Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 46
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Environ Sci Pollut Res Int ; 26(26): 27372-27384, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31321725

RESUMO

In order to enhance the removal of Sb(III) in wastewater, hyperbranched polyamide-functionalized sodium alginate (HA@SA) microsphere was prepared by grafting of hyperbranched polyamide (HA) on the surface of sodium alginate (SA) microsphere. Adsorption properties of Sb(III) were investigated via static and dynamic adsorption tests. The cycling reusability of HA@SA microspheres was explored through adsorption-desorption tests. The changes of HA@SA microspheres before and after adsorption were characterized by FT-IR, SEM-EDS, and XPS. Results showed that the maximum Sb(III) adsorption capacity of HA@SA microspheres reached up to 195.7 mg/g, improved by 1.16 times in comparison with SA microspheres. The Sb(III) adsorption processes of HA@SA microspheres were depicted by pseudo-second-order kinetics and the Langmuir isotherm models with accuracy. It covered a homogeneous single-layer adsorption controlled by chemisorption along with exotherm spontaneously. After recycling for 8 times, the adsorption capacity of HA@SA microspheres still retained higher than 90% of the original value.


Assuntos
Alginatos/química , Antimônio/isolamento & purificação , Nylons/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Antimônio/química , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Varredura , Microesferas , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente , Fatores de Tempo , Águas Residuárias/química , Poluentes Químicos da Água/química
2.
Food Chem ; 293: 378-386, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151625

RESUMO

Considering the negative impacts on human health and the environment, determinations of arsenic (As) and antimony (Sb), is of unquestionable importance. The present study describes the development of innovative and practical deep eutectic solvent (DES) based vortex assisted microextraction (DES-VAME) method for preconcentration of As and Sb from environmental waters, honey and rice prior to analysis by hydride generation-atomic absorption spectrometry (HG-AAS). The use of As(III) and Sb(III) in presence of dithizone at pH 10.5 by means of donor-acceptor mechanism were decided as analytes. Total As and Sb were determined after reduction process. The analytical properties obtained following optimization were as follows. Limit of detection (LOD), precision (as RSD%), recoveries and enhancement factor for As and Sb were calculated as 7.5 ng L-1/15.6 ng L-1, 2.1% /2.7%, 93.5%/96.2% and 104/85, respectively. Following validation with certified reference material, the method was successfully applied to the analysis of real samples.


Assuntos
Antimônio/isolamento & purificação , Arsênico/isolamento & purificação , Análise de Alimentos/métodos , Microextração em Fase Líquida/métodos , Antimônio/análise , Arsênico/análise , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Mel/análise , Concentração de Íons de Hidrogênio , Limite de Detecção , Microextração em Fase Líquida/instrumentação , Oryza/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Solventes/química , Espectrofotometria Atômica/métodos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação
3.
Chemosphere ; 226: 834-840, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30974376

RESUMO

In the environment, antimony as a priority control pollutant is mainly associated with Fe- or Mn- related minerals. In this work, acid birnessite (AB) doped with iron was synthesized as the artificial mineral to study the adsorption and oxidation of antimony. As compared to the pristine birnessite, Fe-doping birnessites show a markedly enhanced removal efficiency for both Sb(III) and Sb(V), where 10% Fe exhibited an excellent adsorption capacity of 759 mg/g Sb(III). The removal of Sb(III) clearly underwent a novel kinetic process of adsorption-desorption- (re-adsorption). By monitoring the kinetics with XRD, XPS, and IR, it is demonstrated that the three-stage kinetics were attributed to the strong interaction between Sb(III) and birnessite, including Sb(III) oxidation, followed by destruction of birnessite and then phase transformation into vernadite. Furthermore, the increase of iron content doped into birnessite enhanced the rate of its phase transition, which led to an increased adsorption of the oxidized antimony on the surface of vernadite by substituting iron and manganese associated with hydroxyl group. This work suggested that the strong interactions between heavy metal ions and mineral particles, more than adsorption, are critical to the transformation, mobility and biotoxicity of antimony in nature.


