CuCl2 Solution Research Articles

Synthesis of Submicrometer-Sized Cu2O Crystals with Morphological Evolution from Cubic to Hexapod Structures and Their Comparative Photocatalytic Activity

We report a facile method for the synthesis of cuprous oxide nanocrystals with systematic morphological evolution. Cubic, truncated cubic, cuboctahedral, truncated octahedral, octahedral, and short hexapod structures have been synthesized in an aqueous solution of CuCl2, NaOH, sodium dodecyl sulfate (SDS) surfactant, and hydroxylamine (NH2OH·HCl) reductant by simply varying the volume of hydroxylamine added to the reaction mixture. A slight modification in the volume of some reagents produced the extended hexapods. The order of the introduction of the reagents is important to the formation of these crystals with distinct morphologies and sharp faces. The sizes of these particles fall mostly in the range of 400−700 nm. Clear transition in the relative intensities of the (111) and the (200) reflection peaks in their XRD patterns was observed. Scattering bands dominate the UV−vis absorption spectra of these crystals. Crystal model analysis revealed that the {111} face contains surface copper atoms with dangl...

Preparation of nano-copper oxide modified glassy carbon electrode by a novel film plating/potential cycling method and its characterization

An electrochemical sensor for H2O2 determination was prepared by electrodepositing nano-copper oxide on glassy carbon electrode by a novel film plating/potential cycling method. A copper film was first cathodically deposited on the surface of GC in CuCl2 solution at −0.4V, then a nano-copper oxide film was in situ deposited on the surface of GC by potential cycling at −0.5 to 0.3V in 0.1molL−1 NaOH solution. The mechanism of nano-copper oxide film formation and factors affecting its electrochemical activity were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. The chronoamperometric detection of H2O2 was carried out at 0.2V in 0.01molL−1 NaOH solution and the linear range was 2–270nmolL−1 with a detection limit of 0.2nmolL−1 (S/N=3), which is lower than that reported in related literatures. The response time to achieve the steady-state current was <1s. No measurable reduce in analytical performance was found by storing the sensor in ambient condition for 30 days. The sensor was successfully applied to measure H2O2 in real water, which exhibited high analytical sensitivity and reproducibility.

Synthesizing nanoscale copper sulfide and modifying its surface

Nanoscale crystals of CuS are synthesized by a wet chemical method in water and modified with 1-dodecanethiol. Double drop mixing of strong solutions of CuCl2 and Na2S with their dilution in situ is used for synthesis. The synthesized nanoparticles are examined by the methods of dynamic light scattering, X-ray diffraction analysis, transmission electron microscopy, and IR and X-ray photoelectron spectroscopy.

Interaction between copper chloride and caffeine as seen by diffusion at 25°C and 37°C

A Taylor dispersion method is used to measure ternary mutual diffusion coefficients (D11, D22, D12 and D21) for aqueous solutions of CuCl2 (1) + caffeine (2) + H2O-(3) at 25 °C and 37 °C at carrier concentrations from (0.000 to 0.020 mol dm−3), for each solute, respectively. The results are compared with these obtained for the binary systems, that is, CuCl2 (1) + H2O (2) and caffeine (1) + H2O (2), also reported here. From these data it is possible to make conclusions about the influence of the caffeine solutes in diffusion of copper chloride.

Facile Fabrication of Porous CuS Nanotubes Using Well-Aligned [Cu(tu)]Cl·1/2H2O Nanowire Precursors as Self-Sacrificial Templates

We have demonstrated for the first time an extremely facile procedure for the preparation of porous CuS nanotubes with good morphological and high chemical purity using [Cu(tu)]Cl·1/2H2O nanowire precursors as self-sacrificial templates at room temperature (thiourea = tu). Well-organized [Cu(tu)]Cl·1/2H2O nanowires with good morphological and high chemical purities were prepared by directly mixing an aqueous solution of CuCl2 with thiourea at room temperature. Well-aligned [Cu(tu)]Cl·1/2H2O nanowires were self-assembled into dandelion- or thornlike architectures depending on the initial concentrations of thiourea and CuCl2. The influence of the architectures of the nanowire precursors on the morphology of the CuS nanotubes product is discussed. The successful fabrication of nanoarchitectures from nanowires via self-sacrificial templates provides an efficient strategy for controllable preparation of hollow nanostructures.

