(2018) Chemosphere_Photocatalytic co-oxidation of As(III) and Orange G using urea-derived g-C₃N₄ and persulfate

Kim J.-G., Park S.-M., Lee M.E., Kwon E.E., Baek K.

(Elsevier Ltd) Chemosphere ISSN: 456535 Vol.212 Issue. Article No. DOI: 10.1016/j.chemosphere.2018.08.081

Urea was thermally degraded to be transformed into graphitic carbon nitride (g-C₃N₄), and the fabricated charring compound was aimed to use a photocatalyst for the simultaneous removal of Orange G (OG) and trivalent arsenic (As(III)) through photocatalytic oxidation. This study experimentally revealed that the degradation of OG substantially restricted the oxidation performance for As(III). To mitigate the unwanted inhibition arising from the decomposition of OG, persulfate (PS) was intentionally added, which synergistically expedited the reaction kinetics for governing the oxidation performance for both OG and As(III). Hydroxyl radicals formed in the presence of g-C₃N₄ become a driving force for PS to expedited sulfate radicals, which substantially increased the oxidation of OG and As(III). The intrinsic structure of g-C₃N₄ enhancing the photocatalytic stability guaranteed the re-usability of the photocatalyst. For instance, the fabricated photocatalyst in this study exhibited the same oxidation performance at least three times. Despite the intrinsic charring compound (i.e., high porosity), this study reported that the synthesized catalyst did not adsorb As species, therefore, the further treatment is required to remove the oxidized As. Thus, all experimental findings suggest that g-C₃N₄ derived from urea and PS could synergistically co-oxidize azo dye compound and As(III) from the aqueous phase. © 2018 Elsevier Ltd

This work was supported by National Research Foundation of Korea (Grant Number: NRF-2015R1D1A1A09060537 by R&D Center for Green Patrol Technologies through the R&D for Global Top Environmental Technologies funded by Ministry of Environment , Republic of Korea (MOE).