scholarly journals Performance of Ethane Dehydrogenation over PtSn Loaded onto a Calcined Mg(Al)O LDH with Three Mg:Al Molar Ratios Using a Novel Method

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 296 ◽  
Author(s):  
Shuqi Fang ◽  
Kang Bi ◽  
Qiao Zhang ◽  
Lingpeng Chen ◽  
Yongming Sun ◽  
...  
Keyword(s):  
Molar Ratio ◽  
Structure And Properties ◽  
Exchange Method ◽  
Molar Ratios ◽  
Ethane Dehydrogenation ◽  
Novel Method ◽  
Layered Solid ◽  
Double Hydroxide ◽  
Positively Charged ◽  
Ptsn Catalysts

Layered double hydroxide (LDH) is a layered solid containing positively charged layers with negatively charged anions as an interchangeable interlayer. In this research, Mg(Al)O supports were synthesized with three different Mg:Al molar ratios, and bimetallic PtSn catalysts were loaded onto the supports via the anion exchange method. The properties of ethane dehydrogenation of the PtSn/Mg(Al)O catalysts were investigated. The results show that the structure and properties of the PtSn/Mg(Al)O catalysts were influenced by the Mg:Al molar ratio of the hydrotalcites, which consequently influenced the ethane dehydrogenation performance. When the Mg:Al ratio was 5:1, the ethane dehydrogenation performance was optimal, relative to the Mg:Al ratios of 2:1 and 10:1.

The Effect of Zinc to Aluminium Molar Ratio on the Physico-Chemical Properties of Zinc-Aluminium-3,4-Dichlorophenoxy Acetate Nanocomposite

2013 ◽  
Vol 756 ◽  
pp. 127-134
Author(s):  
Sheikh Ahmad Izaddin Sheikh Mohd Ghazali ◽  
Mohd Zobir Hussein ◽  
Siti Halimah Sarijo
Keyword(s):  
Layered Double Hydroxide ◽  
Mole Fraction ◽  
Self Assembly ◽  
Chemical Properties ◽  
Zinc Ion ◽  
Molar Ratio ◽  
Basal Spacing ◽  
Molar Ratios ◽  
Assembly Method ◽  
Double Hydroxide

Layered double hydroxide (LDH) hybrid materials of Zn-Al-layered double hydroxide-3,4-dichlorophenoxy acetate acidnanocomposites (ZADs) were prepared by direct self-assembly method. The pH of the solution was adjusted to 7.5 using 2M NaOH. Various Zn2+ to Al3+ molar ratios, R ranging from 1 to 6 were used with a fixed concentration of 3,4-D at 0.3 M. The Powder X-ray diffraction (PXRD) patterns showed the formation of well-ordered nanocomposite with the expansion of basal spacing from 8.9 Å in the Zinc-Aluminium-Layered Double Hydroxide (ZAL) to 18.7 - 22.1 Å in the resulting nanocomposites. The Fourier transform infrared (FTIR)spectra for the nanocomposites showed features for both ZAL and ZAD, showing the successful intercalation of the organic moiety into the LDH interlayer. The percentage loading of 3,4-dichlorophenoxy acetati acid(3,4-D) in LDH was found to be increased from 34.7-48.1 % (w/w), as the mole fraction of Al decreased from 0.44-0.15. This study shows that the mole fraction of zinc ion was replaced by aluminium ion in the LDH plays an important role in controlling the physic-chemical properties of the resulting material.

scholarly journals Synthesis and characterization of two-dimensional (2D) nanosheet zinc aluminum layered double hydroxide (Zn/Al LDH) via an alkali-free route

2021 ◽  
Vol 15 (1) ◽  
pp. 82
Author(s):  
Rabiatul Adawiyah Mohd Agus ◽  
Siti Khatijah Deraman ◽  
Nazrizawati A. Tajuddin
Keyword(s):  
Layered Double Hydroxide ◽  
Nitrate Solution ◽  
Zinc Nitrate ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Sem Image ◽  
Constant Ph ◽  
Xrd Patterns ◽  
Double Hydroxide

