Preconcentration Of Pb Research Articles

Green, fast and selective preconcentration of lead ions from various matrices using a novel magnetic sheet-like resin

A Fe3O4@citric–ascorbic acid based resin was synthesized by a solvent-free route and employed for the green and fast preconcentration of Pb(ii).

Schiff base-functionalised styrofoam resin for preconcentration of metal ions in wastewater and wastewater-irrigated vegetables samples

Polystyrene (PS) was extracted from styrofoam waste and functionalised with schiff base, N,N-bis(salicylidene)cyclohexanediamine (SCHD) through an azo spacer. The resin was characterised and used for preconcentration of Pb(II), Ni(II) and Cd(II) ions prior to their trace determinations by microsample injection system–coupled flame atomic absorption spectrometry (MIS-FAAS). The recoveries of studied metal ions were achieved ≥96.0% with relative standard deviation (RSD) ≤4.5 at optimum parameters: pH 8; resin amount 300 mg; flow rates 3.0 mL min−1 of sample solution; and 2.0 mL min−1 of eluent (2.0 mol L−1 HNO3). The limits of detection (LODs) and limits of quantification (LOQs) were found to be 0.32, 0.23 and 0.21 and 1.10, 0.78 and 0.69 μg L−1, respectively, with preconcentration factors (PFs) of 500, 800 and 1000, respectively. The linear ranges of the method were 1–40, 1–25 and 1–20 μg L−1 for Pb(II), Ni(II) and Cd(II) ions, respectively. The accuracy and validation of the method were evaluated by analysis of certified reference materials (CRMs). The method was successfully applied for preconcentration of studied metal ions in wastewater and wastewater-irrigated vegetable samples.

Preconcentration of some heavy metals by Amberlite XAD-4 functionalized with Phenanthroline and investigation of microwave radiation effect on kinetic of adsorption

Phenanthroline modified Amberlite XAD-4 has been synthesized by coupling it through an azo spacer. The resulting chelating resin, characterized by elemental analysis, thermogravimetric analysis and infrared spectra, was used to preconcentrate Cd, Pb, Fe, Co, Cu and Zn ions. Parameters, such as sorption capacity of the chelating resin, pH and eluent, were evaluated. The effects of electrolytes and cations on the preconcentration were also investigated. Furthermore, effect of microwave power was investigated on adsorption rate of these heavy metals. The obtained results show, time of extraction is reduced significantly by this modification. The detection limit, were found to be 1.4, 4.1, 2.4, 3.9, 3.1, 3.9 μg L−1 for Cd, Pb, Fe, Co, Cu and Zn, respectively. The relative standard deviation of the ten replicate determinations was <7%. The procedure was validated by standard addition and comparison of obtained result by GFAAS method. The developed method was utilized for preconcentration of Cd, Pb, Fe, Co, Cu and Zn in wastewater, potato and preconcentration of Pb in lipstick with satisfactory results.

Facile Synthesis and Characterization of Chrysotile Nanotubes and Their Application for Lead(II) Removal from Aqueous Solution

Chrysotile nanotubes (ChNTs) were synthesized using the hydrothermal method and characterized by XRD, XPS, SEM, TEM, and N2 adsorption-desorption. The results of XRD analysis confirm that the synthetic samples own the pure monoclinic chrysotile. The morphology images show that ChNTs have a hollow nanotubular structure. A batch experiment was employed to evaluate the adsorption efficiency of ChNTs toward Pb(II). The kinetic adsorption of Pb(II) on ChNTs can be described by a pseudo-second-order model very well. The adsorption of Pb(II) on ChNTs are strongly dependent on pH and ionic strength. The adsorption isotherms are fitted well by the Langmuir model, having a maximum adsorption capacity of 25.08 mg·g−1 at 298 ± 1 K. The thermodynamic parameters of the adsorption for Pb(II) indicate that the adsorption process of Pb(II) on ChNTs is spontaneous and endothermic. Herein, this finding suggests that ChNTs can be applied on the preconcentration of Pb(II) in the field of water treatment.