Genesis of the sombric horizon in ultisols (red argisols) in southern Santa Catarina, Brazil

Dark subsurface horizons, with properties similar to the sombric horizon characterized by the USA Soil Taxonomy, are frequent in Southern Brazil. The genesis of this horizon is controversial and poorly understood. This study aimed to describe the occurrence of sombric-like horizons in Ultisols in the South of Santa Catarina State, at low altitudes, and suggest possible processes of humus transference, accumulation and persistence in these horizons. Physical, chemical and mineralogical properties of four Ultisols were evaluated; three were sampled in a toposequence, and another representative one in an isolated profile (RSP). The dark subsurface horizons coincide with the AB and BA transitional genetic horizons; they are acid, low in base saturation, and have a similar clay mineralogy in all horizons. Very high amounts of Fe and Al extracted by ammonium oxalate and sodium pyrophosphate solution as well as maximum Al extracted by CuCl2 solution were observed in these dark subsurface horizons, indicating a possible migration of these elements in the form of organometallic complexes. The contents of Al plus ½ Fe extracted from the RSP soil horizons with ammonium oxalate indicated spodic materials in the sombric-like horizon, although the soil morphology was not compatible with Spodosols. Maximum contents of fine clay were also found in the sombric-like horizon, suggesting Fe and Al migration as clay-humic substances. However, the hypothesis that sombric-like horizons in these soils are a relict feature of a grass paleovegetation, different from the current dense seasonal forest, should not be discarded but investigated in further studies.

Crystal structure of bis[(μ2-hydroxo)-aqua-(1,10-phenanthroline-N,N')copper(II)] phenylacetate hexahydrate, [Cu(C12H8N2)(OH)(H2O)]2[C8H7O2]2 · 6H2O

Article Crystal structure of bis[(μ2-hydroxo)-aqua-(1,10-phenanthroline-N,N')copper(II)] phenylacetate hexahydrate, [Cu(C12H8N2)(OH)(H2O)]2[C8H7O2]2 · 6H2O was published on April 1, 2009 in the journal Zeitschrift für Kristallographie - New Crystal Structures (volume 224, issue 1-4).

One-Pot Synthesis of Interpenetrating Inorganic/Organic Networks of CuO/Resorcinol-Formaldehyde Aerogels: Nanostructured Energetic Materials

For many applications ranging from catalysis to sensors to energetic materials, it is desirable to produce intimate mixtures of nanoparticles. For instance, to improve the reaction rates of energetic materials, the oxidizing agent and the fuel need to be mixed as intimately as possible, ideally at the nanoscopic level. In this context, the acidity of a hydrated CuCl(2) solution reacting toward a network of CuO nanoparticles (a good oxidant) is used to induce one-pot cogelation of a nanostructured network of a resorcinol-formaldehyde resin (RF, the fuel). The resulting wet gels are dried to aerogels, and upon pyrolysis under Ar, the interpenetrating CuO/RF network undergoes a smelting reaction toward metallic Cu. Upon ignition in the open air, pure RF aerogels do not burn, while CuO/RF composites, even with substoichiometric CuO, sustain combustion, burning completely leaving only a solid residue of CuO whose role then has been that of a redox mediator through the smelting reaction.

Sequestration of Copper from β-Amyloid Promotes Selective Lysis by Cyclen-Hybrid Cleavage Agents

Decelerated degradation of beta-amyloid (Abeta) and its interaction with synaptic copper may be pathogenic in Alzheimer disease. Recently, Co(III)-cyclen tagged to an aromatic recognition motif was shown to degrade Abeta in vitro. Here, we report that apocyclen attached to selective Abeta recognition motifs (KLVFF or curcumin) can capture copper bound to Abeta and use the Cu(II) in place of Co(III) to become proteolytically active. The resultant complexes interfere with Abeta aggregation, degrade Abeta into fragments, preventing H2O2 formation and toxicity in neuronal cell culture. Because Abeta binds Cu in amyloid plaques, apocyclen-tagged targeting molecules may be a promising approach to the selective degradation of Abeta in Alzheimer disease. The principle of copper capture could generalize to other amyloidoses where copper is implicated.

