Aqueous Solutions Of Copper Sulfate Research Articles

Zeolite ZSM-5 containing copper ions: The effect of the copper salt anion and NH4OH/Cu2+ ratio on the state of the copper ions and on the reactivity of the zeolite in DeNO x

Isotherms of copper cation sorption by H-ZSM-5 zeolite from aqueous and aqueous ammonia solutions of copper acetate, chloride, nitrate, and sulfate are considered in terms of Langmuir’s monomolecular adsorption model. Using UV-Vis diffuse reflectance spectroscopy, IR spectroscopy, and temperatureprogrammed reduction with hydrogen and carbon monoxide, it has been demonstrated that the electronic state of the copper ions is determined by the ion exchange and heat treatment conditions. The state of the copper ions has an effect on the redox properties and reactivity of the Cu-ZSM-5 catalysts in the selective catalytic reduction (SCR) of NO with propane and in N2O decomposition. The amount of Cu2+ that is sorbed by zeolite H-ZSM-5 from aqueous solution and is stabilized as isolated Cu2+ cations in cationexchange sites of the zeolite depends largely on the copper salt anion. The quantity of Cu(II) cations sorbed from aqueous solutions of copper salts of strong acids is smaller than the quantity of the same cations sorbed from the copper acetate solution. When copper chloride or sulfate is used, the zeolite is modified by the chloride or sulfate anion. Because of the presence of these anions, the redox properties and nitrogen oxides removal (DeNOx) efficiency of the Cu-ZSM-5 catalysts prepared using the copper salts of strong acids are worse than the same characteristics of the sample prepared using the copper acetate solution. The addition of ammonia to the aqueous solutions of copper salts diminishes the copper salt anion effect on the amount of Cu(II) sorbed from these solutions and hampers the nonspecific sorption of anions on the zeolite surface. As a consequence, the redox and DeNOx properties of Cu-ZSM-5 depend considerably on the NH4OH/Cu2+ ratio in the solution used in ion exchange. The aqueous ammonia solutions of the copper salts with NH4OH/Cu2+ = 6–10 stabilize, in the Cu-ZSM-5 structure, Cu2+ ions bonded with extraframework oxygen, which are more active in DeNOx than isolated Cu2+ ions (which form at NH4OH/Cu2+ = 30) or nanosized CuO particles (which form at NH4OH/Cu2+ = 3).

Self-assembled organic⿿inorganic hybrid glucoamylase nanoflowers with enhanced activity and stability

An organic⿿inorganic hybrid glucoamylase nanoflower was prepared in single pot by simple, facile and highly efficient method. The stepwise formation of enzyme-embedded hybrid nanoflowers and influence of experimental parameters viz. pH of solution mixture, enzyme and copper ion concentration on the activity of prepared hybrid nanoflowers were systematically investigated. The self-assembled hybrid glucoamylase nanoflowers were synthesized by mixing aqueous solution of copper sulphate (200mM) with PBS (pH 7.5, 5mM) containing glucoamylase (1mg/mL) in 24h at room temperature. These prepared nanoflowers were further characterized by FT-IR, SEM and XRD. The hybrid nanoflowers exhibited 204% enhanced activity recovery and two folds improvement in thermal stability in terms of half-life (in the range of 50⿿70°C) with respect to the free form. The hybrid glucoamylase nanoflowers retained 70% residual activity after eight successive cycles indicating their excellent durability. Additionally, the nanoflowers retained up to 91% residual activity upto 25 days of storage. Moreover, the conformational changes occurred in glucoamylase structure after preparing hybrid nanoflowers were evaluated by FT-IR spectroscopy data tools.

Practical method to make a discrete memristor based on the aqueous solution of copper sulfate

A new method to realize a discrete memristor is proposed. The device under study consists of a tube filled of aqueous saturated solution of copper sulfate which can be electrolyzed by using two asymmetric copper electrodes, one of which has a considerably smaller cross-sectional area than to the other one. It is shown both theoretically and experimentally that this device has exactly the properties of a memristor if it is designed such that the electrical field and the current density on the thinner electrode when it acts as anode are sufficiently large. Different aspects of the proposed discrete memristor, including pinched hysteresis loop, on-off resistance ratio and memory volatilization, are studied and experimental results are presented.

