Hybrid Approach for Selective Sulfoxidation via Bioelectrochemically Derived Hydrogen Peroxide over a Niobium(V)-Silica Catalyst

James Griffin, Eric Taw, Abha Gosavi, Nicholas E. Thornburg, Ihsan Pramanda, Hyung Sool Lee, Kimberly A. Gray, Justin M. Notestein, George Wells

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

In this work, we demonstrate a combined bioelectrochemical and inorganic catalytic system for resource recovery from wastewater. We designed a microbial peroxide producing cell (MPPC) for hydrogen peroxide (H2O2) production and used this bioelectrochemically derived H2O2 as a green oxidant for sulfoxidation, an industrial reaction used for chemical synthesis and oxidative desulfurization of transportation fuels. We operated an MPPC equipped with a gas diffusion electrode cathode for six months, achieving a peak current density above 1.4 mA cm-2 with 60% average acetate removal and 61% average anodic Coulombic efficiency. We evaluated several cathode buffers under batch and continuous-flow conditions for solubility and pH compatibility with downstream catalytic systems. During 24-h batch tests, a phosphate-buffered MPPC achieved a maximum H2O2 concentration of 4.6 g L-1 and a citric acid-phosphate-buffered MPPC obtained a moderate H2O2 concentration (3.1 g L-1) at a low energy input (1.6 Wh g-1 H2O2) and pH (10). The MPPC-derived H2O2 was used directly as an oxidant for the catalytic sulfoxidation of 4-hydroxythioanisole over a solid niobium(V)-silica catalyst. We achieved 82% conversion of 50 mM 4-hydroxythioanisole to 4-(methylsulfinyl)phenol with 99% selectivity with a 0.5 mol % catalyst loading in 100 min in aqueous media. Our results demonstrate a new and versatile approach for valorization of wastewater through continuous production of H2O2 and its subsequent use as a selective green oxidant in aqueous conditions for green chemistry applications.

Original languageEnglish
Pages (from-to)7880-7889
Number of pages10
JournalACS Sustainable Chemistry and Engineering
Volume6
Issue number6
DOIs
Publication statusPublished - Jun 4 2018

Keywords

  • Bioelectrochemical system
  • Catalysis
  • Green chemistry
  • Microbial peroxide producing cell
  • Resource recovery
  • Sulfoxidation

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment

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