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1.
Water Sci Technol ; 88(11): 2862-2872, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38096074

RESUMO

Elimination of the matrix effect is a major challenge in developing a method for the quantification of heavy metals (HMs) in water samples. In this regard, the current research describes the simultaneous analyses of Cu(II), Cd(II), and Ni(II) ions in water matrices through flame atomic absorption spectrophotometry (FAAS) after preconcentration with carrier element-free co-precipitation (CEFC) technique by the help of an organic co-precipitant, 3-{[5-(4-Chlorobenzyl)-3-(4-chlorophenyl)-1H-1,2,4-triazol-1-yl]-methyl}-4-[2,4-(dichlorobenzylidene)amino]-1H-1,2,4-triazole-5(4H)-thione (CCMBATT). Based on our literature research, CCMBATT was employed for the first time in this study as an organic co-precipitant for the preconcentration of HMs. Factors such as solution pH, concentration of co-precipitant, sample volume, standing time, centrifugation rate, and time were thoroughly examined and optimized to achieve the highest efficiency in terms of HM recovery. The limits of detection (LODs) (with 10 number of tests) of 0.54, 0.34, and 1.95 µg L-1 and the relative standard deviations (RSD %) of 2.1, 3.3, and 3.0 were determined for Cu(II), Cd(II) and Ni(II) ions, respectively. Recovery results of HMs for the spiked samples were in the range of 92.8-101.0%, demonstrating the trueness of the method and its applicability to the water samples matrix.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Cádmio/análise , Rios , Metais Pesados/análise , Água/análise , Limite de Detecção , Espectrofotometria Atômica/métodos , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/análise , Íons
2.
J Water Health ; 21(7): 869-883, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37515559

RESUMO

Natural mulberry leaves and carboxylic acid-modified mulberry (Morus alba L.) leaves were used for the first time to scrutinize the effects of modification on the retention efficiency of an anionic dye (Remazol Brilliant Blue R (RBBR)) from aqueous solutions to suggest an economical and promising adsorbent for the treatment of dye-contaminated water. The characterization of the adsorbents was accomplished through common techniques including SEM, FTIR, and pHpzc determination. Several parameters studied in batch experiments pointed out that the initial pH of 2.0 and the contact time of 240 min were optimum conditions for all the developed RBBR uptake processes. An artificial neural network (ANN) model was applied to formulate a forecast model for the uptake efficiency of RBBR. The experimental data were assessed by different kinetic and isotherm models to explain the mechanism of the developed processes in more detail. Maximum monolayer adsorption capacities of natural mulberry leaves and acetic acid-, citric acid-, and oxalic acid-modified mulberry leaves were determined as 64.5, 95.2, 84.8, and 91.7 mg g-1, respectively, by the Langmuir isotherm model. These results demonstrated that the modification with carboxylic acids significantly increases the anionic dye adsorption capacity of the mulberry leaves.


Assuntos
Morus , Poluentes Químicos da Água , Corantes/química , Cinética , Adsorção , Ácidos Carboxílicos , Redes Neurais de Computação , Água , Folhas de Planta/química , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/análise , Termodinâmica
3.
Environ Monit Assess ; 193(10): 642, 2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-34508274

