scholarly journals REMOVAL OF DIQUATERNARY AMMONIUM CATIONS FROM AS-SYNTHESIZED SSZ-16 ZEOLITE

2017 ◽  
Vol 9 ◽  
pp. 26 ◽  
Author(s):  
Tatana Supinkova ◽  
Ivan Jirka ◽  
Jan Drahokoupil ◽  
Jan Langmaier ◽  
Vlastimil Fila ◽  
...  
Keyword(s):  
Chemical Technology ◽  
Structure Directing Agent ◽  
Phase Purity ◽  
Synthesis Conditions ◽  
Catalytic Transformations ◽  
Optimum Synthesis ◽  
Diquaternary Ammonium

Zeolites are stable microporous aluminosilicates with numerous applications in chemical technology such as separation of species and catalytic transformations. Our study is focused on a weakly explored zeolite SSZ-16 with pore constrictions defined by 8-membered oxygen rings. Key results are the preparation of Et6-diquat-5 dication used as a structure directing agent (SDA) and finding the optimum synthesis conditions with respect to zeolite phase purity. Stability of SDA was examined in conditions similar to those of autoclave synthesis (concentration, pH, temperature). Moreover, the content and location of SDA species in zeolite phase and conditions of SDA decomposition were investigated.

scholarly journals Synthesis, Analysis, and Testing of BiOBr-Bi2WO6Photocatalytic Heterojunction Semiconductors

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xiangchao Meng ◽  
Zisheng Zhang
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Degradation Process ◽  
Light Irradiation ◽  
Enhancement Effect ◽  
Electron Hole ◽  
Experimental Conditions ◽  
Synthesis Conditions ◽  
Optimum Synthesis ◽  
Photocatalytic Activities

In photocatalysis, the recombination of electron-hole pairs is generally regarded as one of its most serious drawbacks. The synthesis of various composites with heterojunction structures has increasingly shed light on preventing this recombination. In this work, a BiOBr-Bi2WO6photocatalytic heterojunction semiconductor was synthesized by the facile hydrothermal method and applied in the photocatalytic degradation process. It was determined that both reaction time and temperature significantly affected the crystal structure and morphologies of the photocatalysts. BiOBr (50 at%)-Bi2WO6composites were prepared under optimum synthesis conditions (120°C for 6 h) and by theoretically analyzing the DRS results, it was determined that they possessed the suitable band gap (2.61 eV) to be stimulated by visible-light irradiation. The photocatalytic activities of the as-prepared photocatalysts were evaluated by the degradation ofRhodamine B (RhB)under visible-light irradiation. The experimental conditions, including initial concentration, pH, and catalyst dosage, were explored and the photocatalysts in this system were proven stable enough to be reused for several runs. Moreover, the interpreted mechanism of the heterojunction enhancement effect proved that the synthesis of a heterojunction structure provided an effective method to decrease the recombination rate of the electron-hole pairs, thereby improving the photocatalytic activity.

scholarly journals Flocculation of a High-Turbidity Kaolin Suspension Using Hydrophobic Modified Quaternary Ammonium Salt Polyacrylamide

Processes ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 108 ◽  
Author(s):  
Jiangya Ma ◽  
Xue Fu ◽  
Wei Xia ◽  
Kun Fu ◽  
Yi Liao
Keyword(s):  
Solid Content ◽  
Experimental Simulation ◽  
Illumination Time ◽  
Flocculation Mechanism ◽  
Synthesis Conditions ◽  
Optimum Synthesis ◽  
Dimethyl Ammonium ◽  
Stirring Time ◽  
High Turbidity ◽  
Method Show

