The sorption of some radiocations on microporous titanosilicate ETS-10

The microporous titanosilicate ETS-10 synthesized from gel with following molar composition: 1.0 Na₂O: 1.49 SiO₂ : 0.2 TiO₂ : 0.6 KF : 1.28 HCl : 39.5 H₂O was subjected to sorption of radioactive cations ¹¹⁵Cd²⁺, ²⁰⁴Hg²⁺, ⁶⁰Co²⁺ and ¹³⁷Cs⁺ (M) from aqueous solution, in the absence of ionic competition. The uptake of these cations on the ETS-10 was compared by means of the distribution coefficient (K_d) versus contact time and sorption capacity (R) at equilibrium. The FT-IR spectra of M-ETS-10 sorption products exhibit a modification of the absorption band, principally at 381 cm^-1.     

Separation of In3+ from Cd2+ on crystalline antimonic acid.115Cd−115mIn generator

The distribution coefficients of Cd²⁺ and In³⁺ on crystalline antimonic(V) acid (C-AA) have been determined in order to find the best conditions for separation of both cations. Very high affinity of C-AA for Cd²⁺ ions enables to separate^115mIn from¹¹⁵Cd in a single-step rapid procedure. The indium fraction obtained was very pure; the amount of radioactive contaminants was less than 0.0005%.     

A Simple Fluorometric Method Using Chlorophyll a for Determination of Hg2+ Ion

A simple and green analytical procedure based on chlorophyll a is presented for the determination of Hg²⁺ ion. Chlorophyll a was extracted and purified from the leaves of pea and is employed as a reagent for analysis of Hg²⁺ ion. It displays remarkable fluorescence emission at 674 nm when excited at 412 nm. The emission intensity decreased significantly on exposure to various concentrations of Hg²⁺ ion. This forms the basis for the determination of Hg²⁺ ion. The proposed method was evaluated for sensitivity and selectivity. The linear concentration range was found to be 2.0–10 μM with r² = 0.997 and the limit of detection for Hg²⁺ ion was 1.3 μM. Ions including Pb²⁺, Cd²⁺, Ag⁺, Zn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Mg²⁺, Mn²⁺, Ru³⁺, Er³⁺, K⁺, Na⁺, NH₄⁺, Cl⁻, NO₃⁻, CH₃COO⁻ and SO₄²⁻ did not interfere with the measurement of Hg²⁺ ion even at 500-fold excess. Since chlorophyll a is widely available in the leaves of most plants, and the extraction and purification process is simple, this technique can provide an alternative, sensitive and economical way to determine Hg²⁺ ion.     

Effect of temperature on the sorption behavior of sodium potassium fluorophlogopite with respect to the heavy metal ions Cd<Superscript>2+</Superscript>, Hg<Superscript>2+</Superscript>, and Pb<Superscript>2+</Superscript>

The effect of temperature on the sorption behavior of a synthesized gel structurally close to the fluorine mica mineral, sodium potassium fluorophologopite, was studied for the heavy metal ions Cd²⁺, Hg²⁺, and Pb²⁺. The synthesized gel was characterized by X-ray powder pattern, energy dispersive spectrometry, infrared spectroscopy, and thermogravimetric analysis and was found to have the composition Na_0.5K_0.5Mg(AlSi₃O₁₀)F₂·6H₂O. The effect of temperature on sorption was studied with respect to varying concentrations of metal ions. The overall sorption capacity of the synthesized gel was found to depend on the number of ion active groups per unit weight of the material. The data were expressed in terms of distribution coefficients (K _d). Sorption data followed Freundlich adsorption isotherms. Studies showed that sorption decreased as the concentration of metal ions increased and increased as the temperature grew, which was evidence that the process was endothermic. The text was submitted by the authors in English.     

