DNA damaging and biochemical effects of potassium tetraborate

Potassium tetraborate (PTB) is a product resulting from the controlled reaction of potassium hydroxide, water and boric acid (BA). It is used in many areas of industry such as disinfectant, detergent and treatment of contact lenses. PTB is one of the boron compounds which is most commonly used in many areas of industry although very limited information is available concerning its toxicity. Therefore, in this study, it is aimed to determine genetic and biochemical effects of PTB in human blood cell cultures (n=4). PTB was added into culture tubes at various concentrations (0-1280 μg/ml). Micronucleus (MN) and chromosomal aberration (CA) tests were performed for genotoxic damage influences estimation. In addition, biochemical parameters (total antioxidant capacity (TAC) and total oxidative status (TOS) were examined to determine oxidative effects. The results indicated that all tested concentrations of PTB were found to be non-genotoxic. In addition, low concentrations (1.25, 2.5 and 5 μg/ml) of PTB caused increases of TAC levels. Furthermore, all concentrations of PTB were not changed the TOS levels in cultured human blood cells. Based on these results, in this study it has been reported for the first time that PTB is not genotoxic and it in creases the antioxidant capacity in human peripheral blood lymphocytes

Effect Of NaoH In Hydrogen Production From NaBH4 By Using Co-B-F And Co-B-P Catalysts

In this study, Co-B-F and Co-B-P catalysts were synthesized in order to produce hydrogen from sodium boron hydride hydrolysis. Sodium hydroxide concentration in hydrogen production from sodium boron hydride is immensely important to stabilize the reaction. In the case of over use of sodium hydroxide, catalytic activity of the catalyst will decrease, On the other hand, In the case of under-use or without any usage of the catalyst, sodium boron hydride degradation will occur. For these reasons, optimum sodium hydroxide concentrations were determined in the case of synthesized Co-B-F and Co-B-P catalysts usage in sodium boron hydride hydrolysis. In the presence of different sodium hydroxide concentrations, reaction rates and reaction rate constants were examined separately which hydrolysis of sodium borohydride with sodium hydroxide concentration was determined to be effective and how important the hydrogen production. Co-BF in the presence of catalyst for hydrogen production rate of 2.5% concentrations of NaOH in 2400 ml / dk.catalyst, Co-BP for the catalysts was 1605 ml / dk.catalyst was determined

Novel activated carbon supported trimetallic PdCoAg nanoparticles as efficient catalysts for the hydrolytic dehydrogenation of ammonia borane

Activated carbon (AC) supported palladium, cobalt and silver nanoparticle (PdCoAg/AC) catalysts were prepared by in situ reduction of sodium borohydride (NaBH4) and characterized by various techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX), Transmission electron microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The PdCoAg/AC catalyst is active in the hydrolysis of ammonia-borane (AB) even at low temperatures. Compared with mono- (Pd) and bi-metallic (PdCo) nanoparticles, this trimetallic (PdCoAg) structure showed greatly increased catalytic activity for AB hydrolysis. Their hydrolysis completion time was 50 s. This study also included full experimental details of kinetic data to determine the activation parameters (Ea, and ) for the rate law and the catalytic hydrolysis of AB. In addition, the PdCoAg/AC catalysts had favorable catalytic activity also after seven runs. Hydrogen generation rate (HG), Ea, and were obtained at 25 °C as 4666.66 mL min−1g−1 (2 mmol AB and 50 mg PdCoAg/AC), 26.836 kJ mol-1, 29.416 kJ mol−1and –108.42 J mol−1K−1, respectively. In addition, the study showed that Pd0.6Co0.2CAg0.2/AC (Pd:Co:Ag atomic ratio = 6:2:2) showed the total turnover frequency (TOF) value of 6624 h−1. These results demonstrate that the PdCoAg/AC catalyst is a promising alternative in search of the practical application of AB as a hydrogen storage material for fuel cell applications

γ-Al2O3 supported/Co-Cr-B catalyst for hydrogen evolution via NH3BH3 hydrolysis

This assay investigates the Co-Cr-B catalyst effect supported on γ-Al2O3 to produce hydrogen (HG) from ammonia-borane hydrolysis (ABH). For characterization of this catalyst, SEM-EDX, XRD, FTIR and BET surface area analysis were performed. The maximum hydrogen generation rate (HGR) with this catalyst used for the ABH was 3260 ml min−1 g−1catalyst. The recyclability tests for the Co-Cr-B/γ-AlO3 catalyst on the ABH have maintained an activity of 68% even after four hydrolysis treatments. Also, the activation energy (Ea) obtained using the Co-Cr-B catalyst supported on γ-AlO3 for the ABH was 56.06 kJ/mol

studıes on catalytıc behavıor of co–cr–b/al2o3 ın hydrogen generatıon by hydrolysıs of nabh4

In this present study, the chemical reduction technique was used to synthesize Al2O3 supported Co-Cr-B catalyst (Co-Cr-B/Al2O3). The effects of the concentration of NaBH4, NaOH, amount of catalyst, ratio of metal/ Al2O3and temperature were discussed in detail. The results show that the reaction rate of hydrolysis first rises up and then goes down subsequently with the increase of NaBH4 concentration, as well as the concentration of NaOH. It was observed that the hydrogen generation rate increases with the molar content of metal changing from 2.5% to 5 wt%. However, when the metal/Al2O3 molar ratio is located from 5% to 20 wt%, the rate of hydrogen generation goes down. The hydrolysis kinetic order and the activation energy ...

