Dilute Copper Sulphate Research Articles

Cementation of copper on zinc in an unsubmerged jet reactor

ABSTRACT Removal of copper by cementation on zinc disc from dilute copper sulfate solution in a recirculating batch reactor which consisted of a horizontal zinc disc impinged by an axial turbulent unsubmerged jet was studied. The effect of different parameters such as initial copper ion concentration, solution velocity, nozzle diameter, and the axial distance between the zinc disc and the unsubmerged jet on the rate of copper ion removal was investigated. The rate of cementation was found to increase with increasing both the solution velocity and the nozzle diameter and decreasing the axial distance between the zinc disc and the unsubmerged jet. The rate of diffusion-controlled cementation of copper ions was expressed in terms of the mass transfer coefficient, the data were correlated by a dimensionless correlation. The high rate of mass transfer of the jet reactor qualifies the reactor for diffusion-controlled heavy metals removal from wastewater and metallic coating by cementation.

Detailed velocity and heat transfer measurements of an advanced insert for impingement cooling

This work reports the results of paired experiments for the aft section of a complex internal cooling flow within a gas turbine vane using Magnetic Resonance Velocimetry (MRV) and steady-state Infrared (IR) thermography. The aft cooling insert for the vane with two-pass impingement was designed at a scale five times larger than the original and built using stereolithography (SLA) fabrication methods. The MRV technique was used to measure the three-dimensional, three-component velocity field for a test case with a Reynolds number range of 2,600 to 7,600 based on diameter of the impingement holes. Flow distribution, impingement hole performance, and cross flow effects are discussed for the experiment in which a dilute aqueous copper sulfate solution was used as the working fluid. A paired experiment with a geometrically similar design employed electrical heating of a thin stainless steel shim to model a constant heat flux boundary condition of an interior wall of the turbine vane. The modeled vane insert was then operated with air as the working fluid at two test conditions with Reynolds numbers in the range of approximately 1,200 to 7,600 based on the diameter of the impingement holes. An IR camera was used to measure the surface temperature of the shim. Using energy balances and the known heat flux, the temperature data were used to determine heat transfer characteristics of the impinging jets for the pressure and suction side surfaces, including the Nusselt number. The MRV and IR data sets provide detailed insight into the surface effects of the flow distribution and the result on the local and area-averaged heat transfer performance. A strong coupling between the velocity field and temperature data provide insight into design feature performance, and serve as a validation data set for matched computational simulations. Finally, a comparison with internal heat transfer correlations is presented using the data from Florschuetz et al. [1]. The results showed a lack of agreement with Florschuetz, leading to the development of a novel methodology for estimating the heat transfer performance of an impinging hole with crossflow. Measurement uncertainty was estimated to be ±5% for velocity and ±5% for the spatially averaged Nusselt number distributions.

Electrodeposition of Cu(111) onto a Ru(0001) seed layer for epitaxial Cu interconnects

The electrodeposition of Cu onto epitaxial Ru(0001) seed layers was investigated from a sulfuric acid-based solution containing dilute copper(II) sulfate and chloride ions. Using galvanostatic deposition at −350 μA/cm2, Cu was deposited epitaxially onto a 30 nm-thick Ru(0001) seed layer, despite a compressive misfit strain between −6.9% and −8.3%, depending on the extent of strain relaxation of the Ru layer. However, rather than depositing as a single crystal, Cu grew as a bicrystal having a common out-of-plane orientation of Cu(111) and two equivalent in-plane orientations. The Cu grain size was large, on the order of micrometers, and the grain boundaries were identified as incoherent ∑3{211} twin boundaries. The Cu initially grew as isolated islands, coalescing into a contiguous film at thicknesses around 50 nm. The Cu film was rough, and thickness and coverage varied over the electrodeposited region. After the initial island growth, Cu void fraction and film roughness both decreased with thickness as the deposit transitioned into a planar film with nanometric islands growing on the film surface. However, at thicknesses exceeding 200 nm, anisotropic growth of large, faceted Cu islands on the planar Cu film again increased the surface roughness. The epitaxially deposited Cu bicrystal showed an improvement in resistivity when compared with polycrystalline Cu similarly electrodeposited onto a polycrystalline Ru seed.

