Photoelectrochemical degradation of anti-inflammatory pharmaceuticals at Bi2MoO6-boron-doped diamond hybrid electrode under visible light irradiation

Bi2MoO6 particles were selectively deposited onto a boron-doped diamond (BDD) surface from amorphous complex solution via a dip-coating method followed by calcination. Its structure was confirmed via Raman and X-ray diffraction analysis. Scanning electron microscopy showed that the resulting Bi2MoO6 particles scattered on the BDD substrate. The photoelectrochemical measurement of the Bi2MoO6-BDD electrode showed a clear improvement in the photocurrent under visible light irradiation, indicating a new hybrid system. Furthermore, the hybrid electrode was applied in the degradation of ibuprofen and naproxen, two kinds of non-steroidal anti-inflammatory drugs via photocatalysis, electro-oxidation, and photoelectrocatalytic processes. It is shown that ibuprofen can be degraded via photocatalysis and electro-oxidation process with the applied bias potential of 2.0 V. By contrast, ibuprofen and naproxen can be rapidly degraded via combined electro-oxiclation and photocatalysis process under visible light irradiation. Furthermore, the degradation rate in the combined process is larger than the sum of photocatalysis and electro-oxiclation processes. The ibuprofen and naproxen were also efficiently mineralized in the combined process. Finally, the main intermediates of ibuprofen degradation were also identified. (C) 2009 Elsevier B.V. All rights reserved.