Semiconducting Polymer Interfaces for Electrochemically Assisted Mercury Remediation

Candeago, Riccardo; Kim, Kwiyong; Vapnik, Haley; Cotty, Stephen; Aubin, Megan; Berensmeier, Sonja; Kushima, Akihiro; Su, Xiao

doi:10.1021/acsami.0c15570

Cited by 22 publications

(16 citation statements)

References 57 publications

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“…It is worth noting that redox-promoted anodic stripping on polymer interfaces can enhance the regeneration efficiency. For example, the anodic stripping by redox-mediated oxidation has been shown to regenerate mercury-deposited polymer electrode (poly(3-hexylthiophene-2,5-diyl)-CNT [carbon nanotube] coated on titanium) with high reversibility (regeneration efficiency >85%) and fast regeneration kinetics (2.08 × 10 −2 s −1 for P3HT-CNT/titanium, compared with 1.70 × 10 −3 s −1 for bare titanium) for reversible mercury capture and release ( Candeago et al., 2020 ), and similar approaches could be employed for other critical metals too.…”

Section: Electrochemical Separations For Selective Recoverymentioning

confidence: 99%

Electrochemical approaches for selective recovery of critical elements in hydrometallurgical processes of complex feedstocks

Kim¹,

Candeago²,

Rim³

et al. 2021

iScience

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Summary Critical minerals are essential for the ever-increasing urban and industrial activities in modern society. The shift to cost-efficient and ecofriendly urban mining can be an avenue to replace the traditional linear flow of virgin-mined materials. Electrochemical separation technologies provide a sustainable approach to metal recovery, through possible integration with renewable energy, the minimization of external chemical input, as well as reducing secondary pollution. In this review, recent advances in electrochemically mediated technologies for metal recovery are discussed, with a focus on rare earth elements and other key critical materials for the modern circular economy. Given the extreme heterogeneity of hydrometallurgically-derived media of complex feedstocks, we focus on the nature of molecular selectivity in various electrochemically assisted recovery techniques. Finally, we provide a perspective on the challenges and opportunities for process intensification in critical materials recycling, especially through combining electrochemical and hydrometallurgical separation steps.

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Section: Electrochemical Separations For Selective Recoverymentioning

confidence: 99%

Electrochemical approaches for selective recovery of critical elements in hydrometallurgical processes of complex feedstocks

Kim¹,

Candeago²,

Rim³

et al. 2021

iScience

Self Cite

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“…Enhancing SeDER removal performance will require that agricultural drainage is concentrated by at least 1 order of magnitude (e.g., through capacitive deionization and electrosorption), while cell design will need to significantly enhance the mass transfer rate of Se oxyanions. Better electrode and cell designs (e.g., functionalized electrode interfaces) could also be coupled with a localized heating strategy to sustain an elevated cathode surface temperature for energy-efficient Se removal …”

Section: Resultsmentioning

confidence: 99%

Competing Ion Behavior in Direct Electrochemical Selenite Reduction

Zou

Mauter

2021

ACS EST Eng.

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Anthropogenic selenium (Se) released in industrial and agricultural wastewaters presents toxicity challenges for local ecosystems. Se direct electrochemical reduction (SeDER) is an effective and thermodynamically favorable approach for Se(IV) removal, but evaluating the feasibility of SeDER in application requires a comprehensive understanding of system performance in complex water matrices. This study evaluates both the cathodic and anodic competing ion behavior in a SeDER process, including both four-and six-electron Se(IV) reduction pathways. The results suggest that sulfate promotes electrochemical Se(IV) removal efficiency by 11−23%, but nitrate hinders Se(IV) removal (2−11% decrease) by occupying cathodic reaction sites. The anodic competing ions, especially chloride, decrease SeDER performance by generating strong oxidants and disrupting Se(IV) reduction pathways. We also find that four-electron Se(IV) reduction outperforms its six-electron counterpart when treating simulated fluegas desulfurization wastewater (with 7 g L −1 Cl − ), with a lowest effluent Se level of 0.23 mg L −1 , a highest removal efficiency of 96.9%, and a threshold deposition capacity of 3.5 g m −2 in a 7-day semicontinuous operation. Electrochemical Se(IV) removal using our prototype batch reactor is not competitive for treating low-Se concentration agricultural wastewaters (up to 24% removal). The results suggest the need for future work to evaluate alternative electrodes and reactor design that reduce water splitting reactions, enhance Faradaic efficiency, and promote mass transfer to the electrode surface.

