Preconcentration Of Iron Research Articles

Iron Ionic Imprinted Polymers IIps for Separation and Preconcentration of Iron from Crude and Fuel Oil

A novel Iron ion-imprinted polymers (IIPs) was synthesized by bulk polymerization using different types of monomers such as 1-vinyl imidazole and Styrene, respectively. Molar ratios of monomer, template and cross-linking agent for polymerization, various monomers and solvents were studied to obtain the largest adsorption capacity for Iron. The prepared Iron-IIPs were characterized using energy dispersive X-ray spectroscopy (EDX), Fourier - transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). The three-dimensional network structure surfaces of Iron-IIPs are unaffected by the elution procedure. Iron ions were successfully eluted from IIPs using a mixed solution from ethanol and acetic acid. The maximum adsorption capacity of Iron-IIPs was is (514.5)µmol/g for Iron-IIP1(using styrene as a monomer) and (429.1) µmol/g for Iron-IIP2(using 1-vinyl imidazole as a monomer). The adsorption by Iron-IIPs followed a Langmuir isotherm models. Solid-phase extraction (SPE) syringe packed with ionic imprinted polymers (IIPs) were used to selective separation for Iron ion from Crude or fuel oil and digest the polymer to determination the Iron by flame atomic absorption spectroscopy (FAAS) Abbreviation IIP-SPE-FAAS.

An Eco-Friendly Cloud Point Extraction for Preconcentration of Iron(III) in Water Samples prior to Spectrophotometric Determination

An Eco-Friendly Cloud Point Extraction for Preconcentration of Iron(III) in Water Samples prior to Spectrophotometric Determination

Preconcentration of Iron, Rare Earth, and Fluorite from Bayan Obo Ore Using Superconducting Magnetic Separation

Bayan Obo ore contains mainly bastnaesite, monazite and associated iron, fluorite, calcite, dolomite, barite, and trace amount of columbite. Due to its complex mineral compositions and similar mineral properties, it is difficult to separate and obtain rare earth and fluorite concentrates with high purity by conventional magnetic separation and flotation. In this paper, a stepwise magnetic separation process comprised of wet permanent magnetic separation (PMS), wet electromagnetic separation (EMS), and superconducting magnetic separation (SCMS) was proposed to pre-concentrate iron, rare earth, and fluorite minerals from Bayan Obo ore. The results showed that iron, rare earth, and fluorite preconcentrates with high purity and low impurity content could be achieved, which might be helpful to shorten the technological process and improve the separation efficiency for the subsequent flotation of iron, rare earth, and fluorite minerals.

Preconcentration of Iron in Some Drug and Water Samples by Coprecipitation with Magnesium Hydroxide Before Spectrophotometric Determination

A method was purposed for preconcentration and determination of iron, in this study. The method consist of these steps respectively: I) Coprecipitation of the iron present in the sample with Mg(OH)2 collector. II) Seperation of the precipitate by centrifuging. III) Solving the precipitation in acid. IV) UV-VIS spectrophotometric determination of the iron concentrated in the resultant lower volume solution using its complexation with thiocyanate. The effects of factors such as centrifugation time, pH and Mg concentration on the absorbance signal were investigated and the optimum values of these factors were determined. Total iron in the sample was brought single oxidation state (Fe(II) or Fe(III)) before coprecipitation procedure. Calibration curve was derived for both of the proceses. The detection limit and working range for the proposed method were found to be 0.01 mgL-1 and 0.03-0.3 mgL-1 respectively. The proposed method was applied to tap water, mineral water samples and Rennie anti-acid drug tablet. The accuracy of the method was tested by analyte spiked method. The accuracy results in terms of Recovery % are between 90-100%. Mostly the relative standart deviations (RSD %) values do not exceed 5%.