Catalytic activity of cobalt-boron-fluoride particles with different solvent mediums on sodium borohydride hydrolysis for hydrogen generation

Catalysts prepared in a different solvent medium have different activities because of its different acidity, basicity and viscosity properties. The synthesis mechanism of cobalt-boron-fluoride in water, propanol and ethanol solvents was evaluated. Characterization studies of cobalt-boron-fluoride catalyst were performed with Brunauer-Emmett-Teller surface area, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy- energy dispersive x-ray spectroscopy measurements. The effects of sodium borohydride (SB), and temperature on the SB hydrolysis reaction with the catalyst samples were studied. The maximum hydrogen generation rate (HGRs) of the cobalt-boron (ethanol solvent) and cobalt-boron-fluoride (ethanol solvent) catalysts were 1942 and 4533 mlmin−1g−1, respectively. The activation energy was 32.45 kJ mol−1

STUDIES ON CATALYTIC BEHAVIOR OF Co–Cr–B/Al2O3 IN HYDROGEN GENERATION BY HYDROLYSIS OF NaBH4

In this present study, the chemical reduction technique was used to synthesize ..

Catalytic activity of cobalt-boron-fluoride particles with different solvent mediums on sodium borohydride hydrolysis for hydrogen generation

Catalysts prepared in a different solvent medium have different activities because of its different acidity, basicity and viscosity properties. The synthesis mechanism of cobalt-boron-fluoride in water, propanol and ethanol solvents was evaluated. Characterization studies of cobalt-boron-fluoride catalyst were performed with Brunauer-Emmett-Teller surface area, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy- energy dispersive x-ray spectroscopy measurements. The effects of sodium borohydride (SB), and temperature on the SB hydrolysis reaction with the catalyst samples were studied. The maximum hydrogen generation rate (HGRs) of the cobalt-boron (ethanol solvent) and cobalt-boron-fluoride (ethanol solvent) catalysts were 1942 and 4533 mlmin-1g-1, respectively. The activation energy was 32.45 kJ mol-1

Hydrogen production through the cooperation of a catalyst synthesized in ethanol medium and the effect of the plasma

In the present study, nanostructured Ni-B catalysts were successfully prepared in ethanol medium using the chemical reduction method for hydrogen production from the catalytic hydrolysis of sodium borohydride (NaBH4). Ni-B nanostructures were characterized by several analysis methods including XRD, SEM/EDS, FT-IR and BET. The effects of factors such as solution temperature, NaBH4 loadings, catalyst amount and NaOH concentration on the performance of these catalysts in the production of hydrogen from alkaline NaBH4 solutions were investigated in detail. In addition, the Ni-B catalyst prepared in ethanol medium and subjected to plasma for the hydrogen production from the catalytic hydrolysis of NaBH4 was investigated. The Ni-B catalyst prepared in ethanol medium showed maximum hydrogen production rate (1000 mL min-1gcatalyst-1) which was approximately 2 times higher than the rate obtained from the Ni-B catalyst prepared in water (400 mL min-1gcatalyst-1) and acethone (550 mL min-1gcatalyst-1). The Ni-B nanoparticles showed the best catalytic activity at 333 K with a maximum hydrogen production rate of 7134 mL min-1gcatalyst-1 and activation energy of 46.83 kJmol-1 for the NaBH4 hydrolysis reaction in the Ni-B catalysts prepared in ethanol and subjected to plasma. As the Ni-B catalyst is inexpensive and easy to prepare, it is feasible to use this catalyst in the construction of practical fuel cells for portable and in situ applications.BEBA

Hydrogen production by using Ru nanoparticle decorated with Fe3O4@SiO2–NH2 core-shell microspheres

Noble metals are commonly used in order to accelerate the NH3BH3 hydrolysis for H2 production as heterogeneous catalysts. The nanoparticles (NPs) of these metals can be applied as active catalysts in fluid reactions. Metal NPs included in the core-shell nanostructures emerged as well-defined heterogeneous catalysts. Additionally, unsupported NPs catalysts can be gathered easily among neighboring NPs and the separation/recovery of these catalysts are not efficient with traditional methods. For this reason, here, silica-shell configuration was designed which was functionalized with a magnetic core and amine groups and Ru NPs were accumulated on Fe3O4@SiO2–NH2 surface for H2 production from NH3BH3. Fe3O4@SiO2–NH2–Ru catalysts demonstrated high catalytic activity as long as it has a hydrogen production rate of 156381.25 mLgcat−1 min−1 and a turnover frequency (TOF) of 617 molH2molcat−1min−1 towards the hydrolysis dehydrogenation of AB at 30 °C. This result is significantly higher than most of the known catalysts