Facile Synthesis of Cu2O Nanocrystals with Systematic Shape Evolution from Cubic to Octahedral Structures

We report a facile method for the synthesis of cuprous oxide nanocrystals with systematic shape evolution. Monodisperse truncated cubic, cuboctahedral, truncated octahedral, and octahedral nanocrystals can be synthesized directly in an aqueous solution of CuCl2, sodium dodecyl sulfate (SDS) surfactant, hydroxylamine (NH2OH·HCl) reductant, and NaOH by simply varying the volume of hydroxylamine added to the reaction mixture. SDS surfactant was found to be necessary for a precise control of the nanocrystal morphology. Adjustment of the volume of NaOH added provides a means to vary the particle size. In the case of octahedral nanocrystals, particles with sizes of 160−460 nm can be prepared. By examining the intermediate products formed, which resemble the final nanocrystal structures, a growth mechanism is proposed. Optical characterization of these Cu2O nanocrystals showed band gap absorption at 470−490 nm and strong light scattering bands extending from the visible to the near-infrared light region. All four samples displayed activity toward photodegradation of rhodamine B molecules, but truncated octahedral and octahedral nanocrystals exhibited a higher extent of the photodecomposition reaction, suggesting the {111} faces of Cu2O nanostructures are catalytically more active than the {100} faces. These nanocrystals should allow the examination of their various properties as a function of the particle shape.

A Plasma Membrane-associated Protein of Arabidopsis thaliana AtPCaP1 Binds Copper Ions and Changes Its Higher Order Structure

PCaP1, a hydrophilic cation-binding protein, is bound to the plasma membrane in Arabidopsis thaliana. We focused on the physicochemical properties of PCaP1 to understand its uniqueness in terms of structure and binding of metal ions. On fluorescence analysis, PCaP1 showed a signal of structural change in the presence of Cu(2+). The near-UV CD spectra showed a marked change of PCaP1 in CuCl(2) solution. The far-UV CD spectra showed the presence of alpha-helices and the intrinsically unstructured region. However, addition of Cu(2+) gave no change in the far-UV CD spectra. These results indicate that Cu(2+) induced a change in the tertiary structure without changing the secondary structure. The protein was sensitive to proteinase in the presence of Cu(2+), supporting that Cu(2+) is involved in the structural change. The PCaP1 solution was titrated with CuCl(2) and the change in the fluorescence spectrum was monitored to characterize Cu(2+)-binding properties. The obtained values of K(d) for Cu(2+) and the ligand-binding number were 10 microM and six ions per molecule, respectively. These findings indicate that PCaP1 has a high Cu(2+)-binding capacity with a relatively high affinity. PCaP1 lacks cysteine and histidine residues. A large number of glutamate residues may be involved in the Cu(2+) binding.

Uptake of Cu2+ by Starch Granules As Affected by Counterions

Potato and wheat starch granules were soaked in 1% aqueous solutions of copper(II) salts: acetate, chloride, and sulfate. Such treatment caused sorption of Cu(2+) ions at the granule surface and their penetration into the granule interior as was proven, for sectioned granules of investigated starch, by scanning electron microscopy combined with an X-ray microanalysis system (energy dispersive spectroscopy). Copper ions incorporated into the granules influenced the starch thermal stability. Uptake of Cu(2+) by potato, determined by flame atomic absorption spectrometry, was much higher than obtained for the wheat starch. Moreover, it was dependent on copper counteranions present in the solution. In all investigated granules, the most effective sorption occurred in the acetate solution. Starch dehydration or/and freezing and thawing, affecting the water-dependent inner structure of the granules, also influenced the amount of Cu(2+) taken from the solutions. Thus, compared to that in native starch, this value was considerably higher in Cu(CH 3COO)2, almost unchanged in CuSO4, and significantly lower in the case of CuCl2 solution. The influence of chloride and sulfate anions seemed to correlate with their water structure-making and structure-breaking ability, affecting the migration of Cu(2+) in the amorphous parts of the granules. However, high Cu uptake observed for acetate solution could be explained on the basis of acetate anion hydrolysis activating the polysaccharide matrix for cation binding. The obtained results provide new information about interactions of starch granules with salt solution and therefore support our understanding of starch properties.

