Redox activity and accelerating capacity of model redox mediators during biodenitrification

Abstract

The aim of this study was to analyse different model redox mediatiors: anthraquinone-2,7-disulphonate (2,7-AQDS), anthraquinone-1-sulphonate (a-AQS), anthraquinone-2-sulphonate (AQS) and anthraquinone-2,6-disulphonate (AQDS), with regard to the structureÀactivity relationship indicated by their cyclic voltammograms, their chemical structure, their oxidationÀreduction potential and their capacity to accelerate the denitrification reaction during denitrification. Compared to the control, the nitrate removal after 21 h of denitrification was enhanced by a factor of 1.94, 1.56, 1.56 and 1.3 by 2,7-AQDS, AQDS, AQS and a-AQS, respectively. The ranking of the mediators based on their reduction potential (E A p ) was 2,7-AQDS > AQDS AQS > a-AQS. E A p was positively correlated with accelerating the denitrification in experiments using 0.024 mmol¢L ¡1 redox mediator, 360 mg L ¡1 NO 3 ¡ ÀN and 5.0 g L ¡1 of dry cell weight. Practical computational approaches (the frontier orbital theory and the atoms-in-molecules theory) and inductive and resonance effects were also used to explain and assess how the molecular structure and stability of the redox mediators affect the accelerating capacity during denitrification.

Evaluation of Reduced Graphene Oxide Modified with Antimony and Copper Nanoparticles for Levofloxacin Oxidation

“…A detailed description of structural, electronic and reactivity features of molecular systems using molecular modelling can confirm the mechanisms involved . Combining voltammetry techniques and molecular modelling makes possible to understand redox mechanisms of electroactive molecules .…”

Riboflavin enhanced denitrification of artificial wastewater under low C/N condition in cold season

“…However, this process consumes industrial resources and raises operating fees. Electron mediators can be applied to lower the activation energy (Ea), which enhances the denitrification rate and the utilization of limited carbon sources under low C/N ratio (Guo et al 2015). The standard redox potential (E0′) of a possible electron mediator should be between the two half reactions of donor-oxidation and denitrification, improving the extracellular electron transport (Van der Zee and Cervantes 2009).…”

Electrochemical oxidation of sulfamethazine on a glassy carbon electrode modified with graphene and gold nanoparticles

“…In general, such techniques enable identification and evaluation of the structural, electronic and reactivity features of molecular systems, and often allow the mechanisms involved to be confirmed [10][11][12]. As a matter of fact, it has been shown that molecular modelling methods and cyclic voltammetry techniques can be associated with understanding the redox mechanism of electroactive species [13][14][15][16][17]. The results of this kind of study may also be extended to drugs design [18,19].…”