Author(s)

Ignace Christian M’Bra^1,2*, Grah Patrick Atheba², Didier Robert¹, Patrick Drogui³, Albert Trokourey²

¹Institut de Chimie et Procédés pour l’Energie, l’Environnement et la Santé (ICPEES), CNRS-UMR7515 Université de Stras-bourg, antenne de Saint-Avold, Université de Lorraine, Saint-Avold, France.
²Laboratoire de Chimie Physique, UFR Sciences des Structures de la Matière et de la Technologie (SSMT), Université Félix Houphouët Boigny d’Abidjan, Côte d’Ivoire.
³Institut National de la Recherche Scientifique (INRS-Eau, Terre et environnement), Université du Québec, Québec, Canada.

Photocatalytic degradation of paraquat (PQ) aqueous solutions was studied in a fixed bed photoreactor under UV irradiation at 368 nm. This contained β-SiC alveolar foams coated with TiO₂ P25 by dip-coating method. SEM analyses revealed that the surface of the film did not exhibit cracks in the presence of TTIP as a binder in the TiO₂ P25 suspension. The following parameters were studied in continuous mode operation: the flow rate in the reactor, the initial concentration of the paraquat, the pH of the solution, the weight of photocatalytic material with the number of foams in the reactor and the weight of the catalyst deposited onto the support. The results showed that by working under optimal operating conditions at natural pH (pH = 6.7), low paraquat (C_o = 10 ppm), and flow (26 mL/min), we recorded approximately (43.16 ± 1.00)% oxidation of paraquat and a decrease in total organic carbon (TOC) of (27.13 ± 1.00)% after about 70 minutes. The apparent rate constant is in the order of (0.0656 ± 0.0010) min^-1. In addition, by increasing the amount of β-SiC foams coated with TiO₂, we improve the degradation of paraquat in the same order. The study of aging of the material showed its stability over time. However, photocatalytic activity was limited after 20 minutes of UV irradiation due to the limitation of the diffusion of the paraquat molecules towards the surface of the photocatalyst. As an outcome, we obtained an efficient TiO₂/β-SiC material for photocatalytic degradation of organic compounds in water.

Photocatalytic Degradation, Paraquat, β-SiC Foam, TiO₂ P25, Water

M’Bra, I. , Atheba, G. , Robert, D. , Drogui, P. and Trokourey, A. (2019) Photocatalytic Degradation of Paraquat Herbicide Using a Fixed Bed Reactor Containing TiO₂ Nanoparticles Coated onto β-SiC Alveolar Foams. American Journal of Analytical Chemistry, 10, 171-184. doi: 10.4236/ajac.2019.105015.