In situ electrochemical dissolution of platinum and gold in organic-based solvent

Jovanovič, Primož; Šelih, Vid Simon; Šala, Martin; Hodnik, Nejc

doi:10.1038/s41529-018-0031-8

Cited by 12 publications

(9 citation statements)

References 38 publications

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“…More insights into electrochemical behavior is provided by combining the cyclovoltammetry and online dissolution profiles of Au. This is achieved by combining the so-called electrochemical flow cell with inductively coupled plasma mass spectrometry analytics (EFC-ICP-MS) [30,31,41,42]. This approach is especially appropriate to study such corrosion phenomena as it allows one to synchronize dissolution and current signal with the potential ramp (Figure 2d).…”

Section: Dissolution Of Polycrystalline Au Disk In the Absence Of Chlmentioning

confidence: 99%

Effect of Particle Size on the Corrosion Behaviour of Gold in the Presence of Chloride Impurities: An EFC-ICP-MS Potentiodynamic Study

et al. 2018

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A profound understanding of the Au dissolution process is a prerequisite for optimal utilization of Au-based materials. This goes for either increasing the corrosion stability of materials in the sectors where the long-term functionality of Au is needed or decreasing the corrosion stability where the recovery of the Au component is crucial. By employing an extremely sensitive online analytical system, consisting of an electrochemical flow cell coupled to an inductively coupled plasma mass spectrometry, in situ potential-resolved dissolution of Au in the ppb range is enabled. A comparative study of two Au based materials, (i) a polycrystalline Au disk and (ii) carbon-supported Au nanoparticles, is presented. As a probe, chloride ions were used to elucidate the distinct differences in the corrosion behavior of the two analogues.

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Section: Dissolution Of Polycrystalline Au Disk In the Absence Of Chlmentioning

confidence: 99%

Effect of Particle Size on the Corrosion Behaviour of Gold in the Presence of Chloride Impurities: An EFC-ICP-MS Potentiodynamic Study

et al. 2018

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“…This process forms, through heap leaching, solutions of the water-soluble Au(CN) 2 – complex, which is recovered from the solution by precipitation, adsorption, and reduction . The environmental and safety concerns over cyanidation have led to recent studies on alternative leaching and separation methods, including the use of various combinations of oxidizing agents and organic solvents, − oxidative mechanochemistry, electrochemical dissolution, and metal–organic framework (MOF)–polymer composites. − These methods often result in the dissolution of gold through the formation of the halometalate AuX 4 – . Selective recovery of gold from aqueous solution has been achieved by coprecipitation of AuBr 4 – with α-cyclodextrin as {[K(OH 2 ) 6 ][AuBr 4 ](α-cyclodextrin) 2 } n , forming chains of these components through supramolecular hydrogen bonding and electrostatic interactions, creating an insoluble crystalline material that can be separated from the bulk material by simple filtration .…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Simple Amides in the Selective Recovery of Gold from Secondary Sources by Solvent Extraction

Doidge

Kinsman²,

et al. 2019

ACS Sustainable Chem. Eng.

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The recycling of metals from end-of-life secondary sources such as electronic waste remains a significant environmental and technological challenge currently detrimental to the development of circular economies. The complex nature of electronic waste, containing a myriad of different elemental metals, means that sophisticated yet simple separation methods need to be developed in order to recycle these valuable and often critical metal resources. In this work simple 2 primary, secondary, and tertiary amides are appraised as reagents that selectively transport gold from aqueous to organic phases in a solvent extraction experiment. While the strength of extraction of gold from single metal solutions is ordered 3 o >2 o >1 o , the 3 o and 2 o amides are ineffective at gold transport from mixed-metal solutions of concentrations representative of smartphones due to the formation of a third, dense phase. Increasing the polarity of the organic phase can negate third phase formation but at the expense of selectivity. The identities of the species that reside in the organic and third phases have been studied by a combination of slope analysis, mass spectrometry, NMR spectroscopy, and computational methods. These techniques show that protonation of the amide L occurs at the oxygen atom, resulting in the protonated dimer HL2 + which acts as a receptor for AuCl4 − to form dynamic supramolecular aggregates in the organic phase. The characterization of a tin complex in the third phase by X-ray crystallography supports these conclusions and furthermore, suggests the preference for the chelation of the proton by two amide molecules instead of the transport of hydronium into the organic phase and its subsequent use as structural template.