Nanomanufacturing of multi-walled carbon nanotubes enhanced electrochemical electrode through surface micromachining

Multi-walled carbon nanotubes (MWNTs) were dispersed into polyimide (PI) by mechanical ball milling and spun on a titanium substrate to form a composite film, which was fabricated by surface micromachining to make the involved CNTs partially exposed on the surface. The partially exposed carbon nanotubes are rooted in the cured PI, and it looks like that CNT were implanted into the surface of the electrode uniformly. The morphology of the electrode was characterised by scanning electron microscope (SEM). The electrochemical activity was evaluated in dilute copper sulphate solution by cyclic voltammetry measurement. The performance of the etched electrode is much better than that of bare and unetched electrodes. The fabricated MWNTs enhanced electrode can be used to detect trace phenol in water.

Intensification of the rate of heavy metal removal from wastewater by cementation in a jet reactor

Removal of copper by cementation on zinc disc from dilute copper sulfate solution in a recirculating batch reactor which consisted of a horizontal zinc disc impinged by an axial turbulent submerged jet was studied. The effect of different parameters such as, initial copper ion concentration, solution flow rate and the axial distance between the zinc disk and submerged jet on the rate of copper ion removal were investigated. The rate of cementation was found to increase with increasing solution flow rate, decreasing the axial distance between jet and zinc disc, and by increasing copper ion concentration. The rate of diffusion controlled cementation of copper ion was expressed in terms of the mass transfer coefficient, the data were correlated with the following dimensionless correlation: Sh = 0.306 S c 0.33 Re 0.997 ( d n / l ) 0.0337 . The high rate of mass transfer of the jet reactor, qualifies the reactor for diffusion controlled heavy metals removal from wastewater.

Effect of solution flow rate and direction on copper electrodeposition process from sulfuric acid electrolyte on porous electrode with high electric conductivity

The effect of solution flow direction and rate on the dynamics of copper electrodeposition onto a premetallized coal-graphite VINN-250 material from a dilute copper sulfate sulfuric acid solution is experimentally studied in the direct-flow mode. A light effect of solution supply on the copper deposit final mass for high and low solution flow rates is found, while the effect of this parameter on the metal distribution within the porous electrode is significant. The most uniform copper deposit distribution throughout the porous electrode is observed in the case of intermediate solution flow rates at its rear supply. The obtained experimental data agree qualitatively with the earlier published mathematical simulation results. Small systematic deviations from numeric calculations can be due to the process disregarded in the mathematical model: the effect of gas phase formed within the porous cathode due to the simultaneous hydrogen evolution.

Stress Corrosion Cracking of Alloy 400 in Copper Sulfate Solution

Abstract Alloy 400 is shown to undergo intergranular corrosion when coupled to a large area of copper in dilute copper sulfate (CuSO4) solutions at 75°C. The mechanism involves dealloying of nickel from the alloy. Slow strain rate testing causes transgranular stress corrosion cracking under the same conditions.

SU-FF-T-48: A QA Device to Perform End-To-End Spatial Accuracy Tests of Target Irradiation in Stereotactic Radiosurgery

Purpose: To ensure the sub‐millimeter accuracy of Radiosurgerytreatments, it is imperative to evaluate and monitor the errors associated with the whole treatment process. We have designed a QA Phantom that makes it possible to perform such accuracy testing.Method and Materials: Our plastic phantom was designed such that it can be mounted in the same stereotactic frame which is fixed on the patient during imaging and irradiation. Small targets at several locations in the phantom can be interchanged depending on the imaging modality used for imaging. Targets made out of Cu are used for CTimaging, or a drop of dilute copper sulfate in a small absorbent medium for MRI. The phantom in the frame and the localization box with the fidutial system is imaged simulating a patient. The images are reconstructed in the treatment planning system and the irradiation set up data for the targets are used for positioning the phantom in the radiation unit. During the irradiation the target is replaced by Gafchromic film, the exact location of the target is marked on the film with a pinhole that was designed to mark the film at the same location as the imaged target. By irradiating the phantom with small cross section beams focused at the target a spot is created on the film. The accuracy of the irradiation given at the target location is evaluated by the deviation of center of the spot on the film from the pinhole. Results & Conclusions: Several end‐to‐end tests were performed for our Gamma Knife unit to demonstrate overall accuracy of the process. Our phantom provides a direct test of the variation in the target irradiation as resulted by possible variations introduced in all the stages of the process of the stereotactic treatment such as imaging,treatment planning, and radiation delivery.