Single-Step Production of Nanostructured Copper-Nickel (CuNi) and Copper-Nickel-Indium (CuNiIn) Alloy Particles

Nanostructured copper-nickel (CuNi) and copper-nickel-indium (CuNiIn) alloy particles were produced from aqueous solutions of copper, nickel nitrates and indium sulfate by hydrogen reduction-assisted ultrasonic spray pyrolysis. The effects of reduction temperatures, at 973 K, 1073 K, and 1173 K (700 A degrees C, 800 A degrees C, and 900 A degrees C), on the morphology and crystalline structure of the alloy particles were investigated under the conditions of 0.1 M total precursor concentration and 0.5 L/min H-2 volumetric flow rate. X-ray diffraction studies were performed to investigate the crystalline structure. Particle size and morphology were investigated by scanning electron microscope and energy-dispersive spectroscopy was applied to determine the chemical composition of the particles. Spherical nanocrystalline binary CuNi alloy particles were prepared in the particle size range from 74 to 455 nm, while ternary CuNiIn alloy particles were obtained in the particle size range from 80 to 570 nm at different precursor solution concentrations and reduction temperatures. Theoretical and experimental chemical compositions of all the particles are nearly the same. Results reveal that the precursor solution and reduction temperature strongly influence the particle size of the produced alloy particles.

Optimization of liquid jet system for laser-induced breakdown spectroscopy analysis

A complex optimization of geometrical and temporal parameters of a jet system (developed in Laser-induced breakdown spectroscopy (LIBS) laboratory of Brno University of Technology) for direct elemental analysis of samples in a liquid state of matter using LIBS was carried out. First, the peristaltic pump was synchronized with the flashlamp of the ablation laser, which reduced variation of the ablated sample amount. Also, the fluctuation of the laser ray angle incident on the jet surface was diminished. Such synchronization reduced signal standard deviations and thus increased repeatability of the measurements. Then, laser energy and distance of the focusing lens from the sample were optimized. The gate delay time and the gate width were optimized for single pulse (SP) experiments; the gate delay time and the inter-pulse delay were optimized for the use of double pulse (DP) variant. Results were assessed according to the highest signal to noise ratios and the lowest relative standard deviations of the signal. The sensitivity of the single pulse and the double pulse LIBS for the detection of heavy metals traces, copper (Cu i at 324.754 nm) and lead (Pb i at 405.781 nm), in aqueous solution of copper (ii) sulfate and lead (ii) acetate, was estimated in terms of limits of detection (LODs). As a result, sensitivity improvement of DP LIBS system was observed, the LOD of Cu obtained with DP was calculated 40% lower than LOD gained from SP technique.

Tunable core–shell particles generated from smart water-soluble chitosan seeds

A chain-like route was presented to create various core–shell particles with soft, aqueous or inorganic cores respectively. Water-soluble chitosan (WSC) gel particles were obtained through gelating the aqueous WSC solution of 0.02g/mL at its isoelectric point. Then, polyelectrolyte complexes were formed and surrounded on the outer surfaces of WSC gel particles by immersing the particles in 2wt% aqueous sodium alginate. Soft WSC cores in these core–shell particles disappeared after maintaining the particles in 1M HCl for 6h. The cores of obtained particles at this step became aqueous, and could be further transformed into inorganic ones via contacting the particles with copper sulfate and sodium sulfide aqueous solutions successively. The composition of the shell was verified with Fourier transform infrared spectroscopy. The formation of various core–shell particles was confirmed with digital photographic observation, thermogravimetric and fluorescence analyses. The whole process was a chain-like one and was able to stop at any stage to harvest a corresponding target.

