Scanning electrochemical microscopy: study of the deposition and stripping mechanism of lead in the presence of copper

Sousa, Maria F.B.; Sánchez, Elisabete Maria Saraiva; Bertazzoli, Rodnei

doi:10.1590/s0103-50532011000600012

Cited by 9 publications

(4 citation statements)

References 24 publications

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“…Due to the difference in electrodeposition potentials between Cu II , Pb II , and Cd II , electrodeposition at varying potentials was carried out from a mixed Cu II , Pb II , and Cd II solution for 200 s. It is predicted that Cu II can be recovered alone at potentials < −0.65 V vs AgCl|Ag, evidenced by a single anodic stripping peak in the voltammogram shown in Figure 5 d. At–0.70 and −0.90 V vs AgCl|Ag, Pb–Cu alloys were deposited. Three anodic stripping peaks are observed, where peak 1 is associated with Cu stripping, while peaks 2 and 3 are associated with stripping of Pb deposited from glassy carbon and copper, respectively, 66 as previously reported. At −1.10 V deposition, an additional peak 4 was evident due to prior electrodeposition of an Cd–Pb–Cu alloy.…”

Section: Results and Discussionsupporting

confidence: 83%

“…At–0.70 and −0.90 V vs AgCl|Ag, Pb–Cu alloys were deposited. Three anodic stripping peaks are observed, where peak 1 is associated with Cu stripping, while peaks 2 and 3 are associated with stripping of Pb deposited from glassy carbon and copper, respectively, as previously reported. At −1.10 V deposition, an additional peak 4 was evident due to prior electrodeposition of an Cd–Pb–Cu alloy.…”

Section: Results and Discussionmentioning

confidence: 99%

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Demetallization of Sewage Sludge Using Low-Cost Ionic Liquids

Yao

Tan

Metcalfe³

et al. 2021

Environ. Sci. Technol.

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Sludge produced from wastewater treatment has little to no value and is typically treated through volume reduction techniques, such as dewatering, thickening, or digestion. However, these methods inherently increase heavy metal concentrations, which makes the sludge unsuitable for land spreading and difficult to dispose of, owing to strict legal requirements/regulations concerning these metals. We addressed this problem, for the first time, by using recyclable low-cost protic ionic liquids to complex these toxic metals through a chemical fractionation process. Sewage sludge samples collected from wastewater plants in the UK were heated with methylimidazolium chloride ([Hmim]Cl, triethylammonium hydrogen sulfate ([TEA][HSO 4 ]) and dimethylbutylammonium hydrogen sulfate ([DMBA][HSO 4 ]) under various operating temperatures, times and solids loadings to separate the sludge from its metal contaminants. Analysis of the residual solid product and metal-rich ionic liquid liquor using inductively coupled plasma-emission spectrometry showed that [Hmim]Cl extracted >90% of Cd II , Ni II , Zn II , and Pb II without altering the phosphorus content, while other toxic metals such as Cr III , Cr VI and As III were more readily removed (>80%) with [TEA][HSO 4 ]. We test the recyclability of [Hmim]Cl, showing insignificant efficiency losses over 6 cycles and discuss the possibilities of using electrochemical deposition to prevent the buildup of metal in the IL. This approach opens up new avenues for sewage sludge valorization, including potential applications in emulsion fuels or fertilizer development, accessed by techno-economic analysis.

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Section: Results and Discussionsupporting

confidence: 83%

Section: Results and Discussionmentioning

confidence: 99%

Demetallization of Sewage Sludge Using Low-Cost Ionic Liquids

Yao

Tan

Metcalfe³

et al. 2021

Environ. Sci. Technol.

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“…Some authors also observed secondary anodic stripping voltammetric peaks when lead was electrodeposited in the presence of copper on glassy carbon electrodes. 43 These secondary peaks were observed between the main peaks of pure metals and they were attributed to the anodic stripping of deposited lead on copper. 43 SiAt-SPCPE also present another anodic peak at +0.33 V which was already detected in cyclic voltammetric studies (Figure 1 inset).…”

Section: Preliminary Studiesmentioning

confidence: 98%

“…43 These secondary peaks were observed between the main peaks of pure metals and they were attributed to the anodic stripping of deposited lead on copper. 43 SiAt-SPCPE also present another anodic peak at +0.33 V which was already detected in cyclic voltammetric studies (Figure 1 inset). This voltammetric peak is probably attributed to an oxidation process of 2-aminothiazole since it is absent at SPCPE.…”

Section: Preliminary Studiesmentioning

confidence: 98%

Fast and simultaneous determination of Pb2+ and Cu2+ in water samples using a solid paraffin-based carbon paste electrode chemically modified with 2-aminothiazole-silica-gel

