XPS, SEM, EDX and EIS study of an electrochemically modified electrode surface of natural chalcocite (Cu2S)

Velásquez, Pablo; Leinen, D.; Pascual, J.; Ramos-Barrado, J.R.; Córdova, Ricardo; Gómez, H.; Schrebler, Ricardo

doi:10.1016/s0022-0728(01)00533-2

Cited by 70 publications

(38 citation statements)

References 20 publications

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“…All the solutions were prepared with analytical grade reagents and Milli-Q water, resistivity 18 MΩ cm. As electrolytic solution it was used T&K medium 12 without ferrous ions with the following composition: 0.5 g of (NH 4 ) 2 SO 4 , 0.5 g of K 2 HPO 4 and 0.5 g of MgSO 4. 7H 2 0 in purified water (q.s.p.…”

Section: Methodsmentioning

confidence: 99%

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Optimization of the use of carbon paste electrodes (CPE) for electrochemical study of the chalcopyrite

Horta¹,

Bevilaqua²,

Acciari³

et al. 2009

Quím. Nova

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Recebido em 30/6/08; aceito em 2/3/09; publicado na web em 4/8/09The use of carbon paste electrodes (CPE) of mineral sulfides can be useful for electrochemical studies to overcome problems by using massive ones. Using CPE-chalcopyrite some variables were electrochemically evaluated. These variables were: (i) the atmosphere of preparation (air or argon) of CPE and elapsed time till its use; (ii) scan rate for voltammetric measurements and (iii) chalcopyrite concentration in the CPE. Based on cyclic voltammetry, open-circuit potential and electrochemical impedance results the recommendations are: oxygen-free atmosphere to prepare and kept the CPE until around two ours, scan rates from 10 to 40 mV s -1 , and chalcopyrite concentrations ≥ 20%.

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Section: Methodsmentioning

confidence: 99%

“…[1][2][3][4] These methods permit to study electrical interactions between the electrode and the electrolyte, and how these interactions change with different oxidation potentials.…”

Section: Introductionmentioning

confidence: 99%

Optimization of the use of carbon paste electrodes (CPE) for electrochemical study of the chalcopyrite

Horta¹,

Bevilaqua²,

Acciari³

et al. 2009

Quím. Nova

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“…It is apparent that there were some changes in absorption peak frequencies or wave numbers from IR spectra in powdered oyster shell prior to and after SDS adsorption as shown in Figure 3 [5,6]. As shown in Table 3 [5], the SDS loaded spectrum demonstrated minor changes in absorption peak frequencies corresponding to various other functional groups with the exception of major shift or changes in the positions of C-H stretching in methyne, C-N stretching in 2° or 3° amine, C=O stretching in carboxyl (carboxylic acid) or carbonyl (ketones) groups, and C=O stretching vibrations in acyl halide (or haloformyl group), i.e., 2883.08 to 2878.84 cm , respectively [5][6][7][8].…”

Section: Atr-ftir Studiesmentioning

confidence: 99%

Chemical, Structural and Elemental Characterization of Biosorbents Using FE-SEM, SEM-EDX, XRD/XRPD and ATR-FTIR Techniques

Shrestha¹

2016

J Chem Eng Process Technol

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The chemical, structural, and elemental composition of any adsorbents plays undoubtedly crucial role and has paramount significance in adsorption process. The present study of chemical, structural, and elemental characterization of powdered Pinus densiflora pine cones, lignite and coconut shell-based activated carbon fiber (ACF), and powdered oyster shell prior employed for anionic surfactant sodium dodecyl sulfate (SDS) adsorption was undertaken using field emission scanning electron microscope (FE-SEM), scanning electron microscope coupled with energy dispersive x-ray (SEM-EDX), X-ray diffraction/X-ray powder diffraction (XRD/XRPD), and multiple internal reflectance (MIR) or attenuated transform reflectance -fourier transform infrared spectroscopy (ATR-FTIR) techniques. The FE-SEM imaging observed at three different magnifications depicted the change in surface texture of aforementioned biosorbents before and after SDS adsorption. SEM-EDX analysis indicated alteration in the concentration and distribution of different compositional elements. The XRD analysis suggested the amorphous character in lignite and coconut shell-based ACF and powdered Pinus densiflora cones, whilst indicating the sample of powdered oyster shell to be crystalline in nature and entirely composed of CaCO 3 with the very trivial amount of impurities. Further, infrared (IR) spectroscopy demonstrated variation in IR spectra of the samples prior to and after surfactant adsorption and also further suggested occurrence of complexing or (complexation) process between ionizable functional groups and DS -or Na + ions of SDS. In addition, iodine number of the lignite and coconut shell-based ACF, powdered Pinus densiflora cones, and powdered oyster shell were found to be 285.86 mg/g, 25.01 mg/g, and 28.48 mg/g, respectively.