Assuntos
Antimônio/isolamento & purificação , Poluentes Ambientais/isolamento & purificação , Ferro/química , Óxidos/química , Adsorção , Antimônio/química , Poluentes Ambientais/química , Cinética , Manganês/química , Metais Pesados , Oxirredução
4.
Molecules ; 24(4)2019 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-30769766

RESUMO

The main aim of the research was to develop a complementary analytical approach consisting of bespoke speciation analysis and non-targeted speciation analysis of As, Sb, and Cr in flavored bottled drinking water samples using HPLC/ICP-DRC-MS and ESI-MS/MS. The scope of two previously developed analytical procedures, (1) multielemental speciation procedure for AsIII, AsV, CrVI, SbIII, and SbV analysis and (2) arsenic speciation procedure for AsB, AsIII, DMA, MMA, and AsV quantification, was extended to the analysis of a new sample type in terms of bespoke speciation analysis. As for the non-targeted speciation, analysis size exclusion chromatography was used with ICP-MS and a complementary technique, ESI-MS/MS, was used for the organic species of As, Sb, and Cr screening. Full validation of procedures 1 and 2 was conducted. Procedure 1 and 2 were characterized with precision values in the range from 2.5% to 5.5% and from 3.6% to 7.2%, respectively. Obtained recoveries ranged from 97% to 106% and from 99% to 106% for procedures 1 and 2, respectively. Expanded uncertainties calculated for procedures 1 and 2 ranged from 6.1% to 9.4% and from 7.4% to 9.9%, respectively. The applicability of the proposed procedures was tested on bottled drinking water samples. Results for the real samples in procedure 1 were in the range from 0.286 ± 0.027 [µg L-1] to 0.414 ± 0.039 [µg L-1] for AsIII, from 0.900 ± 0.083 [µg L-1] to 3.26 ± 0.30 [µg L-1] for AsV, and from 0.201 ± 0.012 [µg L-1] to 0.524 ± 0.032 [µg L-1] for SbV. CrVI and SbIII were not detected in any sample. As for procedure 2, results were in the range from 0.0541 ± 0.0053 [µg L-1] to 0.554 ± 0.054 [µg L-1] for AsB. Results for AsIII and AsV obtained with procedure 2 were in good accordance with results obtained with procedure 1. DMA and MMA were not detected in any sample.


Assuntos
Antimônio/isolamento & purificação , Arsênico/isolamento & purificação , Cromo/isolamento & purificação , Água Potável/química , Antimônio/química , Arsênico/química , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Cromo/química , Humanos , Limite de Detecção , Análise Espectral , Espectrometria de Massas em Tandem
5.
J Environ Manage ; 228: 336-345, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30241039

RESUMO

In order to intuitively and clearly evaluate the potential and current distribution, the fluid flow and mixing, as well as mass transfer involved in electrocoagulation process for As and Sb removal, numerical simulation of electric field, flow field and mass transfer were constructed by Comsol Multiphysics and verified by experiments. Results displayed that the primary current and potential distribution were improved by changing electrode distance or adding insulator in a batch reactor. When configuration 2 and 2 cm electrode distance were applied, a more uniform primary current distribution and higher electrode current efficiency were obtained. In a continuous flow reactor, the increase of flow rate resulted in the left shift of the peak in residence time distribution curve, gradual decrease of the tailing area, reduction of the stagnation zone, and more uniform mixing of the fluid. However, higher than 0.043 L/min was unfavorable to the formation of flocs and its effective combination with pollutants. According to the simulation of mass transfer, at the initial stage, the rate of electrolysis/hydrolysis was greater than that of mass transfer. Fe2+, OH-, and Fe(OH)2 were primarily concentrated on the anode, cathode, and between the two electrodes, respectively. Under the action of electromigration, diffusion and convection, the concentration distribution of Fe(OH)2 increased at the direction of streamline. The concentration of Fe2+ and OH- achieved the minimum value at the outlet. However, Fe(OH)+ concentration and distribution were hardly affected by the treatment time, and once generated, immediately proceed to the next hydrolysis reaction.