Suspended aminosilanized graphene oxide nanosheets for selective preconcentration of lead ions and ultrasensitive determination by electrothermal atomic absorption spectrometry.

The aminosilanized graphene oxide (GO-NH2) was prepared for selective adsorption of Pb(II) ions. Graphene oxide (GO) and GO-NH2 prepared through the amino-silanization of GO with 3-aminopropyltriethoxysilane were characterized by scanning electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. The batch experiments show that GO-NH2 is characterized by high selectivity toward Pb(II) ions. Adsorption isotherms suggest that sorption of Pb(II) on GO-NH2 nanosheets is monolayer coverage, and adsorption is controlled by a chemical process involving the surface complexation of Pb(II) ions with the nitrogen-containing groups on the surface of GO-NH2. Pb(II) ions can be quantitatively adsorbed at pH 6 with maximum adsorption capacity of 96 mg g(-1). The GO-NH2 was used for selective and sensitive determination of Pb(II) ions by electrothermal atomic absorption spectrometry (ET-AAS). The preconcentration of Pb(II) ions is based on dispersive micro solid-phase extraction in which the suspended GO-NH2 is rapidly injected into analyzed water sample. Such features of GO-NH2 nanosheets as wrinkled structure, softness, flexibility, and excellent dispersibility in water allow achieving very good contact with analyzed solution, and adsorption of Pb(II) ions is very fast. The experiment shows that after separation of the solid phase, the suspension of GO-NH2 with adsorbed Pb(II) ions can be directly injected into the graphite tube and analyzed by ET-AAS. The GO-NH2 is characterized by high selectivity toward Pb(II) ions and can be successfully used for analysis of various water samples with excellent enrichment factors of 100 and detection limits of 9.4 ng L(-1).

A SnO2-Sb2O3 nanocomposite for selective adsorption of lead ions from water samples prior to their determination by ICP-OES

We report on the preparation of a SnO2-Sb2O3 nanocomposite (NC) by a reductive facile low temperature route. The structural, morphological, elemental, and optical properties of the NC were investigated. The NC is shown to enable preconcentration of Pb(II) ions from aqueous samples with good selectivity over Cd(II), Cu(II), Hg(II), La(III), Mn(II), Pb(II), Pd(II), and Y(III). The uptake capacity for Pb(II) is ~82.0 mg g−1. The adsorption for Pb(II) can be described by a Langmuir isotherm which indicates that the process is mainly of the monolayer type on a homogeneous surface. A kinetic study reveals the process to follow pseudo-second-order kinetics. Following desorption, the Pb(II) ions were quantified by ICP-OES. The limit of detection is 0.35 μg∙L‾1. The method was applied to the determination of Pb(II) in (spiked) real water samples and gave recoveries ranging from 93.9 to 98.9 %.

Application of graphitic carbon nitride for the removal of Pb(II) and aniline from aqueous solutions

Abstract Graphitic carbon nitride (g-C3N4) was synthesized from urea with a facile approach and was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transformed infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The as-synthesized g-C3N4 was applied as sorbent to remove Pb(II) and aniline from aqueous solutions as a function of contact time, solid content, pH, ionic strength, temperature, and initial concentrations of Pb(II) and aniline. The results indicated that the sorption of Pb(II) was mainly dominated by outer-sphere surface complexation or ion exchange at pH 7.0. The sorption of aniline was mainly attributed to electrostatic interaction at pH 5.0. The sorption isotherms of Pb(II) and aniline on g-C3N4 were well described by the Langmuir model. The thermodynamic parameters calculated from the temperature-dependent sorption isotherms indicated that the sorption of Pb(II) and aniline on g-C3N4 was endothermic and spontaneous processes. Moreover, g-C3N4 could be regenerated through the desorption of Pb(II) and aniline by using 1.0 M HCl solution and alcohol, respectively, and no obvious decline of sorption capacity was found for the recycling results. All these results indicated that g-C3N4 was a promising material for the preconcentration of Pb(II) and aniline from aqueous solutions in real pollution management.