In this work, a novel cationic polyacrylamide (PAMD) was synthesized by acrylamide (AM) diallyl dimethyl ammonium chloride (DMD) and dodecyl polyglucoside (DPL) under low-pressure ultraviolet (UV) initiation. The intrinsic viscosity and cationic degree of PAMD were optimized in copolymerization. The optimum synthesis conditions that affect polymerization were determined to be solid content 30%, DPL content 25%, DMD content 30%, illumination time 135 min, and pH 9. The flocculation performance of flocculant PAMD with a high cationic degree was investigated in the purification of high-turbidity water. The flocculation mechanism was correspondingly studied and summarized based on Fourier transform-infrared (FTIR) analysis. Finally, the results of an experimental simulation using the response surface method show that 98.9% supernatant transmittance was achieved under dosage 4 mg/L, fast stirring time 20 min, pH 7, and stirring speed 320 rpm.

scholarly journals Green Synthesis and Characterization of High-Purity Monodispersed Cupric Oxide (CuO) Nanopowder

2019 ◽  
Vol 801 ◽  
pp. 351-356
Author(s):  
Yuan Teng Foo ◽  
Li Ting Foo ◽  
Ladan Shahcheragh ◽  
Bahman Amini Horri ◽  
Babak Salamatinia
Keyword(s):  
Green Synthesis ◽  
High Purity ◽  
Cupric Oxide ◽  
Sol Gel ◽  
Synthesis Method ◽  
Ionic Exchange ◽  
Synthesis Conditions ◽  
Calcination Temperatures ◽  
Optimum Synthesis ◽  
Exchange Material

In this study, high quality monodispersed nanocrystalline cupric oxide (CuO) nanopowder was prepared through novel sol-gel green synthesis method, assisted by sodium alginate (Na-ALG) as the green ionic exchange material. The morphology and structural properties of CuO nanopowders synthesized with and without the incorporation of extrusion dripping, at different Na-ALG solution concentrations and calcination temperatures, were studied using thermalgravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and Raman spectroscopy. Optimum synthesis conditions were identified, resulting in high-purity, monodispersed nanocrystalline CuO powder in the range of 9.92 – 12.4 nm, which could have a promising future in various applications.

scholarly journals Synthesis of high-silica ZSM-5 with seeds in the presence of ethanol and amine

Cerâmica ◽  
2019 ◽  
Vol 65 (375) ◽  
pp. 378-387
Author(s):  
T. R. D. Mendonça ◽  
J. R. Santos ◽  
L. R. A. Sarmento ◽  
D. C. M. Silva ◽  
O. M. S. Cysneiros ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Organic Compounds ◽  
Nitrogen Adsorption ◽  
Structure Directing Agent ◽  
X Ray ◽  
Synthesis Conditions ◽  
Combined Use ◽  
Cracking Reaction ◽  
High Silica ◽  
Alternative Structure

Abstract The possibility of crystallization of ZSM-5 with high Si/Al ratio was evaluated through the combined use of crystallization seeds and organic compounds that are not conventional directing agents for ZSM-5 (ethanol, methylamine, ethylamine, propylamine, butylamine, isopropylamine and diethylamine) in order to find a less toxic and costly route of synthesis. In addition, the influence of the stirring during the crystallization step on the properties of the ZSM-5 obtained in these synthesis conditions was verified. The obtained zeolites were analyzed by X-ray diffractometry in order to understand the effects of the templates. The analyses of NH3-TPD, nitrogen adsorption, SEM, and TG/DTA were performed for the samples with better crystallinity. The procedure was successfully employed for the synthesis of MFI samples using propylamine as an alternative structure-directing agent. Its mean crystallite size ranged from 23 to 24 nm and was efficient in the cracking reaction of n-hexane.

Growth of Carbon Nanocoils Using Chemical Vapor Deposition

2009 ◽  
Vol 79-82 ◽  
pp. 1851-1854
Author(s):  
C.C. Su ◽  
Y.L. Hsieh ◽  
S.H. Chang
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Silicon Substrates ◽  
Synthesis Conditions ◽  
Optimum Synthesis ◽  
Coil Geometry ◽  
Vapor Deposition Technique ◽  
Electro Magnetic ◽  
Mechanical Sensing

We present the synthesis of carbon nanocoils using the chemical vapor deposition technique with metal catalysts on silicon substrates. The optimum synthesis conditions and coil geometry are summarized. The coils have distribution of the outside diameter of 300 nm to 1200 nm, wire diameter of 150 nm to 400 nm and the pitch of the coil of 150 nm to 1200 nm. Applications of the developed carbon nanocoils can be electro-mechanical sensing and the electro-magnetic insulation.