基于苯并噻唑Zn2+荧光探针及其细胞造影应用

设计合成基于苯并噻唑Zn²⁺荧光增强型探针BHP,在HEPES缓冲液中测其对Zn²⁺识别性能。实验结果表明,BHP对Zn²⁺有较高的选择性,对其他金属离子如Cd²⁺,Fe²⁺,Ni²⁺,Pb²⁺,Hg²⁺,Al³⁺,Mn²⁺,Ag⁺,Cu²⁺,Co²⁺,Na⁺,K⁺,Mg²⁺和Ca²⁺无明显荧光增强响应。BHP与Zn²⁺按1：1计量比配位,在生理条件下荧光强度不受pH值影响。在HeLa细胞中对Zn²⁺的造影表明BHP可用于生物体Zn²⁺检测。     

A new phenothiazine-based fluorescence sensor for imaging Hg2+ in living cells

A new phenothiazine-based sensor PHE-Ad for monitoring Hg²⁺ has been designed and synthesized based on the intramolecular charge transfer (ICT) mechanism. The probes were characterized by FTIR, ¹H NMR, and HRMS, and their optical properties were detected by UV and FL. It's showed the probes detection of Hg²⁺ compared to other metal ions (Mg²⁺, Cu²⁺, Hg²⁺, Ag⁺, Co²⁺, Cr³⁺, Al³⁺, Ni²⁺, Zn²⁺, Ca²⁺, Fe³⁺, Fe²⁺, K⁺, Na⁺, and Cd²⁺) based on the test results. Besides, the detection limits were determined to be 2.12 × 10⁻⁸ M through the standard curve plot. In addition, sensor PHE-Ad shows high selectivity and sensitivity for Hg²⁺ with a fast response in a suitable pH range. Furthermore, taking into account its good “turn-on” fluorescent sensing behavior and low cell cytotoxicity, PHE-Ad was successfully applied to detect and image Hg²⁺ in real water samples and living cells, which shows great potentials for application in environmental and biological systems.     

Preconcentration and Determination of Toxic Metals by A New Calix[4]arene Bonded HPLC Column

The present study deals with the preconcentration and determination of toxic metal ions using p-tetranitrocalix[4]arene (3) appended silica-based new HPLC column. The synthesized material was characterized using Fourier transform infrared and scanning electron microscopy techniques. The sorption characteristics of the HPLC column were investigated for three toxic metals (Cd²⁺, Hg²⁺ and Pb²⁺) in column agreement. The experiments were performed in five steps that were monitored using a UV–visible diode-array detector. However, all the HPLC experimental results were reconfirmed by using atomic absorption spectrophotometer. The effect of concentration on the sorption efficiency of the column was evaluated for all the three metals and the data obtained were investigated using Langmuir, Freundlich and Dubinin–Redushkevich (D–R) sorption isotherms. The value of coefficient of determination (R ²), i.e. 0.99, suggested that the Freundlich sorption isotherm was found to be the best-fit model for all the three toxic metal ions, whereas, mean free energy was calculated from the D–R isotherm as 5.3, 5.7, and 5.8 kJ/mol for Pb²⁺, Cd²⁺, and Hg²⁺, respectively; suggesting that physical electrostatic force is involved in the sorption process. The developed method was validated for system efficiency, accuracy, and precision.

     

A new Hg2+ fluorescent sensors based on 1,3-alternate thiacalix[4]arene (L) and the complex of [L+Hg2+] as turn-on sensor for cysteine

A new thiacalix[4]arene derivative in a 1,3-alternate conformation bearing four naphthalene groups through crown-3 chains has been synthesized, which exhibits high selectivity toward Hg²⁺ by forming a 1:2 complex, among other metal ions ( Na⁺, K⁺, Mg²⁺, Ba²⁺, Ca²⁺, Sr²⁺, Cs⁺, Mn²⁺, Fe²⁺, Cd²⁺, Co²⁺, Ni²⁺, Cu²⁺, Li⁺, and Zn²⁺) with a low detection limit (3.30×10^?7 M). The metal ion-binding properties were studied by fluorescence, AFM, and ¹H NMR spectroscopy. The in situ prepared [Hg²⁺+L] complex shows well recognition ability for cysteine with a low detection limit (2.23×10^?7 M) through fluorescence turning on. The mechanism of fluorescence turning on is the host L releasing from [L+Hg²⁺] for [Cys+Hg²⁺] complex formed. Thus the paper reports secondary-sensor design: Hg²⁺ as a first sensor for [L+Hg²⁺] form, cysteine as a second sensor for Hg²⁺ releasing from the [L+Hg²⁺] complex after cysteine adding in.     

