Preconcentration Of Lead Ions Research Articles

Development of magnetic porous coordination polymer adsorbent for the removal and preconcentration of Pb(II) from environmental water samples

A novel porous coordination polymer adsorbent (BTCA-P-Cu-CP) based on a piperazine(P) as a ligand and 1,2,4,5-benzenetetracarboxylic acid (BTCA) as a linker was synthesized and magnetized to form magnetic porous coordination polymer (BTCA-P-Cu-MCP). Fourier transform infrared (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), field emission scanning electron microscope(FESEM), energy-dispersive X-ray spectroscopy(EDS), CHN, and Brunauer-Emmett-Teller(BET) analysis were used to characterize the synthesized adsorbent. BTCA-P-Cu-MCP was used for removal and preconcentration of Pb(II) ions from environmental water samples prior to flame atomic absorption spectrometry(FAAS) analysis. The maximum adsorption capacity of BTCA-P-Cu-MCP was 582mgg-1. Adsorption isotherm, kinetic, and thermodynamic parameters were investigated for Pb(II) ions adsorption. Magnetic solid phase extraction (MSPE) method was used for preconcentration of Pb(II) ions and the parameters influencing the preconcentration process have been examined. The linearity range of proposed method was 0.1-100μgL-1 with a preconcentration factor of 100. The limits of detection and limits of quantification for lead were 0.03μgL-1 and 0.11μgL-1, respectively. The intra-day (n = 7) and inter-day (n = 3) relative standard deviations (RSDs) were 1.54 and 3.43% respectively. The recoveries from 94.75 ± 4 to 100.93 ± 1.9% were obtained for rapid extraction of trace levels of Pb(II) ions in different water samples. The results showed that the BTCA-P-Cu-MCP was steady and effective adsorbent for the decontamination and preconcentration of lead ions from the aqueous environment.

A microextraction procedure based on a task-specific ionic liquid for the separation and preconcentration of lead ions from red lipstick and pine leaves.

First, the extraction and preconcentration of ultratrace amounts of lead(II) ions was performed using microliter volumes of a task-specific ionic liquid. The remarkable properties of ionic liquids were added to the advantages of microextraction procedure. The ionic liquid used was trioctylmethylammonium thiosalicylate, which formed a lead thiolate complex due to the chelating effect of the ortho-positioned carboxylate relative to thiol functionality. So, trioctylmethylammonium thiosalicylate played the roles of both chelating agent and extraction solvent simultaneously. Hence, there is no need to use a ligand. The main parameters affecting the efficiency of the method were investigated and optimized. Under optimized conditions, this approach showed a linear range of 2.0-24.0 ng/mL with a detection limit of 0.0010 ng/mL. The proposed method was applied to the extraction and preconcentration of lead from red lipstick and pine leaves samples prior to electrothermal atomic absorption spectroscopic determination.

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).

Utilization of facile synthesized Fe3O4 nanoparticles as a selective support for preconcentration of lead ions from food and environmental samples

In this research, magnetic Fe3O4 nanoparticles were synthesized by a simple reaction system that takes 5 min at room temperature utilizing FeSO4 as the only iron source. Then their surface was modified with (3-aminopropyl)triethoxysilane and 4-bromo-3-(thiazol-2-ylimino)methylphenol using the Mannich reaction. Modified sorbent showed high selectivity for lead ions in the pH range of 6.5–8.0 as the relative selectivity factor (αr) of lead with respect to other cations was in the range of 150–1500. Fourier transform infrared, scanning electron microscopy, X-ray powder diffraction, vibrating sample magnetometry and elemental analysis techniques have been used for characterization of the prepared sorbent. The reusability of the sorbent was also investigated, and it was found that this sorbent is stable for up to eight adsorption–elution cycles without any noticeable drop-off in the recovery of lead ions.

Synthesis and characterisation of nano structure lead (II) ion-imprinted polymer as a new sorbent for selective extraction and preconcentration of ultra trace amounts of lead ions from vegetables, rice, and fish samples

This paper describes the preparation of new Pb(II)-imprinted polymeric particles using 2-vinylpyridine as a functional monomer, ethylene glycol dimethacrylate as the cross-linker, 2,2′- azobisisobutyronitrile as the initiator, diphenylcarbazone as the ligand, acetonitril as the solvent, and Pb(NO3)2 as the template ion, through bulk polymerisation technique. The imprinted lead ions were removed from the polymeric matrix using 5mL of HCl (2mol.L−1) as the eluting solvent. The lead ion concentration was determined by flame atomic absorption spectrometry. Optimum pH for maximum sorption was obtained at 6.0. Sorption and desorption of Pb(II) ions on the IIP particles were quite fast and achieved fully over 5min.In the proposed method, the maximum sorbent capacity of the ion-imprinted polymer was calculated to be 75.4mgg−1. The preconcentration factor, relative standard deviation, and limit of detection of the method were found to be 245, 2.1%, and 0.42ngmL−1, respectively. The prepared ion-imprinted polymer particles have an increased selectivity toward Pb(II) ions over a range of competing metal ions with the same charge and similar ionic radius. This ion-imprinted polymer is an efficient solid phase for extraction and preconcentration of lead ions in complex matrixes. For proving that the proposed method is reliable, a wide range of food samples with different and complex matrixes was used.

Synthesis, characterization, and application of modified silica in the removal and preconcentration of lead ions from natural river water

This paper describes the synthesis, modification, and application of modified silica for the removal of lead ions from aqueous medium. The modification reaction provided a reduction in surface are from 737 to 399 m2 g−1, which was attributed to the 4-amine-2-mercaptopyrimidine molecule attachment onto its surface. The characterization through FTIR spectra demonstrated bands at 3347 cm−1 assigned to N–H stretching vibrations and the absence of thiol bands at 2600 e 2547 cm−1 at Si-mod spectrum is an indicative that the attachment occurred via SH groups. The linearization of adsorption isotherm data through the modified Langmuir equation resulted in a maximum adsorption capacity of 2.9 μmol g−1. The material was applied in a continuous flow system in the preconcentration of water samples from Parana River and the results were in agreement with metal concentration determined directly through atomic absorption spectrometry with graphite furnace. The method validation was performed through analysis of water standard reference material (1643e), which also presented a 7.2-fold enrichment factor.

A sensitive spectrophotometric method for lead determination by flow injection analysis with on-line preconcentration

A new flow injection (FI) system for the determination of Pb(II) at trace level with a preconcentration step and spectrophotometric detection is proposed. It is based on preconcentration of lead ions on chitosan and dithizone–lead complex formation in aqueous medium (pH 9). The chemicals and FIA variables influencing the performance of the system were optimized and applied to the determination of lead in natural, well, and drinking water samples. It is a simple, highly sensitive, and low cost alternative methodology. The method provided a linear rage between 25 and 250μgl−1, a detection limit of 5.0ngml−1 and a sample throughput of 15h−1. The obtained results of spiked samples are in good agreement between the proposed method and ICP-AES.