Environmental decontamination using photocatalytic fuel cells and photoelectrocatalysis-microbial fuel cells

BACKGROUND To decontaminate sites of pollutants, fuel cell and bio-electrochemical fuel cell reactors can degrade pollutants and generate electricity simultaneously, potentially decrease cost, energy consumptions and treatment cycle. In this study, a photocatalytic fuel cell (PFC) and PEC-MFC (integrated photo-electro-catalysis with microbial fuel cell) were investigated to decontaminate sand/water polluted by RhB, antibiotics and heavy metal ions. RESULTS In the PFC, paired electrodes with ZnIn 2 S 4 -AgAgCl/GO or ZnIn 2 S 4 -RGO/MnO 2 , effectively removed pollutants in sand/water. The removal of RhB was 95.6% in 100 min with an external resistance of 1 Ω under aeration. Adding cyclo-dextrin increased pollutant removals, realized 66% removal of RhB in overlying water, and significant removal in sand after 5 h, and 70% removal of tetracycline in overlying water, but only 60% without cyclodextrin after 4 h. Adding KMnO 4 and NaHSO 3 promoted decontamination of tetracycline from sand/water, tetracycline in water was almost completely degraded in 3.5 h with the addition, but only about 65% without any addition. In the PEC-MFC, integrating photo-electro-catalytic electrode with bio-anode, Cr(VI) in the cathode chamber was reduced rapidly and the concentration of RhB in sand decreased quickly, nearly complete in 2 h. The Cr(VI) in sand was reduced in several hours, so that, compared with previous reports, the treatment time is significantly shortened. CONCLUSION The PFC and PEC-MFC systems are successful in decontaminating sand/water in polluted sites and are cost-effective and sustainable methods. By building an on-site or off-site system with washing and cycling of the liquid stream, it could be a convenient remediation method for polluted sites. © 2018 Society of Chemical Industry