Investigation of adsorption mechanism of Fe, Cu, and Zn ions in extraction and preconcentration process on synthesized graphene oxide using an indole derivative

3-(chloro(2-methyl-1H-indol-3-yl)methyl)-2-methyl-1H-indole (MIMI) was chosen for separation and preconcentration of iron (III), copper (II), and zinc by solid-phase extraction (SPE). Ion–MIMI chelates are adsorbed onto synthesized graphene oxide (GO) as adsorbent, eluted with HNO3 and determined by flame atomic absorption spectrometry (FAAS). The adsorption mechanism of titled metal complexes on GO was investigated by using computational chemistry approach based on PM7 semi-empirical potential energy surface. The influences of analytical parameters were investigated. The interference effect of common cations tested did not interfere with the recovery of understudied ions. The preconcentration factor of 312.5 and the detection limits of 0.62, 0.28, and 0.05 ng mL−1 for iron (III), copper (II), and zinc, respectively, were obtained. The developed SPE method was successfully utilized for the determination of trace metal ions in different certified reference materials and real samples (including water, cheese, honey, tomato, leaves of spinach, and milk) by FAAS.

Halloysite Nanotubes as a New Adsorbent for Solid Phase Extraction and Spectrophotometric Determination of Iron in Water and Food Samples

Halloysite nanotubes (HNTs) have been introduced as a new solid phase extraction adsorbent for preconcentration of iron(II) as a complex with 2,2-bipyridine. The cationic complex is effectively adsorbed on the sorbent in the pH range of 3.5–6.0 and efficiently desorbed by trichloroacetic acid. The eluted complex has a strong absorption around 520 nm, which was used for determination of Fe(II). After optimizing extraction conditions, the linear range of the calibration graph was 5.0–500 μg/L with a detection limit of 1.3 μg/L. The proposed method was successfully applied for the determination of trace iron in various water and food samples, and the accuracy was assessed through the recovery experiments and analysis of a certified reference material (NIST 1643e).

Preconcentration of ultra-trace amounts of iron and antimony using ion pair solid phase extraction with modified multi-walled carbon nanotubes

Ion pair solid phase extraction was applied to the simultaneous preconcentration of iron and antimony. The ion pairs consisting of FeCl4− or SbCl4− anions and the benzyldimethyltetradecyl ammonium cation were formed on the surface of multi-walled carbon nanotubes, then eluted with nitric acid, and the elements finally quantified by ETAAS. The adsorption capacities of the impregnated MWCNTs are 9.2 mg g−1 for iron and 27.5 mg g−1 for antimony. The following analytical figures of merit were determined for iron and antimony, respectively: Enrichment factors of 210 and 230, assay precisions of ±5.3 % and ±4.8 %, linear calibration plots from 0.7 to 9.4 and 13.0 to 190 ng L−1, and detection limits of 0.17 and 3.5 ng L−1. The method was applied to the determination of iron and antimony in human hair, synthetic sample, and to the certified reference materials gold ore (MA-1b) and trace elements in water (SRM 1643d).

Membrane preconcentration of iron in seawater samples and on-site determination in spectrophotometry

A novel method for on-site determination of trace iron was developed using membrane preconcentration and spectrophotometric detection. Fe(II)-ferrozine complex was reacted with cetyltrimethylammonium bromide (CTAB) to form a Fe(II)-ferrozine-CTAB paired compound, which was collected on a membrane by filtration under vacuum. The membrane was immersed in 2 mL of ethanol-nitric acid and the absorbance of the solution measured for quantitative analysis. Various factors affecting the iron collection and determination were investigated. With different sample preconcentration volumes, the range of determination was broadened to 0.5–120 μg/L. The detection limit of this method reached 0.19 μg/L and the recoveries were between 97.2 and 109% when the concentration enrichment was about 45. The relative standard deviation (n = 7) was 1.9% for samples containing 10 μg/L Fe. Twelve seawater samples were analyzed on-site using the proposed method, and two were also analyzed in inductively coupled plasma mass spectrometry. No significant difference was shown between the two methods by the Student’s t-test. The method has also been used on-site for iron enrichment experiments with phytoplankton and concluded to be simple, accurate and inexpensive.