Modification of natural sorbent for providing it with bactericidal and bacteriostatic properties

Currently, the problem of water purification from chemical and microbiological contaminations is very important. Sorption technologies are one of the effective and easy-to-use water purification techniques. To prevent the growth of microbiological contaminations on the surface of investigated sorbents, the surface of the investigated sorbents was treated by aqueous solution of copper sulphate with the further study of bactericidal and bacteriostatic activity. The results of sorption efficiency of original and modified zeolite samples of Kholinsk deposit are presented in this paper. These results were obtained, when Zn 2+ and Pb 2+ ions were removed from the simulated solutions. It was concluded that it is possible to provide natural zeolites with bactericidal and bacteriostatic properties.

One-Step Synthesis of Copper and Cupric Oxide Particles from the Liquid Phase by X-Ray Radiolysis Using Synchrotron Radiation

The deposition of copper (Cu) and cupric oxide (Cu4O3, Cu2O, and CuO) particles in an aqueous copper sulfate (CuSO4) solution with additive alcohol such as methanol, ethanol, 2-propanol, and ethylene glycol has been studied by X-ray exposure from synchrotron radiation. An attenuated X-ray radiation time of 5 min allows for the synthesis of Cu, Cu4O3, Cu2O, and CuO nano/microscale particles and their aggregation into clusters. The morphology and composition of the synthesized Cu/cupric oxide particle clusters were characterized by scanning electron microscopy, scanning transmission electron microscopy, and high-resolution transmission electron microscopy with energy dispersive X-ray spectroscopy. Micro-Raman spectroscopy revealed that the clusters comprised cupric oxide core particles covered with Cu particles. Neither Cu/cupric oxide particles nor their clusters were formed without any alcohol additives. The effect of alcohol additives is attributed to the following sequential steps: photochemical reaction due to X-ray irradiation induces nucleation of the particles accompanying redox reaction and forms a cluster or aggregates by LaMer process and DLVO interactions. The procedure offers a novel route to synthesize the Cu/cupric oxide particles and aggregates. It also provides a novel additive manufacturing process or lithography of composite materials such as metal, oxide, and resin.

Preparation and study of concentrated hydrosols of copper nanoparticles using of weak reducing agents

We propose a facile and environmentally friendly method to prepare concentrated copper nanoparticles dispersion via reduction of aqueous copper(II) sulfate solution with ascorbic acid or glucose in the presence of gelatin as stabilizer. The so synthesized hydrosols have been examined using a set of physicochemical methods (ex situ and in situ) in order to determine the nanoparticles features.

Modeling the retention mechanism for high-performance liquid chromatography with a chiral ligand mobile phase and enantioseparation of mandelic acid derivatives.

The chromatographic retention mechanism describing relationship between retention factor and concentration of Cu(2+) (l-phenylalanine)2 using chiral ligand mobile phase was investigated and eight mandelic acid derivatives were enantioseparated by chiral ligand exchange chromatography. The relationship between retention factor and concentration of the Cu(2+) (l-phenylalanine)2 complex was proven to be in conformity with chromatographic retention mechanism in which chiral discrimination occurred both in mobile and stationary phase. Different copper(II) salts, chiral ligands, organic modifier, pH of aqueous phase, and conventional temperature on retention behavior were optimized. Eight racemates were successfully enantioseparated on a common reversed-phase column with an optimized mobile phase composed of 6 mmol/L of l-phenylalanine or N,N-dimethyl-l-phenylalanine and 3 mmol/Lof copper(II) acetate or copper(II) sulfate aqueous solution and methanol.

Electrochemical Characterization of Cathodized Copper Oxide Thin Films

Cathodic electrodeposited copper oxide thin films were prepared using 0.1 M aqueous (distilled water) copper sulfate solution onto the surface of stainless steel substrates. Deposited samples were characterized by structural and morphological analysis using XRD and SeM. Prepared samples were also analyzed using cyclic voltammetry, charge-discharge, and impedance spectroscopy. electrode shows nearly rectangular capacitive behavior. The highest specific capacitance of 62 F/gm was calculated at a scan rate of 1 mV/sec in 1M Na2SO4 electrolyte. The internal resistance observed from the Nyquist plot which is about 1.95 Ω. Using the ZsimpWin software matched equivalent circuit and circuitry parameters were reported.

