In this study, iron-oxide (magnetite) synthesized by co-precipitation method and binary TiO2-Fe3O4 and ternary rGO-TiO2-Fe3O4 nanocomposites (called GTF) prepared by hydrothermal method. Crystal structure and bonds, studied by X-ray diffraction (XRD) and FTIR analysis, respectively. The morphology of samples was studied by SEM. The average size of nanoparticles estimated ~12. 3 nm and saturation magnetization of nanocomposites obtained by VSM, was 40. 26 emu/g. The photocatalytic activity of synthesized nanocomposites determined by degradation of methyl orange under UV light irradiation. The ternary nanocomposites showed ~98. 7 % degradation of methyl orange which has a remarkable improvement compared to TiO2-Fe3O4 binary nanocomposites with 84 % degradation.

Food packaging ensures long-term storage and protection of all types of food against physical, chemical and biological factors. In some food packaging, one of the purposes of packaging is to keep its contents away from oxygen and external contaminants. Today, it is an important part of the materials used to package food from petroleum products. This has caused many environmental problems. One of the proposed solutions for this issue is the use of materials with photocatalytic activity along with synthetic (petroleum) polymers. Minerals that have this property include titanium dioxide and zinc oxide. These light-sensitive materials are excited by receiving light. Hence, a hole (h*) in the valence band and an electron (e-) in the conduction band of these semiconductor compounds are created. The electron-hole pair leads to the production of active radicals which are responsible for attacking the plastic polymer chains. Consequently, changes in weight, mechanical properties, and plastic morphology are observed by realizing carbon dioxide and carbonyl groups. These changes demonstrate the decomposition of petroleum based polymers in the environment.

The first-principles calculations of the structural, Elastic, and phonon dispersion properties of cubic structure of tungsten trioxide have been performed with a Generalized Gradient Approximation (GGA) and ultrasoft-pseudopotential method based on the density functional theory. The pressure dependence of the elastic constants, bulk modulus, shear modulus, Young modulus, elastic Debye temperature, elastic anisotropy factor, Poisson ratios, Ductility, elastic velocities and Kleinmann parameter are presented. An analysis for the calculated elastic constants has been made to reveal the mechanical instability of WO3 up to 150 GPa. From the phonon dispersions of WO3, it is seen that the phonon frequencies increase as the volume decreases. The results show that the lattice constant and cell volume are in good agreement with experimental results. The elastic properties of tungsten trioxide, cubic, are examined for the first time.

AgBr-Bi24Br10O31 nanosheets were prepared by a facile single-step co-precipitation method at the presence of 1-Butyl-3-methylimidazolium bromide ([BMIM]Br) ionic liquid (IL) as the bromide source and template agent. The products were well characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), Diffuse Reflectance Spectroscopy (DRS), nitrogen adsorption-desorption isotherms (BET), Fourier Transform InfraRed (FT-IR) spectroscopy, and Scanning Electron Microscopy (TEM). The XRD pattern well confirmed the presence of both Bi24O31Br10 and AgBr crystalline phases in the structure. In addition, the SEM micrographs indicated that the sample has sheet-like morphology, and the thickness of the sheets is below 100 nm. According to the photocatalytic experiments, the product was incredibly efficient for the degradation of Acid Blue 92 (AB92) solutions under visible light. Also, the results of recycling experiments implied the high capacity of the prepared nanosheets for the repeated treatment of the wastewater solution which is great of importance for being introduced a catalyst in practical applications.

Direct yellow is one of the contaminations in the wastewater, which is dangerous for environmental health. In the present study, Co3O4-ZnO-Ag nanocomposite was synthesized as a photocatalyst using two-stage precipitation method. The synthesized powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy, differential thermal and weight loss analysis, and UV-Vis spectroscopy. XRD patterns showed that the size of ZnO crystallites increase with increasing the silver content. SEM micrographs showed that the size of particles in the sample with 3% silver was in the range of 20-300 nm. UV-Vis absorption spectrum of the prepared powders revealed that absorption in the visible region increases by adding metallic Ag. Calculation of the band gap energy indicated that by increasing the Ag content, the band gap energy of the samples decreases. Investigation of photocatalyst behavior for degradation of direct yellow dye exhibited that by adding 3% Ag to Co3O4-ZnO nanocomposite, the degradation efficiency improved from 71% to 89%. However further increase of Ag reduced the degradation kinetics, because Ag nanoparticles act as sites for accumulation of electrons and recombination of electron-hole pair.

At present, the emission of carbon dioxide from the combustion of fossil fuels into the atmosphere is one of the biggest concerns for the future. In this regard, the development of clean energy produced from sunlight is one of the appropriate solutions for energy supply in the future. The process of photocatalytic reduction of carbon dioxide is a relatively new method that, collects and stores solar energy to value-added materials, while reduces the negative effects of greenhouse gases through the consumption of carbon dioxide. So far, various semiconductors have been used as photocatalysts in this process. Metal-organic frameworks with unique properties such as band and electron structure, adjustable light absorption and high carbon dioxide absorption are of great interest. In this study, different aspects of these materials and methods to improve their performance, such as the use of optical sensitizers, combination with conventional semiconductors, the use of molecular catalysts and functionalization with amine groups for adsorption of Carbon dioxide has been investigated.

Securities such as banknotes are permanently in contact with the human body according to their type of use and they are handed out daily among different people. This method of application makes these papers extremely contaminated and increases the possibility of transmission of pathogens by them. Therefore, the creation of self-cleaning properties in these types of papers is necessary. Titanium dioxide is one of the most widely used materials in papermaking that nowadays, its nanometer dimensions are considered as a photocatalyst. In this study, direct attachment of titanium dioxide nanoparticles to cellulosic fibers by controlled hydrolysis TiCl4 with urea in the presence of cellulose fibers was used which the homogenization of the suspension was done by ultrasonic waves. The cellulose fibers used were linter cotton fiber. The results of antibacterial and photocatalytic tests showed a very good performance against gram-positive and gram-positive bacteria and methylene blue degradation, respectively, but the results of mechanical and optical tests of the papers were undesirable and limit the use of these particles without applying any modifying method.