The effect of different molar ratios on the synthesis of zinc aluminium layered double hydroxide (Zn/Al LDH) via an alkali-free route was carried out in this research. This method was prepared by mixing zinc nitrate solution, aluminium nitrate solution, and ammonium carbonate solution at a constant pH of 8.5 with a spanning ratio of Zn to Al from 4:1, 3:1, and 2:1. The XRD patterns showed crystal nanostructure of Zn/Al LDHs was successfully formed. The lattice parameters (a and c) were slightly increased with the increasing of Zn/Al molar ratio. A larger hexagonal platelet is observed in the SEM image align with the high molar ratio of Zn/Al synthesized. The same trend has been observed in the FTIR spectra.   Keywords: Zn/Al LDH, alkali-free route, different molar ratio, XRD, SEM, FTIR

scholarly journals Removal of methylene blue from aqueous solution using Mg-Fe, Zn-Fe, Mn-Fe layered double hydroxide

2020 ◽  
Vol 81 (12) ◽  
pp. 2522-2532
Author(s):  
Zhongliang Shi ◽  
Yanmei Wang ◽  
Shuyu Sun ◽  
Cheng Zhang ◽  
Haibo Wang
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Langmuir Adsorption ◽  
Molar Ratios ◽  
Pseudo Second Order ◽  
Co Precipitation ◽  
Double Hydroxide ◽  
Double Hydroxides

Abstract Layered double hydroxides (LDH) with highly flexible and adjustable chemical composition and physical properties have attracted tremendous attention in recent years. A series of LDH with different M (Mg, Zn, Mn)-Fe molar ratios were synthesized by the double titration co-precipitation method. The effect of the factors, including M (Mg, Zn, Mn) : Fe molar ratio, pH, and M-Fe LDH dosage, on the ability of the prepared M-Fe LDH to remove cationic methylene blue (MB) dye from aqueous solution were investigated. Results indicated that the removal efficiency of MB (10 mg/L) was the best at the M (Mg, Zn, Mn): Fe molar ratio of 3:1 by using 2.0 g/L of M-Fe LDH at pH 6.0 under 298.15 K. Mg-Fe LDH had the highest removal performance (71.94 mg/g at 298.15 K) for MB compared to those of the Zn-Fe and Mn-Fe LDH. Zn-Fe LDH with the smallest activation energy resulted in the fastest adsorption rate of MB. The pseudo-second-order model and Langmuir adsorption isotherm were also successfully applied to fit the theory of M-Fe LDH for removal of MB.

Investigation of Antibacterial Property and Photocatalytic Activity of Recyclable Ag/ZnOw Composites

2014 ◽  
Vol 472 ◽  
pp. 831-834
Author(s):  
Jie Wang ◽  
Xiao Yong Pan ◽  
Ling Peng ◽  
Yu Liu ◽  
Nian Jie Wang
Keyword(s):  
Silver Nanoparticles ◽  
Photocatalytic Performance ◽  
Antibacterial Property ◽  
Photocatalytic Property ◽  
Molar Ratio ◽  
Structure And Properties ◽  
Simple Method ◽  
Molar Ratios ◽  
Photocatalytic Activities ◽  
Oxide Whisker

Silver-deposited zinc oxide whisker (Ag/ZnOw) composites with different Ag/Zn molar ratios (MRs) were successfully synthesized by a simple method. Subsequently, the structure and properties of these composites were characterized using various tests. It is found that the silver nanoparticles are located on the root of ZnOw, which is beneficial for the antibacterial and photocatalytic performance of ZnOw. The Ag/ZnOw composite exhibits better antibacterial and photocatalytic activities than that of the pure ZnOw, and the efficiency of both properties increase with increasing molar ratio of Ag/Zn. Moreover, the mechanism which governs the photocatalytic property of the composite has also been discussed thoroughly.