Determination of Iron by Dispersive Liquid-Liquid Microextraction Procedure in Environmental Samples

A greener analytical procedure based on dispersive liquid-liquid microextraction (DLLME) coupled to flame atomic absorption spectrometry (FAAS) detection was developed. Various influencing factors on the separation and preconcentration of iron, such as the acidity of the aqueous solution, extraction and disperser solvent type and their volume have been investigated systematically, and the optimized operation conditions were established. Under the optimum conditions i.e., pH 4.0, [DPTH] = 5x10-3%, a preconcentration factor of 45 was reached. The lower limit of detection (LOD) obtained under the optimal conditions was 9 μg L-1. The precision for 8 replicate determinations at 50 and 100 μg L-1 of Fe were 1.8 % and 4.4 % relative standard deviation (R.S.D.), respectively. The calibration graph using the preconcentration method was linear from 10 to 5000 μg L-1, with a correlation coefficient of 0.9904. The proposed method was successfully applied to the preconcentration and determination of iron in food, vegetation, soil and water samples.

Speciation and preconcentration of iron by cloud point extraction combined with fibre optic linear array detection spectrophotometry

A highly selective method for speciation and preconcentration of iron was developed using cloud point extraction (CPE) combined with fibre optic-linear array detection spectrophotometry (FO-LADS). Cloud point extraction method was based on the chromogenic reaction of Fe(II) and Fe(III) with 1-(2-pyridylazo)-2-naphthol (PAN) and then preconcentration of formed complexes using octylphenoxy polyethoxy ethanol (Triton X-114). When the system temperature is higher than the cloud point extraction temperature (CPT) of selected surfactant, the complex of Fe(II) with 1-(2-pyridylazo)-2-naphthol (PAN) could enter surfactant-rich phase, whereas the complex of Fe(III) remained in aqueous phase. Thus, an in situ separation of Fe(II) and Fe(III) could be realized. An iron complex in the surfactant-rich phase was determined by fibre optic-linear array detection spectrophotometry.The main factors affecting the cloud point extraction, such as pH, concentration of (PAN) and Triton X-114, equilibration temperature and time, were investigated systematically. Under the optimized conditions, the enhancement factors of 167 and 158 were obtained for Fe(II) and Fe(III) respectively, the limits of detection (LOD) was 0.2 μg L−1 for Fe(II) and 0.5 μg L−1 for Fe(III). The relative standard deviations (n = 5, c = 40.0μg L−1) was lower than 3%. The proposed method is highly selective without any interference ions. This method was successfully applied to the speciation of iron in different samples with satisfactory results.

Determination and Preconcentration of Iron (II) in Aqueous Solution with Amberlite XAD-4 Functionalized with 1-amino-2-naphthole by Flame Atomic Absorption Spectrometry

Determination and Preconcentration of Iron (II) in Aqueous Solution with Amberlite XAD-4 Functionalized with 1-amino-2-naphthole by Flame Atomic Absorption Spectrometry

The Use of Polyphenolic Compounds from Black Tea for the Solid Phase Extraction and Determination of Trace Iron in Drinking Water

AbstractA simple and selective solid phase extraction procedure for the trace analysis of iron(III) in water samples has been developed. Sodium dodecyl sulfate coated alumina, modified with polyphenolic compounds (extracted from black tea) was used for the extraction and preconcentration of iron(III) from water samples before determination by flame atomic absorption spectrometry. Due to the complexation reaction between iron(III) and polyphenol compounds, iron(III) was quantitatively extracted on the proposed sorbent and then eluted by 2.0 mL of HCl (1.0 mol/L). The effects of extraction parameters, such as pH and volume of sample solution, amount of polyphenolic compounds, type of eluting agent and the effect of interfering ions on the extraction of iron(III), were investigated. It was found that the proposed method had a good linear range (15.0–100.0 μg/L) and a low detection limit (10.0 μg/L). The procedure was successfully applied for iron determination in drinking water samples.

Preconcentration of Iron(III), Lead(II), Cobalt(II) and Chromium(III) on Amberlite XAD-1180 Resin Loaded with 4-(2-Pyridylazo)-resorcinol (PAR) and Their Determination by FAAS

