Implementation of concurrent electrolytic generation of two homogeneous mediators under widened potential conditions to facilitate removal of air-pollutants

Abstract

Electro-scrubbing is being developed as a futuristic technology for the removal of air-pollutants. To date, only one homogeneous mediator for the removal of air pollutants has been generated in each experiment using a divided electrolytic flow cell in an acidic medium. This paper reports the concurrent generation of two homogenous mediators, one at the anodic half-cell containing an acidic solution and the other at the cathodic half-cell containing a basic solution. The concept was inspired by the change in pH that occurs during water electrolysis in a divided cell. A 10 M KOH electrolyte medium assisted in the electrochemical generation of low valent 14% Co¹⁺ ([Co^I(CN)₅]^4-) mediator formed from reduction of [Co^II(CN)₅]^3- which was accompanied by a change in the solution 'oxidation reduction potential' (ORP) of -1.05 V Simultaneously, 41% of Co³⁺ was generated from oxidation of Co^IISO₄ in the anodic half-cell. No change in the solution ORP was observed at the cathodic half-cell when both half-cells contain 5 M H₂SO₄, and Co³⁺ was formed in the anodic half-cell. An electro-scrubbing approach based on the above principles was developed and tested on gaseous-pollutants, CH₃CHO and CCl₄, by Co³⁺ and Co¹⁺, respectively, with 90 and 96% removal achieved, respectively.