1,8-萘酰亚胺为发色团的Zn2+荧光探针的合成及性能研究

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。     

Instrumental neutron activation analysis (INAA) of Nok sculptures in I. P. Stanback Museum

Biochar prepared from Triticum aestivum straw (SB) was used to investigate the sorption separation of Cd²⁺ and Co²⁺ ions in single and binary systems. The maximum adsorption capacity of SB was higher for Cd²⁺ ions and the process was strongly pH dependent. Adsorption data in the binary system Cd²⁺–Co²⁺ were well described by the extended Langmuir model and the values of affinity parameter b indicate a higher affinity of SB to Cd²⁺ in comparison with Co²⁺ ions. The mechanisms for the removal of Cd and Co by biochar were evidenced by the different instrumental analyses as well as by chemical speciation modeling. Elemental mapping of SB revealed spatial distributions of cobalt and cadmium on biochar surfaces. The role of functional groups in metal sorption was confirmed by FTIR. Results demonstrate that SB is a promising heavy metal-immobilizing agent for contaminated soils or water.     

Polymer‐based fluorescence sensors incorporating chiral binaphthyl and benzo[2,1,3]thiadiazole moieties for Hg2+ detection

Three chiral polymers P‐1 , P‐2 , and P‐3 could be obtained by the polymerization of (R)‐6,6′‐dibutyl‐3,3′‐diiodo‐2, 2′‐binaphthol (R‐M‐1) , (R)‐6,6′‐dibutyl‐3,3′‐diiodo‐2,2′‐bisoctoxy‐1,1′‐binaphthyl ( R‐M‐2 ), and (R)‐6,6′‐dibutyl‐3,3′‐diiodo‐2,2′‐bis (diethylaminoethoxy)‐1,1′‐binaphthyl ( R‐M‐3 ) with 4,7‐diethynyl‐benzo[2,1,3]‐thiadiazole ( M‐1) via Pd‐catalyzed Sonogashira reaction, respectively. P‐1 , P‐2 , and P‐3 can show pale red, blue–green, and orange fluorescence. The responsive optical properties of these polymers on various metal ions were investigated by fluorescence spectra. Compared with other cations, such as Co²⁺, Ni²⁺, Ag⁺, Cd²⁺, Cu²⁺, and Zn²⁺, Hg²⁺ can exhibit the most pronounced fluorescence response of these polymers. P‐1 and P‐2 show obvious fluorescence quenching effect upon addition of Hg²⁺, on the contrary, P‐3 shows fluorescence enhancement. Three polymer‐based fluorescent sensors also show excellent fluorescence response for Hg²⁺ detection without interference from other metal ions. The results indicate that these kinds of tunable chiral polybinaphthyls can be used as fluorescence sensors for Hg²⁺ detection. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 997–1006, 2010     

Salacca zalacca skin and its modified form as biosorbents for Hg2+ removal from aqueous solution

ABSTRACT

A chemically modified-biosorbent was prepared by attaching dithizone onto Salacca zalacca skin waste for Hg²⁺ bioremoval. The material was synthesized by refluxing dithizone 5% with the Salacca zalacca skin powder followed by drying. The material was characterized through scanning electron microscopy, gas sorption analysis, and Boehm titration. The applicability of the material as biosorbent was tested for Hg²⁺ adsorption at room temperature. Findings suggested that the modification altered the surface properties of the biosorbent as indicated by the increased values for such surface parameters as specific surface area, pore volume, and quantitative functional groups. Particularly, the material demonstrated a high removal efficiency during Hg²⁺ adsorption, which fit the pseudo-second-order kinetics. The removal efficiency of Hg²⁺ was not influenced by the adsorbent dosage of 1–4?g/L.     

