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Textile industries significantly impact the contamination of wastewater. Conventional wastewater treatment methods consider the most common pollutants; however, they are very expensive and commonly produce toxic by-products. In the scientific community, advanced oxidation processes appear to be the most appealing, and a majority of the published work considers heterogeneous photocatalysis for the degradation of various toxic chemicals. For convenience, the reaction is performed directly in the water environment. In this work, a metal-free graphitic carbon nitride (g-C3N4) was prepared through a simple thermal method using urea as a precursor. Prepared g-C3N4 was deposited on the surface of the alumina ceramic ring by the dip-coating method using ethylene glycol as binder. The alumina ceramic ring, as substrate, was prepared by the slip casting method. Photocatalytic properties of immobilised graphitic carbon nitride were used for degradation of methylene blue as a model pollutant under simulated solar light irradiation. The photocatalyst was characterised by XRD, FTIR, UV-Vis DRS, TGA, BET and SEM/EDX analyses. The photocatalytic degradation of MB from an aqueous solution was found to increase with increasing irradiation time. It was found that the graphitic carbon nitride immobilised on alumina ceramic is convenient for largescale environmental applications because the whole setup is cheap, nontoxic, easy to operate and offers reusability with a high removal rate of MB after three consecutive cycles. [ABSTRACT FROM AUTHOR]

This work presents the immobilisation of titanium dioxide (TiO2) nanoparticles (NPs) and reduced graphene oxide (rGO)-TiO2 nanocomposite on glass sheets for photocatalytic degradation of methylene blue (MB) under different radiation sources such as ultraviolet and simulated solar radiation. The TiO2 NPs and rGO-TiO2 nanocomposite were synthesised through a simple hydrothermal method of titanium isopropoxide precursor followed by calcination treatment. Deposition of prepared photocatalysts was performed by spin-coating method. Additionally, ethylene glycol was mixed with the prepared TiO2 NPs and rGO-TiO2 nanocomposite to enhance film adhesion on the glass surface. The photocatalytic activity under ultraviolet and simulated solar irradiation was examined. Further, the influence of different water matrices (milli-Q, river, lake, and seawater) and reactive species (h+, •OH, and e−) on the photocatalytic efficiency of the immobilised rGO/TiO2 nanocomposite was careful assessed. MB dye photocatalytic degradation was found to increase with increasing irradiation time for both irradiation sources. The immobilisation of prepared photocatalysts is very convenient for environment applications, due to easy separation and reusability, and the investigated rGO/TiO2-coated glass sheets demonstrated high efficiency in removing MB dye from an aqueous medium during five consecutive cycles. [ABSTRACT FROM AUTHOR]

This study presents a novel method for the development of TiO2/reduced graphene oxide (rGO) nanocomposites for photocatalytic degradation of dyes in an aqueous solution. The synergistic integration of rGO and TiO2, through the formation of Ti–O–C bonds, offers an interesting opportunity to design photocatalyst nanocomposite materials with the maximum absorption shift to the visible region of the spectra, where photodegradation can be activated not only with UV but also with the visible part of natural solar irradiation. TiO2@rGO nanocomposites with different content of rGO have been self-assembled by the hydrothermal method followed by calcination treatment. The morphological and structural analysis of the synthesized photocatalysts was performed by FTIR, XRD, XPS, UV-Vis DRS, SEM/EDX, and Raman spectroscopy. The effectiveness of the synthesized nanocomposites as photocatalysts was examined through the photodegradation of methylene blue (MB) and rhodamine B (RhB) dye under artificial solar-like radiation. The influence of rGO concentration (5 and 15 wt.%) on TiO2 performance for photodegradation of the different dyes was monitored by UV-Vis spectroscopy. The obtained results showed that the synthesized TiO2@rGO nanocomposites significantly increased the decomposition of RhB and MB compared to the synthesized TiO2 photocatalyst. Furthermore, TiO2@rGO nanocomposite with high contents of rGO (15 wt.%) presented an improved performance in photodegradation of MB (98.1%) and RhB (99.8%) after 120 min of exposition to solar-like radiation. These results could be mainly attributed to the decrease of the bandgap of synthesized TiO2@rGO nanocomposites with the increased contents of rGO. Energy gap (Eg) values of nanocomposites are 2.71 eV and 3.03 eV, when pure TiO2 particles have 3.15 eV. These results show the potential of graphene-based TiO2 nanocomposite to be explored as a highly efficient solar light-driven photocatalyst for water purification. [ABSTRACT FROM AUTHOR]