Assuntos
Antimônio/isolamento & purificação , Arsênico/isolamento & purificação , Eletrocoagulação/métodos , Eletrodos , Eletrólise
6.
Chemosphere ; 213: 533-540, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30253325

RESUMO

Co-contamination of arsenic (As) usually occurs with antimony (Sb) in Sb mine ores. However, the mobility and bio-availability of Sb and As in different types of mine impacted soils have received relatively little attention. This study aimed to investigate the fraction, mobility and removal of Sb and As in three types of polluted soils using environmentally friendly and cost-effective extractants. In the present study, lightly polluted (L), moderately polluted (M), and 3) highly polluted (H) soils were collected from the Xikuangshan (XKS) mine area in Hunan, China. Toxicity risk assessment, fraction and extraction of Sb and As were performed to evaluate Sb and As mobility and availability. According to the speciation fractions, the percent of residual Sb was larger than As in all studied soils, which suggested that As is far more mobile than Sb. Sb and As extractabilities from selected polluted soils were compared and ranked as: citric acid > tartaric acid > EDTA > HCl > Na2HPO4 > CaCl2. Citric acid showed the highest extractabilities for both Sb and As (up to 24% for total Sb and 41% for total As respectively). Moreover, obvious alteration of Sb and As fractionations in three types of soils were observed after chemical extractions. The mobility of Sb and As increased after extraction by citric acid and tartaric acid, suggesting that these organic acids can make soil trace metals more bio-available and that, Sb/As polluted soils can be remediated via phytoextraction.


Assuntos
Antimônio/isolamento & purificação , Arsênico/isolamento & purificação , Poluentes do Solo/isolamento & purificação , Antimônio/análise , Antimônio/farmacocinética , Arsênico/análise , Arsênico/farmacocinética , Disponibilidade Biológica , China , Ácido Cítrico , Poluentes do Solo/análise , Poluentes do Solo/farmacocinética , Tartaratos
7.
J Sep Sci ; 41(19): 3660-3668, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30058764

RESUMO

Six compounds including two n-butyrophenone isomers and two stibene isomers were obtained from Rheum tanguticum Maxim. Two n-butyrophenone isomers with a separation factor of 1.14 were successfully separated by recycling high-speed counter-current chromatography after ten cycles. Two stibene isomers were successfully separated by preparative high-performance liquid chromatography. High-performance liquid chromatography analysis showed that the purities of the compounds were all over 98%. These compounds were identified as lindleyin, isolindleyin, resveratrol-4'-O-(2″-O-galloyl)-glucopyranoside, resveratrol-4'-O-(6''-O-galloyl)-glucopyranoside, emodin 1-O-ß-d-glucoside, and 3,5-dihydroxy-4'-methoxystilbene-3-O-ß-d-glucopyranoside. The results indicated that recycling high-speed counter-current chromatography and preparative high-performance liquid chromatography could be effective combination for the preparation of bioactive compounds from Rheum tanguticum Maxim.


Assuntos
Antimônio/isolamento & purificação , Butirofenonas/isolamento & purificação , Rheum/química , Antimônio/química , Butirofenonas/química , Cromatografia Líquida de Alta Pressão , Distribuição Contracorrente , Estereoisomerismo
8.
Ecotoxicol Environ Saf ; 156: 125-134, 2018 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-29549735

RESUMO

A significant amount of antimony (Sb) enters into the environment every year because of the wide use of Sb compounds in industry and agriculture. The exposure to Sb, either direct consumption of Sb or indirectly, may be fatal to the human health because both antimony and antimonide are toxic. Firstly, the introduction of Sb chemistry, distribution and health threats are presented in this review, which is essential to the removal techniques. Then, we provide the recent and common techniques to remove Sb, including adsorption, coagulation/flocculation, membrane separation, electrochemical methods, ion exchange and extraction. Removal techniques concentrate on the advantages, drawbacks, economical efficiency and the recent achievements of each technique. We also take an overall consideration of experimental conditions, comparison criteria, and economic aspects.