RESUMO

The present research describes the successful preparation of melon peel biochar modified with CoFe2O4 (MPBC/CoFe2O4) followed by its usage as a new sorbent to separate, preconcentrate, and determine the toxic heavy metal ions by magnetic solid-phase extraction. The metal ion desorption was performed by 0.1 M HCl solution with a volume of 5.0 mL. Flame atomic absorption spectrometry (FAAS) was utilized for detection of the analyte levels. SEM-EDX, TEM, XRD, and FTIR techniques were carried out to illuminate the structure of MPBC/CoFe2O4. The fundamental variables affecting the adsorption and elution efficiencies of the analyte ions including solution pH, MPBC/CoFe2O4 amount, type and concentration of eluent, adsorption and desorption equilibrium time, and sample volume were optimized. The detection limits were calculated as 0.41, 1.82, and 3.16 µg L-1 for Cu2+, Cd2+, and Pb2+ ions, respectively, with the relative standard deviation of lower than 4.2%. There were no substantial interference effects on the analyte ion recovery due to the presence of foreign ions at high levels. Five minutes of contact time was adequate to attain the adsorption equilibrium. The adsorption capacity of MPBC/CoFe2O4 was obtained as 106.4, 65.4, and 188.7 mg g-1 for Cu2+, Cd2+, and Pb2+ ions, respectively, by utilizing Langmuir isotherm model. The pseudo-second order model is favorable to identify the adsorption kinetics. The method was validated by spike/recovery test, and then, it was successfully implemented to determine the aforementioned analyte levels in sea and stream water, pepper, black cabbage, eggplant, and tomato samples.


Assuntos
Cucurbitaceae , Poluentes Químicos da Água , Adsorção , Cádmio/análise , Carvão Vegetal , Monitoramento Ambiental , Concentração de Íons de Hidrogênio , Chumbo , Extração em Fase Sólida , Espectrofotometria Atômica , Verduras , Água , Poluentes Químicos da Água/análise
4.
J Environ Health ; 77(6): 86-93, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25619041

RESUMO

In the study described in this article, the authors examined the relationship between heavy metals in the drinking water and cancer densities in residential areas. The Turkish cities of Trabzon, Rize, and Giresun in the eastern Black Sea region were chosen as the study areas. Cancer registry data, population information, heavy metal chemical analysis results for drinking water, and other spatial information for the region were collected in a database designed in GIS. Information on a total of 13,012 registered cancer cases from the years 2000-2007 was obtained from a cancer record center and depicted spatially on a map. The incidence values explaining cancer density in residential units were calculated. Chemical analyses were then conducted to determine the presence of 17 different heavy metals by collecting a total of 541 drinking water samples. It was determined that among the 17 analyzed heavy metals, beryllium, nickel, antimony, and molybdenum had a significant relationship with cancer incidence values in the residential units.


Assuntos
Carcinógenos/análise , Água Potável/análise , Metais Pesados/análise , Neoplasias/epidemiologia , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Sistemas de Informação Geográfica , Incidência , Modelos Lineares , Neoplasias/induzido quimicamente , Espectrofotometria Atômica , Turquia/epidemiologia
5.
Acta Chim Slov ; 60(2): 287-93, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23878931

RESUMO

A simple and highly sensitive separation and preconcentration procedure, which has minimal impact on the environment, has been developed. The procedure is based on the carrier element free coprecipitation (CEFC) of Co(II), Cu(II), and Ni(II) ions by using 2-{4-[2-(1H-indol-3-yl)ethyl]-3-(4-methylbenzyl)-5-oxo-4,5-dihydro- 1H-1,2,4-triazol-l-yl}-N'-(pyridin-2-yl methylidene)acetohydrazide (IMOTPA), as an organic coprecipitant. The levels of analyte ions were determined by flame atomic absorption spectrometry (FAAS). The detection limits for Co(II), Cu(II) and Ni(II) ions were found to be 0.40, 0.16 and 0.17 microg L(-1), respectively, and the relative standard deviations for the analyte ions were lower than 3.0%. Spike tests and certified reference material analyses were performed to validate the method. The method was successfully applied for the determination of Co(II), Cu(II) and Ni(II) ions levels in sea and stream water as liquid samples and red pepper, black pepper, and peppermint as solid samples.


