Initial Copper Ion Concentration Research Articles

Copper recovery in a spouted vessel electrolytic reactor (SBER)

An investigation of copper recovery from acidic solutions in a particulate, cylindrical spouted vessel of conductive particles is presented. The effects of current, initial copper ion concentration, supporting electrolyte concentration, particle loading, liquid flow rate, solution pH, and temperature on copper recovery rate, current efficiency and energy efficiency of the electrolytic deposition process were investigated under galvanostatic conditions. Experiments were also conducted to investigate the effects of backdissolution or ‘backstripping’ of the deposited metal in the acidic solution. It is hypothesized that the latter occurs via both chemical and electrochemical anodic oxidation in the bed of conductive particles. It was found that sparging of the electrolyte solution with selected gases to remove dissolved oxygen increased the current efficiency by as much as 30 under certain conditions. Finally, a numerical kinetic model of electrochemical deposition and backstripping, coupled with mass transfer in the particulate cathode bed, is presented that describes the behaviour of the net copper recovery curves reasonably well.

Sorption of Copper(II) from Aqueous Solution by Peat

The use of peat for removal of copper(II) from aqueous solution has been investigated at various initial copper ion concentrations and masses of peat. The equilibrium sorption study can be described by the Langmuir equation and defined in terms of the operating lines for each batch contacting system. The mechanisms of the rate of sorption of copper(II) were analysed using the Elovich equation and a pseudo-second-order model. Both rate mechanisms provided a very high degree of correlation of the experimental sorption rate data suggesting either model could be used in design applications.

Fixed-bed biosorption of Cu2+by polyacrylonitrile-immobilized dead cells of Saccharomyces cerevisiae

Dead cells of Saccharomyces cerevisiae 54 were immobilized by entrappment in polyacrylonitrile. The beads obtained were used to adsorb copper in an up-flow fixed-bed column. The effect of polymer content and cell loading were studied to optimize the porosity and the efficiency in copper removal of the biosorbent beads in a batch system. The optimal concentration of the polyacrylonitrile was assumed to be 12%(w/v) and a concentration of 0.5 g cell dry weight in 1 g polymer was most effective in adsorption of Cu2+. The adsorption capacity of this biosorbent was 27 mg Cu2+/g dry biomass at 200 mg/l initial concentration of copper ions. Adsorption of Cu2+ in a batch system was studied using different initial concentrations of the solute. The optimal conditions in the up-flow column of the following parameters were determined: flow rate, bed height, and initial concentration of Cu2+ of the solutions. Results of fixed-bed biosorption showed that breakthrough and saturation time appeared to increase with the bed height, but decrease with the flow rate and the initial concentration. The linearized form of the Thomas equation was used to describe dynamic adsorption of metal ions. As a result, the adsorption capacity of the batch system and the column system was compared. Desorption of copper ions was achieved by washing the column biomass with 0.1 M HCl at an eluent flow rate of 1 ml/min. The reusability of the immobilized biomass was tested in five consecutive adsorption-desorption cycles. The regenerated beads retained over 45% of their original adsorption capacity after five A/D cycles.

Removal of copper ions from aqueous solutions by a steel-making by-product

A study is made of the use of a steel-making by-product (rolling mill scale) as a material for removing Cu 2+ ions from aqueous solutions. The influence of contact time, initial copper ion concentration and temperature on removal capability is considered. The removal of Cu 2+ ions from an aqueous solution involves two processes: on the one hand, the adsorption of Cu 2+ ions on the surface of mill scale due to the iron oxides present in the latter; and on the other hand, the cementation of Cu 2+ onto metallic iron contained in the mill scale. Rolling mill scale is seen to be an effective material for the removal of copper ions from aqueous solutions.

Removal of copper ions from aqueous solution by tree fern

Tree fern, an agricultural by-product, was used for the sorptive removal of copper ions from aqueous solution. The experimental data was analysed by Langmuir, Freundlich and Redlich-Peterson isotherms. The equilibrium sorption capacity of copper ions was determined from the Langmuir equation and found to be 11.7 mg/g. A batch sorption model, based on the assumption of the pseudo-second-order mechanism, was developed to predict the rate constant of sorption, the equilibrium sorption capacity and the initial sorption rate with the effect of initial copper ion concentration and the tree fern dose. Various thermodynamic parameters, such as Δ G 0, Δ H 0 and Δ S 0, have been calculated. The thermodynamics of copper ion/tree fern system indicates spontaneous and endothermic nature of the process.

BATCH Pb 2+ AND Cu 2+ REMOVAL BY ELECTRIC FURNACE SLAG

An evaluation of the application of electric furnace slag (EFS) as an adsorbent to remove Pb 2+ and Cu 2+ from industrial effluents is presented. The paper examines phase composition of EFS by using X-ray diffraction of powder. In the batch experiments, parameters studied include the effect of initial concentration of lead and copper ions, temperature, and contact time. Over the temperature range studied (293–313 K) the results of adsorption experiments could be fitted by using both Langmuir and Freundlich models and thermodynamic values of Δ G 0, Δ H 0 and Δ S 0 corresponding to each adsorption process were calculated. Satisfactory conformity between experimental data and the model-predicted values was expressed by the correlation coefficient ( R 2). Both Langmuir and Freundlich models described the Pb 2+ and Cu 2+ sorption processes adequately, with correlation coefficient ( R 2) values ranging from 0.9760 to 0.9994. Data from this study indicated the potential use of the tested electric furnace slag, a by-product from “Felis” foundry in Sisak, Croatia, as Pb 2+ and Cu 2+ sorbents from the industrial effluents.