Silva¹,

Costa²,

Takeuchi³

et al. 2011

J. Braz. Chem. Soc.

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Um eletrodo de pasta de carbono preparado com parafina sólida como aglutinante e quimicamente modificado com sílica funcionalizada com grupos 2-aminotiazol foi empregado na quantificação simultânea de Pb 2+ e Cu 2+ em amostras de água por meio de voltametria de redissolução anódica. O presente método emprega um tempo curto de pré-concentração (180 s), o qual permitiu a quantificação simultânea e confiável de Pb 2+ e Cu 2+ de maneira bastante rápida. Foram obtidos limites de detecção de 7,3 e 90 nmol L −1 para Pb 2+ e Cu 2+ , respectivamente. Estes valores estão abaixo das concentrações máximas permitidas destes metais em água potável segundo a legislação brasileira, indicando que o método proposto é aplicável para o monitoramento de Pb 2+ e Cu 2+ em amostras de água. Estudos de recuperação foram realizados em quatro amostras de água enriquecidas, sendo obtidas porcentagens de recuperação próximas a 100% para todas as amostras analisadas, demonstrando a boa acuracidade do método proposto.A solid paraffin-based carbon paste electrode modified with 2-aminothiazole functionalized silica-gel was used for simultaneous quantification of Pb 2+ and Cu 2+ in water samples by anodic stripping voltammetry. The present method uses short preconcentration time (180 s), which allowed reliable and simultaneous quantification of Pb 2+ and Cu 2+ in a very fast way. Detection limits of 7.3 and 90 nmol L −1 were obtained for Pb 2+ and Cu 2+ , respectively. These values are below their maximum concentrations allowed in drinking water by Brazilian legislation, indicating that the proposed method is useful to monitoring Pb 2+ and Cu 2+ in water samples. Recovery studies were performed in four spiked water samples and the results shown recovery percentages close to 100% for all analyzed samples, demonstrating the good accuracy of the proposed method.Keywords: anodic stripping voltammetry, carbon paste electrode, 2-aminothiazolefunctionalized silica gel, lead and copper determination, water samples IntroductionEnvironmental contamination by heavy metals is a growing concern because they are very toxic, bioaccumulative and totally non-degradable. Therefore, environmental monitoring of heavy metals is of great importance for many reasons, such as identification of pollutant sources, understanding pollutant dissemination, anticipation of remediation procedures, etc. Copper and lead are two very important metallic pollutants because they are toxic and abundant. Contamination of natural waters by anthropogenic activities is one of the main ways to introduce heavy metals in the environment. Therefore, quantification of metallic ions in water samples is very important in order to preserve safe water resources for world population. In all regions around the world, legislative instruments are very restrictive regarding copper and lead contents in water for human consumption. In Brazil, for example, limits for Pb 2+ and Cu 2+ in drinking water are 0.01 mg L −1 (48 nmol L −1 ) and 2 mg L −1 (31 μmol L −1 ) , respectively. 1 Graphite furnace ato...

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Switchable Polyacrylonitrile‐Copolymer for Melt‐Processing and Thermal Carbonization—3D Printing of Carbon Supercapacitor Electrodes with High Capacitance

2022

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allowing fast charge-discharge kinetics, long cycling stability, and high capacitance. [1][2][3][4] Typically, such carbon electrodes are produced from active carbon powders. [5] The required structural integrity of the electrode can only be achieved by mixing the active carbon powder with binders; however, these binders are often electrochemically inert and decrease the overall performance of the electrodes by blocking the surface and porosity of the active material. To produce electrodes without binder, carbon fiber non-wovens present ideal materials for components in fuel cells, batteries, and supercapacitors. [5][6][7][8][9][10][11] The most widely used precursor for carbon fibers and materials is polyacrylonitrile (PAN). [12] PAN can be converted into carbon materials in a two-step thermal conversion process. The first step is called stabilization, in which the nitrile groups engage in mostly intramolecular cyclization reactions, forming polymer ribbons. Stabilization is conducted in an oxidative atmosphere between 200 and 300 °C. [13][14][15] Strong dipolar interactions between the nitrile groups entail a high melting temperature T m , well above the activation energy for the cyclization reaction-or stabilization. The second step is the carbonization, in which the polymer ribbons fuse to graphitic domains. Carbonization is conducted in an inert atmosphere above 1000 °C. [13,16,17] Because of its sensitivity towards high temperatures-with potential for thermal run-away, due to the exothermic nature of the stabilization reaction-PAN is typically processed from solution.However, solution processing limits the final architectures of the desired carbon materials to fibers and films. [18][19][20] Fiber spinning and film formation processes are energy consuming and costly, as they require large amounts of solvents, which on an industrial scale have to be recovered and eventually disposed of. [21][22][23][24] A much more economic manufacturing approach would be to process PAN from its melt. [17,25,26] This strategy would enable 3D printing techniques such as polymer extrusion-based additive manufacturing (EAM) with full freedom-ofdesign, expanding the possible shapes of carbon materials from 1D fibers and 2D films to monolithic 3D workpieces. To our advantage, EAM would allow fully automated shaping of PAN into complex structures. EAM is scalable, fast, solvent-free, and Polyacrylonitrile (PAN) represents the most widely used precursor for carbon fibers and carbon materials. Carbon materials stand out with their high mechanical performance, but they also show excellent electrical conductivity and high surface area. These properties render carbon materials suitable as electrode material for fuel cells, batteries, and supercapacitors. However, PAN has to be processed from solution before being thermally converted to carbon, limiting its final format to fibers, films, and non-wovens. Here, a PAN-copolymer with an intrinsic plasticizer is presented to reduce the melting temperature and avoid undesired entering of the t...

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Scanning electrochemical microscopy: study of the deposition and stripping mechanism of lead in the presence of copper

Cited by 9 publications

References 24 publications

Demetallization of Sewage Sludge Using Low-Cost Ionic Liquids

Demetallization of Sewage Sludge Using Low-Cost Ionic Liquids

Fast and simultaneous determination of Pb2+ and Cu2+ in water samples using a solid paraffin-based carbon paste electrode chemically modified with 2-aminothiazole-silica-gel

Switchable Polyacrylonitrile‐Copolymer for Melt‐Processing and Thermal Carbonization—3D Printing of Carbon Supercapacitor Electrodes with High Capacitance

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