Assuntos
Cobalto/análise , Cobre/análise , Contaminação de Alimentos/análise , Níquel/análise , Poluentes Químicos da Água/análise , Limite de Detecção , Modelos Químicos , Padrões de Referência , Espectrofotometria Atômica
6.
Environ Monit Assess ; 185(2): 1107-15, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22527456

RESUMO

A new, simple, and rapid separation and preconcentration procedure, for determination of Pb(II), Cd(II), Zn(II), and Co(II) ions in environmental real samples, has been developed. The method is based on the combination of coprecipitation of analyte ions by the aid of the Mo(VI)-diethyldithiocarbamate-(Mo(VI)-DDTC) precipitate and flame atomic absorption spectrometric determinations. The effects of experimental conditions like pH of the aqueous solution, amounts of DDTC and Mo(VI), standing time, centrifugation rate and time, sample volume, etc. and also the influences of some foreign ions were investigated in detail on the quantitative recoveries of the analyte ions. The preconcentration factors were found to be 150 for Pb(II), Zn(II) and Co(II), and 200 for Cd(II) ions. The detection limits were in the range of 0.1-2.2 µg L(-1) while the relative standard deviations were found to be lower than 5 % for the studied analyte ions. The accuracy of the method was checked by spiked/recovery tests and the analysis of certified reference material (CRM TMDW-500 Drinking Water). The procedure was successfully applied to seawater and stream water as liquid samples and baby food and dried eggplant as solid samples in order to determine the levels of Pb(II), Cd(II), Zn(II), and Co(II) ions.


Assuntos
Ditiocarb/química , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Contaminação de Alimentos/análise , Água Doce/química , Metais/análise , Molibdênio/química , Água do Mar/química , Cádmio/análise , Cádmio/química , Precipitação Química , Cobalto/análise , Cobalto/química , Poluentes Ambientais/química , Análise de Alimentos/métodos , Íons/análise , Chumbo/análise , Chumbo/química , Metais/química , Espectrofotometria Atômica , Zinco/análise , Zinco/química
7.
Environ Monit Assess ; 185(7): 6003-11, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23184397

RESUMO

The abundantly available industrial waste product Morus alba L. pomace (MAP) is one of the cost-effective biosorbent for removal of metal ions from aqueous solutions. Hence, in the present study, we aimed to test the ability of MAP to remove Cd(II) ions through batch biosorption process. Firstly, MAP was characterized using several techniques, and then the influence of various experimental parameters such as initial pH of the aqueous solution, initial Cd(II) concentration, contact time, MAP concentration, and temperature were evaluated upon the biosorption process. It was found that the maximum uptake of Cd(II) ions occurred at initial pH 6.0 and optimum contact time was observed as 60 min. Cd(II) ions adsorption on MAP analyzed by the Langmuir and Freundlich isotherm models and the maximum monolayer biosorption capacity of MAP was found to be 21.69 mg g(-1) by using the Langmuir isotherm model. The pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models were employed to describe the biosorption kinetics. In order to investigate the thermodynamic properties of the biosorption process, the changes in the Gibbs free energy (∆G), enthalpy (∆H), and entropy (∆S) were also evaluated and it has been concluded that the process was feasible, spontaneous, and endothermic in the temperature range of 5-40 °C.


Assuntos
Cádmio/metabolismo , Morus/metabolismo , Poluentes Químicos da Água/metabolismo , Adsorção , Biodegradação Ambiental , Cádmio/análise , Cátions Bivalentes/análise , Cátions Bivalentes/metabolismo , Concentração de Íons de Hidrogênio , Morus/crescimento & desenvolvimento , Temperatura , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise
8.
J Environ Manage ; 92(12): 3082-90, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21856065

