Development and testing of bioelectrochemical reactors converting wastewater organics into hydrogen peroxide

Abstract

In a bioelectrochemical system, the energy content in dissolved organic matter can be used to power the production of hydrogen peroxide (H2O2), which is a potentially useful chemical at wastewater treatment plants. H2O2 can be produced by the cathodic reduction of oxygen. We investigated four types of gas-diffusion electrodes (GDEs) for this purpose. A GDE made of carbon nanoparticles bound with 30% polytetrafluoroethylene (PTFE) (wt./wt.C) to a carbon fiber paper performed best and catalyzed H2O2 production from oxygen in air with a coulombic efficiency of 95.1%. We coupled the GDE to biological anodes in two bioelectrochemical reactors. When the anodes were fed with synthetic wastewater containing acetate they generated a current of up to ∼0.4 mA/mL total anode compartment volume. H2O2 concentrations of ∼0.2 and ∼0.5% could be produced in 5 mL catholyte in 9 and 21 h, respectively. When the anodes were fed with real wastewater, the generated current was ∼0.1 mA/mL and only 84 mg/L of H2O2 was produced.

Key findings

• ▸A GDE made of carbon nanoparticles bound with 30% polytetrafluoroethylene (PTFE) (wt.
• ▸1%.
• ▸4 mA/mL total anode compartment volume.
• ▸2 and ∼0.
• ▸5% could be produced in 5 mL catholyte in 9 and 21 h, respectively.

Keywords

Identifiers

DOI

10.2166/wst.2012.255

Journal

Water Science and Technology

Year

2012