Preparation of a New Sorbent, Cetyltrimethylammonium Bromide (CTAB)- Modified Obsidian, for the Separation and Preconcentration of Pb(II) and Cd(II) Ions in Food and Water Samples

Preparation of a New Sorbent, Cetyltrimethylammonium Bromide (CTAB)- Modified Obsidian, for the Separation and Preconcentration of Pb(II) and Cd(II) Ions in Food and Water Samples

Few-layered graphene oxides as superior adsorbents for the removal of Pb(II) ions from aqueous solutions

Few-layered graphene oxides (GOs) were successfully synthesized from graphite using Hummers’ method. The synthesized GOs were characterized in detail by SEM, AFM, XRD, and FTIR spectroscopy. The prepared GOs were used as adsorbents to preconcentrate Pb(II) ions from large volumes of aqueous solutions. The effects of pH, ionic strength and temperature on the removal of Pb(II) ions from solution to GOs were investigated. The sorption of Pb(II) on GOs was dependent on pH values and independent of ionic strength, which suggested that Pb(II) sorption on GOs was mainly dominated by strong inner-sphere surface complexation. The maximum adsorption capacities (C smax ) of Pb(II) on GOs were calculated to be 344 mg/g at 293 K, 487 mg/g at 308 K, and 758mg/g at 333 K, respectively. The C smax values are the highest sorption capacities of today’s materials for the sorption of Pb(II) ions from aqueous solutions. The thermodynamic parameters were calculated from the temperature-dependent sorption isotherms, and the results indicated that Pb(II) sorption on GOs was spontaneous and endothermic. The results suggested that the GOs were promising materials for the preconcentration of Pb(II) and other kinds of heavy metal ions from aqueous solutions in environmental pollution cleanup in real work.

Synthesis and characterisation of novel chelating resin for selective preconcentration and trace determination of Pb(II) ions in aqueous samples by innovative microsample injection system coupled flame atomic absorption spectrometry

Expanded polystyrene (EPS) foam waste (white pollutant) was utilised for the synthesis of novel chelating resin i.e. EPS-N = N-α-Benzoin oxime (EPS-N = N-Box). The synthesised resin was characterised by FT-IR spectroscopy, elemental analysis, and thermogravimetric analysis. A selective method for the preconcentration of Pb(II) ions on EPS-N = N-Box resin packed in mini-column was developed. The sorbed Pb(II) ions were eluted with 5.0 mL of 2.0 mol L−1 HCl and determined by microsample injection system coupled flame atomic absorption spectrometry (MIS-FAAS). The average recovery of Pb(II) ions was achieved 95.5% at optimum parameters such as pH 7, resin amount 400 mg, flow rates 1.0 mL min−1 (of eluent) and3.0 mL min−1 (of sample solution). The total saturation capacity of the resin, limit of detection (LOD) and limit of quantification (LOQ) of Pb(II) ions were found to be 30 mg g−1, 0.033 μg L−1 and 0.107 μg L−1, respectively with preconcentration factor of 300. The accuracy, selectivity and validation of the method was checked by analysis of sea water (BCR-403), wastewater (BCR-715) and Tibet soil (NCS DC-78302) as certified reference materials (CRMs). The proposed method was applied successfully for the trace determination of Pb(II) ions in aqueous samples.