Sorption behavior of Co2+, Zn2+ and Ba2+ ions on alumina,kaolinite and magnesite

The sorption behavior of Ba²⁺, Co²⁺ and Zn²⁺ ions on alumina, kaolinite and magnesite have been investigated using the batch method.⁶⁰Co,⁶⁵Zn and¹³³Ba were used as radiotracers. The mineral samples were separated into different particle size fractions using an Andreasen Pipette. The particle sizes used in the sorption experiments were all less than 38 m. Synthetic groundwaters were used which had compositions similar to those from the regions where the minerals were recovered. The samples were shaken with a lateral shaker at 190 rpm, the phases were separated by centrifuging and adioactivity counted using a NaI(Tl) detector. Kinetic studies indicated that sorption onto the minerals took place in two stages with the slower process dominating. The highest sorption was observed on alumina. Both Freundlich and Dubinin-Radushkevich type isotherms were found to describe the sorption process well. The distribution ratio,R _d was found to be a function of the liquid volume to solid mass ratio. TheR _d 's for sorption on binary mixtures of minerals were experimentally determined and compared with those predicted fromR _d values of each individual mineral.     

Ion-pair extraction of transition metal cations from aqueous media using novel N2O2-macrocyclic crown ligands

Three new macrocyclic crown ether ligands containing nitrogen–oxygen donor atoms were designed and synthesized from 1,4-bis(2′-formylphenyl)-1,4-dioxabutane and 4-nitro-o-phenylenediamine. Ion-pair extraction of metal picrates such as Ag⁺, Hg²⁺, Cd²⁺, Zn²⁺, Cu²⁺, Ni²⁺, Mn²⁺, Co²⁺, and Pb²⁺ from aqueous phase to the organic phase was carried out using the novel ligands. The solvent effect over the metal picrate extractions was investigated at 25 ± 0.1 °C by using UV–visible spectrometry. The extractability and the values of the extraction constants (log K_ex) were determined for the extracted complexes.     

Mo3S132− Intercalated Layered Double Hydroxide: Highly Selective Removal of Heavy Metals and Simultaneous Reduction of Ag+ Ions to Metallic Ag0 Ribbons

We demonstrate a new material by intercalating Mo₃S₁₃^2? into Mg/Al layered double hydroxide (abbr. Mo₃S₁₃-LDH), exhibiting excellent capture capability for toxic Hg²⁺ and noble metal silver (Ag). The as-prepared Mo₃S₁₃-LDH displays ultra-high selectivity of Ag⁺, Hg²⁺ and Cu²⁺ in the presence of various competitive ions, with the order of Ag⁺>Hg²⁺>Cu²⁺>Pb²⁺≥Co²⁺, Ni²⁺, Zn²⁺, Cd²⁺. For Ag⁺ and Hg²⁺, extremely fast adsorption rates (≈90 % within 10 min, >99 % in 1 h) are observed. Much high selectivity is present for Ag⁺ and Cu²⁺, especially for trace amounts of Ag⁺ (≈1 ppm), achieving a large separation factor (SF_Ag/Cu) of ≈8000 at the large Cu/Ag ratio of 520. The overwhelming adsorption capacities for Ag⁺ (q_m^Ag=1073 mg g^?1) and Hg²⁺ (q_m^Hg=594 mg g^?1) place the Mo₃S₁₃-LDH at the top of performing sorbent materials. Most importantly, Mo₃S₁₃-LDH captures Ag⁺ via two paths: a) formation of Ag₂S due to Ag-S complexation and precipitation, and b) reduction of Ag⁺ to metallic silver (Ag⁰). The Mo₃S₁₃-LDH is a promising material to extract low-grade silver from copper-rich minerals and trap highly toxic Hg²⁺ from polluted water.     

A highly selective colorimetric and fluorescent chemosensor for Cr2+ in aqueous solutions

A new rhodamine-based chemosensor was synthetized through a modified copper-catalyzed [3+2]-cycloaddition of an azidocoumarin with an alkynyl-rhodamine. Its sensing properties toward various metal cations in aqueous solutions were investigated by colorimetric changes, UV–vis and fluorescence spectroscopies. The sensor exhibited a high selectivity for Cr²⁺ over Cr³⁺ and other divalent cations such as Cu²⁺, Mg²⁺, Zn²⁺, Ca²⁺, Cd²⁺, Co²⁺, Hg²⁺ and Ni²⁺. The linear range of detection by fluorescence spectroscopy is 0.07–3.5 mM, with a detection limit of ca. 64 μM. The binding mode of Cr²⁺ with the sensor was rationalized through experimental evidences.     