A Heavy Metal Biotrap for Wastewater Remediation Using Poly-γ-Glutamic Acid

Poly-gamma-glutamic acid (gamma-PGA) obtained from Bacillus licheniformis ATCC 9945 was evaluated as a potential biosorbent material for use in the removal of heavy metals from aqueous solution. Copper (Cu(2+)) was chosen as the model heavy metal used in these studies since it is extensively used by electroplating and other industries, has been the model for many other similar studies, and can be easily assayed through a number of convenient methods. Cu(2+)-gamma-PGA binding parameters under varying conditions of pH, temperature, ionic strength, and in the presence of other heavy metal ions were determined for the purified biopolymer using a specially designed dialysis apparatus. Applying the Langmuir adsorption isotherm model showed that gamma-PGA had a copper capacity approaching 77.9 mg/g and a binding constant of 32 mg/L (0.5 mM) at pH 4.0 and 25 degrees C. Cu(2+)-gamma-PGA adsorption was relatively temperature independent between 7 and 40 degrees C, while an increase in ionic strength led to a decrease in metal ion binding. Cd(2+) and Zn(2+) ions compete with Cu(2+) for binding sites on the gamma-PGA biopolymer. Metal uptake by gamma-PGA was further tested using a tangential flow filtration apparatus in a diafiltration mode in which metal was continually processed through a dilute solution of gamma-PGA without allowing for equilibrium to be established. The circulating polymer solution was able to complex metal as well as successfully prevent passage of unbound copper ions present in solution through the membrane. Using 500 mL of a 0.2% gamma-PGA solution, up to 97% of a 50 mg/L copper sulfate solution processed at a flow rate of 115 mL/min was retained by the polymer. For a 10 mg/L solution of Cu(2+) as copper sulfate, filtrate concentrations of Cu(2+) never rose above 0.6 mg/L while processing 2.5 L of dilute copper sulfate.

Cementation treatment of copper in wastewater: mass transfer in a fixed bed of iron spheres

The cementation of cupric ions from dilute copper sulfate using a fixed bed of iron spheres was studied. The extent of copper recovery and excess of iron consumption in similar conditions to those of copper bearing wastewater was experimentally determined. Determinations were made over a large range of cupric ions concentrations, for different solution flow rates and beds with different heights. The cementation reaction was found to proceed with two different regimes: a steady regime and unsteady regime with different initial cupric ions concentration. The rate of cementation for each regime were calculated and represented by the product k ̄ a e of the overall mass transfer coefficient k ̄ and the effective surface area a e.The values for unsteady regime was found to increase with increasing initial cupric concentration and decrease with bed height especially at high flow rates, while they stay nearly constant in the steady regime. Empirical correlations giving the factor J D of the mass transfer as a function of the Reynolds numbers for each regime are proposed by introducing an apparent mass transfer coefficient. The correlations equations obtained were thus compared to the prediction of other empirical models when possible.

Cementation reactions in the presence of nitrogen compounds

The effect of aniline derivatives on the rate of cementation of copper from dilute copper sulfate solution on iron rods was investigated. The variables studied were concentration of CuSO 4, temperature, organic additives, and their concentrations. It was found that the cementation reaction was first-order in the presence and in the absence of additives. Nitrogen compounds were found to decrease the rate of cementation by 10 to 80% depending on the type of inhibitor as well as its concentration.The adsorption isotherm, the effect of temperature, and the percentage inhibition show that the order of inhibition is p -chloroaniline>o -chloroaniline>m -chloroaniline and p -chloroaniline>p -aminobenzoic acid>p -aminoacetophenone. The thermodynamic parameters Δ S ≠, Δ G ≠, Δ H ≠ were given.

Importance of Surface Preparation in Electrochemical Investigations of the Copper System in Dilute Copper Sulfate Solutions

The electrochemistry of the copper‐copper sulfate system has been investigated with the purpose of using this system in measurements of secondary and tertiary distributions of current density in electrochemical reactors. The copper concentration was in the range 1 to 10 mol m−3 in the presence of sulfuric acid as supporting electrolyte. Efforts were mainly concentrated on the preparation technique of the surface of a rotating disk electrode and its influence on the polarization curves. Impedance measurements and scanning electron microscopy observations of the copper surface were used to characterize the surface. Polarization of the electrode at limiting current in the investigated solution for a few minutes was shown to be the most reliable technique of preparation. Then kinetic parameters of the copper system and the diffusion coefficient were determined under controlled conditions of the electrode surface by low scan rate voltammetry. The i‐E were modeled by the Butler‐Volmer model proposed by Bockris et al. The obtained data are compared with published results and discussed.

