Photocatalytic degradation and mineralization of perfluorooctanoic acid (PFOA) using a composite TiO2 −rGO catalyst

Abstract

The inherent resistance of perfluoroalkyl substances (PFASs) to biological degradation makes necessary to develop advanced technologies for the abatement of this group of hazardous substances. The present work investigated the photocatalytic decomposition of perfluorooctanoic acid (PFOA) using a composite catalyst based on TiO and reduced graphene oxide (95% TiO/5% rGO) that was synthesized using a facile hydrothermal method. The efficient photoactivity of the TiO-rGO (0.1gL) composite was confirmed for PFOA (0.24mmolL) degradation that reached 93±7% after 12h of UV-vis irradiation using a medium pressure mercury lamp, a great improvement compared to the TiO photocatalysis (24±11% PFOA removal) and direct photolysis (58±9%). These findings indicate that rGO provided the suited properties of TiO-rGO, possibly as a result of acting as electron acceptor and avoiding the high recombination electron/hole pairs. The release of fluoride and the formation of shorter-chain perfluorocarboxilyc acids, that were progressively eliminated in a good match with the analysed reduction of total organic carbon, is consistent with a step-by-step PFOA decomposition via photogenerated hydroxyl radicals. Finally, the apparent first order rate constants of the TiO-rGO UV-vis PFOA decompositions, and the intermediate perfluorcarboxylic acids were found to increase as the length of the carbon chain was shorter.

Evidences of the Effect of GO and rGO in PCL Membranes on the Differentiation and Maturation of Human Neural Progenitor Cells

“…Fabrication of PCL‐Graphene Membranes : GO and rGO were synthetized following a modified Hummer’s method as described elsewhere . The Raman characterization of the GO and rGO nanomaterials showed that the D/G intensity ratio decreased from 0.96 for GO to 0.28 for rGO, confirming the correct reduction of GO nanomaterials.…”

On the Role of the Cathode for the Electro-Oxidation of Perfluorooctanoic Acid

“…More recently, photocatalytic treatments have been applied for PFOA degradation. This technology achieved high PFOA removal (x PFOA > 90%) when using modified TiO 2 photocatalysts such as Cu-TiO 2 [17], Pb-TiO 2 [18], and rGO-TiO 2 [19].…”

Tailoring photocatalysts and elucidating mechanisms of photocatalytic degradation of perfluorocarboxylic acids (PFCAs) in water: a comparative overview

“…The result showed that rGO-TiO 2 (5%rGO) performed up to 93 ± 7% of removal efficiency in the decomposition of 0.24 mmol L −1 PFOA for 12 h under UVvisible light irradiation (medium-pressure mercury lamp, 200-600 nm). 72 Ga 2 O 3 -based photocatalysts Nanostructured Ga 2 O 3 has also received attention, which exhibits wide bandgap semiconductor (bandgap >3.0 eV), interesting photoluminescence, excellent conduction, and tunable optical properties. 73 Diverse nanostructures of Ga 2 O 3 have been synthesized and applied successfully for photodegradation of PFOA, including nanoparticles, 52 monoclinic rod-shaped crystals, 62 needle-like, 74 and sheaf-like nanomaterial.…”