59 research outputs found

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

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    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

    Review of Analytical Methods for Identification and Determination of Triptans

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    A review of analytical methods for identification and determination of triptans which are a group of tryptamine based drugs used in the acute treatment of migraine headaches is presented. In this review article, various methods used for determination of triptans have been covered. The methods have been divided into four groups accordingly to the applied analytical techniques: chromatographic, electrochemical, spectrometric, and capillary electrophoretic

    BET, TG–DTG, FT-IR, SEM, iodine number analysis and preparation of activated carbon from acorn shell by chemical activation with ZnCl2

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    Activated carbons were produced from acorn shell by chemical activation with zinc chloride (ZnCl2) at 600 °C in N2 atmosphere and their characteristics were investigated. The effects of activation temperature, duration time, impregnation concentration of agent and impregnation time were examined. Adsorption capacity was demonstrated with BET and iodine number. The obtained activated carbons were characterized by measuring their porosities and pore size distributions. BET surface area of the best produced activated carbon was 1289 m2/g. The surface chemical characteristics of activated carbons were determined by FT-IR spectroscopic method. The microstructure of the produced activated carbons was examined by scanning electron microscopy (SEM). Thermal gravimetry (TG) and derivative thermal gravimetry (DTG) analysis of produced activated carbon was carried out

    Efficient hydrogen production with controlled hydrochloric acid addition using Ni-based catalyst synthesized in ethanol solvent

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    A Ni-based catalyst was synthesized in ethanol solvent by chemical reduction with sodium borohydride(NaBH4). This catalyst was used to catalyze the hydrolysis reaction of NaBH4 with hydrochloric acid (HCl) including different concentrations. Surface morphologies and characteristic properties of the Ni-based catalysts synthesized in the ethanol and water solvents were studied using scanning electron microscopy (SEM), X-ray diffraction (XRD), surface area measurements, and Fourier-transform infrared spectroscopy (FTIR) analyses, respectively. The maximum HGRs of the Ni-based (water) and Ni-based (ethanol) catalysts were 173 and 1054 ml g-1min-1, respectively. In addition, the HGR with 0.25 M HCl addition on the hydrolysis reaction using the Ni-based catalyst prepared in the ethanol solvent was about 1526 ml g-1min-1. Kinetic studies are performed according to the power law kinetic model. The activation energy (Ea) for the HG from the acidified hydrolysis reaction of NaBH4 using the Ni-based (ethanol) catalyst was found as 49 kJ mol-1

    Semi-methanolysis reaction of potassium borohydride with phosphoric acid for effective hydrogen production

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    The methanol and water solvents were used for the production of hydrogen from potassium borohydride. In addition, phosphoric acid was selected as the green catalyst so that this semi-methanolysis reaction would be more effective for the first time. The semimethanolysis of potassium borohydride is investigated depend on potassium borohydride, phosphoric acid concentrations and temperatures. The maximum normalized hydrogen production rate obtained from this semi-methanolysis reaction with 1 M phosphoric acid as a catalyst was 5779 ml min 1 g 1. In addition, this semi-methanolysis reaction was completed in 5 s. Kinetic studies have been carried out with the power law kinetic model. The activation energy obtained for this semi-methanolysis reaction is 1.45 kJ mol 1

    Fast and effective hydrogen production from ethanolysis and hydrolysis reactions of potassium borohydride using phosphoric acid

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    The hydrogen production from potassium borohydride (KBH4) with the ethanolysis and hydrolysis reactions using the phosphoric acid as a catalyst is performed for the first time. KBH4 concentration, phosphoric acid concentration and temperature effects were investigated for the optimum hydrogen production from ethanolysis and hydrolysis reactions of KBH4. The maximum hydrogen production rates in the ethanolysis and hydrolysis reactions with 1 M phosphoric acid are 6423 and 4296 ml min 1g 1, respectively. At the same time, the ethanolysis and hydrolysis reactions with the 1 M acid concentration were completed within 7 and 9 s, respectively. The total conversions obtained for the volume ratio of KBH4/acid of (1:1) were 100%. The power law kinetic model is performed for the kinetic studies. The activation energies for the ethanolysis and hydrolysis reactions of KBH4 using phosphoric acid are found as 2.98 and 2.60 kJ mol 1