Assuntos
Antimônio/isolamento & purificação , Saúde Pública , Animais , Monitoramento Ambiental , Cadeia Alimentar , Contaminação de Alimentos/análise , Água Subterrânea/química , Humanos , Solo/química , Poluentes do Solo/isolamento & purificação , Verduras/química , Poluentes Químicos da Água/isolamento & purificação
9.
Environ Sci Pollut Res Int ; 25(1): 916-929, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29076021

RESUMO

This study gives a contribution to assess the efficacy of some LDHs (layered double hydroxides) in Sb(V) uptake and understand the mechanisms involved in the removal process. Uncalcined nitrate Mg/Al LDHs and the mixed Mg-Al oxides derived from calcined carbonate Mg/Al LDHs mainly remove Sb(OH)6- from aqueous solution through the formation of a brandholzite-like phase (a non-LDH compound with general formula Mg[Sb(OH)6]2·6H2O), although with a different efficiency (< 50 and 90-100% of Sb(V) removed, respectively). The formation of a brandholzite-like compound highlights the fundamental role of Mg in the removal process. The Sb(OH)6- removal capacity of uncalcined nitrate Mg/Al LDHs increases from 22 to 46% as the Mg/Al molar ratio decreases from 4 to 2 thanks to the increasing excess of positive charge of brucite-like sheets and the expanding interlayer thickness due to the different spatial orientations of nitrate groups (flat for Mg/Al = 4, perpendicular for Mg/Al = 2). The presence of Fe3+ in the trivalent cationic site of carbonate LDHs (Mg/(Al + Fe) = 3/(0.5 + 0.5)) improves the Sb(OH)6- removal capacity of their calcined products. When Mg is replaced by Zn in the divalent cationic site of carbonate LDHs and the sorption experiments are performed using the mixed Zn-Al oxides derived from calcination, Sb(OH)6- is mainly removed from the solution through the reconstruction of an antimonate LDH structure (i.e., a zincalstibite-like compound with general formula Zn2Al(OH)6[Sb(OH)6]). The removal efficiency of calcined carbonate Zn/Al LDHs is high and comparable to that of calcined carbonate Mg/Al LDHs; however, the mechanisms involved in the removal process are substantially different: entrance of Sb(OH)6- in the interlayer in the first case, adsorption of Sb(OH)6- onto the surface and formation of a new phase (a brandholzite-like compound) in the second case. In both cases, the removal processes are described with the pseudo-second-order kinetic model; the theoretical maximum adsorption capacity determined with the Langmuir isotherm results to be 4.54 and 4.37 mmol g-1 for calcined carbonate Mg/AlFe and Zn/Al LDHs, respectively.


Assuntos
Antimônio/química , Cátions/química , Hidróxidos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Antimônio/isolamento & purificação , Cinética , Nitratos/química , Oxirredução , Poluentes Químicos da Água/isolamento & purificação
10.
Environ Sci Technol ; 49(18): 11115-24, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26301862

RESUMO

Zirconium oxide (ZrO2)-carbon nanofibers (ZCN) were fabricated and batch experiments were used to determine antimonite (Sb(III)) and antimonate (Sb(V)) adsorption isotherms and kinetics. ZCN have a maximum Sb(III) and Sb(V) adsorption capacity of 70.83 and 57.17 mg/g, respectively. The adsorption process between ZCN and Sb was identified to be an exothermic and follows an ion-exchange reaction. The application of ZCN was demonstrated using tap water spiked with Sb (200 µg/L). We found that the concentration of Sb was well below the maximum contaminant level for drinking water with ZCN dosages of 2 g/L. X-ray photoelectron spectroscopy (XPS) revealed that an ionic bond of Zr-O was formed with Sb(III) and Sb(V). Based on the density functional theory (DFT) calculations, Sb(III) formed Sb-O and O-Zr bonds on the surface of the tetragonal ZrO2 (t-ZrO2) (111) plane and monoclinic ZrO2 planes (m-ZrO2) (111) plane when it adsorbs. Only an O-Zr bond was formed on the surface of t-ZrO2 (111) plane and m-ZrO2 (111) plane for Sb(V) adsorption. The adsorption energy (Ead) of Sb(III) and Sb(V) onto t-ZrO2 (111) plane were 1.13 and 6.07 eV, which were higher than that of m-ZrO2 (0.76 and 3.35 eV, respectively).