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“…1. Chalcocite voltammograms with surface reactions in aqueous solutions have been frequently reported (Sato, 1960;Velasquez et al, 2001). The peak at 0.15V with the breadth from approximately 0.05 to 0.25 V on the positive-going sweep was attributed to the oxidation of chalcocite resulting in the formation of cupric oxide and a sulfur-rich sub-layer (covellite) as shown in Reaction (1).…”

Section: Cyclic Voltammetry Studiesmentioning

confidence: 91%

“…A fresh electrode surface was prepared between the experimental runs by abrading with silicon carbide abrasive paper (1200 grits), rinsed with deionized water prior to each experiment (Velasquez et al, 2001;Smith et al, 2009). …”

Section: Electrochemical Measurementsmentioning

confidence: 99%

Slime coating mitigation on mineral surfaces in froth flotation by saline water

Zhao¹

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Fine and ultra-fine particle flotation is central to the mining industry as a result of the need to treat low grade and difficult ores which require fine grinding to liberate valuable minerals from gangue minerals. However, the flotation of fine and ultra-fine particles is not efficient and a slime coating with slime gangue particles attaching to valuable minerals is one of the most popular barriers. A slime coating prevents the adsorption of collectors on the surface of valuable minerals resulting in low flotation recovery or low product quality.Saline water is also an important issue in the mining industry. In Western Australia, bore water with a high ionic strength has to be used at mine sites for production, site rehabilitation, and downstream processing because fresh water is not available locally. In Queensland, most mine sites have adopted water re-use as a means for making freshwater savings. However, water re-use results in increased salinity in site water stores, which is driven largely by evaporation and ongoing salt inputs from spoil, minerals and groundwater. Flotation relies on a large amount of water and therefore the impact of saline water on flotation performance has gained more and more attention.In this research, the role of saline water in the mitigation of slime coatings was studied and a generic approach to improve fine and ultra-fine particle flotation by using saline water was developed, building on the previous research. A model slime coating system was established by using copper minerals in the presence of clay particles. It was found that chalcocite flotation was depressed in the presence of bentonite slimes while chalcopyrite flotation was less affected.Electrostatic interactions between copper minerals and clay particles were found to be responsible for the different flotation of chalcocite and chalcopyrite in the presence of clay minerals. It was found that surface oxidation occurred during II grinding and changed the surface properties of chalcopyrite and chalcocite.Chalcocite was strongly oxidized while chalcopyrite was slightly oxidized after the grinding with stainless steel media. The different extent of surface oxidation resulted in the different electrical property of chalcocite and chalcopyrite surfaces.The strongly oxidized chalcocite surface became positively charged after grinding at the same pH and electrostatically attractive to bentonite particles resulting in the depressed chalcocite flotation. In contrast, the slightly oxidized chalcopyrite surface remained negatively charged after grinding at pH 9.0 and entropically repulsive from bentonite slime particles. Therefore, bentonite slimes did not influence chalcopyrite flotation as much as chalcocite flotation.Mitigation of slime coatings on chalcocite in flotation by using electrolytes was further investigated and kaolinite was used to introduce the slime. The results indicated that in tap water, the presence of kaolinite slimes depressed chalcocite flotation. With the addition of electrolytes to the flotation...

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XPS, SEM, EDX and EIS study of an electrochemically modified electrode surface of natural chalcocite (Cu2S)

Cited by 70 publications

References 20 publications

Optimization of the use of carbon paste electrodes (CPE) for electrochemical study of the chalcopyrite

Optimization of the use of carbon paste electrodes (CPE) for electrochemical study of the chalcopyrite

Chemical, Structural and Elemental Characterization of Biosorbents Using FE-SEM, SEM-EDX, XRD/XRPD and ATR-FTIR Techniques

Slime coating mitigation on mineral surfaces in froth flotation by saline water

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