Novel naphthalene-based fluorescent chemosensors for Cu2+ and Fe3+ in aqueous media

Three novel compounds bearing 2,7-dihydroxylnaphthalene capable of detecting Cu²⁺ or Fe³⁺ have been synthesised based on photoinduced electron transfer. The ability of these compounds for complex transition metal ions has been studied, and complex stoichiometry for Cu²⁺ and Fe³⁺ complex has been determined in the Tris–HCl (0.01 M DMSO/H₂O (v/v) 1:1, buffer, pH 7.4) solution system by fluorescence titration experiments. These chemosensors form a 1:1 complex with Cu²⁺ or Fe³⁺ and show a fluorescent quenching with a binding constant of (4.46 ± 0.29) × 10³ and (8.04 ± 0.26) × 10⁴, respectively.     

TEMPO-oxidized cellulose hydrogel for efficient adsorption of Cu2+ and Pb2+ modified by polyethyleneimine

Cellulose - In this study, the hydrogel was prepared by dissolving and regenerating poplar cellulose in NaOH/urea/water system. The TEMPO-oxidized cellulose hydrogels (TCH) were prepared using...     

Theoretical studies on the interaction of anionic collectors with Cu+, Cu2+, Zn2+ and Pb2+ ions

 The influence of collector structure on interaction with metal cations was modelled by computational ab initio methods. The interaction energies were calculated between metal ions (Cu⁺, Cu²⁺, Zn²⁺ and Pb²⁺) and selected collector anions: ethyl xanthate, ethyl trithiocarbonate, dithiobutyric acid, ethyl dithiocarbamate, diethyl dithiocarbamate, diethylphosphinecarbodithioic acid and diethoxyphosphinecar bodithioic acid. The strongest interaction was found with diethyl dithiocarbamate. The results give qualitative information on the effect of the collector structure on the initial adsorption steps on sulphide mineral flotation. Received: 25 September / Accepted: 11 October 2001 / Published online: 22 March 2002     

Cu x O@DNA sphere-based electrochemical bioassay for sensitive detection of Pb2+

Microchimica Acta - The authors show that copper nanoclusters capped with tannic acid (TA-CuNCs) are viable fluorescent probes for the determination of the activity of pyrophosphatase (PPase). The...     

改性壳聚糖的制备及对Cu2+Pb2+的吸附研究

用巯基乙酸作为巯基化剂,对壳聚糖进行改性,选择了巯基化的条件.实验表明,在浓度为188mg/L的铜溶液中,CTS-SH的最大吸附率达90.3%以上,吸附容量为27.76mg/g,在浓度为203mg/L的铅溶液中,对铅的最大吸附率达到99%以上,在浓度为1.015g/L的铅溶液中,最大吸附率达95.5%.此时的吸附容量为97.4mg/g,吸附容量大于147.2mg/g时的吸附率为36.3%.经XRD及EMS图片的分析,可以看出,改性壳聚糖在吸附前后,结构发生了改变.     

Insights into the photophysics,protonation and Cu2+ ion coordination behaviour of anthracene-9,10-dione-based chemosensors

Carboxylic acid–diamine-based Cu²⁺ chromogenic sensors (3 and 4) exhibited colour switching from red to blue with good sensitivity and selectivity towards Cu²⁺ among other physiologically important alkali, alkaline earth and heavy metal ions. This colour-switching phenomenon arises due to selective deprotonation of aryl amine NH by Cu²⁺. Significantly, chemosensor 3 (λ_max 492 nm) shows multiple modes of complexation towards Cu²⁺. It is very much evident from the appearance of blue colour (λ_max 615 nm) at pH >7.0 and yellow colour (λ_max 465 nm) at pH < 4.0. In addition, chemosensor 3 exhibits a unique logic gate system that involves ‘INHIBIT’ and ‘TRANSFER’ logic gates.     

Influence of Different Microplastic Forms on pH and Mobility of Cu2+ and Pb2+ in Soil

Microplastics, due to their surface properties, porosity and electrostatic interactions have a high affinity for cations sorption from the aqueous phase. As soil is a complex matrix, interactions between microplastics, soil constituents and heavy metals (HM) may modify the soil microenvironment for heavy metal mobilization/immobilization processes. In order to better understand the problem, three commonly found forms of microplastics in soil (fibers, fragments and microbeads) were mixed with Cu²⁺- or Pb²⁺-contaminated soil and incubated at 22 °C for 180 days. In soil samples pH and the content of water and acid exchangeable species of metals were analyzed. The results of this study showed that the presence of microplastics in HM-contaminated soil affected metal speciation, increasing the amount of easily exchangeable and potentially bioavailable forms of Cu²⁺ or Pb²⁺ in the tested soil. Soil pH also increased, confirming that microplastic particles affect soil properties relevant to the sorption/desorption process of metal cations. Overall, the smallest microplastic particles (≤1 mm), such as fibers or glitter microbeads, had a greater impact on the change in the sorption and desorption conditions of metals in tested soil than larger particles. The findings of our study show that microplastic form, shape and size should be considered as important factors that influence the soil properties and mobility of heavy metals in soil.     

