The determination of titanium with edta

The determination, of titanium EDTA by means of a back-titration with standard copper has been investigated. The phenomenon of an irreversible color change has been eliminated by the addition of hydrogen peroxide prior to the addition of EDTA and adjustment of pH.It is theorized that peroxide displaces the hydroxyl (or oxygen) ion in the hydroxy-EDTA- titanium complex and thus inhibits precipitation.     

一例水溶液中识别铜离子的染料探针

通过罗丹明B与乙二胺反应生成的中间体合成了一例可以对铜离子进行比色检测的探针R-Cu.R-Cu可以实现对在HEPES(5 mmol/L;pH 7.4)溶液中Cu2+的比色可视化识别,加入Cu2+后,R-Cu的吸收明显增强,呈现出罗丹明B的紫红色.探针对Cu2+具有较高的选择性和灵敏性,对其他常见的金属离子具有较强的抗干扰能力.该探针可以在较宽的特别是近中性pH环境下有效检测Cu2+,最低检出限为2.70×10?7 mol/L.     

Uncertainty of the concentration of a copper calibration solution

The postulated uncertainty of many commercially available standard solutions is estimated on the basis of uncertainties of individual preparation steps. The declared concentration of Cu standard solution (1000 ± 2) mg/L was verified by gravimetric analysis (found (1000.7 ± 0.4) mg/L), isotope dilution with commercial and laboratory-prepared isotope-enriched solutions (found (1000.6 ± 16.8) mg/L and (1002.4 ± 3.6) mg/L, respectively), and by atomic absorption spectrometry (found (1001.4 ± 5.3) mg/L). Uncertainty budgets of all used methods are given and the procedures of uncertainty estimation are fully documented.     

Optimization of the solution composition for laser-induced chemical liquid phase deposition of copper

Optimal compositions of autocatalytic solutions for laser-induced deposition of copper were established. The copper salt concentration range in which the process gives the best results was determined. It is shown that optical microscopy, as a means of controlling the topology of the deposited structures, has limited applicability. The results obtained by this method should be verified by alternative techniques, e.g., electron microscopy or measurements of the electrical conductivity of deposited structures.     

Role of clay-based membrane for removal of copper from aqueous solution

The present study focuses on the fabrication of polysulfone (PSf)-clay minerals impregnated hybrid membrane for treatment of Cu (II) ions. Blending and phase inversion methods have been employed to develop clay-based membranes by the mixing of bentonite, sepiolite and zeolite in the matrix of PSf. Moreover, characterization of fabricated membranes was carried out using SEM, FTIR, zeta potential, pore size and water contact angle measurement. Adsorption and filtration experiments were conducted to evaluate the permeation performance of the membrane. Obtained results of permeation study reveal that the presence of clay minerals in the matrix of modified membrane not only increases the adsorption and rejection efficiency for Cu (II) but, it also improves the flux of pure water. Among all developed membranes, the membrane prepared by the mixing of zeolite demonstrates the highest adsorption (2.82 mg/g) and rejection value (97%) towards Cu (II) at low pressure (0.5 bar). Regeneration performance results confirm the reusability of membrane up to 3–5 cycles along with 82.5–90% metal recovery. Based on significant metal recovery, clay-based low-cost zeolite/PSf membrane could be used to remove Cu (II) from water at low pressure to replace current conventional membrane.     

Correction to: Primary standardization of the massic activity of a 233Pa solution

Journal of Radioanalytical and Nuclear Chemistry - In the original publication, the value “2.611·104 Bq g?1” in the sentence “The measured massic...     

Parameters of electrical double layer on the boundary copper electrode/water-organic solution of copper sulfate

By the method of impedance spectroscopy the properties of the phase boundary of Cu|H₂O + i-C₃H₇OH + CuSO₄ system were investigated. The impedance hodographs were obtained, in the form of circles with displaced centers. The capacity values of electrical double layer, exchange currents, and resistance of the electrolyte solution depending on the mole fraction of 2-propanol were determined. The role of organic component in the formation of the electrical double layer in the studied system is elucidated.     

Modelling the matrix interference of iron in the multivariate determination of copper by stripping voltammetry Instrument standardization

Two different standardization procedures have been applied in order to minimize the experimental effort necessary to determine copper in presence of iron by differential pulse anodic stripping voltammetry. The significant matrix interference caused by iron in the voltammetric determination of copper has been successfully solved by using partial least squares (PLS) regression. The use of this multivariate regression implies a large number of training set samples, so a standardization method was required. In fact, the standardization methods used have reduced the calibration samples needed in future determinations by up to 75%. Moreover, PLS regression allowed both metals to be determined simultaneously by using an adequate experimental design, without any limitation to their respective concentrations and without the need to know the level of interference.     

