Photocatalytic degradation of contaminants of concern with composite NF-TiO2 films under visible and solar light

Abstract

1This study reports the synthesis and characterization of composite nitrogen and fluorine 2 co-doped titanium dioxide (NF-TiO2) for the removal of contaminants of concern 3 (COCs) in wastewater under visible and solar light. Monodisperse anatase TiO2 4 nanoparticles of different sizes and Evonik P25 were assembled to immobilized NF-5TiO2 by direct incorporation into the sol-gel or by the layer-by-layer technique. The 6 composite films were characterized with X-ray diffraction, high resolution-transmission 7 electron microscopy, environmental scanning electron microscopy, and porosimetry 8 analysis. The photocatalytic degradation of atrazine, carbamazepine, and caffeine was 9 evaluated in a synthetic water solution and in an effluent from a hybrid biological 10 concentrator reactor (BCR). Minor aggregation and improved distribution of 11 monodisperse titania particles was obtained with NF-TiO2-monodisperse (10 and 50 12 nm) from the layer-by-layer technique than with NF-TiO2 + monodisperse TiO2 (300 13 nm) directly incorporated into the sol. The photocatalysts synthesized with the layer-by-14 layer method achieved significantly higher degradation rates in contrast with NF-TiO2-15 monodisperse titania (300 nm) and slightly faster values when compared with NF-TiO2-16 P25. Using NF-TiO2 layer-by-layer with monodisperse TiO2 (50 nm) under the solar 17 light irradiation, the respective degradation rates in synthetic water and BCR effluent 18 were 14.6 and 9.5  10

Degradation of 1,4-dioxane from industrial wastewater by solar photocatalysis using immobilized NF-TiO2 composite with monodisperse TiO2 nanoparticles

“…Considering the SEM analysis (Fig. 3), the films had a rough and porous surface quite similar to the previous findings [40]. According to the porosimetry analysis, the immobilized catalyst had a relatively moderate BET surface of 69.5 m 2 g −1 and porosity of 33.6%.…”

“…The composite NF-TiO 2 -monodisp.TiO 2 films were prepared by a modified method reported by Barndõk et al [40]. Briefly, two different TiO 2 solutions were alternately deposited on a borosilicate substrate by dip-coating using a so-called layer-bylayer method (6 layers in total).…”

“…Moreover, the optical and physicochemical properties of the film for NF-TiO 2 photocatalysis were improved by adding P25-TiO 2 nanoparticles into the NF-TiO 2 sol-gel [39]. In a recent study [40], the incorporation of lab-made monodisperse titania nanoparticles [29] layer-by-layer on NF-TiO 2 , instead of the direct addition of P25-TiO 2 , further improved the catalyst, resulting in an effective degradation of various wastewater contaminants. However, the performance of immobilized NF-TiO 2 composite with monodisperse TiO 2 (NF-TiO 2 -monodisp.TiO 2 ) has not been tested on heavily loaded industrial effluents containing contaminants such as 1,4-dioxane.…”

A review of solar and visible light active TiO2 photocatalysis for treating bacteria, cyanotoxins and contaminants of emerging concern

“…This report suggests that as no photoproducts were observed from the dehalogenation of ATR by electron transfer, it can be said that the OH are responsible for the ATR oxidation process. NF doped TiO 2 systems have also been analysed for ATR elimination under visible and solar irradiation [170,171].…”

Photocatalytic degradation of salicylic acid and caffeine emerging contaminants using titania nanotubes

“…The strong alkaline effluent's environment could affect the photocatalytic reactions as the surface of TNT's is negatively charged at pH values above ̴ 6 which means that the adsorption of the CAF on the surface of catalyst is hindered by the action of repulsive electrostatic forces [51]. Another observation that explains the inferior degradation rates in the alkaline environment is the formation of by-products [41,52,53], as can be seen by the emergent peaks around 245 and 300 nm in respective UV-Vis absorbance spectra (Fig.7c).…”