RESUMO

The ability of Turkish illitic clay (TIC) in removal of Cd(II) and Pb(II) ions from aqueous solutions has been examined in a batch adsorption process with respect to several experimental conditions including initial solution pH, contact time, initial metal ions concentration, temperature, ionic strength, and TIC concentration, etc. The characterization of TIC was performed by using FTIR, XRD and XRF techniques. The maximum uptake of Cd(II) (11.25 mg g(-1)) and Pb(II) (238.98 mg g(-1)) was observed when used 1.0 g L(-1) of TIC suspension, 50 mg L(-1) of initial Cd(II) and 250 mg L(-1) of initial Pb(II) concentration at initial pH 4.0 and contact time of 240 min at room temperature. The experimental data were analyzed by the Langmuir, Freundlich, Temkin and Dubinin Radushkevich (D-R) isotherm models. The monolayer adsorption capacity of TIC was found to be 13.09 mg g(-1) and 53.76 mg g(-1) for Cd(II) and Pb(II) ions, respectively. The kinetics of the adsorption was tested using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models. The results showed that the adsorption of Cd(II) and Pb(II) ions onto TIC proceeds according to the pseudo-second-order model. Thermodynamic parameters including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes indicated that the present adsorption process was feasible, spontaneous and endothermic in the temperature range of 5-40 °C.


Assuntos
Silicatos de Alumínio/química , Cádmio/química , Chumbo/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Cádmio/análise , Argila , Concentração de Íons de Hidrogênio , Íons , Cinética , Chumbo/análise , Concentração Osmolar , Temperatura , Termodinâmica , Poluentes Químicos da Água/análise
9.
J AOAC Int ; 94(1): 286-92, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21391505

RESUMO

Cloud-point extraction (CPE) using the non-ionic surfactant Triton X-100 was used successfully to remove a highly toxic dye, rhodamine 6G (R6G), from water and wastewater. The effects of different analytical parameters such as pH, concentration of Triton X-100 (TX-100) and salts, equilibrium temperature, and incubation time on the efficiency of the extraction of R6G were studied in detail, and optimum conditions for dye extraction were obtained. Thermodynamic parameters including changes in Gibbs free energy, enthalpy, and entropy were also calculated, and these parameters indicated that the CPE of R6G was feasible, spontaneous, and endothermic in the temperature range of 75-95 degrees C. The equilibrium solubilization capacity of TX-100 was found to be 1.10 mmol/mol by using Langmuir isotherm models. No significant interference effects were observed in the presence of phenol and its derivatives, some acidic and basic dyes and most of the anions and cations. It was concluded that the CPE process described in this paper can be an alternative technique for removal of dyes and other pollutants from waters and wastewaters.


Assuntos
Corantes/isolamento & purificação , Rodaminas/isolamento & purificação , Eliminação de Resíduos Líquidos/métodos , Concentração de Íons de Hidrogênio , Resíduos Industriais/análise , Octoxinol , Água do Mar/análise , Solubilidade , Tensoativos , Termodinâmica , Poluentes Químicos da Água/isolamento & purificação , Abastecimento de Água/análise
10.
Anal Chim Acta ; 688(1): 75-83, 2011 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-21296208

RESUMO

Activated carbon was produced from tea-industry wastes (TIWAC) and employed as a low cost and effective solid phase material for the separation, preconcentration and speciation of chromium species without using a complexing agent, prior to determination by flame atomic absorption spectrometry (FAAS). The characterization of TIWAC was performed by utilizing several techniques such as Fourier Transform Infrared (FTIR) Spectroscopy, Scanning Electron Microscopy (SEM), and elemental analysis. The adsorption experiments were conducted in a batch adsorption technique. Under the experimental conditions, Cr(VI) adsorption amount was nearly equal to zero, however the adsorption percentage of Cr(III) was in the range of 95-100%. Therefore total chromium was determined after the reduction of Cr(VI) to Cr(III) and Cr(VI) was calculated by subtracting Cr(III) concentration from total chromium concentration. The suitable conditions for adsorption and speciation processes were evaluated in terms of pH, eluent type and volume, TIWAC concentration, adsorption and desorption contact time, etc. Adsorption capacity of TIWAC was found to be 61.0 mg g(-1). The detection limit for Cr(III) was found to be 0.27 µg L(-1) and the preconcentration factor was 50 for 200mL of sample volume. The procedure was applied to the determination and speciation of chromium in stream, tap and sea water. Also, the proposed method was applied to total chromium preconcentration in microwave digested tobacco and dried eggplant samples with satisfactory results. The method was validated by analyzing certified reference materials (CRM-TMDW-500 Drinking Water and CRM-SA-C Sandy Soil C) and the results were in good agreement with the certified values.