scholarly journals Influence of Zn/Fe Molar Ratio on Optical and Magnetic Properties of ZnO and ZnFe2O4Nanocrystal as Calcined Products of Layered Double Hydroxides

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Abdullah Ahmed Ali Ahmed ◽  
Zainal Abidin Talib ◽  
Mohd Zobir Hussein ◽  
Moayad Husein Flaifel ◽  
Naif Mohammed Al-Hada
Keyword(s):  
Magnetic Properties ◽  
Near Infrared ◽  
Mixed Oxides ◽  
Diffuse Reflectance Spectroscopy ◽  
Molar Ratio ◽  
Nanometer Scale ◽  
X Ray Diffraction ◽  
Molar Ratios ◽  
Double Hydroxide ◽  
Double Hydroxides

The coprecipitation method has been used to synthesize layered double hydroxide (Zn-Fe-LDH) nanostructure at different Zn2+/Fe3+molar ratios. The structural properties of samples were studied using powder X-ray diffraction (PXRD). LDH samples were calcined at 600°C to produce mixed oxides (ZnO and ZnFe2O4). The crystallite size of mixed oxide was found in the nanometer scale (18.1 nm for ZnFe2O4and 43.3 nm for ZnO). The photocatalytic activity of the calcination products was investigated using ultraviolet-visible-near infrared (UV-VIS-NIR) diffuse reflectance spectroscopy. The magnetic properties of calcined LDHs were investigated using a vibrating sample magnetometer (VSM). The calcined samples showed a paramagnetic behavior for all Zn2+/Fe3+molar ratios. The effect of molar ratio on magnetic susceptibility of the calcined samples was also studied.

Effect of Different Molar Ratios of Fenton Reagents on the Surface Modification of CNTs

2011 ◽  
Vol 236-238 ◽  
pp. 2036-2039
Author(s):  
Yin Qiang ◽  
Jian Hua Xin
Keyword(s):  
Carbon Nanotubes ◽  
Molar Ratio ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
Uv Treatment ◽  
X Ray ◽  
Molar Ratios ◽  
Fenton Reagents ◽  
Result Show ◽  
Novel Method

A novel method——Fenton/UV treatment, was used to modificate carbon nanotubes (CNTs) in our research. Effects of different molar ratios of Fenton reagents on the surface of CNTs were studied in our work. The purity of CNTs was investigated by TGA. The functional groups on the surface of CNTs were investigated by FTIR spectra, and the phase analysis of CNTs was investigated by X-ray diffraction analysis (XRD). The result show that it can introduce a great deal of hydroxyl groups onto the surface of carbon nanotubes, and almost never introduce impurities, when the molar ratio of Fe2+and H2O2 is 1:40.

Synthesis of Calcium/Aluminium-Ciprofloxacin-Layered Double Hydroxide for a New Antibacterial Drug Formulation

2021 ◽  
Vol 317 ◽  
pp. 233-238
Author(s):  
Monica Limau Jadam ◽  
Zaemah Jubri ◽  
Siti Halimah Sarijo
Keyword(s):  
Layered Double Hydroxide ◽  
Drug Formulation ◽  
Molar Ratio ◽  
Basal Spacing ◽  
Antibacterial Drug ◽  
X Ray Diffraction ◽  
Exchange Method ◽  
Prospective Application ◽  
Double Hydroxide ◽  
Novel Drug

An antibacterial drug, ciprofloxacin (Cipro) was successfully encapsulated into Ca/Al-layered double hydroxide (CLDH) with molar ratio Ca/Al = 3:1 (R3) by anion exchange method at optimum concentration of 0.2 M Cipro. The successful intercalation was confirmed by patterns analysis of powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), elemental analysis (CHNS) and accelerated surface area and porosity (ASAP) analysis. Basal spacing of CLDH synthesized in this study is 8.7 Å. Due to the inclusion of Cipro into the layered CLDH, basal spacing expanded to 16.2 Å in Ca/Al-Cipro-LDH (CCLDH) compare to in CLDH. The FTIR spectra of the hybrid nanocomposite show resemblance peaks of the layered double hydroxide (LDH) and Cipro, indicating the inclusion of the drug anion into the LDH interlamellae. The percentage loading of Cipro calculated from the data obtained from CHNS is 75.9% (w/w). This shows that Ca/Al-layered double hydroxide, CLDH has prospective application as the host for ciprofloxacin (1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid), an antibacterial drug for a novel drug delivery formulation.

