Sustainable Generation of a Homogeneous Ni(I) Catalyst in the Cathodic Compartment of a Divided Flow Electrolytic Cell for the Degradation of Gaseous Carbon Tetrachloride by Electroscrubbing

Muthuraman, G.; Moon, Ilkyeong

doi:10.1021/acssuschemeng.5b01383

Cited by 26 publications

(17 citation statements)

References 47 publications

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“…Through the combination of paired electrolysis and wet scrubbing (electroscrubbing), many gas pollutants, such as benzene [30] and odorous gases [31] have been removed using electrogenerated oxidative mediators by MEO (mediated electrochemical oxidation). In addition, homogeneous [Ni(I)(CN)4] 3was generated electrochemically on a Cu metal electrode at cathodic half-cell by constant current electrolysis for the first time and used to remove gaseous CCl4 by MER (mediated electrochemical reduction) at electroscrubbing [32]. In a very recent study on carbon tetrafluoride (CF4) degradation, electrochemical production of mediator Cu 1+ facilitated a regenerative chemical reaction at room temperature, resulting in product transformation to trifluoroethane and ethanol without HF using Cu 1+ [Ni 2+ (CN)4] 1- [33].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

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Sustainable removal of N2O by mediated electrocatalytic reduction at ambient temperature electro-scrubbing using electrogenerated Ni(I) electron mediator

Muthuraman

Ramu

McAdam

et al. 2019

Journal of Hazardous Materials

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Section: Accepted Manuscriptmentioning

confidence: 99%

“…Because of solubility restriction in aqueous medium, many nickel complexes used as modified electrode or dissolved in non-aqueous medium [39][40][41][42]. In reverse, [Ni(II)(CN)4] 2is quite soluble in alkaline media [32] and yields a reduction potential of -900 mV(vs Ag/AgCl)…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Sustainable removal of N2O by mediated electrocatalytic reduction at ambient temperature electro-scrubbing using electrogenerated Ni(I) electron mediator

Muthuraman

Ramu

McAdam

et al. 2019

Journal of Hazardous Materials

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“…2A curve a) indicating the low oxidation state of Ni(II), in this case Ni(I) formation. 34 Ni(I) formation as a measure of the reduction efficiency, which was determined as mentioned in the Experimental section, increased with increasing electrolysis time to 9% (4.3 mM) for a 120 min duration ( Fig. 2A curve b).…”

Section: Resultsmentioning

confidence: 95%

“…Once the NO gas was introduced into the electrogenerated Ni(I)/Ni(II)-containing solution, the reduction efficiency of Ni(II) decreased to 1.83 mM (3%) and was varied slightly as long as NO was purged into the solution, which indicates that a reaction between Ni(I) and NO occurred, called mediated reduction. The Ni(II) reduction efficiency increased reached approximately 7% (3.4 mM) once the NO was stopped, showing that the process is sustainable, 34 and Ni(I) can be generated without additional chemicals. As reported in the literature, NO is relatively insoluble in water, 14 but if scrubbed through a 9 M KOH solution, 100 ppm of the feed NO absorbed nearly 10 ppm in 15 min (Fig.…”

Section: Resultsmentioning

confidence: 97%

Synergistic Effect of Mediated Electrochemical Reduction and Mediated Electrochemical Oxidation on NO Removal by Electro-Scrubbing