Assuntos
Antimônio/isolamento & purificação , Carbono/química , Nanofibras/química , Poluentes Químicos da Água/isolamento & purificação , Zircônio/química , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Modelos Moleculares , Nanofibras/ultraestrutura , Espectroscopia Fotoeletrônica , Teoria Quântica , Soluções , Temperatura Ambiente , Água/química , Difração de Raios X
11.
Environ Technol ; 36(20): 2647-56, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25894550

RESUMO

This study investigated whether a combined application of hydroxyapatite and ferrihydrite could immobilize lead and antimony in shooting range soil in which the level of lead contamination is markedly higher than that of antimony. In addition, we evaluated the stability of lead and antimony immobilized by the combined application with varying soil pH. The levels of water-soluble lead and antimony for the combined application were lower than those of single applications of hydroxyapatite or ferrihydrite, indicating that the combined application could suppress the levels of water-soluble lead and antimony by 99.9% and 95.5%, respectively, as compared with the levels in shooting range soil without immobilization material. The amounts of residual lead and amorphous Fe/Al oxide-bound antimony fractions in sequential extraction increased with a decrease in the exchangeable and carbonate lead fractions as well as in non-specifically bound and specifically bound antimony fractions. The alteration of lead and antimony phases to chemically more stable ones as a result of the combined application would result in the suppression of their mobility. The stability of immobilized lead and antimony in the combined application was equal to that of lead with a single application of hydroxyapatite and that of antimony with a single application of ferrihydrite within neutral to alkaline pH conditions, respectively. Therefore, this study suggests that the combined application of hydroxyapatite and ferrihydrite can simultaneously immobilize lead and antimony in shooting range soil with neutral to alkaline pH.


Assuntos
Antimônio/isolamento & purificação , Durapatita/química , Recuperação e Remediação Ambiental/métodos , Compostos Férricos/química , Chumbo/isolamento & purificação , Poluentes do Solo/isolamento & purificação , Antimônio/química , Armas de Fogo , Concentração de Íons de Hidrogênio , Chumbo/química , Poluentes do Solo/química
12.
J Environ Sci (China) ; 26(2): 307-14, 2014 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-25076522

RESUMO

We fabricated and characterized two hybrid adsorbents originated from hydrated ferric oxides (HFOs) using a polymeric anion exchanger D201 and calcite as host. The resultant adsorbents (denoted as HFO-201 and IOCCS) were employed for Sb(V) removal from water. Increasing solution pH from 3 to 9 apparently weakened Sb(V) removal by both composites, while increasing temperature from 293 to 313 K only improved Sb(V) uptake by IOCCS. HFO-201 exhibited much higher capacity for Sb(V) than for IOCCS in the absence of other anions in solution. Increasing ionic strength from 0.01 to 0.1 mol/L NaNO3 would result in a significant drop of the capacity of HFO-201 in the studied pH ranges; however, negligible effect was observed for IOCCS under similar conditions. Similarly, the competing chloride and sulfate pose more negative effect on Sb(V) adsorption by HFO-201 than by IOCCS, and the presence of silicate greatly decreased their adsorption simultaneously, while calcium ions were found to promote the adsorption of both adsorbents. XPS analysis further demonstrated that preferable Sb(V) adsorption by both hybrids was attributed to the inner sphere complexation of Sb(V) and HFO, and Ca(II) induced adsorption enhancement possibly resulted from the formation of HFO-Ca-Sb complexes. Column adsorption runs proved that Sb(V) in the synthetic water could be effectively removed from 30 microg/L to below 5 microg/L (the drinking water standard regulated by China), and the effective treatable volume of IOCCS was around 6 times as that of HFO-201, implying that HFO coatings onto calcite might be a more effective approach than immobilization inside D201.


