Photoluminescence of Solid Solutions GaS1-xSеx0.1аt% (x=0.10) Irradiated with γ-Quanta

The study investigated the photoluminescent properties of undoped and rare-earth element erbium - doped solid solutions GaS1-xSex0.1аt% irradiated with gamma-quanta. Erbium doping reduces the photoluminescence intensity in solid solutions. After irradiation Dg= 300-1000Gy, the photoluminescence intensity increases. An increase in the photoluminescence intensity in irradiated solid solutions is explained by a decrease in the concentration of centers responsible for the fast recombination channel and associated with lattice defects. At T=77K, due to the decay of bound Frenkel pairs, Si and Vs appear in the sulfur sublattice. The Si defects are responsible for the increase in the intensity of the green luminescence band. The redistribution of photoluminescence intensity in the range of 0.520 - 0.600 µm is due to the transfer energy to rare-earth centers in activated crystals. The performed investigations allow us to conclude that doping with erbium leads the appearance of a series of emission lines in the visible region of the spectrum

Molecular Hydrogen Production by Radiolysis of Water on the Surface of Nano-ZrO2 Under the Influence of Gamma Rays

In this research, the radiation-heterogeneous processes of water decomposition on the surface of zirconium dioxide nanoparticles (n-ZrO2) were studied. The kinetics of buildup of molecular hydrogen during the radiolytic processes of water decomposition was also examined. The production of H2 and H2O2 through water radiolysis was investigated to develop a computational model and disclose the kinetic behavior of water radiolysis. The enthalpy of ZrO2 nanoparticles was studied at the temperature range T=1200-2900 K, in which ZrO2 nanoparticles has a two-phase transition. Some of the electrons were transported to the surface of the nanoparticles during the physical and physicochemical stages of the process and emitted into the water. At the same time, the migration of energy carriers in radioactively active oxide compounds changed at different intervals depending on the composition, structural stability, and electro-physical properties of the oxides

Importance of the radiations in water splitting for hydrogen generation

The review article examines the production of molecular hydrogen from the decomposition of water by various irradiation methods. The article shows different types of radiation: UV radiation, visible radiation, gamma radiation, X-ray radiation and neutron radiation. Electrons generated by radiation inside a nanoparticle of radius R suspense in fluid water are diffused with equal probability in all directions inside the particle and gradually lose their kinetic energy as a result of elastic and inelastic collisions. Some of these electrons are transported to the nanoparticle surface during the physical and physicochemical stages of the process and emitted into the water. It is extremely important for the formation of nanostructured materials after exposure to ordered nanostructure from the new phase with a period of a few nanometers, promoting the preservation of the properties of materials under high irradiation

Mechanism of Hydrogen Production in The Processes of Radiation Heterogeneous Splitting of Water with the Presence of Nano-Metal and Nano-MeO

In the study, the optimal values of the ratio of the distance between particles to the particle size in the radiation-heterogeneous radiolysis of water in nano-Me and nano-MeO systems were determined. In those systems, the effect of water density and system temperature on the radiation-chemical release of molecular hydrogen obtained from thermal and radiation-thermal decomposition of water was considered. The article also determined the effect of particle sizes and the type of sample taken on the radiation chemical yield of molecular hydrogen. In the presented article, the change of molecular hydrogen according to adsorbed water and catalyst was studied. Thus, in the case of a suspension of nano-zirconium in water, the energy of electrons emitted from the metal is completely transferred to water molecules, which leads to an increase in the yield of hydrogen. When radiolysis of water in the presence of nano-metals, energy transfer can be carried out mainly with the participation of emitted electrons. Therefore, in the case of radiolysis of water in suspension with n-Zr, the yield of hydrogen increases by 5.4 times compared to the processes of radiolysis in an adsorbed state. However, in radiation-heterogeneous processes of obtaining hydrogen from water in contact with metal systems, it is necessary to take into account that as a result of these processes surface oxidation occurs and after a certain time the systems are converted to n-Me-MeO+H2Oliq. systems. For nano sized oxide compounds, the mean free path of secondary electrons formed as a result of primary processes of interaction of quanta with atoms is commensurate with the particle sizes of nano-oxides (λ ≈ R_(H-оxides)). Further, these electrons interact with the electronic subsystem of silicon. For nanocatalysts, the length of free paths of secondary and subsequent generations of electrons is greater than the size of catalyst particles (R_cat≤100nm). Usually, their energy is sufficient to conduct independent radiolytic processes in the contact medium of the catalyst

