Range Of Cu2 Research Articles

Эвдиалит Кольского полуострова — перспективный источник получения композиционных Zr – Ti – SiO2 сорбентов цветных металлов и радионуклидов

Based on the products of hydrochloric acid decomposition of eudialyte concentrate, composite zirconium-titanium-silica sorbents with a SiO2 content of 10 – 30 wt.% were synthesized and their surface was modified into H+ and Na+-form. All samples were studied by chemical, X-ray phase, BET and BJH assays. It is shown that all the obtained samples of silica-containing Zr – Ti – SiO2 sorbents are mesoporous. At the same time, the pores have a predominantly wedge-shaped shape with open ends, and the maximum pore volume has pores with a diameter lying in the range of 10 – 50 nm (∼ 50 % of the total pore volume). Based on the obtained values of the specific capacity of the adsorption monolayer of the surface of the SiO2 samples and the value of the Gibbs energy change (ΔGo) during nitrogen sorption, it is concluded that the modification of the surface of the synthesized Zr – Ti – SiO2 sorbents does not affect the physicochemical properties of their surfaces and the mechanism of nitrogen sorption. The sorption activity of synthesized samples with respect to Cu2+, Co2+ and Sr2+ ions was studied in batch experiments. It was found that the modification of the obtained samples into the H+-form has less effect on their sorption capacity than their conversion to the Na+-form, does not depend on the content of SiO2 in them in the range of 10 – 30 % and decreases in the range of Cu2+ − Co2+ − Sr2+.

Структурно-поверхностные и сорбционные свойства композиционных Zr-Ti- SiO2 сорбентов на основе минерального сырья Кольского полуострова для извлечения цветных металлов и радионуклидов из водных растворов

Samples of composite zirconium-titanium-silica sorbents were synthesized and studied by chemical, X-ray phase, BET and BJH analyses. It is shown that all the obtained samples of silica-containing Zr-Ti-SiO2 sorbents are mesoporous. In this case, the pores have a predominantly wedge-shaped shape with open ends. It was found that the modification of the obtained samples into the H+ form has less effect on their sorption capacity than their conversion to the Na+ form, does not depend on the content of SiO2 in them in the range of 10–30 % and decreases in the range of Cu2+-Cs+-Co2+-Sr2+.

A new six-membered spiro-rhodamine probe for Cu2+ and its imaging in mitochondria and lysosomes of Hela cells

Different from five-membered rhodamine spirolactam (Rh-OH), a new six-membered spiro-rhodamine probe (SRh-OH) bearing urea structure has been developed in this paper. Compared with five-membered Rh-OH, six-membered SRh-OH exhibited higher selectivity and sensitivity to Cu2+ in aqueous solution. Upon addition of 10 equiv. Cu2+, the molar extinction coefficient of SRh-OH at 563 nm can be up to 4.73 × 104 Lmol−1cm−1. In the range of Cu2+ from 0 to 28 μM, there was an excellent linear relationship between the absorption or emission intensity and Cu2+ concentration. The detection limit of SRh-OH was as low as 26 nM (S/N = 3). The reversible binding mode of SRh-OH with Cu2+ was further confirmed by S2− and EDTA addition. Bio-imaging showed SRh-OH can map the distribution of Cu2+ not only in mitochondria but also in lysosomes of Hela cells.

Photoluminescence lifetime based nickel ion detection by glutathione capped CdTe/CdS core-shell quantum dots

Here we have demonstrated a methodology for detecting nickel ions in aqueous medium using photoluminescence (PL) lifetime of the probe made of glutathione capped CdTe/CdS core-shell quantum dots. The ratio of (τavg)probe/(τavg)probe+Ni2+ has been developed as an analytical signal for detecting Ni2+ ions. The plot of (τavg)probe/(τavg)probe+Ni2+ versus concentration of Ni2+ revealed a linear positive slope and the sensitivity was 0.61 L/mg, which is in good agreement with that determined from conventional Stern-Volmer plot (i.e., 0.64 L/mg). The limit of Ni2+ detection was 23 μg/L. The temperature dependent steady state PL quenching, time-resolved PL decay and photocatalytic dye degradation in absence and in presence of Ni2+ suggested that the PL quenching by Ni2+ is due to pure collision based dynamic quenching with favourable electron transfer process. On the other hand, the present method was not applicable for Cu2+ detection as the ratio of (τavg)probe/(τavg)probe+Cu2+ was non-responsive over the given range of Cu2+ concentration. The PL quenching by Cu2+ comprised of a combination of dynamic quenching and due to interaction of Cu2+ with the probe. It has been concluded that ratio of (τavg)probe/(τavg)probe+analyte can be a promising analytical signal for detecting metal ions, particularly for those exhibiting dynamic PL quenching.

Effects of Ca2+ initial concentration on Cu2+ selective adsorption from aqueous solution by modified sugarcane bagasse under batch and column condition

ABSTRACT Tetraethylenepentamine (TEPA) modified sugarcane bagasse (SCB), as a potential biosorbent to selective removal of Cu2+ from high calcium-containing wastewater, was prepared and characterised. Adsorption performances of the modified SCB toward Cu2+ were investigated, and effects of Ca2+ under different initial concentration on Cu2+ adsorption were carried out under both batch and dynamic conditions. Results showed that adsorption isotherm of Cu2+ on modified SCB fitted Sip isotherm model well, and the optimum pH range for Cu2+ adsorption was from 4.0 to 6.0. Dynamic adsorption of Cu2+ on the modified SCB fixed-bed column showed a typical S shape breakthrough curve, which could be predicted well by Bohart-Adams model. Competitive adsorption results in the binary system showed that molar ratio of Cu2+ and Ca2+ adsorbed on the modified SCB was 36.0:1, 15.0:1, 10.7:1, 7.8:1, 6.6:1 and 4.7:1 at of initial concentration ratio of these two metal ions 1:25 1:50 and 1:100 under batch condition, while that was 110:1, 41.7:1, 32.5:1, 27.0:1, 20.9:1 and 16:1 under dynamic condition. Operating at dynamic condition was better than batch condition for Cu2+ selective removal by the modified SCB. Wastewater treatment results showed that the TEPA modified SCB fixed-bed column could recycle Cu2+ from high calcium-containing aqueous solution, and it had great potential in practical application.