Experimental investigations of five different mosses on accumulation capacities of Cu, Pb and Zn

Uptake of Pb, Cu and Zn by different epiphytic moss species Floribundaria floribunda (Doz. & Molk.) Fleisch., Taxiphyllum giraldii (C. Muell.) Fleisch. and Thuidium sparsifolium (Mitt.) Jaeg., an epilithic moss Thuidium delicatulum (L.) Mitt. and a leafy liverwort Ptychanthus striatus (Lehm. & Linderb.) Nees. was studied experimentally. The plant bodies were treated with single metal and mixed metal solutions of Pb(NO3)2, CuCl2 and ZnCl2 at different concentrations ranging from 10−10 to 10−2 mol L−1. Higher uptake of Pb, Cu and Zn by T. giraldii, T. sparsifolium and P. striatus than by F. floribunda and T. delicatulum was shown in both treatments. Compared with the single metal treatment, the uptake of Zn was very low at higher concentrations in the mixed metal treatment. A slight depletion of Zn was noticed in the long-term exposure. Leaching of naturally accumulated Zn from the mosses and leafy liverwort was also observed when treated with higher concentrated (10−4, 10−2 mol L−1) Pb(NO3)2 and CuCl2 solutions. Similarly, the leaching of naturally accumulated Cu was observed in leafy liverwort P. striatus with 10−2 mol L−1 Pb(NO3)2 and ZnCl2 treatments. However, insignificant changes were observed on naturally accumulated Pb and Cu in mosses. From these experiments, the epiphytic mosses T. giraldii and T. sparsifolium, which have high Cation exchange capacity and large leaf surface area, have been found to be suitable for assessing heavy metal concentration in a moderately or slightly contaminated environment.

The enhancement of WO3-catalyzed photodegradation of organic substances utilizing the redox cycle of copper ions

WO3 is a visible-light-responsive photocatalyst and an n-type semiconductor photocatalyst, but its photocatalytic activity toward organic substances is low. We utilized several transition metal ions as redox mediators in attempts to improve the photoactivity of WO3, and a drastic improvement was observed only when Cu2+ ions were utilized for WO3-catalyzed photodegradation of organic substances. More specifically, the CO2 generation rates for the photodegradation of formaldehyde and methanol in the presence of Cu2+ ions were about 1000 and 150 times as high, respectively, as the rates in the absence of Cu2+ ions. We confirmed that Cu2+ was reduced to Cu+ through the transfer of a photoexcited electron from WO3 and that Cu+ was easily re-oxidized to Cu2+ by oxygen in air. This redox cycle could assist in the reduction of oxygen in the photocatalytic reaction, and the reaction was particularly efficient when Cu2+ was introduced to the system as a CuCl2 solution. Photodegradation was achieved with a WO3 photoelectrode in a two-compartment cell in which the Cu2+ solution was separated from wastewater containing organic substances by an ion-exchangeable membrane, simulating practical use. The anodic photocurrent generated by the photodegradation of organic substances was observed at the WO3 photoelectrode without applying any external bias.

Thermochemical Study of Solutions of Copper(II) Chloride in Methanol-Rich Water + Methanol Mixtures

The calorimetric enthalpies of dilution of water + methanol solutions of CuCl2 (m < 3.3 mol/kg; methanol mole fractions of 0.5–1.0) with corresponding water + alcohol solutions at 298. 15 K are studied. These data are used to calculate the enthalpies of dilution and the relative partial molar enthalpies for the entire solution and its components (solvent and solute). The data are considered in terms of the structural evolution of the solution and copper(II) chloride complexing; these factors influence the dissolution energy of the electrolyte and its state in solution.

