Characterization of As (V), As (III) by selective reduction/adsorption on palladium nanoparticles in environmental water samples (original) (raw)
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Arsenic (III) Adsorption Using Palladium Nanoparticles from Aqueous Solution
2017
The presence of Arsenic in drinking water is the greatest threat to health effects especially in water. The purpose of this study is application of green palladium nanoparticles for removal of trivalent Arsenic from aqueous solutions and also the impact of some factors such as retention time, pH, concentration of palladium nanoparticles and Arsenic concentrations was studied. The values for Arsenic removal from aqueous solutions were measured by furnace atomic adsorption spectrometry (Conter AA700). In the study, Langmuir and Freundlich isotherm models and pseudo-second order kinetic model were studied. The results of optimization is shown that 0.5 g of nanoparticles can removed %99.8 of Arsenic with initial concentration of 0.5 g/l, in 5 minutes at pH=4. Langmuir model, Freundlich model (R2=0.94) and pseudo-second order kinetic model (R2=0.99) shown high correlation for removing of Arsenic from aqueous solutions. It was found, palladium nanoparticles can be used as an efficient m...
2020
A new spectrophotometric reagent synthesized and characterized. new spectrophotometric method for the simultaneous determination of arsenic (III) and arsenic (V) at nano-trace levels using developed. HNA spectrophotometric determination of arsenic (III&V). This novel spectrophotometric reagent reacts in a slightly acidic dimethylformamide (DMF) to produce highly absorbent red chelate with has an absorption maximum at 505 nm. The absorbance intensity of the metal min at (45±5) coefficient and Sandell’s sensitivity were found to be 2.46×10 calibration graphs were obtained for 0.01 quantification limit of the reaction system was found to be 10 stoichiometric composition of the chelate is 3:2 (As: HNA anions and complexion agents (like, chloride, phosphate interfere in the determination. The developed method was successfully used in the determination of total arsenic in several certified reference materials (alloys, steels, ores, human urine, hair, nails, bovine milk), soil samples, foo...
Talanta, 2011
The simple and rapid preconcentration technique using cloud point extraction (CPE) was applied for the determination of As(V) and total inorganic arsenic (As(V) plus As(III)) in water samples by means of FAAS. As(V) has formed an ion-pairing complex with Pyronine B in the presence of cetyl pyridinium chloride (CPC) at pH 8.0 and extracted into the non-ionic surfactant Triton X-114, after centrifugation the surfactant-rich phase was separated and diluted with 1.0 mol L −1 HNO 3 in methanol. The proposed method is very versatile and economic because it exclusively used conventional FAAS. After optimization of the CPE conditions, a preconcentration factor of 120, the detection and quantification limits of 1.67 and 5.06 g L −1 with a correlation coefficient of 0.9978 were obtained from the calibration curve constructed in the range of 5.0-2200 g L −1. The relative standard deviation, RSD as a measure of precision was less than 4.1% and the recoveries were in the range of 98.2-102.4%, 97.4-101.2% and 97.8-101.1% for As(V), As(III) and total As, respectively. The method was validated by the analysis of standard reference materials, TMDA-53.3 and NIST 1643e and applied to the determination of As(III) and As(V) in some real samples including natural drinking water and tap water samples with satisfactory results. The results obtained (34.70 ± 1.08 g L −1 and 60.25 ± 1.07 g L −1) were in good agreement with the certified values (34.20 ± 1.38 g L −1 and 60.45 ± 1.78 g L −1).
Arsenic in Water: Determination and Removal
Arsenic - Analytical and Toxicological Studies, 2018
Depending on the physical, chemical and biogeochemical processes and condition of the environment, various arsenic species can be present in water. Water soluble arsenic species existing in natural water are inorganic arsenic (iAs) and organic arsenic (oAs) species. All acidic species, according to the chemical equilibrium, have well-recognized molecular and ionic forms in water. The distribution of iAs and oAs species is a function of pH value of water traces of arsenic that are found in groundwater, lakes, rivers and ocean. The WHO provisional guideline value for arsenic in drinking water is 10 μg L −1. The most selective and sensitive methods for determination of total arsenic and its species in water are coupled techniques including chromatography, optical methods and mass spectrometry. Determination of arsenic species is of crucial importance for selection of arsenic removal technology. Best available technologies are based on absorption, precipitation, membrane and hybrid membrane processes. Adsorption is considered to be relatively simple, efficient and low-cost removal technique, especially convenient for application in rural areas. Sorbents for arsenic removal are biological materials, mineral oxides, activated carbons and polymer resins.
