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1.

The aim of this study is to prepare magnetic beads which can be used for the removal of heavy metal ions from synthetic solutions. Magnetic poly(ethylene glycol dimethacrylate‐vinyl imidazole) [m‐poly(EGDMA‐VIM)] beads were produced by suspension polymerization in the presence of magnetite Fe3O4 nano‐powder. The specific surface area of the m‐poly(EGDMA‐VIM) beads was found to be 63.1 m2/g with a size range of 150–200 µm in diameter and the swelling ratio was 85%. The average Fe3O4 content of the resulting m‐poly(EGDMA‐VIM) beads was 12.4%. The maximum binding capacities of the m‐poly(EGDMA‐VIM) beads were 32.4 mg/g for Cu2+, 45.8 mg/g for Zn2+, 84.2 mg/g for Cd2+and 134.5 mg/g for Pb2+. The affinity order on mass basis is Pb2+>Cd2+>Zn2+>Cu2+. Equilibrium data agreed well with the Langmuir model. pH significantly affected the binding capacity of the magnetic beads. Binding of heavy metal ions from synthetic wastewater was also studied. The binding capacities were 26.2 mg/g for Cu2+, 33.7 mg/g for Zn2+, 54.7 mg/g for Cd2+ and 108.4 mg/g for Pb2+. The magnetic beads could be regenerated up to about 97% by treating with 0.1 M HNO3. These features make m‐poly(EGDMA‐VIM) beads a potential candidate for support of heavy metal removal under magnetic field.  相似文献   

2.
The complexation reaction between 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane ligand (Kryptofix5) and Zn2+, Ni2+, Co2+, Pb2+ and Cu2+ ions were studied conductometrically in acetonitrile solution. The formation constants of the resulting 1:1 complexes were calculated from the computer fitting of the molar conductance and absorbance measurements in various mole ratios. The enthalpy and entropy changes of the complexation reactions were derived from titration conductometry in acetonitrile at various temperatures. At 25 °C, the stability of the resulting complexes varied in the order Pb2+ > Zn2+ > Cu2+> Co2+> Ni2+.  相似文献   

3.
A new crown ether carrying two anthryl groups with nitrogen–sulfur donor atom was designed and synthesized by the reaction of the corresponding macrocyclic compound and 9-chloromethyl anthracene. The influence of metal cations such as Al3+, Zn2+, Fe2+, Fe3+, Co2+, Ni2+, Mn2+, Cu2+, Cd2+, Hg2+ and Pb2+ on the spectroscopic properties of the ligand was investigated in acetonitrile–tetrahydofuran solution (1/1) by means of absorption and emission spectrometry. Absorption spectra show isosbestic points in the spectrophotometric titration of Fe2+, Fe3+, Al3+, Cu2+ and Hg2+. The results of spectrophotometric titration experiments disclosed the complexation stoichiometry and complex stability constant of the novel ligand with Fe2+, Fe3+, Al3+, Cu2+and Hg2+cations. The presence of excess amounts of Al3+, Zn2+, Fe2+, Fe3+, Co2+, Ni2+, Mn2+, Cu2+, Cd2+, Hg2+ and Pb2+ cations caused an enhancement of anthryl fluorescence. The ligand showed good sensitivity for Zn2+ with respect to other metal cations with linear range and detection limit of 1.4 × 10?7 to 4.1 × 10?6 M and 1.0 × 10?8 M respectively.  相似文献   

4.
Two crown ethers carrying pyrene side arms with nitrogen-sulfur donor atom were designed and synthesized by the reaction of the corresponding macrocyclic compounds and 1-bromomethyl-pyrene. The influence of metal cations such as Al3+, Zn2+, Fe2+, Fe3+, Co2+, Ni2+, Mn2+, Cu2+, Cd2+, Hg2+ and Pb2+ on the spectroscopic properties of the ligands was investigated in acetonitrile-tetrahydrofuran (1:1) by means of absorption and emission spectrometry. Absorption spectra show isosbestic points in the spectrophotometric titration of Al3+, Zn2+, Fe2+, Ni2+, Cu2+, and Pb2+ with 16-membered crown ether. Similar results were obtained for Al3+, Fe2+, Hg2+, Cu2+ and Pb2+ with 14-membered crown ether. The results of spectrophotometric titration experiments disclosed the complexation stoichiometry and complex stability constants of the novel ligands with these cations. According to spectrofluorimetric titration measurements the 14-membered diazadithia crown ether showed sensitivity for Pb2+ with linear range and detection limit of 1.3 × 10?6 to 5.2 × 10?5 M and 5.2 × 10?7 M, respectively. The 16-membered diazadithia crown ether showed sensitivity for Ni2+ with linear range and detection limit of 1.3 × 10?7 to 5.2 × 10?6 M and 4.1 × 10?8 M, respectively.  相似文献   

