Electrochemically generated homogeneous Cu[Ni(CN)4](3-) towards gaseous CF4 removal using electro-scrubbing

( G. Muthuraman ),( A. G. Ramu ),문일식 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0

Growing semiconducting industries leaves similar amount of CF4 to the environment that are dangerous to the healthy environment and humans. Among few ways to remove CF4, electrochemical way of its removal become simple and futuristic technology. Metal complexes are more suitable to use as a mediator in the MER process due to stabilize the active low valent state of metal ion. The present investigation focuses on removal of gaseous CF4 using electrogenerated Cu(I)[Ni(II)(CN)4](2-) in KOH medium. At a first step, electrochemical reduction of Cu(II)[Ni(CN)4](2-) was optimized at different electrodes like TiO2, Ag, carbon. The reduction efficiencies changes calculated using titration with KMnO4. Cyclic voltammetry analysis at said electrodes correlated with the reduction of Ni(II)(CN)4(2-). Finally, CF4 removal was carried out under optimized conditions using electro-scrubbing with online FTIR gas analyzer and removal efficiency found 99%.

Development of tubular reactor and zeolite separator for effective generation of Co(3+)

( G. Muthuraman ),( A. G. Ramu ),문일식 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0

For minimization of working electrochemical cell area, cylindrical cell development is inevitable. Successful operation of divided cylindrical cell possible only by developing tubular stable separator, which will keep the anodic and cathodic compartments separated from each other for bringing out required anodic and cathodic reactions. Here zeolite coated ceramic tubular membrane was attempted in newly developed tubular cell assembly for its initial optimization through Co(2+) oxidation. First, firm attachment of cylindrical membrane was confirmed by migration of Co(2+) ions that was analyzed by UV-visible spectroscopy. Then, electrolysis was carried out in presence of Co(2+) ions at anodic part in H2SO4 medium. The oxidation efficiency of Co(2+) calculated by potentiometric titration and compared with the results of plate and frame type cell divided by Nafion membrane at 30 ºC.

Two electron mediators generation concurrently at MFI-type zeolite membrane divided tubular cell: An electrolysis study

( G. Muthuraman ),( A. G. Ramu ),문일식 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

The robustness and high volumetric conversion performance of tubular electrochemical reactor was disclosed to generate a single mediator in our recent publiation. In the present investigation, two homogeneous mediators Co(III) and [Ni(I)(CN)₄]^3- have been generated using a tubular MFI-type zeolite coated membrane divided electrochemical cell via paired electrolysis. The electro-generation of Co(III) and [Ni(I)(CN)₄]^3- were achieved in highly acid and highly base pHs respectively. The achieved Co(III) and [Ni(I)(CN)₄]^3- concentrations by the MFI-type membrane containing tubular cell was 57% and 15%, which are equal to the commonly used Nafion324 membrane in planar arrangement. At the same time no migration of Co(II) or [Ni(II)(CN)₄]^2- were observed and additional results will be discussed finally.

Sustainable degradation of carbon tetrafluoride to non-corrosive useful products by incorporating reduced electron mediator within electro-scrubbing

Muthuraman, G.,Ramu, A.G.,Cho, Y.H.,McAdam, E.J.,Moon, I.S. Elsevier 2018 Journal of industrial and engineering chemistry Vol.63 No.-