Desalination, 2011
A hydride generation-inductively coupled plasma optical emission spectrometry (ICP-OES) technique was developed to determine inorganic As, including total As, As(III), and As(V), in drinking water samples in optimized conditions as follows: wavelength of 193.7 nm, integration time of 5-10 s, RF power of 1.3 kW, and the flow rates of plasma gas and auxiliary gas of 15 and 0.2 l/min for ICP-OES, the sample flow rates of 1.2 ml/min, reductant, and acid 0.4 ml/min and carrier gas 0.3 l/min, 0.4% (w/v) NaBH 4 with 40% (w/v) KI within 10 min as a reductant for total As, 0.4% (w/v) NaBH 4 for As(III) and 2 mol/l HCl for hydride generation. As(V) was obtained from the difference between total As and As(III). The linear dynamic range was 1-100 µg/l with a correlation coefficient of 0.9998. The limit of detection of total As, As(III), and As(V) was 0.38, 0.07, and 0.37 µg/l, respectively. The limit of quantification of total As, As(III), and As(V) was 1.28, 0.24, and 1.17 µg/l, respectively. 94.9-99.1% recovery for each As species was achieved. This fast and easy method was applied to determine arsenic in drinking water samples with satisfactory recovery (79-112%).
Evaluation of a Novel Water Treatment Residual Nanoparticles as a Sorbent for Arsenic Removal
Journal of Nanomaterials, 2015
A novel sorbent, water treatment residual nanoparticles (nWTR), was synthesized and used to remove As(V) from water solutions. The kinetics and equilibrium of As(V) adsorption by nWTR were evaluated. The kinetic data for nWTR at 3 different pH values indicate that As(V) sorption is biphasic, is favored at low pH values, and followed the power function and first-order kinetics models fit. The results of the batch adsorption study showed that nWTR was effective in As(V) removal and its removal capability was 16 times higher than that of bulk WTR. Fourier transmission infrared (FTIR), SEM-EDX spectra, and As fractionation results indicate the crucial role of surface hydroxyl groups in As retention onto nWTR and the high capability of nWTR to immobilize As(V). The stability of As-nWTR surface complexes is suggested as less than 2% of adsorbed As(V) was released from nWTR after 4 consecutive desorption cycles.
Acta chimica slovenica, 2005
A simple, sensitive, rapid and reliable preconcentration method has been developed for spectrophotometric determination of trace amounts of arsenic. Arsenic was retained on a minicolumn of adsorbent naphthalene, as an ion associate of arsenomolybdate and methyltrioctylammonium ions. The contents of column was dissolved in a small volume of N,N-dimethylformamide (DMF) having stannous chloride (SnCl 2) as a solvent. To take advantage of the procedure the reagent concentration and reaction condition must be optimized. Effects of different parameters such as molybdate percent, hydrochlorice acid concentration in aqueous solution, the flow rate of the sample solution through the minicolumn, selection of a suitable solvent to dissolve the adsorbent and also various salts and metal ions as interferences were investigated. Recording the variation in absorbance at a wavelength of 715 nm at room temperature completes the determination of arsenic concentration. The method allows determination of arsenic in the range of 1-8 ng mL-1 in the initial solution with r=0.999 (n=6). The relative standard deviation for 15 replicate measurements of 6.0 ng mL-1 of arsenic was 1.3% and the 3s detection limit was 0.067 ng mL-1. The preconcentration factors of 100 and 167 could be achieved when using a 5 and 3 mL DMF for dissolving adsorbent, respectively. The optimized method was successfully applied to determination of arsenic in natural water, synthetic sample and fish.
Mikrochimica Acta, 2011
Gold nanoparticles (AuNPs) were used as a new chemical modifier for the determination of arsenic and antimony in salt solutions by electrothermal atomic absorption spectrometry. The AuNPs were prepared by reducing chloroauric acid with sodium citrate. The effects of pyrolysis and atomization temperatures, the amounts of interferents and modifier on the sensitivities of arsenic and antimony were investigated. As and Sb remain in the graphite tube up to 1,100°C, which is sufficient for the determination of the two metals in certified reference materials and spiked sea water samples within a 95% confidence level with low RSD (<10%). The detection limits (N = 10 at 3σ) for As and Sb in sea water are 2.3 μg L-1 and 3.0 μg L-1, respectively. Almost no background as well as a blank value was detected for AuNPs. Figure Schematic illustration of the preparation of the TiO2@Au nanoparticles and modification with MUA
Journal of Nanoanalysis, 2014
On-line solid phase extraction (SPE) based on nano adsorbent for pre-concentration of inorganic arsenic in water and waste water samples was developed prior to determine by hydride generation atomic absorption spectrometry (HG-AAS). By hydride generation simulation system (HGSS), the inorganic arsenic in liquid samples changed to hydride form and pass through nano platinum multi wall carbon nanotube (3 wt % Pt, NPt-MWCNT,). The hydride form of arsenic (AsH3), pre-concentrated on NPt-MWCNTs and then completely desorption by electric heater accessory at 200oC for determining. The detection limit (LOD) and linear range of perposed method were obtained 0.4 ng L-1 and 6 –410 ng L-1 respectively(R2 = 0.9988). The relative standard deviations (%RSD) at 100 ng L-1 of analyte were found less than 5%. The capacity and efficiency of nano adsorbent were 75 mg g-1 and 96% at  argon flow rate less than 100 ml min-1. The developed method was applied successfully to determination of ultra trace of inorganic arsenic in environmental samples by HG-AAS.