (Δt = 0.75 s) is considered. At lower concentration region of vanadium, V(V), the rate of V(V) transfer is directly proportional to its concentration. With the increase in [V(V)], slowly extractable V(V) species are formed gradually resulting in decrease in rate. Rate is directly proportional to the square root of [TOA]. It is reported that the most favorable extractable V(V) species exists in maximum amount at pH 2, and so, log F vs pH plots show a maximum at pH~2. The flux of V(V) transfer in most cases is found to be decreased with increasing [NO3-]. Reaction orders with respect to [V(V)], pH and [NO3-] have been attempted to be estimated, but in vein due to non-linearity of plots in most cases. Activation energies for the present system is ~-12 kJ/mol. This is unexpected but explained. Due to irregular variation of the composition of extractable species with [V(V)], [H+]; as well as temperature; it is not possible to elucidate the value of rate constant (k) and mechanism in simple way. [ABSTRACT FROM AUTHOR]

Taguchi method has been realized efficient for output improvement in research and development stage; so that high-quality items can be quickly produced at lower costs. Optimization of emulsion liquid membrane (ELM) for chromium extraction is achieved by Taguchi method. One of the main objectives of this work deals with the extraction of Cr(VI) using tri-octyl phosphine oxide (TOPO) as a carrier. Six parameters, namely carrier, surfactant, and internal phase concentration, feed phase pH, stirring speed and emulsion/external feed phase ratio, were chosen as the control factors while the initial concentration of chromium was chosen as the external noise factor. The results have been analyzed using analysis of variance (ANOVA) and signal-to-noise (S/N) ratio. From our results, combinations of all factors studied have a potential interaction. It can be noticed that the optimum external to emulsion ratio is the highest level. Indeed, this trend leads to treating large volumes of more dilute Cr(VI) solutions. This reflects the importance of ELM in which our system deviates from equilibrium that means a high mass transfer occurred. Maximum contribution for Cr(VI) extraction is obtained as 89.498% for TOPO concentration followed by Span 80 (4.393%), and the other parameters have a lower significance on ELM process (ranging from 1.750% to 1.299%). [ABSTRACT FROM AUTHOR]

In the method, soil was fused together with NaCO and NaO at 600 °C, uranium and thorium were leached out with HCl, HNO and HF, and HClO was used to eliminate the residual HF through evaporation. The leaching solution (2 M HNO) was passed through a Microthene-TOPO column to adsorb uranium and thorium. Thorium was first eluted with 2 M HCl and electrodeposited in 0.025 M HCO + 0.15 M HNO on a stainless steel disc. Uranium was eluted with a 0.025 M ammonium oxalate solution and also electrodeposited. Both thorium and uranium isotopes on the discs were measured separately by α-spectrometry. [ABSTRACT FROM AUTHOR]

Solid-phase extractant PVA[TTA][TOPO] beads containing thenoyltrifluoroacetone (TTA) and trioc - tylphoshine oxide (TOPO) were prepared for the removal of Sr(II) from aqueous solutions. PVA[TTA] [TOPO] beads were characterized by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and thermal gravimetry analysis (TGA). Kinetic parameters for pseudo first-order and pseudo second-order models and correlation coefficients (r²) of the Sr(II) were calculated, so the results showed that the kinetic data of Sr(II) removal by the prepared solid-phase extractant PVA[TTA][TOPO] beads followed the pseudo-second order reaction model. The equilibrium data fitted well with Langmuir-Freundlich isotherm model and the maximum removal capacity of Sr(II) was 12.59 mgg-1. The optimum pH region was in the wide range of 4-10. The result showed that PVA[TTA][TOPO] beads prepared in this study could be used as a solid-phase extractant for the removal of radioactive Sr(II) from aqueous solution. [ABSTRACT FROM AUTHOR]

El castillo de Constantina es una construcción realizada de un solo impulso, pero partiendo de una construcción previa (la camisa o antemural) y con algunas fases constructivas posteriores de menor relevancia, la datación de este edificio hay que situarla entre 1466 y 1474 años en los que Rodrigo Ponce de León fue alcaide de este castillo. La intervención arqueológica del año 2006 significó el diagnóstico de este yacimiento a nivel arquitectónico, arqueológico e histórico. Por todo ello, estimamos que se trata de un ejemplo excelente para documentar gráficamente la geometría de los restos arqueológicos encontrados y su relación con el entorno de la manera más fidedigna posible. Estas posibilidades en alza han estimulado la exigencia cada vez mayor en la toma de datos geomáticos de levantamientos topoarqueológicos.