Effect of surfactants on the rate of diffusion‐controlled Cementation of copper from dilute solutions on a stationary zinc disc in stirred vessels

AbstractThe effect of surfactants on the rate of diffusion‐controlled cementation of copper from dilute copper sulphate solutions on a stationary zinc disc in a stirred vessel was studied. Variables investigated were rotational speed of the impeller, concentration and type of surfactants and concentration of copper sulphate solution. These variables were studied for their effect on the mass transfer coefficient of copper cementation. The mass transfer coefficient was found to increase with increasing rotational speed of the impeller and concentration of copper sulphate solution. It was found that surfactants decrease the rate of mass transfer during cementation by an amount ranging from 9.5 to 25° depending on the rotational speed of the impeller and type of surfactant added. Increasing surfactant concentration was found to decrease the mass transfer coefficient. The ability of different surfactants to decrease the mass transfer coefficient increases in the order: CTMAB < SABS < NPPGE. Mass transfer data were correlated, in absence and in presence of surfactants, by the following equations respectively: Where Sh is Sherwood number, Re is Reynolds number, and Sc is Schmidt number.

Effect of surface-active substances on the rate of production of copper powder from copper sulphate solutions by cementation on zinc rods in gas sparged reactors

The effect of surface-active substances on the rate of diffusion-controlled cementation of copper on a single vertical zinc rod from dilute copper sulphate solutions was studied. Variables investigated were: nitrogen superficial velocity, concentration and type of surface-active substance. These variables were studied for their effect on the mass transfer coefficient of copper cementation. The mass transfer coefficient was found to increase with increasing superficial gas velocity. Increasing surfactant concentration was found to decrease the mass transfer coefficient. It was found that surfactants decrease the mass transfer coefficient by an amount ranging from 14% to 39% depending on the superficial gas velocity and type of surfactant added. The ability of the four types of surfactants to decrease the mass transfer coefficient increases in the order: CTMAB < Aspecon-1030 < SABS < NPPGE. Mass transfer data were correlated by the equation: Sh = 7.25 We 0.88 Sc 0.33 for the conditions: Sc = 1430 and 4.2 < We < 43.6, where Sh is a Sherwood number, We is a Weber number and Sc is a Schmidt number. In parallel with measuring the mass transfer coefficient, gas hold-up and solution surface tension were also measured to assess how these parameters are affected by the presence of surface-active substances.

Comparison of Artifact from Craniomaxillofacial Internal Fixation Devices

This study compares artifact from craniomaxillofacial internal fixation devices in magnetic resonance images and examines heating and magnetic deflection effects on these devices. Stainless steel wires, microfixation plates of vitallium and titanium, and minifixation and mandibular reconstruction plates of stainless steel, vitallium, and titanium were evaluated. The plates were mounted on a dry skull and submerged in dilute copper sulfate solution. All images were obtained in duplicate by two independent, nonblinded teams of observers with a 1.5-T Signa magnetic resonance system. Each team ranked artifact size for each material by computerized measurement. The rank order of artifact size for each material within each fixation system group and between fixation groups was identical between the two teams. Bath and plate temperatures were recorded before and after imaging. Artifact production was related to hardware size and composition. Titanium hardware caused the least amount of black-hole artifact. Vitallium and stainless steel fixation devices of similar size produced significantly more artifact. No significant heating or magnetic deflection effects were seen with any of the fixation devices.

Corrosion Inhibition of Cobalt with a Thin Film of Cu‐BTA

Electrochemical techniques, ellipsometry and x‐ray photoelectron spectroscopy were used to evaluate the use of benzotriazole, alone or in combination with boric acid/borate buffer and dilute copper sulfate for the protection of cobalt. The data indicate that in slightly alkaline solutions benzotriazole is a strong inhibitor for cobalt corrosion, whereas in water and neutral solutions it produces a barely measurable effect. In the presence of benzotriazole and Cu+2 ions, spontaneous reduction of copper ions leads to the formation of a thin film of Cu‐BTA on the cobalt surface. This film acts as a corrosion protector that is better than benzotriazole, with a significant reduction of the corrosion rate even during subsequent exposure to solutions without inhibitors.