Preparation and Application of a Novel Formaldehyde-Free Fixing Agent

2015 ◽  
Vol 713-715 ◽  
pp. 2793-2797
Author(s):  
Jian Ping Liu
Keyword(s):  
Ammonium Chloride ◽  
Sodium Sulfite ◽  
Ammonium Persulfate ◽  
Color Fastness ◽  
Reactive Dyeing ◽  
Synthesis Conditions ◽  
Optimum Synthesis ◽  
Initiation System ◽  
Binary Polymer

Using diallylamine , hydrochloric and dimethyl diallyl ammonium chloride as reactants, ammonium persulfate / sodium sulfite as initiation system,binary polymer was prepared in water phase.The binary polymer was applied to cotton of reactive dyeing as a fixing agent,propreities of fixing fabric were tested.The results showed that the optimum synthesis conditions were as follows: 50 g of diallylamine, 600 g of 40% dimethyl diallyl ammonium chloride,6 g of ammonium persulfate, dropping of initiation at 80°C for 3 h.The reactive dyeings after binary polymer treatment had fairly good color fastness with 4-5 grade to dry rubbing,4 grade to wet rubbing, color fastness with good to soaking and formaldehyde-free.

Fe/SiO2 Nanocomposite Soft Magnetic Materials

2001 ◽  
Vol 703 ◽  
Author(s):  
S. Hui ◽  
Y. D. Zhang ◽  
T. D. Xiao ◽  
Mingzhong Wu ◽  
Shihui Ge ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Materials ◽  
Annealing Temperature ◽  
Magnetic Measurements ◽  
Soft Magnetic Materials ◽  
Crystallographic Structure ◽  
Ferromagnetic Behavior ◽  
Soft Magnetic ◽  
Synthesis Conditions ◽  
Optimum Synthesis

ABSTRACTIn an effort to explore new highly resistive soft magnetic materials, Fe/SiO2 nanocomposite materials have been synthesized using a wet chemical reaction approach in which the precursor complex was annealed at various temperatures. The crystallographic structure, nanostructure, morphology, and magnetic properties of the synthetic Fe/SiO2 particles were studied by x-ray diffraction, transmission electron microscopy, and magnetic measurements. The experimental results show that for this approach, the [.alpha]-Fe particles are coated with amorphous silica. The progress of the reaction, the purity of Fe/SiO2 in the synthetic powder, and the Fe particle size are highly dependent on the annealing temperature. By adjusting the annealing temperature, the particle size can be controlled from approximately 20 nm to 70 nm. For the synthetic nanopowder obtained by H2 reduction at 400 °C, there exists a superparamagnetic behavior below room temperature; while for the nanopowders obtained by reduction at higher temperatures, the ferromagnetic behavior is dominant. Based on these studies, optimum synthesis conditions for Fe/SiO2 nanocomposites is determined.

scholarly journals A Guide to Water Free Lithium Bis(oxalate) Borate (LiBOB)

2021 ◽  
Author(s):  
Ceren Zor ◽  
Yaprak Subaşı ◽  
Durata Haciu ◽  
Mehmet Somer ◽  
Semih Afyon
Keyword(s):  
Low Cost ◽  
Lithium Carbonate ◽  
Phase Changes ◽  
Protective Atmosphere ◽  
Ambient Conditions ◽  
Protective Measures ◽  
Synthesis Conditions ◽  
Optimum Synthesis ◽  
Physical And Chemical ◽  
Processing Steps