Assuntos
Carbono/química , Cromo/análise , Resíduos Industriais/análise , Espectrofotometria Atômica/métodos , Poluentes Químicos da Água/análise , Cromo/isolamento & purificação , Concentração de Íons de Hidrogênio , Cinética , Oxirredução , Chá/química , Poluentes Químicos da Água/isolamento & purificação
11.
J Hazard Mater ; 172(1): 353-62, 2009 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-19656623

RESUMO

A natural bentonite modified with a cationic surfactant, cetyl trimethylammonium bromide (CTAB), was used as an adsorbent for removal of phenol from aqueous solutions. The natural and modified bentonites (organobentonite) were characterized with some instrumental techniques (FTIR, XRD and SEM). Adsorption studies were performed in a batch system, and the effects of various experimental parameters such as solution pH, contact time, initial phenol concentration, organobentonite concentration, and temperature, etc. were evaluated upon the phenol adsorption onto organobentonite. Maximum phenol removal was observed at pH 9.0. Equilibrium was attained after contact of 1h only. The adsorption isotherms were described by Langmuir and Freundlich isotherm models, and both model fitted well. The monolayer adsorption capacity of organobentonite was found to be 333 mg g(-1). Desorption of phenol from the loaded adsorbent was achieved by using 20% acetone solution. The kinetic studies indicated that the adsorption process was best described by the pseudo-second-order kinetics (R(2) > 0.99). Thermodynamic parameters including the Gibbs free energy (DeltaG degrees), enthalpy (DeltaH degrees), and entropy (DeltaS degrees) were also calculated. These parameters indicated that adsorption of phenol onto organobentonite was feasible, spontaneous and exothermic in the temperature range of 0-40 degrees C.


Assuntos
Fenol/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Bentonita/química , Cetrimônio , Compostos de Cetrimônio/química , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Varredura/métodos , Fenol/química , Espectrofotometria/métodos , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termodinâmica , Fatores de Tempo , Difração de Raios X
12.
J AOAC Int ; 92(1): 257-62, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19382584

RESUMO

A coprecipitation method has been established for speciation of chromium(III) and chromium(VI) in real samples. The procedure is based on the coprecipitation of Cr(III), by using a new organic coprecipitant, 3-phenyl-4-o-hydroxybenzyl-idenamino-4,5-dihydro-1,2,4-triazole-5-one, without adding any carrier element. After reduction of Cr(VI) by concentrated H2SO4 and ethanol, the method was applied to the determination of total Cr. The level of Cr(VI) was calculated by the difference of total Cr and Cr(III) levels. For optimum recovery of Cr(III), different analytical factors such as pH, amount of coprecipitant, centrifugation rate and time, and effect of sample volume, were investigated. The influences of some anions, cations, and transition metals on the recoveries were also investigated, and no significant interferences were observed. The preconcentration factor was 100. The detection limit based on 3 times standard deviation (sigma) of the blank (n = 10) for Cr(III) was 0.50 microg/L. In order to evaluate the accuracy of the method, certified reference materials (CRM-TMDW-500 Drinking Water and National Institute of Standards and Technology Standard Reference Material 1573a Tomato Leaves) were analyzed, and the results obtained were in good agreement with certified values. The presented procedure was applied for Cr speciation in various solid and liquid samples with successful results.


