Use of amidoximated hydrogel for removal and recovery of U(VI) ion from water samples

Poly(acrylamidoxime-co-2-acrylamido-2-methylpropane sulfonic acid) (PAMSA) hydrogel was prepared by copolymerization of acrylonitrile and 2-acrylamido-2-methylpropane sulfonic acid as monomer, N,N'-methylenebis(acrylamide) as crosslinking agent and potassium peroxodisulfate as initiator. Amidoximated copolymer network was prepared by the reaction of copolymer network with hydroxylamine hydrochloride. A batch procedure was used for the determination of the characteristics of the U(VI) solid phase extraction from the amidoximated hydrogel. The determination of U(VI) was performed by spectrophotometric method using arsenazo-III as complexing agent. Optimal pH value for the quantitative preconcentration was 3, and full desorption was achieved with 3 mol L-1 HClO4. The adsorption process can be well described by the pseudo-second-order kinetic model, and the equilibrium adsorption isotherm was closely fitted with the Langmuir model. A preconcentration factor of 20 and the three sigma detection limit of 2.8 mu g L-1 (n = 20) were achieved for uranium(VI) ions. The PAMSA hydrogel was used for separating and preconcentrating the uranyl ion existing in sea water samples, thermal spring water samples and the certified reference materials (TMDA 64; fortified lake water sample). (C) 2010 Elsevier B.V. All rights reserved

Synthesis of a Novel Chelating Resin for the Separation and Preconcentration of Uranium(VI) and Its Spectrophotometric Determination

A novel chelating polymer including three different functional groups, such as amidoxime (-C(NH2)=NOH), azo (-N=N-) and carboxylic acid (-COOH), was synthesized. The poly(acrylamidoxime-co-(1-(2-pirydylazo)-2-naphtyl-2-methacrylate)-co-methacrylicacid) (APM) polymer, prepared in three steps, was characterized by FT-IR and elemental analyses. The resin was used for solid-phase extractive separation and the preconcentration of trace amounts of uranium(VI). The determination of U(VI) was performed by a spectrophotometric method using Arsenazo III as a complexing agent. The optimum conditions were found for the quantitative recovery of U(VI) (pH 5; eluent, 3 mol L-1 HClO4; sample and eluent flow rates, 1 mL min(-1) etc.). The capacity of the APM resin for U(VI) was found to be 24.2 mg g(-1). A preconcentration factor of 37.5 and the three sigma detection limit of 1.6 mu g L-1 (n = 20) were achieved for U(VI) ions. The polymer was used for separating and preconcentrating the uranyl ion existing in seawater samples and a certified reference material (TMDA 70; fortified lake water sample)

Synthesis, characterization and application of a novel ion-imprinted polymer for selective solid phase extraction of copper(II) ions from high salt matrices prior to its determination by FAAS

A new Cu(II)-imprinted sorbent has been prepared by using 5-methyl-2-thiozylmethacrylamide (MTMAAm). The monomer of Cu(II)-MTMAAm complex was synthesized and copolymerized in the presence of ethyleneglycol dimethacrylate cross-linker via bulk polymerization method. The resulting Cu (II)-imprinted polymer was characterized by FT-IR spectroscopy and scanning electron microscopy (SEM). Copper ions were removed from the polymer with 1.0 mol L-1 HNO3 and determined by flame atomic absorption spectrometry (FAAS). The imprinted polymer showed higher selectivity for Cu(II) in comparison to the non-imprinted polymer. Relative selectivity coefficients (k') for Cu(II)/Zn(II), Cu(II)/Ni (II) and Cu(II)/Co(II) were 9.1, 14.8 and 26.6, respectively. The imprinted polymer was examined as a column packing material for solid phase extraction of Cu(II) from various matrices. The effects of solution pH, acid eluents and interfering ions were investigated. The poylmer possesses selective extraction of Cu (II) within pH range from 5.0 to 6.5. The relative standard deviation and limit of detection (3 s) of the method were evaluated as 1.4% and 0.9 mu g L-1, respectively. The accuracy of the method was verified by analysis of two certified reference materials (CWW-TM-D and SRM 3280) and then applied to the determination of Cu in seawater, lake water and tap water samples, and hemodialysis concentrates and multivitamin/multielement supplements. (C) 2013 Elsevier B.V. All rights reserved.A new Cu(II)-imprinted sorbent has been prepared by using 5-methyl-2-thiozylmethacrylamide (MTMAAm). The monomer of Cu(II)&ndash;MTMAAm complex was synthesized and copolymerized in the presence of ethyleneglycol dimethacrylatecross-linker via bulk poly merization method. The resulting Cu(II)-imprinted polymer was characterized by FT-IR spectroscopy and scanning electron microscopy (SEM). Copper ions were removed from the polymer with 1.0 mol L&minus;1 HNO3 and determined by flame atomic absorption spectrometry (FAAS). The imprinted polymer showed higher selectivity for Cu(II) in comparison to the non-imprinted polymer. Relative selectivity coefficients (k&prime;) for Cu(II)/Zn(II), Cu(II)/Ni(II) and Cu(II)/Co(II) were 9.1, 14.8 and 26.6, respectively. The imprinted polymer was examined as a column packing material for solid phase extraction of Cu(II) from various matrices. The effects of solution pH, acid eluents and interfering ions were investigated. The poylmer possesses selective extraction of Cu(II) within pH range from 5.0 to 6.5. The relative standard deviation and limit of detection (3s) of the method were evaluated as 1.4% and 0.9 &micro;g L&minus;1, respectively. The accuracy of the method was verified by analysis of two certified reference materials (CWW-TM-D and SRM 3280) and then applied to the determination of Cu in seawater, lakewater and tap water samples, and hemodialysis concentrates and multivitamin/multielement supplements.</p