Studies on Synthetic Inorganic Ion Exchangers-III Quantitative Separations of Mg2+ -Pb2+, Zn2+ - Pb2+ Cu2+ - Pb2+, Al3+ - Pb2+, Zn2+ - Cd2+, and Mg2+ - Cd2+ on Lead Antimonate Columns

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.     

Complexation and thermodynamic studies of oxathiadibenzocrown ethers with Cu2+, Pb2+, Zn2+ and Cd2+ ions

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.     

反相高效液相色谱法同时测定镉、铅、铜和锌

 研究了meso-四（对羟基苯基）卟啉为柱前衍生化试剂与Cd2+,Pb2+,Cu2+和Zn2+离子的配合反应条件及配合物在C18色谱柱上的分离条件,建立了反相高效液相色谱快速分离光度检测Cd2+,Pb2+,Cu2+和Zn2+的新方法。配合物和试剂在15 min内出峰完毕。4种离子的检出限为: Cd2+0.02 ng,Pb2+0.02 ng, Cu2+0.02 ng,Zn2+0.12 ng;线性范围为:Cd2+0.8 μg/L～150 μg/L,Pb2+0.8 μg/L～300 μg/L,Cu2+0.8 μg/L～500 μg/L,Zn2+5.0 μg/L～1 000 μg/L;方法的日内相对标准偏差为:2.8%～4.8%,测定低、中、高3个浓度的日间相对标准偏差为3.7%～9.7%。     

A highly selective visual and fluorescent sensor for Pb2+ and Zn2+ and crystal structure of Cu2+ complex based-on a novel single-armed Salamo-type bisoxime

A novel single-armed Salamo-type bisoximes (H₄L) has been designed and synthesised. An obvious colour change from yellow (H₄L) to pale pink (HL-Pb²⁺) which can be visually observed by the naked eye in visible light. H₄L can act as a fluorescent sensor for ratiometric recognition of Zn²⁺ with high selectivity and sensitivity. Crystallographic data of the [Cu(HL)(μ-OAc)Cu] reveals that the two Cu²⁺ ions are both penta-coordinated with square pyramidal geometries, and forms a 2D supramolecular plane structure by hydrogen bonding interactions.     

Simultaneous determination of Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ by using second-derivative spectrophotometry method

A new method of simultaneous determination of Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ is proposed here by using the second-derivative spectrophotometry method. In pH=10.35 Borax-NaOH buffer, using meso-tetra (3-methoxyl-4-hydroxylphenyl) porphyrin ([T-(3-MO-4-HP)P]) as chromomeric reagent, micelle solution was formed after Tween-80 surfactant was added into the solution containing Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ ions. The original absorption spectrum of the above complexes was obtained after heating in the boiling water for 25 min. The second-derivative absorption peaks of five metal-porphyrin complexes can be separated from the original absorption spectrum by using chemometric tool. In this way, Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ ions can be determined simultaneously. Under the optimal conditions, the linear ranges of the calibration curve were 0-0.60, 0-0.60, 0-0.40, 0-0.80 and 0-0.48 μg mL(-1) for Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+, respectively. The molar absorptivity of these color systems were 1.38×10(5), 1.01×10(5), 3.24×10(5), 1.07×10(5) and 1.29×10(5)Lmol(-1)cm(-1). The method developed in this paper has advantages in selectivity, sensitivity, operation and can effectively resolve spectra overlapping problem. This method has been applied to determine the real samples with satisfactory results.     

Chemically modified kapok fiber for fast adsorption of Pb2+, Cd2+, Cu2+ from aqueous solution

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.     