Breakaway properties of film formed on copper and copper alloys in erosion–corrosion by mass transfer equation

AbstractErosion–corrosion tests on copper and three types of copper alloys in a 1 wt% solution of CuCl2 were carried out at various flow velocities using a jet‐in‐slit testing apparatus, which is capable of reproducing various hydrodynamic conditions. A damage profile of a specimen was developed using a surface roughness meter to evaluate locally occurring damage. The damage depth rate for copper, beryllium copper, and a 70/30 copper nickel alloy increased with increasing flow velocity, and suddenly increased at a certain velocity, which is called the breakaway velocity. The breakaway velocities at the central and disturbed part of a specimen were different for each sample, indicating that the hydrodynamic conditions of the flowing solution had an effect. The damage depth rate, calculated from the mass transfer equation, which involved mass transfer in the concentration diffusion layer and in the corrosion product film, could be fitted to the experimental data, suggesting that the mass transfer equation can be applied to the evaluation of erosion–corrosion damage. The corrosion product film was exponentially broken away at velocities higher than the breakaway velocity. The breakaway properties of the corrosion product film were confirmed to be different for each material, since the power of the exponential equation was different for each sample.

One-step template-free solution route for Cu(OH)2 nanowires

Cu(OH)2 nanowires with a diameter of 8–10 nm and lengths of tens of micrometers were fabricated in the basic solution by dropping simply NaOH solution into CuCl2 solution at ambient temperature. The formation mechanism of nanowires was discussed. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to characterize the samples.

STUDIES ON THE INTERACTION BETWEEN BIRCH VENEER AND COMPOUNDS WITH BIOCIDE POTENTIAL ACTION

This paper discusses the results of study concerning the interaction between the birch veneer and some compounds with biocide potential action are presented. With this end in view the samples of veneer were immersed in solutions with a concentration of 5% of the following products: unmodified straw lignin or modified through hydroxymethylation, furan resin and tannins dissolved in 0.1 N ammonia solution. To make a comparison, the same combined treatments were applied, using ammonia solutions of some copper compounds (CuCl2 and copper-ammonia solution) and the above mentioned organic compounds to obtain in situ their complexes. The stability of the treatments was followed through successive elution with distillated water of the impregnated samples. The toxicity of the extracts was followed by germination tests of tomato seeds. The obtained results highlighted that the stability of the treatments are in agreement with the nature’s products, the functionality and the complex forming degree, that determine their interaction with the veneer.

Identification of two types of exchangeable sites for monovalent copper ions exchanged in MFI-type zeolite

Three different approaches have been used to characterize the state of exchanged copper ions in copper-ion-exchanged MFI (CuMFI) samples. (1) Two types of an ion-exchangeable site with different adsorption properties for N(2) or CO molecules were identified depending on the pre-treatment temperature (723 or 873 K) of a sample prepared by using an aqueous solution of CuCl(2). (2) The state of the active sites formed by the evacuation of a sample at 873 K that had been prepared using a mixture solution of aqueous NH(4)CH(3)COO and Cu(CH(3)COO)(2) was analysed utilizing both (13)C(18)O and (12)C(16)O to identify the two types of active adsorption sites for CO molecules. (3) CuMFI samples prepared by the ion-exchange method employing anhydrous CuCH(3)COO showed a surprising adsorption feature characterized by a single IR band occurring at 2159 cm(-1) due to the adsorbed CO molecules, but there was no corresponding IR band due to adsorbed N(2) molecules. A successful preparation of CuMFI, in which the monovalent copper ions exclusively occupied another one of the two types of ion-exchangeable sites, was also carried out utilizing the solid-ion exchange method using Cu(CH(3)COO)(2).H(2)O. This site exhibits an IR band occurring at 2151 cm(-1) for CO molecules and also acts as an active site for N(2) molecules. These experimental data correlate, and clearly indicate that there are at least two types of exchangeable sites for copper ions in MFI-type zeolites.

Hydrothermal synthesis and optical properties of CuS nanoplates

CuS nanoplates have been successfully prepared in the presence of cation surfactant cetyltrimethylammonium bromide (CTAB) by hydrothermally treating the solution of CuCl 2·2H 2O and Na 2S·9H 2O at 180 °C for 24 h. The as-prepared CuS nanoplates are of hexagonal phase and are single crystal. The thickness and edge length of the nanoplates are about 15 nm and 60 nm, respectively. The products was characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, photoluminescence measurements and ultraviolet–visible light spectrophotometer. The influences of synthetic parameters, such as reaction time and CTAB, on the morphologies of the products have been investigated.