Assuntos
Cromo/análise , Abastecimento de Água/normas , Ânions/análise , Cátions/análise , Cromo/isolamento & purificação , Concentração de Íons de Hidrogênio , Indicadores e Reagentes , Solanum lycopersicum/química , Folhas de Planta/química , Sensibilidade e Especificidade , Triazóis , Água/análise , Abastecimento de Água/análise
13.
J Hazard Mater ; 168(2-3): 888-94, 2009 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-19327886

RESUMO

The present study was carried out to assess the ability of original waste mud (o-WM) and different types of activated waste mud which are acid-activated (a-WM) and precipitated waste mud (p-WM), in order to remove excess of fluoride from aqueous solution by using batch technique. The p-WM exhibited greater performance than the others. Adsorption studies were conducted as a function of pH, contact time, initial fluoride concentration, adsorbent concentration, temperature, etc. Studies were also performed to understand the effect of some co-existing ions present in aqueous solutions. Adsorption process was found to be almost independent of pH for all types of waste mud. Among the kinetic models tested for p-WM, pseudo-second-order model fitted the kinetic data well with a perfect correlation coefficient value of 1.00. It was found that the adequate time for the adsorption equilibrium of fluoride was only 1h. Thermodynamic parameters including the Gibbs free energy (DeltaG degrees ), enthalpy (DeltaH degrees ), and entropy (DeltaS degrees ) revealed that adsorption of fluoride ions on the p-WM was feasible, spontaneous and endothermic in the temperature range of 0-40 degrees C. Experimental data showed a good fit with the Langmuir and Freundlich adsorption isotherm models. Results of this study demonstrated the effectiveness and feasibility of WM for removal of fluoride ions from aqueous solution.


Assuntos
Fluoretos/isolamento & purificação , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Soluções , Termodinâmica , Água/química
14.
J Hazard Mater ; 167(1-3): 294-9, 2009 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-19181444

RESUMO

A separation/preconcentration procedure, based on the coprecipitation of Cr(3+), Fe(3+), Pb(2+) and Zn(2+) ions using a new organic coprecipitant, 3-phenly-4-o-hydroxybenzylidenamino-4,5-dihydro-1,2,4-triazole-5-one (POHBAT) without adding any carrier element has been developed. The method, thus, has been called carrier element-free coprecipitation (CEFC). The resultant concentrated elements were determined by flame atomic absorption spectrometric determinations. The influences of some analytical parameters including pH of the solution, amount of the coprecipitant, standing time, centrifugation rate and time, sample volume and diverse ions were investigated on the quantitative recoveries of analyte ions. The validation of the present preconcentration procedure was performed by the analysis of two certified reference materials. The recoveries of understudy analytes were found in the range of 93-98%, while the detection limits were calculated in the range of 0.3-2.0 microg L(-1). The precision of the method evaluated as relative standard deviation (R.S.D.), was in the range of 3-7% depend on the analytes. The proposed method was successfully applied to environmental samples for the determination of the analytes.


Assuntos
Triazóis/química , Poluentes Químicos da Água/isolamento & purificação , Precipitação Química , Cromo/isolamento & purificação , Poluentes Ambientais/isolamento & purificação , Ferro/isolamento & purificação , Chumbo/isolamento & purificação , Padrões de Referência , Espectrofotometria Atômica , Zinco/isolamento & purificação
15.
J Hazard Mater ; 166(2-3): 1480-7, 2009 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-19167162

RESUMO

The objective of this study was to assess the adsorption potential of a waste mud (WM) for the removal of lead (Pb(II)) ions from aqueous solutions. The WM was activated with NaOH in order to increase its adsorption capacity. Adsorption studies were conducted in a batch system as a function of solution pH, contact time, initial Pb(II) concentration, activated-waste mud (a-WM) concentration, temperature, etc. Optimum pH was specified as 4.0. The adsorption kinetic studies indicated that the overall adsorption process was best described by pseudo-second-order kinetics. The equilibrium adsorption capacity of a-WM was obtained by using Langmuir and Freundlich isotherm models and both models fitted well. Adsorption capacity for Pb(II) was found to be 24.4 mg g(-1) for 10 g L(-1) of a-WM concentration. Thermodynamic parameters including the Gibbs free energy (Delta G degrees), enthalpy (Delta H degrees), and entropy (DeltaS degrees) indicated that the adsorption of Pb(II) ions on the a-WM was feasible, spontaneous and endothermic, at temperature range of 0-40 degrees C. Desorption studies were carried out successfully with diluted HCl solutions. The results indicate that a-WM can be used as an effective and no-cost adsorbent for the treatment of industrial wastewaters contaminated with Pb(II) ions.