Development of 2-acetylpyridine-4-phenyl-3-thiosemicarbazone functionalized polymeric resin for the preconcentration of metal ions prior to their ultratrace determinations by MIS-FAAS

2-Acetylpyridine-4-phenyl-3-thiosemicarbazone (APPT) ligand was incorporated onto Amberlite XAD-2 resin through an azo spacer and characterized by FTIR spectroscopy, elemental analysis, TGA, and SEM analysis. The synthesized resin was used for the preconcentration of Pb(II), Zn(II), Co(II), Ni(II), Cu(II), and Cd(II) ions. The sorbed metal ions were eluted with 10 mL of 2.0 mol L-1 HCl and determined by microsample injection coupled flame atomic spectrometry (MIS-FAAS). The recoveries of studied metal ions were \ge 95.1 % with RSD \ge 4.0 % at optimum pH 8; resin amount, 300 mg; flow rates, 2.0 mL min-1 (of eluent) and 3.0 mL min-1 (sample solution). The limits of detection (LOD) and limits of quantifications (LOQ) of the studied metal ions were 0.11, 0.05, 0.07, 0.08, 0.09, and 0.03; and 0.37, 0.17, 0.21, 0.13, 0.31, and 0.10 m g L-1, respectively, with a preconcentration factor of 500 for the 6 studied metal ions. The total saturation capacity of the resin was 0.36, 1.20, 1.50, 1.61, 1.07, and 0.71 mmol g-1, respectively.

Removal and preconcentration of lead(II), cadmium(II) and chromium(III) ions from wastewater samples using surface functionalized magnetite nanoparticles

The potential removal and preconcentration of lead(II), cadmium(II), and chromium(III) ions from wastewaters were investigated and explored. Magnetite nanoparticles were chemically modified with p-nitro aniline. The aniline-coated magnetite nanoparticles (ANMNPs) were fully characterized by FT-IR, XRD, SEM, and TEM measurements. Batch studies were performed to address various experimental parameters for the removal and determination of these ions. ANMNPs showed high tendency to investigated metal ions, in this order: Cr(III) > Cd(II) > Pb(II), owing to the strong contribution of surface loaded aniline. The potential applications of ANMNPs adsorbent for removal and preconcentration of Pb(II), Cr(III), and Cd(II) from wastewaters as well as drinking tap water samples were successfully accomplished giving recovery values of (98–101 %), without any noticeable interference of the wastewater or drinking tap water matrices.

Novel solid-phase extractor based on functionalization of multi-walled carbon nano tubes with 5-aminosalicylic acid for preconcentration of Pb(II) in water samples prior to determination by ICP-OES

New solid-phase extractor (MWCNTs-5-ASA) was synthesized via covalent immobilization of 5-aminsalicylic acid onto multi-walled carbon nanotubes (MWCNs). The success of the functionalization process was confirmed using Fourier transform infrared spectroscopy, scanning electron microscope, and surface coverage determination. Batch experiments were conducted as a function of pH to explore MWCNTs-5-ASA efficiency to extract several metal ions viz., Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II). It was found that Pb(II) exhibits the highest extraction percentage with maximum adsorption capacity 32.75 mg g(-1). Its binding performance was well fitted with Langmuir sorption isotherm. On the other hand, the selective separation and preconcentration of trace Pb(II) under dynamic conditions prior to determination by inductively coupled plasma-optical emission spectrometry was investigated under different parameters. These included the rate of flow and volume of sample solution, in addition to the type of the eluate, its volume and concentration. The effect of a variety of foreign ions on the recovery percentage was also evaluated. Trace Pb(II) ions present in 500 mL aqueous solution adjusted to pH 4.0 were retained on 50 mg of MWCNTs-5-ASA and completely eluted using 4.0 mL of 2 M HNO₃. The limit of detection and the precision of the method were 0.25 ng mL(-1) and 2.8%, respectively (N = 5). This methodology has been applied for the determination of Pb(II) in water samples with good results.