Corrosion of copper electrode in sodium sulfide solution

The electrochemical reactions of a copper electrode in Na₂S solutions were studied using cyclic voltammetry, potentiostatic and galvanostatic measurements. In addition surface examination and morphological studies were applied using scanning electron microscopy (SEM), energy dispersive analysis of X-rays (EDAX). There are three anodic peaks were found in the anodic branch of the voltammogram’s. These peaks may be corresponding successively to the formation of Cu₂S, CuS and Cu₂O. On the other hand, the cathodic branch contains four peaks. These peaks correspond to the reduction of copper oxide and copper sulfide formed on the anodic branch.     

Precipitation of copper 8-hydroxyquinaldate from homogeneous solution

Copper can be precipitated quantitatively, over a wide range of pH, by 8-hydroxyquinaldine produced from the hydrolysis of 8-acetoxyquinaldine. The copper 8-hydroxyquinaldate can be weighed as either the monohydrate or the anhydrous dichelate. Differences in the appropriate pH conditions, between the PFHS and conventional precipitation methods, and between thorium and copper precipitations from homogeneous solution, are accounted for.     

Mediated electrochemical synthesis of copper nanoparticles in solution

Environmentally friendly mediated electrochemical synthesis of copper nanoparticles in the solution using a copper anode as a source of copper ions has been realized for the first time. It is shown that at the potential of the redox pair MV²⁺/MV?⁺ methylviologen MV²⁺ is able to mediate a reduction of Cu²⁺ ions in 60% aqueous DMF/0.1 M Bu₄NBF₄. Copper nanoparticles build large aggregates (200—250 nm) in the absence of a stabilizer. The use of polyvinylpyrrolidone as a stabilizer makes it possible to obtain smaller copper nanoparticles (20—50 nm) of spherical and oval shape and to characterize them by physicochemical methods.     

Studies on uranyl complexes-III Uranyl complexes of edta

The uranyl complexes of EDTA have been studied by potentiometry ; stability constants of the 1:1 and 2:1 (metal to ligand) chelates have been determined, as well as the respective hydrolysis and polymerization constants. Possible structures for these species are discussed. To account for the abnormally high stability of UO(2)(H(2)O)HL-, hydrogen bonding between a protonated nitrogen atom of the ligand and one oxygen atom of UO(2)(2+) is suggested.     

A solution growth technique for the preparation of copper (II) selenide thin films

A solution growth technique has been developed for the deposition of thin films of copper(II) selenide on glass substrate using a copper(II) salt solution, triethanolamine, ammonia, and sodium selenosulfate as the reacting agents. The material has been characterized through X-ray powder photography, optical absorption, and Hall measurements at room temperature. The films are found to be degenerate and p type with a Moss-Burstein shifted direct band gap of 2.14 eV.     

The standard potential of copper amalgam electrode and the activity coefficient of copper sulphate in aqueous solution

A simple and easily reproducible method for obtaining the e.m.f. of the cell Cu(Hg)/CuSO₄(m)/Hg₂SO₄, Hg and for avoiding the formation of red deposit on the amalgam electrode is described. E.M.F. readings of the cell for CuSO₄ concentration ranging from 0.01 to 1.0 m were recorded. Methods which have been used to calculate the E° of the cell have been reviewed and a value of +0.3443 V was obtained for the standard potential of the copper amalgam electrode.     

The titration of nickel with edta at ph 2.8

A method for determining nickel using EDTA is described. A small excess of EDTA is added, the pH adjusted to 2.7–2.9 and the solution back-titrated with thorium nitrate, against ahzarin-S as indicator. Quantities of cobalt up to 10 mg do not interfere.In addition an approximate determination of the complex-forming constant of Th-EDTA is described, based on the decrease in extinction of an Ni-EDTA solution to which Th⁺⁴ has been addd.     

Perimidine-based synthetic receptors for determination of copper(II) in water solution

Perimidine-based chelators 1 and 2 were prepared, and their structures were confirmed by ¹H and ¹³C NMR, MS spectroscopy and elemental analysis. These compounds were studied as specific synthetic receptors for the recognition of transition metal ions. They exhibited high affinity and selectivity towards Cu(II) ions. The conditional binding constants, linear dynamic range and detection limit were determined by UV–vis spectroscopy. These parameters demonstrated high potential of the prepared synthetic receptors for the recognition and determination of Cu(II) ions. The minimum detectable concentrations of Cu(II) ions for the synthetic receptors 1 and 2 were 270 and 75 nM (R ² = 0.9915 and 0.9964) in aqueous medium (water/DMSO; 99:1 (v/v)), respectively.     

Influence of surfactants on laser-induced copper deposition from solution

The influence of surfactants on the result of laser induced copper deposition from solution on the dielectric surface was studied. The dependences of the topology of the copper structures on the hydrophilic—lipophilic balance of non-ionogenic surfactants was found. The surface tension at the gas phase—solution interface was measured. The best results of laser deposition are obtained by the use of non-ionogenic surfactants with low values of hydrophilic—lipophilic balance.