Assuntos
Cobre , Resíduos Industriais/prevenção & controle , Chumbo/isolamento & purificação , Mineração , Adsorção , Concentração de Íons de Hidrogênio , Íons , Cinética , Hidróxido de Sódio , Soluções , Temperatura , Termodinâmica , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/isolamento & purificação
16.
J Hazard Mater ; 162(1): 292-9, 2009 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-18585857

RESUMO

A new method for the preconcentration of some trace metals (Co, Ni, Cu, and Cd) as complexed with ammonium pyrrolidynedithiocarbamate (APDC) was developed using a mini-column filled with Amberlite XAD-2000 resin. Metal contents were determined by flame atomic absorption spectrometry (FAAS) after the metal complexes accumulated on the resin were eluted with 1M HNO(3) in acetone. The effects of the analytical parameters such as sample pH, quantity of complexing agent, eluent type, resin quantity, sample volume, sample flow rate, and matrix ions were investigated on the recovery of the metals from aqueous solutions. The relative standard deviation (R.S.D.) of the method was <6%. The validation of the method was confirmed using two certified reference materials (CRM TMDW-500 Drinking Water and CRM SA-C Sandy Soil C). The method was successfully applied to some stream waters and mushroom samples from Eastern Black Sea Region (Trabzon city) of Turkey.


Assuntos
Poluentes Ambientais/análise , Metais Pesados/análise , Adsorção , Agaricales/química , Cromatografia por Troca Iônica , Monitoramento Ambiental , Concentração de Íons de Hidrogênio , Indicadores e Reagentes , Resinas de Troca Iônica , Resinas Sintéticas , Soluções , Espectrofotometria Atômica , Turquia , Água , Abastecimento de Água/análise
17.
Anal Chim Acta ; 632(1): 35-41, 2009 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-19100880

RESUMO

A new, simple, rapid and sensitive separation, preconcentration and speciation procedure for chromium in environmental liquid and solid samples has been established. The present speciation procedure for Cr(III) and Cr(VI) is based on combination of carrier element-free coprecipitation (CEFC) and flame atomic absorption spectrometric (FAAS) determinations. In this method a newly synthesized organic coprecipitant, 5-chloro-3-[4-(trifluoromethoxy) phenylimino]indolin-2-one (CFMEPI), was used without adding any carrier element for coprecipitation of chromium(III). After reduction of chromium(VI) by concentrated H(2)SO(4) and ethanol, the procedure was applied for the determination of total chromium. Chromium(VI) was calculated as the difference between the amount of total chromium and chromium(III). The optimum conditions for coprecipitation and speciation processes were investigated on several commonly tested experimental parameters, such as pH of the solution, amount of coprecipitant, sample volume, etc. No considerable interference was observed from the other investigated anions and cations, which may be found in natural water samples. The preconcentration factor was found to be 40. The detection limit for chromium(III) corresponding to three times the standard deviation of the blank (N=10) was found 0.7 microg L(-1). The present procedure was successfully applied for speciation of chromium in several liquid and solid environmental samples. In order to support the accuracy of the method, the certified reference materials (CRM-TMDW-500 Drinking Water and CRM-SA-C Sandy Soil C) were analyzed, and standard APDC-MIBK liquid-liquid extraction method was performed. The results obtained were in good agreement with the certified values.