New monoacylhydrazidate-coordinated Mn2+ and Pb2+ compounds

By the simple hydrothermal self-assembly, four new monoacylhydrazidate-coordinated compounds [Mn(APTH)(2)(H(2)O)] 1, [Pb(APTH)(2)]·0.25H(2)O 2, [Pb(2)(EPDH)(4)(H(2)O)] 3 and [Pb(MPDH)(2)] 4 (APTH = 3-aminophthalhydrazidate, EPDH = 5-ethylpyridine-2,3-dicarboxylhydrazidate, MPDH = 6-methylpyrinde-2,3-dicarboxylhydrazidate) were obtained. It is noteworthy that APTH was derived from the in situ reduction reaction of NPTH (3-nitrophthalhydrazide) with N(2)H(4)·H(2)O as the reducer, whereas EPDH and MPDH were derived respectively from the in situ acylation reactions of epdca and mpdca (epdca = 5-ethylpyridine-2,3-dicarboxylic acid, mpdca = 6-methylpyridine-2,3-dicarboxylic acid) with N(2)H(4)·H(2)O. The photoluminescence analysis indicates that compounds 3 and 4 possess luminescence properties with maximum emissions at 531 nm for 3, and 600 nm for 4, respectively. The density functional theory (DFT) calculations indicate that the emission for compound 3 can be ascribed to a combination of the intra-ligand and inter-ligand charge transfers, while the emission for compound 4 is assigned to the intra-ligand charge transfer.     

Study of sorption of Pb2+, Cd2+, Zn2+ and Cu2+ from wastewater on synthetic analogues of clintonite

The study describes a sorption of metal ions Pb²⁺, Cd²⁺, Zn²⁺ and Cu²⁺ on a synthetic mica clintonite. Synthesis of analogues of clintonite was carried out by using inorganic salts as sources of silicon and aluminum in the hydrothermal method. Alkaline conditions were applied to increase the nucleation rate. Powdered clintonite obtained after mechanical grinding was used for the removal of metal ions from the wastewater. The sorption experiments were done under batch process to measure the concentrations of metal ions. Effects of pH, contact time between sorbent and sorbate solution, amount of sorbent and temperature on the sorption of metal ions were studied. The sorption was shown to increase with the pH of the medium. The optimal conditions for sorption of metal ions on synthetic analogues of clintonite were determined.     

Photoactive chemosensors 4: a Cu protein cavity mimicking fluorescent chemosensor for selective Cu recognition

Fluorescent chemosensor 3 can sense Cu²⁺ ions (1-8 μM) even in the presence of elevated levels of Ni²⁺, Cd²⁺, Zn²⁺, Hg²⁺, Ag⁺ and Pb²⁺ (5000 μM). 3 can also analyze for Ag⁺ ions (50-500 μM) in the presence of Ni²⁺, Cd²⁺, Zn²⁺, Hg²⁺ and Pb²⁺ (5000 μM) but Cu²⁺ strongly interferes.     

Competitive adsorption of Pb2+, Cu2+, and Cd2+ ions on microporous titanosilicate ETS-10

In the present study, the competitive adsorption characteristics of binary and ternary heavy metal ions Pb2+, Cu2+, and Cd2+ on microporous titanosilicate ETS-10 were investigated in batch systems. Pure microporous titanosilicate ETS-10 was synthesized with P25 as the Ti source and characterized by the techniques of X-ray diffraction (XRD), field emission-scanning electron microscope (FESEM), nitrogen adsorption, and zeta-potential. Equilibrium and kinetic adsorption data showed that ETS-10 displays a high selectivity toward one metal in a two-component or a three-component system with an affinity order of Pb2+ > Cd2+ > Cu2+. The equilibrium behaviors of heavy metals species with stronger affinity toward ETS-10 can be described by the Langmuir equation while the adsorption kinetics of the metals can be well fitted to a pseudo-second-order (PSO) model.     

Adsorption of humic substances by macro weakly basic ion-exchange resin and their effects on removal of Cu2+ and Pb2+

<正>Adsorption ofhumic,tannic and gallic acids by a macro weakly basic ion-exchange resin JN-01 was studied.The adsorption capacity of this resin for gallic and tannic acids is much higher than that for humie acid,which can be explained on the basis of both their molecular size and ionization degree.Furthermore,humic acid is separated into different components with molecular weight in the range from 2000 Da to 100000 Da by ultra-filter,and their adsorption isotherms on resin JN-01 indicate that humic acid's molecular weight is an important factor which makes significant influence on adsorption.Finally,changes in the amount of Cu~(2+) and Pb~(2+) adsorbed on resin JN-01 as a function of the concentration of each of these three acids were studied.A large increase in the heavy metal ions uptake is observed in the presence of humic substance,such advantages are due to the interactions between the heavy metal ions and the unbound functional groups of the adsorbed organic acids.