Photocatalytic degradation of methylene blue by UV‐assistant TiO₂ and natural sericite composites

Abstract

BACKGROUND In order to prepare an environmental‐friendly photocatalyst, natural mineral sericite is used as the substrate of photocatalysts. In this study, the TiO2‐sericite composite materials are synthesized by a facile sol‐gel process, followed via a calcination treatment that can improve the crystallinity of the nano‐sized TiO2. The prepared composites are characterized by XRD, Raman, FTIR, UV‐vis, SEM, and BETanalysis. The effects of the molecular ratio of TiO2 to sericite and the calcination temperature are also examined. RESULTS Sericite is not only served as a substrate for nano‐sized TiO2 to fabricate the micro‐sized composite materials but also affect the formation of different crystalliniteTiO2. The characteristic results show that the addition of sericite can stabilize the crystal phase of TiO2; therefore, the sericite can maintain the crystalline anatase of TiO2 even after the calcination at 700 °C and 900 °C. Accordingly, the adsorption test and the photocatalytic degradation of methylene blue are conducted to verify the photocatalytic performance of the TiO2‐sericite composite materials. It indicates that the synergetic effect of TiO2‐sericite composites can facilitate the photocatalytic degradation of TiO2 accompanied by the initial adsorption of methylene blue by sericite. Based on the presence of various radicals, including ·OH, ·O2−, and 1O2, the mechanism of photocatalytic degradation of methylene blue via TiO2‐sericite composites are successfully proposed. CONCLUSION The excellent activity reveals that TiO2‐sericite composites are with potential employed as ecological‐friendly photocatalysts in the degradation of pollutants. © 2020 Society of Chemical Industry

Adsorption and Photocatalytic Mineralization of Bromophenol Blue Dye with TiO2 Modified with Clinoptilolite/Activated Carbon

“…Evidently, the single catalyst load results favored the TiO 2 due to its high active sites and hydroxyl radicals, which entrapped the contaminants [31,32]. This affirms that the photocatalytic nature of TiO 2 , once activated by UV radiations, produces a very reactive species, which led to the degradation of the organic substance in the solutions [29,36].…”

“…Scanning electron microscopy (SEM) at the University of Cape Town, South Africa was employed to characterize the surface morphologies of the TiO2, A-TiO2, and Z-TiO2 nanocomposites, and the results obtained are presented in Figure 2. It is observed (Figure 2a) that the TiO2 with no covering has very hexagonal and unformulated structures with abundant pores to accommodate other materials [31,33,35]. The average grain size (Figure 2a Subsequently, the EDX images at 100 µm for the TiO2 (Figure 3a), A-TiO2 ( Figure 3b), and Z-TiO2 (Figure 3c) revealed the possible hybridization with well-dispersed TiO2 on the A-TiO2 and Z-TiO2 nanocomposites.…”

“…The composites (A-TiO 2 , Z-TiO 2 ) were synthesized based on a modified low-temperature co-precipitation method [31,35]. First, 30 g of AC and 10 g of TiO 2 was added to 200 mL of deionized water and sonicated (45 kHz at 80 • C) for 1 h. After the sonication, the samples were oven-dried at 80 • C for 24 h, which resulted in A-TiO 2 .…”

“…Figure 2. It is observed (Figure 2a) that the TiO 2 with no covering has very hexagonal and unformulated structures with abundant pores to accommodate other materials [31,33,35]. The average grain size (Figure 2a where is the wavelength of X-ray radiation (CuKα = 0.15406 nm), K is a constant taken as 0.98, β is the first line width at half maximum height (FWHM) of the peak (determined using Origin software), and θ is the diffracting angle (2θ = 25.28° for 101 planes).…”

Innovative TiO2‐based photocatalysis: recent advances and emerging applications

“…It notes the photocatalytic efficiency over TiO 2 is limited by the inactive under visible light irradiation and the quick recombination of the photogenerated electron–hole pairs. Hence, several efforts have made substantial contributions to the promoting of TiO 2 ‐based photocatalysis, including the incorporation of co‐catalysts, 3‐6 metal/nonmetal elements doping, 7‐11 fabricating composite systems 12‐15 . In particular, Ani et al .…”