Preparation and Characterization of Iron Oxide Nano-adsorbent by Enteromorpha Flexuosa Algae obtained from Yanbu Red Sea, Saudi Arabia: Preparation and Characterization of Iron Oxide Nano-adsorbent by Enteromorpha Flexuosa Algae obtained from Yanbu Red Sea, Saudi Arabia

Water contamination caused by toxic cadmium metal ions is a worldwide problem. There is a need to explore new methods of cadmium removal from water. The green algae Enteromorpha flexuosa, obtained from the Red Sea in Yanbu, Saudi Arabia, was used to prepare iron nanoparticles. TEM, FT-IR, XRD, and SEM techniques were used to characterize the prepared nanoparticles. The prepared nanoparticle's surface was rough, with nanoparticle sizes ranging from 10 to 50 nm. The developed nanoparticles were used to adsorb cadmium ions from water in batch mode. With a 25.0 µg/L concentration, a temperature of 25˚C, 7.0 pH, 60 minutes contact time and 0.5 g/L dose, the maximum removal of cadmium was 48.2 µg/g. The sorption efficiency was measured using the Dubinin-Radushkevich, Temkin, Langmuir and Freundlich models. The amounts of ΔG° were -8.0, -9.93 and -12.24 kJ/mol while the values of ΔS° and ΔH° were -30.96 x 10-3 kJ/mol and 37.79 x 10-2 kJ/mol. These data confirmed the endothermic nature of cadmium metal ions removal. Along with the liquid film diffusion process, the adsorption adopted the kinetics of pseudo-second-order type. The recorded adsorption method is fast, cost-effective, and environmentally friendly and can be applied for testing the elimination of cadmium metal ions in natural waters

An Ionic-Liquid-Imprinted Nanocomposite Adsorbent: Simulation, Kinetics and Thermodynamic Studies of Triclosan Endocrine Disturbing Water Contaminant Removal

The presence of triclosan in water is toxic to human beings, hazardous to the environment and creates side effects and problems because this is an endocrine-disturbing water pollutant. Therefore, there is a great need for the separation of this notorious water pollutant at an effective, economic and eco-friendly level. The interface sorption was achieved on synthesized ionic liquid-based nanocomposites. An N-methyl butyl imidazolium bromide ionic liquid copper oxide nanocomposite was prepared using green methods and characterized by using proper spectroscopic methods. The nanocomposite was used to remove triclosan in water with the best conditions of time 30 min, concentration 100 µg/L, pH 8.0, dose 1.0 g/L and temperature 25 °C, with 90.2 µg/g removal capacity. The results obeyed Langmuir, Temkin and D-Rs isotherms with a first-order kinetic and liquid-film-diffusion kinetic model. The positive entropy value was 0.47 kJ/mol K, while the negative value of enthalpy was −0.11 kJ/mol. The negative values of free energy were −53.18, −74.17 and −76.14 kJ/mol at 20, 25 and 30 °C. These values confirmed exothermic and spontaneous sorption of triclosan. The combined effects of 3D parameters were also discussed. The supramolecular model was developed by simulation and chemical studies and suggested electrovalent bonding between triclosan and N-methyl butyl imidazolium bromide ionic liquid. Finally, this method is assumed as valuable for the elimination of triclosan in water

Seawater Splitting for Hydrogen Generation Using Zirconium and Its Niobium Alloy under Gamma Radiation

Hydrogen production is produced for future green energy. The radiation–chemical yield for seawater without a catalyst, with Zr, and with Zr1%Nb (Zr = 99% Nb = 1%) were (G(H2) = 0.81, 307.1, and 437.4 molecules/100 eV, respectively. The radiation–thermal water decomposition increased in γ-radiation of the Zr1%Nb + SW system with increasing temperature. At T = 1273 K, it prevails over radiation processes. During the radiation and heat radiation heterogeneous procedures in the Zr1% Nb + SW system, the production of surface energetic sites and secondary electrons accelerated the accumulation of molecular hydrogen and Zr1%Nb oxidation. Thermal radiation and thermal processes caused the metal phase to collect thermal surface energetic sites for water breakdown and Zr 1%Nb oxidation starting at T = 573 K