Improvement of the photocatalytic activity of cupric oxide by deposition onto a natural clinoptilolite substrate

CuO was loaded onto clinoptilolite particles and used in the photodegradation of benzene-1,2-diamine (BD) under UV irradiation. The photocatalyst was prepared by ion exchanging of parent natural clinoptilolite with copper(II) sulfate aqueous solution (0.4molL−1) for 20h followed by drying and calcination at 450°C for 8h. Raw and modified samples were characterized by XRD, SEM–EDAX, DRS and BET methods. The degradation extents were evaluated by UV–vis absorption spectrophotometric, chemical Oxygen demand (COD) and HPLC methods. The primary objective was to determine the optimal conditions for experimental parameters which were obtained as: 2.0gL−1 of the photocatalyst, 20mgL−1 of benzene-1,2-diamine, pH 6.0 and 43mmolL−1 of H2O2. The degradation process obeyed first-order kinetics.

CHARACTERISTICS OF GLOW DISCHARGE ABOVE THE SURFACE OF COPPER SULFATE BASED SOLUTION

This paper presents results of a study of space and electrical characteristics of atmospheric pressure glow discharge in air above the surface of distilled water and 5%-20% aqueous solution of copper sulfate. The current-voltage characteristics and the value of cathode voltage drop in the discharge, the photographs of the glow discharge at different interelectrode distances and the emission spectra of the discharge have been obtained.

Magnetic field effects on copper metal deposition from copper sulfate aqueous solution.

Effects of a magnetic field (≤0.5 T) on electroless copper metal deposition from the reaction of a copper sulfate aqueous solution and a zinc thin plate were examined in this study. In a zero field, a smooth copper thin film grew steadily on the plate. In a 0.38 T field, a smooth copper thin film deposited on a zinc plate within about 1 min. Then, it peeled off repeatedly from the plate. The yield of consumed copper ions increased about 2.1 times compared with that in a zero field. Mechanism of this magnetic field effect was discussed in terms of Lorentz force- and magnetic force-induced convection and local volta cell formation.

J0310202 ポーラスアルミナテンプレートの最適化及びナノワイヤ面ファスナーの創製([J031-02]電子情報機器・半導体デバイス・電子部品の冷却技術(2),材料力学部門)

Characteristic of nanowire is gradually attracting many researchers with potential applications of nano devices, nano sensors, solar sells and so on. This paper describes fabrication and evaluation of Cu nanowire surface fastener grown in porous aluminum. To fabricate nanowire surface fastener, at first anodic aluminum oxide (AAO) template are fabricated by two steps anodization method in 0.01 M, 0.1 M and 1.0 M sulfuric acid. Next, Cr and Au films were evaporated on the patterned side of Si wafer as a conductive working electrode. Nanowire surface fastener was formed via electrical deposition in copper sulfate aqueous solution. After etching in 3 M NaOH aqueous solution to remove porous aluminum, we obtained nanowire surface fastener on Si wafer perpendicular to its surface. High density Cu nanowires with average diameter of 20 nm were observed by scanning electron microscope. In order to understand the performances of Cu nanowire surface fastener, electrical and mechanical properties of them were studied in details.

Electrodeposition process for the fabrication of copper dendrites film with stable superhydrophobicity

Copper dendrites on the copper surface were successfully prepared by electrodeposition in acidic copper sulfate aqueous solution containing ethanol. The XRD (X-ray diffraction) patterns indicate that the Cu dendrites possess fcc (face-centered cubic) crystal structure. The contact angle of the as-prepared Cu dendrites surface without palmitic acid modification is almost 0° and the surface is completely wetted by water. After modified with palmitic acid, the Cu dendrite surface shows superhydrophobicity with a contact angle of 160°. The polarization curves reveal that the superhydrophobic Cu dendrites surface exhibits a distinct passivation phenomenon, which could provide enhanced corrosion resistance for the substrate in the aqueous solution. The weight loss measurements show that the corrosion values of superhydrophobic surface is much lower than that of the bare copper, further meaning that the as-prepared surface has the anticorrosion performance.