Assuntos
Antimônio/isolamento & purificação , Compostos Férricos/química , Adsorção , Resinas de Troca de Ânions/química , Carbonato de Cálcio/química , Concentração de Íons de Hidrogênio , Concentração Osmolar
13.
J Agric Food Chem ; 62(34): 8586-93, 2014 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-25072530

RESUMO

A UV Fenton-like digestion method was developed first time for a complete digestion of milk samples by using 1.6 g L(-1) Fe3O4 magnetic nanoparticles, 0.2% (v/v) nitric acid, and 6% (w/w) H2O2. During the digestion, the liberated As-, Sb-, and Bi-containing species were preconcentrated onto the surface of Fe3O4 magnetic nanoparticles, which were conveniently separated with a hand-held magnet and subsequently dissolved in hydrochloric acid prior to hydride generation atomic fluorescence spectrometric detection. Owing to the integration of UV Fenton-like digestion, solid phase extraction, and magnetic separation into a single step, the developed method significantly simplifies sample preparation steps and reduces chemical consumption and hazardous waste. Limits of detection of 0.0015, 0.0022, and 0.0025 µg L(-1) were obtained for As, Sb, and Bi, respectively, using a 50 mL milk sample. The method was applied to the determination of these elements in a Certified Reference Material and milk samples.


Assuntos
Antimônio/química , Arsênico/química , Bismuto/química , Técnicas de Química Analítica/métodos , Contaminação de Alimentos/análise , Leite/química , Extração em Fase Sólida/métodos , Animais , Antimônio/isolamento & purificação , Arsênico/isolamento & purificação , Bismuto/isolamento & purificação , Peróxido de Hidrogênio/química , Ferro/química , Nanopartículas de Magnetita/química , Extração em Fase Sólida/instrumentação
14.
Int J Phytoremediation ; 16(4): 347-65, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24912236

RESUMO

Allchar mine is an abandoned arsenic-antimony-thallium deposit located on the northwestern part of Kozuf Mt., Republic of Macedonia. Allchar is a unique deposit within the world, due to the variety of its mineral composition especially and in the high content of thallium. The aim of this work was to assess the level of contamination at this post-mining area as well as to determine the intensity of accumulation of various elements (Ag, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Ga, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Sb, Sr, Tl, V, and Zn) with focus on As, Sb and Tl, in two endemic Viola species from this locality (Viola allcharensis G. Beck, Viola arsenica G. Beck) and one Balkan endemic species (Viola macedonica Boiss. & Heldr.). Samples of different plant parts and soil were digested and then analysed by ICP-AES. It was found that the accumulation of As, Sb, and Tl in these endemic species is significantly high. In this study a systematic investigation of the As-Sb-Tl contamination of soils and their bioavailability was carried out using the extraction procedure in order to explore the mobility and potential bioavailability of the As, Sb, and Tl.


Assuntos
Metais Pesados/metabolismo , Poluentes do Solo/metabolismo , Viola/metabolismo , Antimônio/análise , Antimônio/isolamento & purificação , Antimônio/metabolismo , Arsênico/análise , Arsênico/isolamento & purificação , Arsênico/metabolismo , Biodegradação Ambiental , Monitoramento Ambiental , Flores/metabolismo , Metais Pesados/análise , Metais Pesados/isolamento & purificação , Mineração , Especificidade de Órgãos , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Caules de Planta/metabolismo , Sementes/metabolismo , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/isolamento & purificação , Tálio/análise , Tálio/isolamento & purificação , Tálio/metabolismo
15.
Appl Radiat Isot ; 86: 57-62, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24491376

RESUMO

Whatman 3MM™ and Tec-Control™ systems were evaluated as ITLC-SG alternatives for 99mTc-radiopharmaceuticals. They compare well in accuracy and reproducibility, and are faster and more convenient than ITLC-SG. Tec-Control™ radiochemical purity values for 99mTc-sestamibi were more conservative than ITLC-SG. Full solvent migration was not reproduced for 99mTc-tetrofosmin in Tec-Control™, and for this Whatman 3MM™ is preferred. Developing times were 10-15 min, 7-9 min and ~1min for ITLC-SG, Whatman 3MM™ and Tec-Control™, respectively. Overall, Tec-Control™ strips are preferred due to speed and ease of use.