    Influence of process parameters on enhanced hydrogen generation via semi-methanolysis and semi-ethanolysis reactions of sodium borohydride using phosphoric acid

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    The sodium borohydride(NaBH4) semi-methanolysis and semi-ethanolysis reactions to produce hydrogen are investigated using phosphoric acid(H3PO4) for the first time. The NaBH4 concentration, H3PO4 concentration, and temperature parameters on these semialcoholysis reactions are evaluated. The normalized hydrogen generation rates (HGRs) obtained from the NaBH4 semi-methanolysis and semi-ethanolysis acidified using 0.5 M H3PO4 are 11684 and 9981 ml min 1 g 1, respectively. Moreover, the completion times of these semi-methanolysis and semi-ethanolysis reactions with 0.5 M H3PO4 acid concentration are 0.10 and 0.116 min, respectively. Kinetic studies with the power-law mode

    Removal of methylene blue from aqueous solutions by using cold plasma-and formaldehyde-treated onion skins

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    In this paper, the use of cold plasma-treated and formaldehyde-treated onion skins as a biosorbent has been investigated to remove methylene blue dye from aqueous solutions. The surface characteristics of the treated onion skins were investigated using Fourier Transform–infrared spectroscopy. The influence of process variables such as adsorbent dosage, initial dye concentration and pH were studied. Equilibrium isotherms were analysed by Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. The results indicated that the data for adsorption of methylene blue onto onion skins fitted well with the Langmuir isotherm model. The sorption capacities for cold plasma-treated and formaldehyde-treated onion skins by Langmuir isotherm were found to be 250 and 166.67 mg/g, respectively. The equilibrium time was found to be 150 min for 50 mg/l dye concentrations. The maximum removals for cold plasma-treated and formaldehyde-treated onion skins obtained were 90.94 and 95.54% at natural pH 10.0 for adsorbent doses of 0.15 g/200 ml, respectively. The rates of sorption were found to conform to pseudo-first-order kinetics. Results indicated that onion skins could be used as a biosorbent to remove methylene blue dye from contaminated waters

    Preparation and characterization of activated carbon from acorn shell by physical activation with H2O–CO2 in two-step pretreatment

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    Activated carbons have been prepared by physical activation with H2O–CO2 in two-step pre-treatment including ZnCl2–HCl from acorn shell at 850 °C. The active carbons were characterized by N2 adsorption at 77 K. Adsorption capacity was demonstrated by the iodine numbers. The surface chemical characteristics of activated carbons were determined by FTIR spectroscopic method. The microstructure of the activated carbons prepared was examined by scanning electron microscopy. The maximum BET surface area of the obtained activated carbon was found to be around 1779 m2/g

    Optimisation of sepiolite clay with phosphoric acid treatment as support material for CoB catalyst and application to produce hydrogen from the NaBH4 hydrolysis

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    Herein, the CoB catalyst supported on the sepiolite clay treated with phosphoric acid was utilized to produce hydrogen from the NaBH4 hydrolysis. In order to analyse the performance of the phosphoric acid treated sepiolite clay supported-CoB catalyst, the NaBH4 concentration effect, phosphoric acid concentration effect, phosphoric acid impregnation time effect, CoB catalyst percentage effect, and temperature effect were studied. In addition, XRD, XPS, SEM, TEM, BET, and FTIR analysis were performed for characterization of CoeB catalyst supported on the acid-treated sepiolite. The completion time of this hydrolysis reaction with CoeB (20%) catalyst supported on the sepiolite treated by 5 M phosphoric acid was approximately 80 min, whereas the completion time of this hydrolysis reaction with acid-free sepiolite-supported CoeB (20%) catalyst was approximately 260 min. There is a five-fold increase in the maximum production rate. The maximum hydrogen production rates of this hydrolysis reaction at 30 and 60 C were found as 1486 and 5025 ml min 1g 1 catalyst, respectively. Activation energy was found as 21.4 kJ/mol. This result indicates that the acid treatment on sepiolite is quite successful. The re-usability of NaBH4 hydrolysis reaction by CoB catalyst supported on sepiolite treated phosphoric acid for successive five cycles of NaBH4 at 30 C was investigated
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