Micromanufacturing by selective jet electrodeposition process

This paper describes the study of the jet electrodeposition process for fabrication of microsize metal parts. Three-dimensional microparts of copper were fabricated using copper sulfate aqueous solution as an electrolyte and a round nozzle with a diameter of 137 μm. Fabricated parts were observed using scanning electron microscope and Tool Maker’s microscope. The experimental results verified that electrodeposition mainly occurs selectively around the spot where electrolyte jet was impinged. Single-axis features (pin-like shapes) have been successfully fabricated, but complex features (like square-shaped part) had edge effect and geometrical inaccuracies. It was concluded that the non-uniform distribution of metal ions at work surface causes the uneven distribution of current over the work surface. This results into uneven and discontinuous deposition known as edge effect and inaccuracies in the fabricated microparts which may be reduced by uniform distribution of ions.

Simple one step electrochemical preparation of copper nanostructures

Nanostructures based on copper (CuNSs) are promising materials in different fields of application. To this end, in this work we have studied a simple one-step electrosynthesis of CuNSs directly onto ITO electrode surface starting from an aqueous solution of copper sulphate. We have investigated the effects of the presence of electrolyte salts such as K2SO4, Na2SO4 and (NH4)2SO4 and we have found that they gave rise to the formation of a number of remarkably different forms of nanostructures. In particular, when the electrodeposition was conducted in presence of K2SO4 fractal-like or dendritic structures consisting of a long central backbone and sharp side branches were observed. The resulting CuNSs were characterized by SEM, XRD and by electrochemical techniques. Studies on the electrocatalytic behaviour of dendritic CuNSs modified electrodes towards the oxidation of L-tyrosine in 0.05M NaOH solution showed a 1.0 10−6 ÷ 7.0 10−5M linear range and a detection limit of ca. 6.0 10−7M.

Synthesis of copper telluride nanowires using template-based electrodeposition method as chemical sensor

Copper telluride (CuTe) nanowires were synthesized electrochemically from aqueous acidic solution of copper (II) sulphate (CuSO4·5H2O) and tellurium oxide (TeO2) on a copper substrate by template-assisted electrodeposition method. The electrodeposition was conducted at 30 °C and the length of nanowires was controlled by adjusting deposition time. Structural characteristics were examined using X-ray diffraction and scanning electron microscope which confirm the formation of CuTe nanowires. Investigation for chemical sensing was carried out using air and chloroform, acetone, ethanol, glycerol, distilled water as liquids having dielectric constants 1, 4·81, 8·93, 21, 24· 55, 42·5 and 80·1, respectively. The results unequivocally prove that copper telluride nanowires can be fabricated as chemical sensors with enhanced sensitivity and reliability.

Decolorization of a binary azo dyes mixture using CuO incorporated nanozeolite-X as a heterogeneous catalyst and solar irradiation

The photodecolorization of a mixture of the methylene blue and rhodamine B cationic dyes was studied using CuO/nano-zeolite X catalyst under solar irradiation. Nano-zeolite crystals were synthesized by hydrothermal crystallization. The photocatalyst was prepared by the calcinations process at 450°C for 12h followed by anion exchange process of the parent nano-zeolite NaX in a copper(II) sulfate aqueous solution (0.2M) for 24h. All samples were characterized by X-ray diffraction (XRD), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), BET and diffuse reflectance spectroscopy (DRS) methods. The particles sizes of the nano-zeolite NaX crystals were calculated in the ranges of 7–10nm and 75–85nm by XRD and SEM, respectively. The decolorization extent of the dyes in their mixture was measured spectrophotometrically at their respective λmax values. The decolorization kinetics was fitted well to the Langmuire–Hinselwood first order rate law. The effects of various operating parameters including pH, the amount of the catalyst, the amount of loaded CuO, the initial dyes concentrations, H2O2 and KBrO3 doses on the photodecolorization efficiency were studied at atmospheric conditions. The chemical oxygen demand (COD) experiments were performed at regular intervals to confirm the mineralization extent of the dyes.