Assuntos
Cromatografia em Camada Delgada/métodos , Tecnécio/isolamento & purificação , Antimônio/isolamento & purificação , Controle de Qualidade , Compostos Radiofarmacêuticos/química , Reprodutibilidade dos Testes , Sulfetos/isolamento & purificação , Medronato de Tecnécio Tc 99m/isolamento & purificação , Tecnécio Tc 99m Sestamibi/isolamento & purificação , Coloide de Enxofre Marcado com Tecnécio Tc 99m/isolamento & purificação
16.
J Hazard Mater ; 268: 229-36, 2014 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-24509094

RESUMO

Hematite coated magnetic nanoparticle (MNP@hematite) was fabricated through heterogeneous nucleation technique and used to remove trace Sb(III) from water. Powder X-ray diffraction, transmission electron microscopy (TEM), and alternating gradient magnetometry were utilized to characterize the prepared adsorbent. TEM image showed that MNP@hematite particles were spherical with size of 10-30nm. With saturation magnetization of 27.0emu/g, MNP@hematite particles could be easily separated from water with a simple magnetic process in short time (5min). At initial concentration of 110µg/L, Sb(III) was rapidly decreased to below 5µg/L by MNP@hematite in 10min. Sb(III) adsorption capacity of MNP@hematite was 36.7mg/g, which was almost twice that of commercial Fe3O4 nanoparticles. The removal of trace Sb(III) was not obviously affected by solution pH (over a wide range from 3 to 11), ionic strength (up to 100mM), coexisting anions (chloride, nitrate, sulfate, carbonate, silicate, and phosphate, up to 10mM) and natural organic matters (humic acid and alginate, up to 8mg/L as TOC). Moreover, MNP@hematite particles were able to remove Sb(III) and As(III) simultaneously. Trace Sb(III) could also be effectively removed from real tap water by MNP@hematite. The magnetic adsorbent could be recycled and used repeatedly.


Assuntos
Antimônio/isolamento & purificação , Compostos Férricos/química , Nanopartículas de Magnetita/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Arsenicais/isolamento & purificação , Concentração de Íons de Hidrogênio , Cinética , Concentração Osmolar , Soluções
17.
Talanta ; 115: 814-8, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24054667

RESUMO

A simple, sensitive and efficient method of ultrasound-assisted emulsification of solidified floating organic drop microextraction (USE-SFODME) coupled to electrothermal atomic absorption spectrometry for the speciation of antimony at different oxidation state Sb(III)/Sb(V) in environmental samples was established. In this method, the hydrophobic complex of Sb(III) with sodium diethyldithiocarbamate (DDTC) is extracted by 1-undecanol at pH 9.0, while Sb(V) remains in aqueous phase. Sb(V) content can be calculated by subtracting Sb(III) from the total antimony after reducing Sb(V) to Sb(III) by l-cysteine. Various factors affecting USE-SFODME including pH, extraction solvent and its volume, concentration of DDTC, sonication time, and extraction temperature were investigated. Under the optimized conditions, the calibration curve was linear in the range from 0.05 to 10.0 ng mL(-1), with the limit of detection (3σ) 9.89 ng L(-1) for Sb(III). The relative standard deviation for Sb(III) was 4.5% (n=9, c=1.0 ng mL(-1)). This method was validated against the certified reference materials (GSB 07-1376-2001, GBW07441), and applied to the speciation of antimony in environmental samples (soil and water samples) with satisfactory results.