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“…45 For example, ILs have been reported to alter solvation of metal ions, influencing electrochemical deposition processes, 46−48 and polymeric additives have been found to act as moderators for metal deposition, as they are adsorbed on electrode surfaces. 49,50 Recent studies have also reported on surface functionalization of interfaces using conducting polymers to mediate electrochemical reactions of interest in other environmental applications, including water purification 51 and advanced electrochemical separations. 52 Thus, this study is focused on understanding the role of electrolytes based on NOHMs with an ionically tethered polyetheramine canopy (HPE) (NOHM-I-HPE) in the electrodeposition of Zn, with the objective of discerning any potential near-electrode surface effects of NOHMs.…”

Section: T H Imentioning

confidence: 99%

“…Although the study using Cu(II) demonstrated potential opportunities for NOHMs as electrolyte additives, little is still known about the near-electrode surface behavior of NOHMs in electrolyte solutions and their effect on the electrodeposition of metal ions of interest (e.g., zinc (Zn)) in various electrochemical systems. − Other complex electrolytes containing additives such as ILs and polymers have been found to have a nonideal behavior on electrode surfaces and impact metal deposition . For example, ILs have been reported to alter solvation of metal ions, influencing electrochemical deposition processes, − and polymeric additives have been found to act as moderators for metal deposition, as they are adsorbed on electrode surfaces. , Recent studies have also reported on surface functionalization of interfaces using conducting polymers to mediate electrochemical reactions of interest in other environmental applications, including water purification and advanced electrochemical separations …”

Section: Introductionmentioning

confidence: 99%

Mechanistic Study of Controlled Zinc Electrodeposition Behaviors Facilitated by Nanoscale Electrolyte Additives at the Electrode Interface

Hamilton

Feric

Gładysiak

et al. 2022

ACS Appl. Mater. Interfaces

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Nanoparticle organic hybrid materials (NOHMs) are liquid-like materials composed of an inorganic core to which a polymeric canopy is ionically tethered. NOHMs have unique properties including negligible vapor pressure, high oxidative thermal stability, and the ability to bind to reactive species of interest due to the tunability of their polymeric canopy. This makes them promising multifunctional materials for a wide range of energy and environmental technologies, including electrolyte additives for electrochemical energy storage (e.g., flow batteries) and the electrochemical conversion of CO2 to chemicals and fuels. Due to their unique transport behaviors in fluid systems, an understanding of the near-electrode surface behavior of NOHMs in electrolyte solutions and their effect on electrochemical reactions is still lacking. In this work, the complexation of zinc (Zn) by NOHMs with an ionically tethered polyetheramine canopy (HPE) (NOHM-I-HPE) was studied using attenuated total reflectance Fourier transform infrared and Carbon-13 nuclear magnetic resonance spectroscopy. Additionally, various electrochemical techniques were employed to discern the role of NOHM-I-HPE during zinc electrodeposition, and the results were compared to those of the electrochemical system containing untethered HPE polymers. Our findings confirmed that NOHM-I-HPE and HPE reversibly complex zinc in the aqueous electrolyte. NOHM-I-HPE and HPE were found to block some of the electrode active sites, reducing the overall current density during electrodeposition, while facilitating the formation of smooth zinc deposits, as revealed by surface imaging and diffraction techniques. Observed variations in the current density responses and the degree of passivation created by the NOHM-I-HPE and HPE adsorbed on the electrode surface revealed that their different packing behaviors at the electrode–electrolyte interface influence the zinc deposition mechanism. The presence of the nanoparticle and ordering offered by the NOHMs as well as the structured conformation of the polymeric canopy allowed the formation of void spaces and free volumes for enhanced transport behaviors. These findings provided insights into how structured electrolyte additives such as NOHMs can allow for advancements in electrolyte design for controlled deposition of metal species from energy-dense electrolytes or for other electrochemical reactions.

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Semiconducting Polymer Interfaces for Electrochemically Assisted Mercury Remediation

Cited by 22 publications

References 57 publications

Electrochemical approaches for selective recovery of critical elements in hydrometallurgical processes of complex feedstocks

Electrochemical approaches for selective recovery of critical elements in hydrometallurgical processes of complex feedstocks

Competing Ion Behavior in Direct Electrochemical Selenite Reduction

Mechanistic Study of Controlled Zinc Electrodeposition Behaviors Facilitated by Nanoscale Electrolyte Additives at the Electrode Interface

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