Simultaneous removal of phenol and dichromate from aqueous solution through a phenol-Cr(VI) coupled redox fuel cell reactor

To eliminate contaminants like phenol and dichromate from aqueous solutions is still a hot research interest. In contrast to a traditional method within high intensity of energy input, both dichromate and phenol were removed within self-powered process through a phenol-Cr(VI) coupled redox fuel cell reactor, which was uniquely assembled on Ni/C anode the electro-oxidation of phenol takes place to give electrons and then go through the external circuit reducing Cr(VI) to Cr(III) on the cathode. Taking an example of 0.94 g L−1 phenol in 0.2 M phosphate buffer solution (PBS) serving as the anolyte and 0.15 g L−1 Cr(VI) in 0.5 M H2SO4 serving as the catholyte, a net power density of 0.184 W m−2 at 0.61 V can be gained. A removal efficiency of 98.6% for 0.94 g L−1 phenol within 132 h and 99.8% for 0.30 g L−1 Cr(VI) within 60 h can be readily achieved in the system. This confirmed in the fed-batch mode that either the contaminants of phenol and Cr(VI) in solutions is effectively removed or the energy contained in chemicals as the form of electricity has been exactly retrieved.