<P><B>Abstract</B></P> <P>The degradation of CF<SUB>4</SUB> gas using existing technologies produces other types of greenhouse gas (CO<SUB>2</SUB>) and corrosive side products. The main aim of this study is to degrade CF<SUB>4</SUB> gas at room temperature into useful products without producing corrosive side products by mediated electrochemical reduction (MER) process using an electrogenerated Cu<SUP>1+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>]<SUP>1−</SUP> mediator. Initial studies on the electrolytic reduction of the hetero-bimetallic complex in catholyte solution at anodized Ti cathode was monitored by oxidation/reduction potential (ORP) variation whether the Cu<SUP>2+</SUP> or Ni<SUP>2+</SUP> was reduced in the Cu<SUP>2+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>] and confirmed by electron spin resonance (ESR) spectroscopy the Cu<SUP>1+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>]<SUP>1−</SUP> formation. The concentration variation of Cu<SUP>1+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>]<SUP>1−</SUP> during CF<SUB>4</SUB> injection demonstrated the degradation of CF<SUB>4</SUB> followed the MER by electrogenerated Cu<SUP>1+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>]<SUP>1−</SUP>. Maximum removal efficiency of CF<SUB>4</SUB> using electroscrubbing process was 96% at room temperature. Through the variation in gas phase parameters, the gas phase mass transfer coefficient was calculated that can facilitate scale up the developed process. Fourier transform infrared spectroscopy analysis in both the gas and solution phases showed that CH<SUB>3</SUB>CH<SUB>2</SUB>OH was the main product that formed during the removal of CF<SUB>4</SUB> by electrogenerated Cu<SUP>1+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>]<SUP>1−</SUP> at electroscrubber along with a small amount of CF<SUB>3</SUB>CH<SUB>3</SUB> intermediate. Importantly, this mechanism also avoided formation of the corrosive product HF.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A Cu<SUP>2+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>] complex was established for carbon tetrachloride degradation to non-corrosive useful product. </LI> <LI> ORP and ESR results demonstrated Cu<SUP>1+</SUP> formation at cathodic half-cell during electrolysis. </LI> <LI> Mass transfer analysis identifies rate limiting behavior and routes to optimization. </LI> <LI> Ethanol found to be a main product in the degradation of CF<SUB>4</SUB> my MER at electro-scrubbing </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P> <B>Synopsis:</B> Ethanol generation was established during the degradation of CF<SUB>4</SUB> by mediated electrocatalytic reduction using electrogenerated Cu<SUP>1+</SUP>[Ni<SUP>2+</SUP>(CN)<SUB>4</SUB>]<SUP>1−</SUP> at electro-scrubbing process.</P> <P>[DISPLAY OMISSION]</P>

Electrochemical study of [Ni(II)(CN)₄]^2-complexinthe1-butyl-3-methylimidazolium hexafluorophosphate RTIL

( G. Muthuraman ),( K. Kannan ),문일식 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

The study of metal ions in RTIL is a booming area in electrochemistry field. In particularly sufficient redox behavior of metal ions can act as mediators in the RTIL electrolyte to synthesis the organic compounds in green way. But selection of suitable mediator is a challenging role for the green organic synthesis. Apart from metal ions, many metal complexes such as Ni(Salen), Co(Salen), Ni(byp) have been widely investigated in the RTIL their solubility restricts to use in industrial applications. Cyanide ligand with metalation is a simple and strongest especially highly soluble nature. Based on this idea we have investigated reduction behavior of [Ni(CN)₄]^2- complex in the 1-butyl-3-methylimidazolium hexa fluoro phosphate ([bmim]PF₆) RTIL and the Ni complex were analyzed to derive electrochemical parameters towards industrial applications.

Electrochemical behavior of Co²⁺ in PF^-₆, CF₃SO₃^-, (CF₃SO₂)₂^- and BF^-₄ anion containing RTILs

( G. Muthuraman ),( K. Kannan ),문일식 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

The Room temperature ionic liquids have wide range of scope in the electrochemical and non-electrochemical fields and access to use as green solvent in the synthesis of organic compounds. RTIL`s electrochemical properties are depends on the anion and cation moiety in the system. The electrochemical potential window of imidazolium IL is related to an anions group bounded with cation moiety, where cell potential corresponds to anion moiety like PF<sup>-</sup><sub>6</sub>(4V), CF<sub>3</sub>SO<sub>3</sub><sup>-</sup> (5V), (CF<sub>3</sub>SO<sub>2</sub>)<sup>-</sup><sub>2</sub>(6V) and BF<sup>-</sup><sub>4</sub> (4V). The influence of RTIL`s anion moiety can able control the electrochemical behavior of the dissolved metal. With this idea, we performed the cyclic Voltammogram study on CoCl₂ in 4 different RTIL contained 1-butyl-3-methylimidazolium as cation and all above mentioned species as anions. The electrochemical redox properties of Co²⁺/Co³⁺ were analyzed on different electrodes like Pt, Ti and Graphite.

