Real time potentiometric macro flow sensor: An innovative tool to monitor electrogenerated electron mediator in high concentrated electrolyte during electrolysis and air pollutants removal

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>An ex-situ potentiometric titrations were normally performed using an oxidation/reduction potential (ORP) electrode to monitor the electrochemically generated active electron mediators, either oxidants or reductants, in a mediator generation plant. In the present investigation, an attempt was made to monitor electron mediator [Ni<SUP>1+</SUP>(CN)<SUB>4</SUB>]<SUP>3-</SUP> (Ni(I)) in-situ in a high electrolyte concentration (9 M KOH) during its electrochemical generation. A ring type flow cell developed using a 0.6 cm diameter electrode was tested on a standard redox couple of [Fe<SUP>3+</SUP>(CN)<SUB>6</SUB>]<SUP>3-</SUP> (Fe(III))/[Fe<SUP>2+</SUP>(CN)<SUB>6</SUB>]<SUP>4-</SUP> (Fe(II)) at different ratios during solution flow. The found results suggested that direct determination of an electrochemically prepared electron mediator is possible using a potentiometric method. A periodical potential change in the in-situ linear sweep voltammetry of electrogenerated Ni(I) during its electrochemical generation allowed the direct determination of electrogenerated Ni(I) by the ring type flow cell. A calibration plot derived from chemically synthesized Ni(I) using an ex-situ potentiometric titration or UV–visible spectra was used to monitor electrogenerated Ni(I) by the in-situ method. The electrochemically generated Ni(I) concentration detected in the 0–4.5 mmol/L region that followed non-Nernstian behavior. A change in the Ni(I) concentration during N<SUB>2</SUB>O removal at the scrubber column suggesting that air pollutant removal can be monitored using the in-situ flow sensor cell, once how many electron involved in the removal process.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Established a macro flow sensor for in-situ monitoring low valent metal ions during its electrogeneration. </LI> <LI> Periodical limiting peak potential change during electrolysis favors to sense Ni(I). </LI> <LI> A 0–5 mm Ni(I) range derived with a slope of non-Nernstian behavior. </LI> <LI> A defined Ni(I) concentration change when N<SUB>2</SUB>O removal correlates automation is possible by in-situ sensor. </LI> </UL> </P>