Separation and preconcentration of lead, chromium and copper by using with the combination coprecipitation-flame atomic absorption spectrometric determination

A coprecipitation method was developed for the quantitative separation and preconcentration of Pb(II), Cr(III) and Cu(II) ions. Analytes were coprecipitated using a triazole derivative (2-{4-[2-(1H-indol-3-yl)ethyl]-3-(4-chlorobenzyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}-N-aryl methylidene acetohydrazid). The analytes were analyzed by flame atomic absorption spectrometry. The parameters such as sample pH, amount of reagent, sample volume, matrix effects etc. were investigated. The enrichment factor for the analyzed metal ions was obtained as 50. The relative standard deviations (RSD) were in the range of 2.8–4.1%. The accuracy of the proposed procedure was checked by the analysis of the CRM-C-Sandy Soil C. The method was successfully applied to real samples.

Ultralayered Co3O4 as a new adsorbent for preconcentration of Pb(II) from water, food, sediment and tobacco samples

In this study, ultralayered Co3O4 adsorbent was synthesized and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The surface area of the solid material was found to be 75.5m2g−1 by BET method. The ultralayered Co3O4 was used for the first time as an effective adsorbent for the preconcentration of the Pb(II) ions in various samples prior to flame atomic absorption detection. Analytical parameters affecting the solid phase extraction of Pb(II) such as pH, adsorption and elution contact time, eluent volume and concentration, sample volume and common matrix ions were investigated. The recovery values for Pb(II) were found to be ≥92% even in the presence of 75,000mgL−1 Na(I), 75,000mgL−1 K(I), and 75,000mgL−1 Ca(II) ions. 10s vortexing time was enough for both adsorption and elution contact times. The elution was easily made with 2mL of 2.0molL−1 HNO3. The reusability (170 cycles) and adsorption capacity (35.5mgg−1) of ultralayered Co3O4 were excellent. The preconcentration factor of the method and detection limit were found to be 175 and 0.72µgL−1, respectively. The described method was validated with certified reference material (RM 8704 Buffalo River Sediment, BCR-482 Licken and SPS-WW1 Batch 111-Wastewater) and spiked real samples. It was also applied for the preconcentration of Pb(II) ions in various water (well water, mineral water, waste water and sea water), food (cauliflower and barley), street sediment and tobacco samples.

Application of β-cyclodextrin in polymeric solid phase for separation and determination of lead in different environmental matrices

Immobilization of β-cyclodextrin on Dowex resin as an insoluble polymeric matrix by covalent bond presents a new solid-phase medium for preconcentration of Pb (II) at trace level in environmental samples prior to its flame atomic absorption spectrometric determination. The method is based on the sorption of lead after passing on modified Dowex sorbent in a column. The effect of several parameters such as pH, flow rate of sample, eluent kind and volume was investigated. The sorption capacity of the matrix has been found to be 0.4996 mg g−1 of adsorbent with the preconcentration factor of 250 for Pb (II). Nitric acid (3 M) as an eluent was sufficient to obtain quantitative recovery (>95%) for Pb (II). The optimum flow rate was 10 ml min −1. The calibration curve was linear in the range of (3–250 ng mL−1) with a correlation coefficient of 0.9995. The limit of detection (LOD) based on three times the standard deviation of the blank was 1.37 ng mL−1. The relative standard deviation (RSD) for determination of 10 ng mL−1 and 100 ngmL−1 of Pb (II) was 3.00 % and 0.58 % (n = 10), respectively. The method was successfully applied to determination of lead in some environmental samples such as tap water, river water, soil and rice.

Determination of Lead in Biological Samples of Children with Different Physiological Consequences Using Cloud Point Extraction Method

In present study, lead (Pb) level in biological samples of children with physiological disorders (liver, bone, and gastrointestinal; age ranged 1-10years) have been assessed. For comparison purpose, age-matched healthy children were also selected. Cloud point extraction (CPE) was employed for preconcentration of Pb in acid-digested biological samples prior to its determination by flame atomic absorption spectrometry (FAAS). Dithizone (diphenylthiocarbazone) and nonionic surfactant Triton X-114 (TX-114) were used as complexing reagent and extractant, respectively. The effects of several experimental variables on proposed CPE were evaluated. Under the optimum experimental conditions, the observed detection limit (LOD) and the enhancement factor (EF) were 0.08μgL(-1) and 53, respectively. Relative standard deviation (RSD) of 10μgL(-1) Pb was 3.4%. It was observed that children with liver-, bone-, and gastrointestinal-related disorders had three- to fourfold higher Pb level in blood and scalp hair samples.