In this study, a solid phase extraction method has been developed for the preconcentration and separation of the elements Cr(III), Fe(III), Co(II) and Pb(II) at trace levels by using a column packed with Amberlite XAD-1180 resin loaded with 4-(2-pyridylazo)-resorcinol (PAR) reagent. After preconcentrating, the metals retained on the column were eluted with 20 mL of 3 mol/L HNO 3 and then determined by flame atomic absorption spectrometry (FAAS). The factors affecting the recovery of the elements, such as pH, type and concentration of eluent, volume of sample and elution solution, and matrix components, were also ascertained. The recoveries of Cr(III), Fe(III), Co(II) and Pb(II) were found to be 99 ± 4, 97 ± 3, 95 ± 3 and 98 ± 4%, respectively, under the optimum conditions at 95% confidence level and the relative standard deviations found by analyzing of nine replicates were ≤ 4.4%. The preconcentration factors for Cr(III), Fe(III), Co(II) and Pb(II) were found as 75, 125, 50 and 75 respectively. The detection limits (DL, 3s/b) were 3.0 μg/L for Cr(III), 1.25 μg/L for Fe(III), 3.3 μg/L for Co(II), and 7.2 μg/L for Pb(II). The recoveries achieved by adding of metals at known concentrations to samples and the analysis results of Buffalo river sediment (RM 8704) show that the described method has a good accuracy. The proposed method was applied to tap water, stream water, salt and street dust samples.

Kinetic Spectrophotometric Determination of Total Iron in Natural Water by Flow Injection Analysis Using On-Line Preconcentration

A new flow injection catalytic spectrophotometric method for on-line preconcentration and determination of total iron in natural water is described. The method is based on a combination of iron-catalyzed oxidation of diaminoditolyl by potassium bromate and the use of on-line preconcentration of iron onto 8-hydroxy-quinoline immobilized on silica gel. The corresponding calibration graph is linear over the range of 2.0–110 ng mL−1 for Fe(III) using a time-based technique for 5 min preconcentration. The relative standard deviation of 11 measurements of 60 ng mL−1 Fe(III) was 0.67%. The method was applied to the determination of iron in natural water. The results obtained by the proposed method were compared with those obtained by ICP-AES. The t-test showed no significant differences between the two methods at a confidence level of 95%.

Determination of trace levels of iron in a seawater sample using isotope dilution/inductively coupled plasma mass spectrometry.

An analytical method for trace levels of iron in a seawater sample using isotope dilution ICP-MS was developed. Preconcentration of iron and the removal of major elements in seawater such as alkali and alkaline-earth elements can be carried out quickly using a chelating resin disk by adjusting the sample pH to 3. The collision cell option of the ICP-MS instrument method was used to improve the performance of the instrument for iron measurements since ArO and ArN interferences could be reduced using this analytical method. About 4 ml min(-1) helium, as the collision gas, were introduced into the cell. 40Ar14N and 40Ar16O which interfere with 54Fe and 56Fe in water had their amounts decreased by 5 orders of magnitude. Then, the isotope dilution method was used for iron determination below ng g(-1) level of trace iron in four environmental reference materials (river water standard sample JAC-0031 (Japan Soc. for Analytical Chemistry), estuarine standard sample SLEW-2 (NRC Canada) and seawater standard samples CASS-3 and NASS-5 (NRC Canada)) were measured. Good agreement between analytical results and certified values of reference materials was obtained, which confirmed the effectiveness of this method.

Cobalt(III) Hexamethylenedithiocarbamate as a New Collector for Flotation Preconcentration of Iron, Nickel, Lead, and Zinc Prior to ETAAS

A fast method for separation of iron, nickel, lead, and zinc from water matrices prior to their atomic absorption spectrometry (AAS) is described. The separation and preconcentration of metals was performed by precipitate colloid flotation with cobalt(III) hexamethylenedithiocarbamate, Co(HMDTC)3, as a new collector. The optimal conditions for flotation of each analyte by Co(HMDTC)3 were determined. After flotation separation analytes were analyzed by flame atomic absorption spectrometry (FAAS) or electrothermal atomic absorption spectrometry (ETAAS) depending of their concentrations in the water sample. The results of AAS analyses are compared with those obtained by inductively coupled plasma‐atomic emission spectrometry. The limit of detection of analytes was determined 0.838 µg/L for iron and 1.105 µg/L for zinc using FAAS and 0.129 µg/L for lead and 0.113 µg/L for nickel by ETAAS.

