Catalytic dechlorination of diclofenac by biogenic palladium in a microbial electrolysis cell.
Diclofenac is one of the most commonly detected pharmaceuticals in wastewater treatment plant (WWTP) effluents and the receiving water bodies. In this study, biogenic Pd nanoparticles ('bio-Pd') were successfully applied in a microbial electrolysis cell (MEC) for the catalytic reduction of diclofenac. Hydrogen gas was produced in the cathodic compartment, and consumed as a hydrogen donor by the bio-Pd on the graphite electrodes. In this way, complete dechlorination of 1 mg diclofenac l(-1) was achieved during batch recirculation experiments, whereas no significant removal was observed in the absence of the biocatalyst. The complete dechlorination of diclofenac was demonstrated by the concomitant production of 2-anilinophenylacetate (APA). Through the addition of -0.8 V to the circuit, continuous and complete removal of diclofenac was achieved in synthetic medium at a minimal HRT of 2 h. Continuous treatment of hospital WWTP effluent containing 1.28 µg diclofenac l(-1) resulted in a lower removal efficiency of 57%, which can probably be attributed to the affinity of other environmental constituents for the bio-Pd catalyst. Nevertheless, reductive catalysis coupled to sustainable hydrogen production in a MEC offers potential to lower the release of micropollutants from point-sources such as hospital WWTPs.
Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Gent, Belgium.
Bart
B
De Gusseme
Maarten
M
Soetaert
Tom
T
Hennebel
Lynn
L
Vanhaecke
Nico
N
Boon
Willy
W
Verstraete
D001419:Bacteria / Q000737:chemistry / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D019149:Bioreactors / Q000382:microbiology; D002384:Catalysis; D004008:Diclofenac / Q000378:metabolism*; D004566:Electrodes; D004572:Electrolysis; D010165:Palladium / Q000378:metabolism*
D004008:Diclofenac; D010165:Palladium