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“…Aluminum and stainless steel as well as metals which are generally considered inert and chemically stable, such as platinum, platinum alloys, and gold, support electrochemical reactions resulting in a change in the chemical composition of the electrolyte. [25][26][27][28] A particularly interesting material that has yet to be investigated in the context of electropermeabilization, is the conducting polymer PEDOT:PSS (poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate). PEDOT:PSS has emerged as a popular material for biomedical devices due to its electrochemical properties, ease of processing, and commercial availability.…”

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confidence: 99%

PEDOT:PSS‐Coated Stimulation Electrodes Attenuate Irreversible Electrochemical Events and Reduce Cell Electropermeabilization

Dijk

Ruigrok

O’Connor

2021

Adv Materials Inter

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Despite decades of investigation and successful applications, the underlying mechanisms that cause the increased permeability of the cell membrane are not fully understood. The formation of aqueous pores in the cell membrane throughout application of the pulse is widely acknowledged, however, molecular dynamic simulations [10,11] do not support the long-lasting permeabilization that is found in experiments. [12,13] Chemical changes to the lipid bilayer and embedded proteins have been hypothesized as an additional mechanism that could explain such difference in timescales. [14] For example, oxidative stress caused by reactive oxygen species (ROS) can initiate chemical reactions such as peroxidation of the membrane lipids which affect the cell membrane integrity. [15] Indeed, generation of ROS and lipid peroxidation have been shown to correlate with the intensity, duration, and number of pulses and increased generation of ROS is associated with higher electroporation efficiencies. [16][17][18][19][20] Electrically induced generation of ROS occurs within cells as well as at the electrode site. [17] At sufficiently high voltages, metallic electrodes induce Faradaic currents that are established by electrochemical reactions at the electrodeelectrolyte interface. Besides ROS, such irreversible Faradic processes might result in pH changing species, formation of gas, chloride oxidation products, and electrode dissolution. [21][22][23][24] The nature and produced species of these reactions strongly depend on the electrode material. Aluminum and stainless steel as well as metals which are generally considered inert and chemically stable, such as platinum, platinum alloys, and gold, support electrochemical reactions resulting in a change in the chemical composition of the electrolyte. [25][26][27][28] A particularly interesting material that has yet to be investigated in the context of electropermeabilization, is the conducting polymer PEDOT:PSS (poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate). PEDOT:PSS has emerged as a popular material for biomedical devices due to its electrochemical properties, ease of processing, and commercial availability. [29][30][31] PEDOT:PSS-coated electrodes exhibit a large charge injection capacity due to the mixed ionic-electronic conduction which benefits neurostimulation applications. [32] Despite its proven record for biomedical applications, the electrochemistry Electroporation or electropermeabilization occurs when cells are exposed to sufficiently high-pulsed electric fields. This phenomenon is now an important technique to facilitate the transmembrane transport of molecules, however, the role of the electrode material and associated electrochemical events remain unclear. Here, it is shown that electrical stimulation with PEDOT:PSScoated electrodes strongly reduces irreversible electrochemical reactions that otherwise lead to changes in pH and the generation of reactive oxygen species. Coated electrodes exhibit a slightly higher threshold for cell stimulation, however,...

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In situ electrochemical dissolution of platinum and gold in organic-based solvent

Cited by 12 publications

References 38 publications

Effect of Particle Size on the Corrosion Behaviour of Gold in the Presence of Chloride Impurities: An EFC-ICP-MS Potentiodynamic Study

Effect of Particle Size on the Corrosion Behaviour of Gold in the Presence of Chloride Impurities: An EFC-ICP-MS Potentiodynamic Study

Evaluation of Simple Amides in the Selective Recovery of Gold from Secondary Sources by Solvent Extraction

PEDOT:PSS‐Coated Stimulation Electrodes Attenuate Irreversible Electrochemical Events and Reduce Cell Electropermeabilization

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