Thermodynamic Study on the Interaction of Copper Ion with Human Growth Hormone

A thermodynamic study on the interaction between the Cu2+ ion and human growth hormone (hGH) was studied at the temperatures 300.15 and 310.15 K in NaCl solution using isothermal titration calorimetry. The new solvation model was used to reproduce the enthalpies of Cu2++hGH interaction over the whole range of Cu2+ concentrations. It was found that there is a set of three identical and non-interacting binding sites for Cu2+ ions. The intrinsic dissociation equilibrium constant and the molar enthalpy of binding are 1313.4 μmol⋅L−1 and −16.80 kJ⋅mol−1 at 300.15 K, and 1648.2 μmol⋅L−1 and −16.40 kJ⋅mol−1 and 310.15 K, respectively. The binding parameters recovered from the new equation are attributed to a structural change of hGH and its biological activity due to metal ion interaction.

A highly sensitive and selective fluorescentCu2+ sensor synthesized with silica nanoparticles

A novel fluorescent nanosensor for the determination ofCu2+ was synthesizedwith N-(quinoline-8-yl)-2-(3-triethoxysilyl-propylamino)-acetamide (QlOEt) grafted onto the surfaceof silica nanoparticles (SiNPs) using the reverse microemulsion method. Spherical SiNPs wereused as substrate and QlOEt was used simultaneously as the binding and readout system forCu2+. This sensor has been realized as a highly sensitive and selectivetechnique for the detection and quantification of trace amounts ofCu2+. The probe exhibits a dynamic response range forCu2+ from2.0 × 10−6 to2.0 × 10−5 M, with adetection limit of 3.8 × 10−7 M. Other alkali, alkaline earth, and transitional metal ions includingLi+,K+,Mg2+,Ca2+,Sr2+,Mn2+,Zn2+,Mo6+,Pb2+,Ag+ had no significantinterference on Cu2+ determination. Poisonous and flammable reagents are avoided during the synthesis of thisnanosensor. Therefore the strategy explored in this work can be extended to the synthesisof other chemo- and biosensors for direct detection of specific targets in an intracellularenvironment.

Luminescent detection of Cu(II) ions in aqueous solution using CdSe and CdSe‐ZnS quantum dots functionalised with mercaptosuccinic acid

AbstractCdSe (core) and CdSe‐ZnS (core‐shell) Quantum Dots (QD's) surface functionalised with mercaptosuccinic acid ligands were prepared. The conjugates were screened against a variety of common metal ions in aqueous solution and selectivity was established for Cu(II) ions based on an “On‐Off” change in fluorescence intensity. The presence of the ZnS shell was found to have a significant effect on both the sensitivity and the range of Cu2+ induced quenching. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

A high performance method for thermodynamic study on the binding of copper ion and glycine with Alzheimer’s amyloid β peptide

The interaction of Cu2+ to the first 16 residues of the Alzheimer’s amyloid β peptide, Aβ(1–16) was studied by isothermal titration calorimetry at pH 7.2 and 37°C in aqueous solution. The Gholamreza Rezaei Behbehani (GRB) solvation model was used to reproduce the enthalpies of interactions of Aβ(1–16) with glycine, Gly+Aβ(1–16), and Cu2+ ions, Cu2+ +Aβ(1–16), over the whole range of Cu2+ concentrations. The binding parameters recovered from the solvation model were attributed to the structural change of Aβ(1–16) due to the glycine and Cu2+ interactions. It was found that there is a set of two identical binding sites for Cu2+ ions. p=2 indicates that the binding has positive cooperativity in the two binding sites. Aβ(1–16) structure is destabilized greatly as a result of binding to Cu2+ ions.

Effect of adsorbed layers on the anodic oxidation of simple organic compounds. Part 3.—Cu adsorption on Pt and its effect on the oxidation of HCOOH

The adsorption and desorption of Cu on a smooth Pt electrode from 1 M H2SO4 solutions which contain a range of Cu2+ concentrations has been studied as a function of potential. The effect of adsorbed Cu on the oxidation rate of HCOOH has been examined at + 0.60 V (RHE). Cu2+ adsorption is controlled largely by an activation process. The slow step in the process is apparently the discharge of Cu2+ at the electrode to Cu+. Desorption of a preadsorbed Cu layer (+0.40 V) is extremely rapid at potentials+ 0.70 V, where no Cu2+ adsorption is normally found. Analysis of the oxidation state of the adsorbing layer by charge and coverage measurements yields a value of 1.92 electrons/site. This indicates that the major part of the layer is Cuads attached to a single Pt surface site. The rate of adsorption of Cu2+ is decreased slightly in the presence of 0.1 M HCOOH. At low coverages (θCuads⩽0.19), a slight enhancement of the HCOOH oxidation rate is observed at +0.60 V. Above this coverage, the oxidation process is inhibited. Results are interpreted in terms of Cu2+ adsorption mechanisms on Pt and the effect of the adsorbed layer on the mechanisms of HCOOH electro-oxidation on Pt.