The use of LiBOB is limited due to slight instability issues under ambient conditions that might require extra purification steps and might result in poorer performances in real systems. Here, we address some of these issues and report the high purity water free LiBOB synthesized with fewer processing steps employing lithium carbonate, oxalic acid, and boric acid as low-cost starting materials, and via ceramic processing methods under protective atmosphere. The physical and chemical characterizations of both anhydrous and monohydrate phases are performed with X-ray powder diffraction (XRPD), Fourier-transform infra-red spectroscopy (FTIR), Raman spectroscopy and scanning electron microscopy (SEM) analyses to determine the degree of the purity and the formation of impurities like LiBOB.H<sub>2</sub>O, HBO<sub>2 </sub>and Li<sub>2</sub>C<sub>2</sub>O<sub>4</sub> as a result of the aging investigations performed. Differential thermal analysis (DTA) is applied to determine the optimum synthesis conditions for anhydrous LiBOB and to analyze the water loss and the decomposition of LiBOB.H<sub>2</sub>O. Aging experiments with the water free LiBOB are carried out to evaluate the effect of humidity in the phase changes and resulting impurities under various conditions. The detrimental effect of even slightest humidity conditions is shown, and protective measures during and after the synthesis of LiBOB are discussed.

scholarly journals Zirconium Oxide Stabilized By Scandium (III) And Cerium (IV) Complex Oxides As The Basis For Preparation Of Thick Films And Multilayers Structures For Low Temperature (600 °C) Fuel Cell

2018 ◽  
Vol 6 (1) ◽  
pp. 16-20
Author(s):  
Oleksandr Vasylyev ◽  
Yehor Brodnikovskyi ◽  
Oleg V'yunov ◽  
Leonid Kovalenko ◽  
Oleg Yanchevskii ◽  
...  
Keyword(s):  
Zirconium Oxide ◽  
Zirconium Dioxide ◽  
Thick Films ◽  
Tape Casting ◽  
Complex Oxides ◽  
Oxygen Conductivity ◽  
Synthesis Conditions ◽  
Optimum Synthesis ◽  
Electrolyte Film ◽  
Porous Anode

Weakly agglomerated zirconium dioxide nanopowders stabilized by complex oxides of scandium (III) and cerium (IV) were synthesized by precipitation from aqueous solutions. Using weakly agglomerated nanopowders, thick films were prepared by tape casting on a-Al2O3 substrates. These thick films have high oxygen conductivity; and their electron conductivity is lower than oxygen conductivity by 4 orders of magnitude. A multilayer system consisting of films of polycrystalline porous anode and solid electrolyte was prepared. The diffusion of cations in the anode boundary layer and change in the chemical composition of the electrolyte film are not observed at optimum synthesis conditions.

Investigation of Synthesis Parameters for Modification of Chitosan with Enrofloxacin

2015 ◽  
Vol 659 ◽  
pp. 436-440
Author(s):  
Saniwan Srithongkham ◽  
Piyawadee Sutcharee ◽  
Amornrat Lertworasirikul
Keyword(s):  
Reaction Times ◽  
Coupling Agents ◽  
Amino Group ◽  
Synthesis Conditions ◽  
E Coli ◽  
Chemical Structures ◽  
Optimum Synthesis ◽  
Carbodiimide Hydrochloride ◽  
Synthesis Parameters ◽  
Ft Ir

This research aims to investigate synthesis parameters for modification of chitosan with enrofloxacin. Most modifications of chitosan are focused on amino group. There are many methods for modification of chitosan, for example, conjugation of amino group with carboxylic group by coupling agents. 1-Ethyl-3-(3-(dimethylamino) propyl) carbodiimide hydrochloride (WSC) andN-hydroxysuccinimide (NHS) are widely used coupling agents for amide formation under mild conditions. Those two coupling agents were applied in this study. Optimum amount and ratio of coupling agents, amount of enrofloxacin and reaction times were investigated. The chemical structures were characterized by Fourier transform infrared spectroscopy (FT-IR). The optimum synthesis conditions were determined from the absorbance ratios. Chitosan-enrofloxacin has antibacterial activity against bothS. aureusandE. coli.

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