Preconcentration and separation of iron, zinc, cadmium and mercury, from waste water using Nile blue a grafted polyurethane foam

The present work describes a novel method for the incorporation of Nile blue A into polyurethane foam matrix. This foam material was found to be very suitable for the extraction of metal ions from aqueous solutions. The characterization of Nile blue A grafted foam and the effect of halide concentration, pH, shaking time, extraction isotherm and capacity have been investigated. This foam material was found to be suitable for the separation and preconcentration of iron (III), zinc (II), cadmium (II) and mercury (II) from waste water. The extraction was accomplished in (15–20) minutes. Iron was separated from acid medium (2–4 M HCl), zinc from (3–5 M HCl), cadmium from (4–6 M HCl) as thiocyanate complexes and mercury was separated from (1–2 M HCl) as chloride.

Testing and Determination of Iron(II, III) as an Adsorbate of Iron(II) Phenanthrolinate by Chromaticity Measurements

It was demonstrated that cation exchangers of different nature can be used for the sorption preconcentration of iron(II) as phenanthrolinate and its determination in the adsorbent phase by diffuse reflectance spectrometry and chromaticity measurements. A procedure was developed for the determination of iron in solutions with a detection limit of 2.5 μg/L. A scale was proposed for the visual determination of iron(II) at concentrations down to 0.4 μg/L. The test procedure was verified using water samples from the Severnaya Dvina estuary and Dvinskii Bay taken during the summer and winter periods in 2000–2001.

Selective solid phase extraction and preconcentration of iron(III) based on silica gel-chemically immobilized purpurogallin

The immobilization of purpurogallin on the surface of amino group containing silica gel phase for the formation of a newly synthesized silica gel-bound purpurogallin (SGBP) is described. The surface modification was studied and evaluated by determination of the surface coverage value by both the elemental analysis and metal probe testing method, which was found to be 0.485 and 0.460 mmol g −1, respectively. The metal sorption properties of SGBP were examined by a series of di- and tri-valent metal ions. The metal capacity values (mmol g −1) for this series of metal ions were also determined under different buffer solutions (pH 1.0–6.0) as well as shaking times by the batch equilibrium technique. The results of this study confirmed the strong affinity and selectivity as well as the fast equilibration and interaction processes of SGBP and Fe(III) compared to the other tested metal ions. The reduction–oxidation process of iron(II)/iron(III) by SGBP was also studied and the results indicated only 2.1% reduction of iron(III) into iron(II). The selectivity incorporated into silica gel phase via the immobilization of purpurogallin was intensively studied for a several binary mixtures containing iron(III)—another interfering metal ion. The determined percentage extraction values of iron(III) from these mixtures were found to be in the range of 94–100%. The potential applications of SGBP as a selective solid extractor for iron(III) from natural tap water samples and real matrices were also studied and the results revealed good percentage extraction values of iron(III) (93.5−94.9±4.6−5.3%) of the spiked iron(III) in the acidified tap water samples as well as a high preconcentration factor of 500 was also established when SGBP was used as a selective solid phase extractor and preconcentration of iron(III) from acidified soft drink samples with percentage recovery values of (98.0−97.4±4.7−5.3%) of the spiked iron(III).

Coprecipitation with lanthanum phosphate as a technique for separation and preconcentration of iron(III) and lead.

The usefulness of coprecipitation with lanthanum phosphate for separation and preconcentration of some heavy metals has been investigated. Although lanthanum phosphate coprecipitates iron(III) and lead quantitatively at pH 2.3, iron(II) can barely be collected at this pH. This coprecipitation technique was applicable to the separation and preconcentration of iron(III) before inductively coupled plasma atomic-emission spectrometric (ICP-AES) determination; the recoveries of iron(III) and iron(II) from spiked water samples were 103-105% and 0.2-0.7%, respectively. The coprecipitation was also useful for separation of 20 microg lead from 100 mL of an aqueous solution that also contained 1-100 mg iron. Coprecipitation of iron was substantially suppressed by addition of ascorbic acid, which enabled recovery of 97-103% of lead added to the solution, bringing the recovery to within 1.6-5.0% of the relative standard deviations. Lanthanum phosphate can also coprecipitate cadmium and indium quantitatively, although chromium(III), cobalt, and nickel and large amounts of sodium, potassium, magnesium, and calcium are barely coprecipitated at pH approximately/= 3.