Preparation and characterization of recyclable Fe3O4@SiO2@TiO2 composite photocatalyst, and investigation of the photocatalytic activity

Degradation of Orange G, Acid Blue 161, and Brillant Green Dyes Using UV Light-Activated GA-TiO2-Cd Composite

In this study, photocatalysts with high photocatalytic activity performance are synthesized by synthesizing graphene aerogel-supported, cadmium-doped TiO2 composites by hydrothermal method for the effective degradation of organic dyes in wastewater. Here, GA-TiO2-Cd is investigated as a photocatalyst for the degradation of toxic dyes named Orange G, Acid Blue 161, and Brilliant Green in the UV part of the light spectrum. As a result of the experiments, it is observed that the effective decomposition of organic dyes is due to graphene aerogel (GA) and cadmium-doped TiO2 nanoparticles. The results show that for 20 ppm solutions of Orange G, Acid Blue 161, and Brilliant Green, dyes are removed at approximately 81.075%, 84.15%, and 95.18% in 120 min. The morphology and elemental analysis of the synthesized composites are determined using SEM-EDS, crystal structure analysis by XRD, chemical bond analysis by FTIR, optical properties by UV-Vis-NIR spectrophotometry, and thermal resistance by TGA analysis.

Fabrication and characterization of new Fe3O4@SiO2@TiO2-CPTS-HBAP (FST-CH) nanoparticles for photocatalytic degradation and adsorption removal of rhodamine B dye in the aquatic environment

In this study, Fe3O4@SiO2@TiO2-CPTS-HBAP (FST-CH) nanoparticle was prepared for the simultaneous adsorption and photocatalytic degradation of aromatic chemical pollutants (Rhodamine B dye) in aqueous solution. FST-CH nanoparticle was characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Energy Dispersive X-Ray (EDX) Fluorescence Spectrometer and X-Ray Diffraction (XRD) spectroscopy. The photocatalytic activity of rhodamine B dye (RhB) was evaluated with a Kerman UV 8/18 vertical roller photoreactor. About 56% of RhB in aqueous medium was adsorbed by FST-CH nanoparticles with only 45 min of stirring in the dark, and about 77.01% was degraded or converted to other structures under the photoreactor for 120 min. The photocatalytic degradation of RhB (apparent rate constant: 0.0026 mg dm-3 min-1) occurred by a pseudo-second order reaction. In addition, the recovery of the prepared magnetic FST-CH nanoparticle by an external magnetic field, exhibiting good magnetic response and reusability, shows that the obtained magnetic FST-CH nanoparticle is stable and maintains high degradation ratio and catalyst recovery even after four cycles. Thus, the prepared FST-CH nanoparticle can be highly recommended for its use in potential applications of water decontamination.

Immobilization of psychrophile Psychrobacter sp. ANT206 onto novel reusable magnetic nanoparticles and its application for nitro-aromatic compounds biodegradation under low temperature

Efficient biodegradation may offer a solution for the treatment of nitro-aromatic compounds (NACs) with toxicity, mutagenicity and persistence in the environment. In this study, dopamine (DA) functionalized magnetic nanoparticles with biocompatibility and hydrophilicity were synthesized and utilized for the immobilization of nitro-aromatic compounds degrading psychrophile Psychrobacter sp. ANT206 harboring the cold-adapted nitroreductase. The prepared nanocarriers were characterized using multiple methods. The highest immobilization yield of cells immobilized by Fe3O4@SiO2@DA was 90.67% under the optimized conditions of 10 °C, pH 7.5, 2 h and cell/support 1.2 mg/mg, and the activity recovery was 89.41%. In addition, the obtained immobilized cells displayed excellent salinity stability and reusability. Moreover, immobilized P. sp. ANT206 strains showed remarkable biodegradation capability on nitrobenzene and p-nitrophenol. This study introduced those novel Fe3O4@SiO2@DA nanoparticles could be applied as ideal and low-cost nanocarriers for the immobilization of cells and large-scale bioremediation of hazardous NACs with perspective applications under low temperature.

The photocatalytic performance and mechanism of magnetically retrievable Z-scheme Cr2O3–Fe3O4/C hetero-nanostructure polyhedra

Magnetically retrievable Cr2O3–Fe3O4/C hetero-nanostructure polyhedra have been fabricated. The formation of Z-scheme Cr2O3–Fe3O4/C obviously improves the visible light absorption and promotes the separation of photogenerated charge carriers.

Porous silicon film overcoating biomass char-supported catalysts for improved activity and stability in biomass pyrolysis tar decomposition

A C-SiO2 core–shell structure catalyst was prepared via a two-step pyrolysis method, and the support effect and reaction mechanism were discussed for this novel system.