5.
《Analytical letters》2012,45(17):3074-3087
Abstract

Insoluble porous solid, macrocyclic 22-membered ring, 1-oxa-6,9,12,15,18-pentaaza-2,22-disilacyclododocosane polysiloxane ligand system has been prepared by the reaction of a macro-silane agent with tetraethylorthosilicate. The macro-silane agent was prepared by the reaction of imino-bis(N-2-aminoethylacetamide) ligand with 3-iodopropyltrimethoxysilane in 1:3 molar ratio. The new prepared polysiloxane system exhibits variable potentials for the extraction of metal ions (Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Ag+, Cd2+, Hg2+, and Pb2+) from aqueous solutions. The ligand system shows high capacity to extract silver, lead, and mercury. Chemisorption of the metal ions by the ligand system at the optimum conditions was found in the order Ag + > Pb2+ > Hg2+ > Cu2+ > Ni2+ > Fe3+ > Co2+ > Cd2+ > Zn2+.  相似文献   

6.
A thermodynamic study of the complexation of Cu2+, Pb2+, Zn2+ and Cd2+ ions with 1 and 2 in acetonitrile has been carried out. The study was conducted in the temperature range 283–308 K using a conductometric technique. The observed molar conductivity, Λ, was found to decrease significantly for mole ratios [L]t/[M]t less than unity in all cases. A model involving 1:1 stoichiometry has been used to analyze the conductivity data. The stability constant, K, for each 1:1 complex was determined from the conductivity data by using a nonlinear least-squares curve fitting procedure. The results show that compound 1 has no peak selectivity for any of the metal cations, while compound 2 selectively associates with Cu2+ and Pb2+. Complexes of 1 have the following stability order Pb2+ > Cu2+ > Zn2+ > Cd2+  and Pb2+ > Cu2+ for the complexes of 2. The ?H° and ?S° values for the complexation process were obtained from the slope and intercept of the Van’t Hoff plots respectively. All ?G° values were negative and were determined from the Gibbs–Helmholtz equation and the significance of these values is discussed.  相似文献   

7.
Abstract

A new inorganic ion exchanger, lead antimonate has been synthesized having an Pb:Sb ratio of 1:5 and cation exchange capacity of 1.46 mequiv./g. It is fairly stable in water and dilute solutions of acids, bases and salts. Ion distribution studies on twenty metal ions have been determined on this gel at pH 1,2,3 and 5. The following mixtures have been separated: Mg2+ - Pb2+, Zn2+ - Pb2+, Zn2+ - Pb2+, Cu2+ - Pb2+, Al3+ - Pb2+, Zn2+ - Cd2+ and Mg2+ - Cd2+. Mg2+ and Al3+ were removed with 0.4 M ammonium nitrate, Cu2+ and Zn2+ with 0.4 M ammonium nitrate + 0.1M nitric acid (1:1), Pb2+ with 0.5M nitric acid and Cd2+ with 0.25M nitric acid. A tentative structure of this material is proposed on the basis of chemical analysis, pH titrations, thermogravimetry and IR spectrophotometry.  相似文献   

8.
Kapok fiber, a natural hollow fiber with thin shell and large cavity, has rarely been used as adsorbent for heavy metal ions. In this paper, kapok fibers were modified with diethylenetriamine pentaacetic acid (DTPA) after hydrophilicity treatment. The adsorption behavior of the resultant kapok-DTPA influenced by pH, adsorption time and initial concentration of metal ion was investigated. The results demonstrate that adsorption equilibrium was reached within 2 min for Pb2+ and Cd2+. Adsorption kinetics showed that the adsorption rate was well fitted by pseudo-second-order rate model. The adsorption isotherms were studied, and the best fit was obtained in the Langmuir model. The maximum adsorption capacities of kapok-DTPA were 310.6 mg g?1 for Pb2+, 163.7 mg g?1 for Cd2+, 101.0 mg g?1 for Cu2+, respectively. After eight desorption and re-adsorption loops, the lost adsorption capacities for Pb2+ and Cu2+ were less than 10 %. Because of the large specific area derived from the hollow fiber structure, kapok-DTPA exhibited much better adsorption capacity compared with many other reported adsorbents based on natural materials.  相似文献   