Muthuraman

Ramu

Ahn

et al. 2016

J. Electrochem. Soc.

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A combined MER (mediated electrochemical reduction) and MEO (mediated electrochemical oxidation) approach was examined for the first time for the efficient removal of NO by electro-scrubbing. The generation of a mediator (Ni(I) from Ni(II)(CN) 4 2− in 9 M KOH) by electrochemical reduction was identified by the changes in the ORP value and potentiometric titration. The Ni(I) formation found to be 9% (4.3 mM) in 2 h electrolysis, which is decreased to 1.83 mM (4%) during addition of NO demonstrates NO removal occurred. The MER of NO at the cathodic half-cell by electro-scrubbing revealed the formation of NH 3 and N 2 . The reductive removal efficiency of NO was almost 100% up to a gas flow rate of 0.25 g min −1 . At the anodic half-cell, the Co(III) mediator from Co(II)SO 4 in 5 M H 2 SO 4 was generated electrochemically with concomitant conversion of NO to NO 3 − in the solution phase with a removal efficiency of 28%. The combination of MEO and MER with electro-scrubbing demonstrates 97% removal efficiency of NO up to 0.5 g min −1 . The combined removal approach is more suitable for high concentrated NO with energy efficiency of 0. Abundantly generated nitric oxide (NO) gas that includes power plant and steel plant etc., is decomposed by many technologies, such as wet scrubbing, catalytic oxidation, and selective catalytic reduction (SCR).1-3 The reduction of NO leads a combination of cationic intermediates and products, N 2 O, NH 2 OH, N 2 , and NH 3 , in the solution phase. [4][5][6] The reduction products varied depending on the catalyst and experimental conditions: on TiO 2 in the colloid solutions to produce NH 3 ; 4 in heterogeneous catalytic reduction process with NH 3 as the reactant produced N 2 ; 7,8 and N 2 O formed on boron-doped graphene method.9 At the same time, the oxidation of NO leads to the anionic products of NO 2 and NO 3 − . 10,11 Heterogeneous catalytic oxidation at the gas phase produced NO 2 , 12 but solution phase oxidation by ozone and H 2 O 2 produced the NO 3 − product. 1,13 Because of the catalytic reaction, NO is solubilized in an aqueous solution, otherwise it less soluble or insoluble in an aqueous solution.14 Using this approach, many oxidant-15,16 and reductant-17 containing wet-scrubbing processes have been adopted in NO removal. Note that the above methods require a continuous catalyst or reactant feed to make the process sustainable.An electron considered to be a green catalyst and can be feed continuously to regenerate the spent catalyst sustainably. Using this approach, electrogenerated Ce(IV) and Mn(III) mediators have been used to oxidize NOx to NO 3 − in HNO 3 medium. 18,19 In a similar method, electrogenerated Ag(II) with a wet scrubber in the name of 'electro-scrubbing' have used NOx oxidation to NO 2 in a single stage scrubber and NO 3 − in a two stage scrubber column. 20 In the presence of SO 2 in NO oxidation using the electrogenerated Ag(II) mediator in highly concentrated nitric acid have shown NO 2 with 60 to 80% of NO 3 − formation. [21][22][23] Note that unless...

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“…To the best of our searching efforts, we found no published article addressing the production of two different mediators effectively in the same divided electrolytic cell in a real flow-cell operation for application toward pollutant abatement. Further, it is surprising that there has been no published report on the mediated electroreduction (MER)-based pollutant treatment in an external reactor column integrated with the cathodic compartment of a direct electrolytic cell for the regeneration of a reductant mediator, and, in a first report on this aspect, we recently studied MER of gaseous CCl 4 using a Ni + mediator 30 and MER of gaseous trichloroethylene by Co + species. 31…”

Section: Introductionmentioning

confidence: 99%

Studies on Effective Generation of Mediators Simultaneously at Both Half-Cells for VOC Degradation by Mediated Electroreduction and Mediated Electrooxidation

et al. 2017

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Of the several electrochemical methods for pollutant degradation, the mediated electrooxidation (MEO) process is widely used. However, the MEO process utilizes only one (anodic) compartment toward pollutant degradation. To effectively utilize the full electrochemical cell, an improved electrolytic cell producing both oxidant and reductant mediators at their respective half-cells, which can be employed for treating two pollutants simultaneously, was investigated. The cathodic half-cell was studied first toward maximum [Co I (CN) 5 ] 4– (Co + ) generation (21%) from a [Co II (CN) 6 ] 3– precursor by optimizing several experimental factors such as the electrolyte, cathode material, and orientation of the Nafion324 membrane. The anodic half-cell was optimized similarly for higher Co 3 (SO 4 ) 2 (Co 3+ ) yields (41%) from a Co II SO 4 precursor. The practical utility of the newly developed full cell setup, combining the optimized cathodic half-cell and optimized anodic half-cell, was demonstrated by electroscrubbing experiments with simultaneous dichloromethane removal by Co + via the mediated electroreduction process and phenol removal by Co 3+ via the MEO process, showing not only utilization of the full electrochemical cell, but also degradation of two different pollutants by the same applied current that was used in the conventional cell to remove only one pollutant.

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Sustainable Generation of a Homogeneous Ni(I) Catalyst in the Cathodic Compartment of a Divided Flow Electrolytic Cell for the Degradation of Gaseous Carbon Tetrachloride by Electroscrubbing

Cited by 26 publications

References 47 publications

Sustainable removal of N2O by mediated electrocatalytic reduction at ambient temperature electro-scrubbing using electrogenerated Ni(I) electron mediator

Sustainable removal of N2O by mediated electrocatalytic reduction at ambient temperature electro-scrubbing using electrogenerated Ni(I) electron mediator

Synergistic Effect of Mediated Electrochemical Reduction and Mediated Electrochemical Oxidation on NO Removal by Electro-Scrubbing

Studies on Effective Generation of Mediators Simultaneously at Both Half-Cells for VOC Degradation by Mediated Electroreduction and Mediated Electrooxidation

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