1P-626 Cyclic voltammetry and capacitance analysis of Co(SO₄)₂ in different cation-containing RTIL towards generation of homogeneous electron mediator

( G. Muthuraman ),( Kannan Karunakaran ),문일식 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

Along with the ionic liquid orientation effect at electrified interface, influence of cations in ionic liquid on the generation of an electron transfer active mediator can have added advantages towards the removal of air pollutants. In this study, [BMIM]NTF₂ and [BMPyr]NTF₂ ionic liquids were used for the oxidation/reduction of Co(II) by CV and impedance analyses. The initial redox behavior of Co(II) in the above two ionic liquids was identified and compared with blank. The [BMPyr]NTF₂ ionic liquid showed stronger adsorption on a Pt electrode than [BMIM]NTF₂. The charge transfer resistance (RCT) during the oxidation of Co(II) was determined to be higher in the [BMPyr]NTF2 ionic liquid. No capacitance variations with the applied potential in a [BMIM]NTF₂ ionic liquid but the [BMPyr]NTF₂ ionic liquid showed a negative charge below -1.0 V and a positive charge beyond -1.0 V.

Electrochemical study on the redox behavior of mediator in 1-Butyl-3methyl imidazolium Trifluoromethane sulfonate Ionic liquid in water mixture

( G. Muthuraman ),( K. Kannan ),문일식 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

Room temperature ionic liquid is said to be a green solvent for the synthesis of organic compounds, most of the reported works were based on the potentiostatic electrolysis in ionic liquid. But galvanostatic electrolysis in RTIL is not easy as aqueous electrolytes because of decomposition of ionic liquid species due to over voltage and addition of organic solvents tends to reduce the cell potential but it has limited to some extent. Based on the idea, we have performed the galvanostatic electrolysis of 1-Butyl-3methyl imidazolium Trifluoromethane sulfonate (BMIMCF₃SO₃) Ionic liquid in presence of water and mediators. Both systems were observed that suppressed the cell potential and 2M BMIMCF₃SO₃ showed the optimum condition for the electrolysis in divided Cell. The redox behavior of mediators in BMIMCF₃SO₃ + H₂O mixture were analyzed by potentiometric titration with aqueous H₂O₂ solution.

Two electron mediators generated at each half-cells facilitated chlorobenzene removal by electroscrubbing

( G. MUTHURAMAN ),( A. G. Ramu ),문일식 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.1

Scalable and simultaneous generation of homogeneous acid Co(III) and base Co(I) electrocatalysts using a divided electrolyzer

Muthuraman, G.,Balaji, S.,Moon, I.-S. THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2018 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.58 No.-

<P><B>Abstract</B></P> <P>A scalable and simultaneous synthesis of Co(III) (Co<SUB>2</SUB>(SO<SUB>4</SUB>)<SUB>3</SUB>) and Co(I) ([Co(I)(CN)<SUB>5</SUB>]<SUP>4−</SUP>) electrocatalysts using a divided electrolyzer is reported for the first time. The overpotential gain of oxygen evolution reaction (OER) by high concentration of an acid and hydrogen evolution reaction (HER) by high concentration of a base was utilized for this new state-of-the art electro-syntheses. Difference in generation rate between acid electrocatalyst Co(III) and base electrocatalyst Co(I) was minimized by controlling the flow of H<SUB>3</SUB>O<SUP>+</SUP> ions from anode to cathode. Also, variation in the nature of cathode materials was found to influence the formation rate of both acid Co(III) and base Co(I) electrocatalysts. We have shown that by selecting a suitable combination of electrode pair and controlling the presence of H<SUB>3</SUB>O<SUP>+</SUP> ions it becomes possible to synthesize 3.5mM of Co(III) and 2.5mM of Co(I) simultaneously in both compartments of a divided electrolytic cell. This achievement on the hitherto unreported development in electrocatalyst synthesis strategy is the first of its kind in divided electrolytic cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Scalable synthesis of two electrocatalysts in a single divided electrolyzer. </LI> <LI> Extended potential window by highly alkaline medium makes more room to generate an electrocatalyst in cathodic half-cell. </LI> <LI> Membrane orientation and suitable cathode material makes higher concentration of two electrocatalysts. </LI> <LI> Scalable electrocatalysts Co(III) — 3.5mM and Co(I) — 2.5mM was achieved under given conditions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>