9.
A new 14-membered crown ether with nitrogen–sulfur donor atom carrying two anthryl groups was designed and synthesized by the reaction of the corresponding macrocyclic compound and 9-(chloromethyl) anthracene. The influence of metal cations such as Al3+, Zn2+, Fe2+, Fe3+, Co2+, Ni2+, Mn2+, Cu2+, Cd2+, Hg2+ and Pb2+ on the spectroscopic properties of the ligand was investigated in acetonitrile–dioxane solution (1/1) by means of absorption and emission spectrometry. The results of spectrophotometric titration experiments disclosed the complexation stoichiometry and complex stability constant of the novel ligand with Fe2+, Fe3+, Al3+, Cd2+, Cu2+, Zn2+, Pb2+ and Hg2+ cations. Absorption spectra show isobestic points in the spectrophotometric titration of these cations. The presence of excess of Al3+, Zn2+, Fe2+, Fe3+, Co2+, Ni2+, Mn2+, Cu2+, Cd2+, Hg2+ and Pb2+ cations caused an enhancement of anthryl fluorescence. Especially, the enhancement in case of the interaction of Hg2+ and Al3+ cations with the ligand was pronounced.  相似文献   

10.
Zusammenfassung Der Einfluß organischer Wasserinhaltsstoffe (z. B. Huminsäure, Ligninsulfonsäure, Acetat, Citrat, EDTE) auf analytische Multielement-Anreicherungen (Cu2+, Fe3+, Mn2+, Pb2+ und Zn2+) an einem Chelat-Ionenaustauscher (Cellulose-Hyphan) wird beschrieben. Erwartungsgemäß verursacht der starke Chelatbildner EDTE erhebliche Störungen. Bereits mg/l-Konzentrationen an EDTE senken die analytische Spurenwiederfindung auf 0 (Pb2+) bis 50% (Mn2+). Durch eine oxidierende UV-Photolyse (Hg-Niederdruck-Strahler, 70 W, 1 h bei 45° C) lassen sich die störenden Wasserinhaltsstoffe (<200 mg/l) einfach und schnell aufschließen. Der UV-Aufschluß wird in seiner Abhängigkeit von Zeit, Oxidationsmittel (H2O2) sowie von organischen bzw. anorganischen Matrices (Ethanol bzw. NaCl) untersucht. Er zeichnet sich im Spurenbereich (je 20 g/l Cd2+, Cu2+, Fe3+, Mn2+, Ni2+, Pb2+, Zn2+) durch gute Reproduzierbarkeit und niedrige Blindwerte (z. B. Fe, Zn<1 g/l) aus. Die Elemente werden mit der Flammen-AAS bestimmt.
UV-photolysis of dissolved organic matter as sample pretreatment for the analytical multielement-enrichment, especially on chelating ion-exchangers
Summary The influence of water-dissolved organic matter (e.g. humic acid, lignin sulphonic acid, acetate, citrate, EDTE) on the analytical multielement-enrichment (e.g. Cu2+, Fe3+, Mn2+, Pb2+, Zn2+) on a chelating ion-exchanger (Cellulose-Hyphan) is described. As expected, the strong chelating agent EDTE causes large interferences. Thus, mg/l-concentrations of EDTE lower the analytical recovery rate to values between 0 (Pb2+) and 50% (Mn2+). In a fast and simple manner, the interfering organic matters in waters (<200 mg/l) can be eliminated by an oxidizing UV-irradiation (Hg-low-pressure lamp, 70 W, 1 h at 45° C). This UV-photolysis is investigated as function of the time, the oxidant (H2O2) and organic resp. inorganic matrices (ethanol resp. NaCl). At the trace level (20 g/l Cd2+, Cu2+, Fe3+, Mn2+, Ni2+, Pb2+, Zn2+, each) it shows a good reproducibility and low blank values (e.g. Fe, Zn<1 g/l). The elements are determined by flame-AAS.