Synthesis and swelling behavior analysis of poly(acrylamidoxime-co-2-acrylamido-2-methylpropane sulfonic acid) hydrogels

An investigation of water uptake behavior of a novel poly(acrylonitrile-co-2-acrylamido-2-methylpropane sulfonic acid-co-N,N'-methylenebisacrylamide) hydrogel system was carried out with two major objectives. First, the study was initiated to understand the effect of various synthesis conditions, i.e., reaction temperature, initiator content, crosslinker content and pH,on the water absorbency of resulting hydrogels. The second reason was to evaluate these hydrogels after reaction with hydroxylamine hydrochloride to convert the C Xi N (nitrile) groups to -C=N-OH (amidoxime) groups. The optimum amidoximation conditions was determined. The structure of the hydrogels, before and after amidoximation, was analyzed with FTIR and thermal methods. The optimum synthesis temperature, initiator concentration and crosslinker content were found to be 55 degrees C, 1.5 (wt.%) and 1.5 (wt.%), respectively. The equilibrium water uptake increases with an increase in initiator (K2S2O8) concentration and crosslinker (BAAm) content up to 1.5% and then it begins to decrease with a further increase in K2S2O8 and BAAm content. The gel undergoes a drastic volume change in the pH range 5, thus indicating the dissociation of NH groups of acrylamidoxime. The pH increased at 7, and this pH shift may be attributed not only to the acidic region, but also the basic region. A drastic volume change is also observed at pH:10, which may be due to the dissociation of the AMPS SO3H groups. The swelling ratio of the hydrogel sample in sea water, tap water and distilled water are collected. According to the results, the maximum swelling ratio was observed in the distilled water. Finally, the nitrile groups can be easly converted into amidoxime groups via treatment with a solution of hydroxylamine. The swelling behavior of hydrogels are in good agreement, before and after amidoximation

Atomic absorption spectrometric determination of Cd(II), Mn(II), Ni(II), Pb(II) and Zn(II) ions in water, fertilizer and tea samples after preconcentration on Amberlite XAD-1180 resin loaded with l-(2-pyridylazo)-2-naphthol

A new chelating resin, 1-(2-pyridylazo)-2-naphthol (PAN) coated Amberlite XAD-1180 (AXAD-1180), was prepared and used for the preconcentration of Cd(II), Mn(II), Ni(II), Pb(II) and Zn(II) ions prior to their determination by flame atomic absorption spectrometry (FAAS). The optimum pH for simultaneous retention of the elements and the best elution means for their simultaneous elution were pH 9.5 and 3 M HNO3, respectively. The sorption capacity of the resin was found to be 5.3 mg/g for Cd and 3.7 mg/g for Ni. The detection limits for Cd(II), Mn(II), Ni(II), Pb(II) and Zn(II) were 0.7, 10, 3.1, 29 and 0.8 mu g/L, respectively. The effects of interfering ions for quantitative sorption of the metal ions were investigated. The preconcentration factors of the method were in the range of 10-30. The recoveries obtained were quantitative (a parts per thousand yen95%). The standard reference material (GBW07605 Tea sample) was analysed for accuracy of the described method. The proposed method was successfully applied to the analysis of various water, urea fertilizer and tea samples

Selective solid phase extraction of copper using a new Cu(II)-imprinted polymer and determination by inductively coupled plasma optical emission spectroscopy (ICP-OES)

This work reports the preparation of a novel Cu(II)-ion imprinted polymer using 2-thiozylmethacrylamide (TMA) for on-line preconcentration of Cu(II) prior to its determination by inductively coupled optical emission spectroscopy (ICP-OES). Cu(II)-TMA monomer (complex) was synthesized and copolymerized via bulk polymerization method in the presence of ethyleneglycoldimethacrylate cross-linker. The resulting polymer was washed with 5% (v/v) HNO3 to remove Cu(II) ions and then with water until a neutral pH. The ion imprinted polymer was characterized by FT-IR and scanning electron microscopy. The experimental conditions were optimized for online preconcentration of Cu(II) using a minicolumn of ion imprinted polymer (IIP). Quantitative retention was achieved between pH 5.0 and 6.0, whereas the recoveries for the non-imprinted polymer (NIP) were about 61%. The IIP showed about 30 times higher selectivity to Cu(II) in comparison to NIP. The IIP also exhibited excellent selectivity for Cu(II) against the competing transition and heavy metal ions, including Cd, Co, Cr, Fe, Mn, Ni, Pb and Zn. Computational calculations revealed that the selectivity of IIP was mediated by the stability of Cu(II)TMA complex which was far more stable than those of Co(II), Ni(II) and Zn(II) that have similar charge and ionic radii to Cu(II). A volume of 10 mL sample solution was loaded onto the column at 4.0 mL min(-1) by using a sequential injection system (FIALab 3200) followed by elution with 1.0 mL of 2% (v/v) HNO3. The relative standard deviation (RSD) and limit of detection (LOD, 3 s) of the method were 3.2% and 0.4 mu g L-1, respectively. The method was successfully applied to determination of Cu(II) in fish otoliths (CRM 22), bone ash (SRM 1400) and coastal seawater and estuarine water samples. (C) 2013 Elsevier B.V. All rights reserved