Effect of drag-reducing polymer on the rate of mass transfer in fixed-bed reactors

Rates of mass transfer were measured for the cementation of copper from dilute copper sulphate solutions containing polyethylene oxide drag-reducing polymer on a fixed bed of zinc pellets. Starting from a Reynolds number (Re) of 550, the rate of mass transfer was found to decrease by an amount ranging from 7.5 to 51% depending onRe and polymer concentration. The percentage decrease in the rate of mass transfer increased with increasingRe, passed through a maximum atRe=1400 and then decreased rapidly with further increase inRe. The possibility of using drag-reducing polymers to reduce power consumption in fixed-bed operation was discussed in the light of the present and previous results.

Interactions of variables in the fluidised-bed electrowinning of copper

The effects of certain variables on the current efficiency and power consumption of a small fluidised-bed electrowinning cell treating dilute copper sulphate solutions have been studied. A factorial experimental design in two levels has been used to investigate the effects of cell current, sulphuric acid concentration, temperature and the presence of iron in the electrolyte, and the results have been analysed by the Yates technique. It is shown that an increase in temperature and the presence of iron in solution both decrease the current efficiency, while an increase in the cell current increases the current efficiency, for conditions where the cathode is not polarized with respect to copper ions. Significant interaction effects on the current efficiency are shown to exist for the case of cell current and iron concentration and for cell current and temperature. These main effects and interactions can be accounted for by a model in which three simultaneous reduction reactions occur at the cathode involving cupric ions, ferric ions and oxygen, with the latter two occurring at their diffusion limited rates. Significant main effects on the power consumption of the cell are shown to exist for cell current, iron concentration and acid concentration. Increasing either of the former two variables increases the power consumption whereas an increase in the latter causes a marked decrease in power consumption, and significant interactions occur between cell current and iron concentration and cell current and acid concentration. An increase in temperature is shown to lead to an increase in the amount of metal deposited on the feeder electrode. The paper concludes with a discussion of the application of fluidised-bed cathodes to the recovery of copper by electrowinning from various types of solutions.

硫酸銅溶液中での鉄に対する銅の化学置換メッキ 錯化剤が存在しない場合

Experiments were carried out to find the mechanism of galvanic displacement: Fe+Cu2+→Fe2++Cu. When iron is immersed in a concentrated copper sulfate solution, e.g., 0.5M, a poorly adherent copper is deposited. In this case FeSO4 or Fe2O3 coprecipitated with the copper because the concentration of Fe2+ near the interface increased rapidly immediately after the immersion. However, atyell adherent copper was deposited by immersion in an acidic dilute copper sulfate solution, e.g., 0.01M, pH 1.5. In this case the rate of copper deposition, namely, the rate of formation of Fe2+ was slow, so that the Fe2+ was permitted to diffuse into the bulk of the solution without precipitating, which was the case of well adherent copper plate. The formulation of immersion plating of copper on iron was: CuSO4 0.0025-0.03M, pH<2.5, room temperature, immersion time 0.5-15min. The copper plating applied under these conditions was adherent to iron, hence copper could be electroplated on it from the ordinary pyrophosphate baths.

Evaluation of Methods for Introducing Materials Directly into the Abomasum of Yearling Cattle

Procedures for introducing a nonabsorbed marker directly into the abomasum were evaluated with 10- to 22-month-old cattle. Excretions of 141Ce surgically placed into the abomasum and 141Ce placed by gelatin capsule into the rumen of the same animals were compared in eight animal trials. Cerium-144, which began its passage from the abomasum, was almost entirely voided within 30 hr, whereas some 141Ce excretion still occurred after 100 hr. Times required for 5, 50, and 90% excretions averaged 15, 18, and 23 hr for abomasal 144Ce doses and 26, 43, and 90 hr for rumen 141Ce doses. Comparison of excretion patterns in other experiments with those described above showed whether a dose entered the abomasum or the rumen. Swabbing the animal's throat with dilute copper sulfate before dosing by syringe diverted very little of the dose to the abomasum. When radiocerium in milk or water at 37 or 18C was suckled from nipple pails, it entered the abomasum. Gelatin capsules also entered the abomasum when administered immediately after suckling and followed by additional suckling.