Spectrophotometric study of complexation of dibenzopyridino-18-crown-6 with some transition and post-transition metal ions in DMSO solution using murexide as a metallochromic ligand

The complexation reaction of dibenzopyridino-18-crown-6 (DBPY 18C6) with Co²⁺, Cu²⁺, Zn²⁺, Pb²⁺, Cd²⁺, Hg²⁺, and Ag⁺ have been studied in DMSO at 25°C by the spectrophotometric method. Murexide was used as a competitive colored ligand. The stoichiometry of metal ion-murexide and metal ions with DBPY18C6 complexes were estimated by mole ratio and continuous variation methods and emphasized by the KINFIT program. The stoichiometry of all the complexes was found to be 1: 1 (metal ion/ligand). The order of stability constants for the obtained metal ion-murexide complexes (1: 1) varies in the order Cu²⁺ > Cd²⁺ > Co²⁺ ∼ Pb²⁺ > Zn²⁺ > Ag⁺ > Hg²⁺. This trend shows that the transition metal ions clearly obey the Irving-Williams role. For the post-transition metal ions, the ionic radius and soft-hard behavior was the major affects in varying of this order. The dibenzopyridino-18-crown-6 complexes with the used metal ions vary as Ag⁺ > Pb²⁺ > Cu²⁺ > Cd²⁺ > Hg²⁺ > Zn²⁺ > Co²⁺. The article is published in the original.     

Novel polyamidoamine‐based hydrogel with an innovative molecular architecture as a Co2+‐, Ni2+‐, and Cu2+‐sorbing material: Cyclovoltammetry and extended X‐ray absorption fine structure studies

An amphoteric polyamidoamine (PAA)‐based hydrogel, named INT‐PAA1, with a novel molecular architecture was prepared and studied as a Co²⁺‐, Ni²⁺‐, and Cu²⁺‐sorbing material. This hydrogel was obtained by the synthesis of a PAA in the presence of a second presynthesized PAA carrying many primary amino groups as side substituents, which acted as a macromolecular crosslinking agent. Therefore, it had an intersegmented structure. INT‐PAA1 exhibited a remarkable sorption capacity and sorption rate for Co²⁺, Ni²⁺, and Cu²⁺ that were advantageously in situ monitored by cyclic voltammetry. An extended X‐ray absorption fine structure spectroscopy characterization of the Co²⁺/INT‐PAA1 complex was also performed. The very fast and quantitative metal‐ion uptake, made apparent by an intense coloring of the hydrogel, showed remarkable potential for environmental applications such as heavy‐metal detection, recovery, and elimination. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2316–2327, 2006     

Polymer‐based colorimetric and “turn off” fluorescence sensor incorporating benzo[2,1,3]thiadiazole moiety for Hg2+ Detection

A conjugated polymer was synthesized by the polymerization of 4,7‐dibromobenzo[2,1,3]thiadiazole ( M‐1 ) with tri{1,4‐diethynyl‐2,5‐bis(2‐(2‐methoxyethoxy)‐ethoxy)}‐benzene ( M‐2 ) via Pd‐catalyzed Sonogashira reaction. The polymer shows strong orange fluorescence. The responsive optical properties of the polymer on various metal ions were investigated through photoluminescence and UV–vis absorption measurements. The polymer displays highly sensitive and selective on‐off Hg²⁺ fluorescence quenching property in tetrahydrofuran solution in comparison with the other cations including Mg²⁺, Zn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Ag⁺, Cd²⁺, and Pb²⁺. More importantly, the fluorescent color of the polymer sensor disappears after addition of Hg²⁺, which could be easily detected by naked eyes. The results indicate that this kind of polymer sensor incorporating benzo[2,1,3]thiadiazole moiety as a ligand can be used as a novel colorimetric and fluorometric sensor for Hg²⁺ detection. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011