18.
Talanta ; 76(2): 469-74, 2008 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-18585308

RESUMO

A new co-precipitation method was developed to separate and pre-concentrate Fe(3+), Cu(2+), Cr(3+), Zn(2+), and Pb(2+) ions using an organic co-precipitant, 3-benzyl-4-p-nitrobenzylidenamino-4,5-dihydro-1,2,4-triazole-5-on (BPNBAT) without adding any carrier element, following flame atomic absorption spectrometric (FAAS) determinations. Effect of some analytical conditions, such as pH of the solution, quantity of the co-precipitant, standing time, centrifugation rate and time, sample volume, and interference of concomitant ions were investigated over the recovery yields of the metal ions. The recoveries of the analyte ions were in the range of 95-102%. The detection limits, corresponding to three times the standard deviation of the blank, were found to be in the range of 0.3-2.0 microg L(-1). The precision of the method, evaluated as the relative standard deviation (R.S.D.) obtained after analyzing a series of 10 replicates, was between 1.6% and 6.0% for the trace metal ions. The method was validated by analyzing two certified reference materials and spiked addition. The proposed procedure was applied for the trace metal ions in some environmental samples.


Assuntos
Oligoelementos/isolamento & purificação , Triazóis/química , Precipitação Química , Reprodutibilidade dos Testes , Espectrofotometria Atômica , Oligoelementos/análise
19.
J Hazard Mater ; 149(2): 317-23, 2007 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-17482351

RESUMO

A simple and accurate method was developed for separation and enrichment of trace levels of gold in environmental samples. The method is based on the adsorption of Au(III)-diethyldithiocarbamate complex on Amberlite XAD-2000 resin prior to the analysis of gold by flame atomic absorption spectrometry after elution with 1 molL(-1) HNO3 in acetone. Some parameters including nitric acid concentration, eluent type, matrix ions, sample volume, sample flow rate and adsorption capacity were investigated on the recovery of gold(III). The recovery values for gold(III) and detection limit of gold were greater than 95% and 16.6 microgL(-1), respectively. The preconcentration factor was 200. The relative standard deviation of the method was <6%. The adsorption capacity of the resin was 12.3 mg g(-1). The validation of the presented procedure was checked by the analysis of CRM-SA-C Sandy Soil certified reference material. The presented procedure was applied to the determination of gold in some environmental samples.


Assuntos
Ouro/química , Ouro/isolamento & purificação , Absorção , Ditiocarb/química , Íons/química , Ácido Nítrico/química , Espectrofotometria Atômica
20.
J Hazard Mater ; 146(1-2): 155-63, 2007 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-17222968

RESUMO

A method for the preconcentration of some transition elements at trace level was proposed using a column filled with Amberlite XAD-2000 resin. Metal ions were adsorbed on XAD-2000 as their diethyldithiocarbamate chelates, then analytes retained on the resin were eluted by 1 mol L(-1) nitric acid in acetone and determined by flame atomic absorption spectrometry (FAAS). The influences of some analytical parameters including pH of sample solution, ligand amount, the type, concentration and volume of elution solution, flow rates of the sample and eluent solutions, adsorption capacity of the resin and sample volume on the preconcentration efficiency have been investigated. The influences of some matrix elements were also examined. The detection limit (N=20, 3 sigma) for Mn(II), Fe(II), Co(II), Cu(II), Cd(II), Zn(II), Pb(II) and Ni(II) were found as 0.20, 0.35, 0.25, 0.20, 0.20, 0.15, 0.45 and 0.25 microg L(-1), respectively. The validation of the procedure was carried out by analysis of certified reference materials. The proposed method was applied to natural waters and kale vegetable (Brassica oleracea var. acephala).


Assuntos
Brassica/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , Ditiocarb/química , Monitoramento Ambiental , Concentração de Íons de Hidrogênio , Metais Pesados/química , Poliestirenos/química , Resinas Sintéticas/química , Extração em Fase Sólida , Turquia , Poluentes Químicos da Água/química
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