Assuntos
Antimônio/isolamento & purificação , Ditiocarb/química , Poluentes do Solo/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Calibragem , Cisteína/química , Emulsões , Álcoois Graxos/química , Concentração de Íons de Hidrogênio , Limite de Detecção , Microextração em Fase Líquida/métodos , Sonicação , Espectrofotometria Atômica
18.
Water Sci Technol ; 68(3): 658-64, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23925195

RESUMO

A novel kind of iron oxide supported on carbon nanotubes (CNTs) was prepared for adsorption of antimony (Sb)(III) in aqueous solution. The iron (III) oxide (Fe2O3)-modified CNTs were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption and Fourier transform infrared spectrometer. Parameters affecting the adsorption efficiencies, including solution pH value, initial Sb(III) concentration, adsorbent dosage, adsorption time and temperature, were investigated. The results indicate that the removal rate of Sb(III) by Fe2O3-modified CNTs is 99.97% under the initial Sb(III) concentration of 1.5 mg/L, adsorbents dosage of 0.5 g/L, temperature of 25 (o)C and pH value of 7.00, which is 29.81% higher than that of the raw CNTs. The adsorption capacity increased correspondingly from 3.01 to 6.23 mg/g. The equilibrium adsorption data can be fitted to the Freundlich adsorption isotherm. In addition, it has been found that the solution pH values and adsorption temperatures have no significant influence on Sb(III) removal.


Assuntos
Antimônio/química , Compostos Férricos/química , Nanotubos de Carbono/química , Poluentes Químicos da Água/química , Adsorção , Antimônio/isolamento & purificação , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos
19.
Waste Manag ; 33(6): 1478-82, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23561798

RESUMO

There has been a recent interest in antimony since the availability in readily mined areas is decreasing compared to the amounts used. It is important in many applications such as flame retardants and in the production of polyester, which can trigger an investigation of the leachability of antimony from plastics using different acids. In this paper, different types of acids are tested for their ability to leach antimony from a discarded computer housing, made of poly(acrylonitrile butadiene styrene), which is a common plastic type used in electrical and electronic equipment. The acid solutions included sodium hydrogen tartrate (0.5M) dissolved in either dimethyl sulfoxide or water (at ca. 23°C and heated to ca. 105°C). The metal content after leaching was determined by inductively coupled plasma optical emission spectroscopy. The most efficient leaching medium was the heated solution of sodium hydrogen tartrate in dimethyl sulfoxide, which leached almost half of the antimony from the poly(acrylonitrile butadiene styrene). Gamma irradiation, which is proposed to improve the mechanical properties in plastics, was used here to investigate the influence of antimony leaching ability. No significant change in the amount of leached antimony could be observed.


Assuntos
Antimônio/isolamento & purificação , Resíduo Eletrônico , Plásticos/química , Resinas Acrílicas/química , Butadienos/química , Computadores , Dimetil Sulfóxido/química , Raios gama , Microscopia Eletrônica de Varredura , Poliestirenos/química , Soluções , Espectroscopia de Infravermelho com Transformada de Fourier , Tartaratos/química , Temperatura Ambiente
20.
Talanta ; 107: 162-6, 2013 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-23598207

RESUMO

A speciation system for antimony (III) and antimony (V) ions that based on solid phase extraction on tetraethylenepentamine bonded silica gel has been established. Antimony was determined by graphite furnace atomic absorption spectrometry (GF-AAS). Analytical conditions including pH, sample volume, etc., were studied for the quantitative recoveries of Sb (III) and Sb (V). Matrix effects on the recovery were also investigated. The recovery values and detection limit for antimony (III) at optimal conditions were found as >95% and 0.020 µg L(-1), respectively. Preconcentration factor was calculated as 50. The capacity of adsorption for the tetraethylenepentamine bonded silica gel was 7.9 mg g(-1). The validation was checked by analysis of NIST SRM 1573a Tomato laves and GBW 07605 Tea certified reference materials. The procedure was successfully applied to speciation of antimony in tap water, mineral water and spring water samples. Total antimony was determined in refined salt, unrefined salt, black tea, rice, tuna fish and soil samples after microwave digestion and presented enrichment method combination.


Assuntos
Antimônio/isolamento & purificação , Monitoramento Ambiental/métodos , Etilenodiaminas/química , Análise de Alimentos/métodos , Sílica Gel/química , Espectrofotometria Atômica/métodos , Antimônio/análise , Grafite/química , Limite de Detecção , Lycopersicon esculentum/química , Folhas de Planta/química , Solo/análise , Extração em Fase Sólida/métodos , Chá/química , Água/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA