Checking the Efficiency of a Magnetic Graphene Oxide–Titania Material for Catalytic and Photocatalytic Ozonation Reactions in Water

Abstract

An easily recoverable photo-catalyst in solid form has been synthesized and applied in catalytic ozonation in the presence of primidone. Maghemite, graphene oxide and titania (FeGOTi) constituted the solid. Additionally, titania (TiO2) and graphene oxide–titania (GOTi) catalysts were also tested for comparative reasons. The main characteristics of FeGOTi were 144 m2/g of surface area; a 1.29 Raman D and G band intensity ratio; a 26-emu g−1 magnetic moment; maghemite, anatase and brookite main crystalline forms; and a 1.83 eV band gap so the catalyst can absorb up to the visible red region (677 nm). Single ozonation, photolysis, photolytic ozonation (PhOz), catalytic ozonation (CatOz) and photocatalytic ozonation (PhCatOz) were applied to remove primidone. In the presence of ozone, the complete removal of primidone was experienced in less than 15 min. In terms of mineralization, the best catalyst was GOTi in the PhCatOz processes (100% mineralization in 2 h). Meanwhile, the FeGOTi catalyst was the most efficient in CatOz. FeGOTi led, in all cases, to the highest formation of HO radicals and the lowest ozone demand. The reuse of the FeGOTi catalyst led to some loss of mineralization efficacy after four runs, likely due to C deposition, the small lixiviation of graphene oxide and Fe oxidation.

Nanocomposite PVDF/TiO2 Photocatalytic Membranes for Micropollutant Removal in Secondary Effluent

“…However, a critical limitation reported for this powdered material is its inability to form stable agglomerates, which could be easily recovered and reused after the treatment [13]. For this reason, different strategies have been proposed to immobilize TiO 2 P25 onto a variety of materials, thus allowing for the photoreactor to operate in a continuous mode [14,15] or the easy recovery of the photocatalyst after its use in batch reactor configurations [16,17]. In this work, TiO 2 P25 nanoparticles have been immobilized onto the structure of a polyvinylidene fluoride (PVDF) membrane to couple the benefits of membrane filtration and TiO 2 photocatalytic oxidation in the removal of MPs from water.…”

Advanced Oxidation Process: Applications and Prospects

“…Díez et al [18] carried out the synthesis and characterization of novel graphene oxide coupled to TiO 2 (GO-TiO 2 ) in order to better understand the performance of this photocatalyst compared to the well-known TiO 2 (P25) from Degussa. Checa et al [19] synthesized and characterized a magnetic graphene oxide titania (FeGOTi) catalyst for application in primidone removal from water, and checked for any possible enhancements. This compound was chosen because its presence is expected in urban wastewater, and its direct reaction with ozone is relatively low.…”