Herrn Prof. Dr. H. Weisz zum 60. Geburtstag gewidmet  相似文献   

11.
A method for solid phase extraction of trace metals such as Cd2+, Cr6+, Cu2+, Fe3+, Mn2+, Ni2+, Pb2+ and Zn2+ using nanometer-sized alumina coated with chromotropic acid prior to determination by inductively coupled plasma atomic emission spectrometry (ICP-AES) has been developed. Various influencing parameters on the separation and preconcentration of trace metals, pH, flow rate, sample volume, amount of adsorbent, concentration of eluent and sorption kinetics have been studied. The detection limits for Cd2+, Cr6+, Cu2+, Fe3+, Mn2+, Ni2+, Pb2+ and Zn2+ were found to be 0.14, 0.62, 0.22, 0.54, 0.27, 0.28, 0.53 and 0.38 ng ml− 1, respectively. The adsorption capacity of the solid phase adsorption material is 10.3, 11.3, 14.5, 16.4, 15.1, 11.7, 15.4 and 16.8 mg g− 1 for Cd2+, Cr6+, Cu2+, Fe3+, Mn2+, Ni2+, Pb2+ and Zn2+, respectively. The preconcentration factor was obtained in the range of 50-100 for all studied metal ions. Coexisting ions over a high concentration range have not shown any significant effects on the determination of aforesaid metal ions. The accuracy of the proposed method was tested by standard reference materials (NIST 1643e: water, NIST 1573a: tomato leaves and NIST 1568a rice flour) and natural waters and the results obtained were in good agreement with the certified values.  相似文献   

12.
Rigid N‐(substituted)‐2‐aza‐[3]‐ferrocenophanes L1 and L2 were easily synthesized from 1,1 ‐dicarboxyaldehydeferrocene and the corresponding amines. Ligands L1 and L2 were characterized by 1H NMR, 13C NMR and single‐crystal X‐ray crystallography. The coordination abilities of L1 and L2 with metal ions such as Cu2+, Mg2+, Ni2+, Zn2+, Pb2+ and Cd2+ were evaluated by cyclic voltammetry. The electrochemical shift (ΔE1/2) of 125 mV was observed in the presence of Cu2+ ion, while no significant shift of the Fc/Fc + couple was observed when Mg2+, Ni2+, Zn2+, Pb2+, Cd2+ metal ions were added to the solution of L1 in the mixture of MeOH and H2O. Moreover, the extent of the anodic shift of redox potentials was approximately equal to that induced by Cu2+ alone when a mixture of Cu2+, Mg2+, Ni2+, Zn2+, Pb2+ and Cd2+ was added to a solution of L1. Ligand L1 was proved to selectively sense Cu2+ in the presence of large, excessive first‐row transition and late‐transition metal cations. The coordination model was proposed from the results of controlled experiments and quantum calculations. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

13.
A rapid method for the extraction and monitoring of nanogram level of Pb2+, Cu2+ and Zn2+ ions using uniform silanized mesopor (SBA-15) functionalized with diethylenetriamine groups and flame atomic absorption spectrometry (FAAS) is presented. The preconcentration factor of the method is 100 and detection limit of the technique is 5.5?ng?mL?1 and 1.4?ng?mL?1 and 0.1?ng?mL?1 for Pb2+, Cu2+ and Zn2+ respectively. The time and the optimum amount of the sorbent, pH and minimum amount of acid for stripping of ions from functionalized SBA-15 were tested. The maximum capacity the functionalized SBA-15 was found to be 183.0 (±1.9) µg, 156.0 (±1.5) µg and 80.0 (±1.6) µg of Pb2+, Cu2+ and Zn2+/mg functionalized SBA-15, respectively.  相似文献   

14.
A new chelating resin containing bis[2-(2-benzothiazolylthioethyl)sulfoxide] was synthesized using chloromethylated polystyrene as material and characterized by elemental analysis and infrared spectra. The adsorption capacities of the newly formed resin for Hg2+, Ag+, Cu2+, Zn2+, Pb2+, Mn2+, Ni2+, Cd2+ and Fe3+ were investigated over the pH range 1.0-6.0. The resin exhibited no affinity for alkali or alkaline earth metal ions. The maximum adsorption capacities of the resin for Hg2+, Ag+, Cu2+, Zn2+, Pb2+, Mn2+, Ni2+, Cd2+ and Fe3+ were 1.49, 0.96, 0.58, 0.11, 0.37, 0, 0.24, 0.36 and 0.25 mmol g−1, respectively. In column operation it had been observed that Hg2+ and Ag+ in trace quantity could be separated from different binary mixtures and Hg2+ could be effectively removed from industrial wastewater and the natural water spiked with Hg2+ at usual pH.  相似文献   

15.
合成了以1,8-萘酰亚胺为发色团,以联吡啶为离子受体的Zn2+荧光探针,并进行了表征及离子识别性能的研究。研究表明该化合物对Zn2+具有良好的识别性能,同时相对于Ca2+, Cd2+, Co2+, Cu2+, Hg2+, Fe3+, Mn2+, Ni2+, Pb2+等金属离子具有良好的选择性。  相似文献   