Evaluation of DMIT [4,5-Dimercapto-1,3-Dithyol-2-Thionate] as chelating agent in a cloud point extraction procedure for Pb2+ determination in water samples

The present study proposes a new method for cloud point preconcentration of Pb2+ ions based on complex formed with [4,5-dimercapto-1,3-dithyol-2-thionate] and posterior determination by flame atomic absorption spectrometry (FAAS). The preconcentration of Pb2+ was carried at pH 5.0 under following conditions: time and temperature of batch at 15 min. and 70oC, respectively, 0.1% (v/v) Triton X-114, 0.003 mol L-1 acetate/acetic acid buffer solution, 1.0 x 10-5 mol L-1 DMIT and 0.5% (m/v) NaCl. Under the best analytical conditions the method provided a limit of detection of 2.85 mg L-1 by preconcentrating 10.0 mL of sample and calibration curve ranging from 0 up to 650 mg L-1 (r = 0.99945). The applicability of proposed method for Pb2+ determination in natural waters without interferences was checked through addition/recovery tests.

Simultaneous pre-concentration of Pb and Sn in food samples and determination by atomic absorption spectrometry

A cloud point extraction (CPE) method has been developed for the pre-concentration and simultaneous determination of lead [Pb(II)] and tin [Sn(II)] using Acridine Orange as complexing reagent and mediated by nonionic surfactant (Triton X-114) by flame atomic absorption spectrometry (FAAS). The main factors affecting analytical performance of CPE have been investigated in detail. The extracted surfactant-rich phase was diluted with (1.0 mol L−1) nitric acid in methanol, prior to subjecting FAAS. The calibration graphs obtained from Pb(II) and Sn(II) were linear in the concentration ranges of 5–1,000 and 10–5,000 μg L−1 with detection limits of 1.40 and 2.86 μg L−1, respectively. The relative standard deviations for 10 replicates containing 25 μg L−1 of Pb(II) and Sn(II) were 2.15 and 2.50 %, respectively. The analytical procedure was verified by the analysis of the standard reference materials NWTMDA-61.2 (water-trace elements) and NIST SRM 1548a (typical diet). The developed method has been applied to the simultaneous determination of total Pb and Sn in canned food samples including juices, tomato paste, corn, and green pea.

β-Cyclodextrin-based polyurethane (β-CDPU) polymers as solid media for adsorption and determination of Pb(II) ions in dust and water samples

In this work, β-CD-based polyurethane copolymers (β-CDPU) have been prepared by reacting β-CD with hexamethylene diisocyanate as cross-linked agent in dry DMF. This polymer showed high selectivity for preconcentration of Pb(II) at trace level prior to its flame atomic absorption spectrometric determination. The effect of several parameters such as pH, flow rate of sample, eluent kind and volume was investigated. The adsorption behaviors and mechanisms of Pb(II) on the samples were also studied. The maximum adsorption amount of Pb(II) was 8 mg g−1 with the preconcentration factor of 250 for Pb(II). The Langmuir isotherm was proved to describe the adsorption data better than the Freundlich isotherm and a pseudo-first-order kinetic model fits the adsorption kinetic processes well. The calibration curve was linear in the range of (3–200 ng mL−1) with a correlation coefficient of 0.9996. The limit of detection based on three times the standard deviation of the blank was 1.15 ng mL−1. The relative standard deviations for the determination of 10 and 100 ng mL−1 of Pb(II) were 3.60 and 0.43 % (n = 10), respectively. The method was successfully applied to the determination of lead in some environmental samples such as Tehran and Bushehr drinking water, river water and dust samples.