Comparison study of copper ion adsorption on chitosan, Dowex A-1, and Zerolit 225

The adsorption of copper ions by chitosan, Dowex A-1, and Zerolit 225 has been investigated. The uptake of copper was determined from changes in concentration as measured by atomic absorption spectrometry. A preliminary investigation on the adsorption was conducted by batch-wise examining the effects on pH and the initial copper ion concentration. It was found that chitosan has an excellent loading capacity of copper, compared with Dowex A-1 and Zerolit 225. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1067–1070, 1998

Electrochemical Cementation of Copper onto Zinc: Kinetics Modifications

Actual interpretation of the enhancement of Cu/Zn cementation kinetics by a “cement critical specific mass” is reconsidered. Working with a rotating disk electrode and varying the initial concentration of copper and zinc ions over a large range, we show that copper deposit is not responsible for the kinetic transition. First, cement peeling off does not change the delay for the appearance of the second stage and the amplitude of the kinetic transition is a function of the initial concentration of zinc ions. Furthermore, the first stage duration decreases, and even this stage may disappear, on a substrate precorroded in the same solution replacing copper ions by Ce(IV) ions. On the other hand, the stage duration increases if a constant polarization is imposed to the substrate. Operating conditions at the interface appear to be the essential parameter. Discussion includes morphological examinations.

Equilibrium and Kinetic Studies of Copper Ion Uptake by Calcium Alginate

Equilibrium and kinetic experiments of copper ion uptake by calcium alginate beads were carried out under different values of pH, ionic strength, initial concentration of copper ion, and amount of calcium alginate. The removal efficiency increases with increasing pH and decreasing ionic strength and initial concentration. The removal of copper occurs rapidly in the first hour, followed by a slow process that takes about 15 h. The copper ion uptake becomes faster with increasing pH and decreasing initial copper concentration and ionic strength. Mass transport of copper ions plays an important role in the kinetics of uptake. Equilibrium experiments show that surface complex formation is the major mechanism for copper ion uptake. Modeling of equilibrium and kinetics was also conducted based on a surface complexation approach. Modeling results showed that the two-pK Basic Stern model can successfully describe the effect of pH on equilibrium uptake. A diffusion-controlled model can also predict the effect of pH on the kinetics.

Transport studies for the sorption of copper ions by chitosan

Abstract The ability of chitosan, prepared from waste prawn shell, to sorb copper (II) ions from aqueous solutions has been studied. Equilibrium studies show that chitosan has a maximum sorption capacity for copper ions of about 40mg/g chitosan. The mass transport characteristics have been investigated by monitoring the kinetics in an agitated batch adsorber. An external mass transfer coefficient and an intraparticle diffusion rate parameter have been determined for a number of system variables including agitation, initial copper ion concentration, chitosan mass, chitosan particle size and solution temperature.

Kinetics of Cu(II) cementation on a pure aluminum disc in acidic sulphate solutions

Abstract The rates of copper cementation on pure aluminum discs were studied as a function of (a) initial copper ion concentration, (b) temperature, (c) initial hydrogen ion concentration, and (d) the effect of the peripheral velocity of the Al disc.At low initial copper ion concentration (1 × 10−4M), there are two rate-controlling processes: ionic diffusion control at temperatures. above 40°C, and surface reaction control at temperatures below 40° C. At higher initial copper ion concentrations (5 × 10−3 M), the rate is controlled by a chemical (surface) reaction.When the-hydrogen ion concentration is increased to 0.7 M, the cementation rate increases. The pH remains constant during the reaction.The cemented deposit is pure copper. The structure. of the deposit is dependent on both temperature and the initial copper ion concentration. At high initial copper ion concentration (5 × 10-3 M) and at high temperatures (75° C), the rate, which was constant initially, increases with increasing deposition. Resume ...

Removal of Cu2+ Ions from Aqueous Solutions Using Copper Resistant Bacteria

Biosorption using resistant microorganisms is an effective process for treatment of industrial effluents and removal of heavy metals from contaminated sites. In this study copper resistant bacteria from fireworks industrial contaminated soil were isolated, enumerated and characterized. The tolerances of the organisms decreased with increase in the copper concentration. The isolated bacterial strain was identified as Bacillus sp. and was resistant to 300 mg/L of copper concentration. Biosorption studies were carried out in the Bacillus sp. The optimum temperature was determined to be 35°C and pH was 8.0. The maximum removal of 88% was obtained at optimum conditions when the initial copper ion concentration was 100 mg/ L. Hence the Bacillus sp. isolated proved to be an efficient biosorbent.DOI: http://dx.doi.org/10.3126/on.v9i1.5733