16.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M2+(aq) + Sr2+(nb) ? M2+(nb) + Sr2+(aq) taking part in the two-phase water–nitrobenzene system (M2+ = Mg2+, Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, ${\text{UO}}_{2}^{2 +} $ , Mn2+, Fe2+, Co2+, Ni2+; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the individual extraction constants of the M2+ cations in the mentioned two-phase system were calculated; they were found to increase in the following cation order: ${\text{UO}}_{2}^{2 + } $  < Zn2+, Ni2+ < Cu2+, Cd2+ < Co2+ < Mg2+ < Ca2+ < Mn2+, Fe2+ < Sr2+ < Pb2+ < Ba2+.  相似文献   

17.
A series of macroporous dithiocarbamate chelate resins, III and V, and an oxidized resin, VI, with high adsorption capacity were prepared. The influence of various reaction conditions of amination, dithiocarboxylation, and oxidation were examined. The structure and the conversion of functional groups of resins were confirmed by IR spectra and elemental analysis. The adsorption capacities of Resin II for Hg2+, Cu2+, Zn2+, and Cd2+ are 4.40, 2.44, 1.77, and 1.36 mmol/g, respectively. The adsorption capacities of Resins V and VI for Cu2+. Zn2+, Ni2+, Co3+, Ag+, Hg2+, Cd2+, Pb2+, and Au3+ are 4.07–0.51 and 3.81–0.59 meq ion/g, respectively. The adsorption rate and the influence of pH on the adsorption percentage of the resins for metal ions were examined. Noble metal, transitional metal, and heavy metal ions can be quantitatively adsorbed by the resins. The adsorbed Cu2+, Pb2+, Cd2+, Co3+, and Ni2+ can be quantitatively eluted with 5N HNO3, and the presence of large amounts of Ca2+, Mg2+, Fe3+, and Al3+ did not interfere.  相似文献   

18.
A simple Schiff base CTS, synthesized between 2-hydroxy-1-naphthaldehyde and 2-benzylthio-ethanamine, was found to be a good turn-on fluorescence probe for the detection of Zn2+, due to the restriction of the rotation of the bond between CN and naphthalene ring and/or the blocking of the photo-induced electron transfer (PET) mechanism of the nitrogen atom to naphthalene ring. Excellent selectivity for Zn2+ was evidenced, over many other competing ions, including Fe3+, Cr3+, Ni2+, Co2+, Fe2+,Mn2+, Ca2+, Hg2+, Pb2+, Cu2+, Mg2+, Ba2+, Cd2+, Ag+, Li+, K+, and Na+, in EtOH/HEPES buffer (95:5, v/v, pH = 7.4). It was noteworthy that Cd2+ had no interference with Zn2+. The stoichiometric complex of CTS-Zn2+ was determined to be 2:1 for CTS and Zn2+ in molar, based on the Job plot and single crystal X-ray diffraction data. The binding constant of the complex was 85.7 M?2 with a detection limit of 5.03 × 10?7 M. The fluorescence bio-imaging capability of CTS to detect Zn2+ in live cells was also studied. These results indicated that CTS could serve as a favorable probe for Zn2+.  相似文献   

19.
Summary A numer of bonded stationary phases were investigated for the separation of Cd2+, Cu2+, Fe3+, Mn2+, Ni2+, Pb2+, and Zn2+ by thin-layer chromatography. The effect of structure, surface loading, type of silica gel and mobile phase concentration was considered.  相似文献   

20.
In order to explore the reuse properties of oxidized chelating resin containing sulfur after adsorption, two kinds of novel chelating resins, poly[4-vinylbenzyl-(2-hydroxyethyl)] sulfoxide (PVBSO) and poly[4-vinylbenzyl-(2-hydroxyethyl)] sulfone (PVBSO2), were synthesized using poly[4-vinylbenzyl-(2-hydroxyethyl)] sulfide (PVBS) as material. Their structures were confirmed by FTIR and XPS. The adsorption properties and mechanism for metal ions such as Au3+, Pt4+, Pd2+, Hg2+, Cu2+, Ni2+, Fe3+, Pb2+, Cd2+, and Zn2+ were investigated. Experimental results showed that PVBSO had good adsorption and selective properties for Au3+, Pd2+ and Cu2+ when the coexisting ion was Pt4+, Ni2+, Pb2+ or Cd2+. In the aqueous system containing Cu2+ and Pb2+ or Cu2+ and Cd2+, PVBSO2 only adsorbed Cu2+. The selective coefficients of PVBSO and PVBSO2 were αAu/Pt = 4.8, αAu/Pd = 11.8, αPd/Pt = 10.9, αCu/Ni = 2.5, αCu/Cd = 41.2, αCu/Pb = ∞, αCu/Ni = 3.0, αCu/Cd = ∞, αCu/Pb = ∞, respectively.  相似文献   

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