Camptothecin in Sterically Stabilized Phospholipid Nano-Micelles: A Novel Solvent pH Change Solubilization Method

2006 ◽  
Vol 6 (9) ◽  
pp. 2996-3000 ◽  
Author(s):  
Otilia M. Y. Koo ◽  
Israel Rubinstein ◽  
Hayat Onyuksel
Keyword(s):  
Topoisomerase I ◽  
Molar Ratio ◽  
Ph Change ◽  
Passive Targeting ◽  
Molar Ratios ◽  
Sterically Stabilized Micelles ◽  
Mean Size ◽  
Novel Method ◽  
Kinetics Of ◽  
Pegylated Phospholipids

Camptothecin (CPT) is a topoisomerase I inhibitor that acts against a broad spectrum of cancers. Unfortunately clinical application of CPT is limited by insolubility, instability, and toxicity problems. To circumvent these delivery problems of CPT, we propose biocompatible, targeted sterically stabilized micelles (SSM) as nanocarriers for CPT (CPT-SSM). SSM composed of polyethylene glycol (PEGylated) phospholipids are attractive nanocarriers for CPT delivery because they are sufficiently small to extravasate through the leaky microvasculature of tumor and inflamed tissues for passive targeting. The purpose of this study was to develop a novel method of preparing CPT-SSM based on its pH dependent, reversible carboxylate-lactone conversion chemistry. CPT carboxylate was added to SSM at pH 5 that favored the formation of active but hydrophobic CPT lactone for spontaneous association with SSM. The kinetics of CPT conversion and CPT-SSM formation, and the effect of varying CPT-PEGylated phospholipid molar ratio on CPT-SSM properties and CPT solubilization were evaluated. CPT converted gradually from the carboxylate form to lactone, and CPT-SSM were formed after 12 h incubation. The mean size of CPT-SSM was ∼14 nm. CPT solubilization (∼12 μg/ml) and other CPT-SSM micelle properties did not change significantly with increasing CPT to PEGylated phospholipid molar ratios using this novel method, unlike the coprecipitation/reconstitution technique previously reported. This reproducible CPT solubilization in SSM was attributed to avoidance of drug aggregate formation by this method. The advantages of our solvent pH change method to prepare CPT-SSM support further investigations of this approach to other hydrophobic drugs similar to CPT in chemistry and also CPT molecular solubilization in other nanocarriers.

Physical - Chemical Issues of Cephalosporin Intercalated Nanoparticles for Life - Threatening Infections Treatment

2001 ◽  
Vol 71 (3) ◽  
pp. 342-349
Author(s):  
Lucian Eva ◽  
Letitia Doina Duceac ◽  
Liviu Stafie ◽  
Constantin Marcu ◽  
Geta Mitrea ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Advanced Characterization ◽  
Generation Cephalosporin ◽  
Fourth Generation ◽  
Exchange Method ◽  
Physico Chemical ◽  
Life Threatening ◽  
Double Hydroxide ◽  
Double Hydroxides

The fourth generation cephalosporin antibacterial agent, cefepime, was loaded into layered double hydroxides for enhancing antibiotic efficiency, reducing side effects, as well as achieving the sustained release property. The intercalation of antibiotic into the inter-gallery of ZnAl-layered double hydroxide (LDH) was carried out using ion exchange method, by this constituting a nano-sized organic-inorganic hybrid material for a controlled release novel formulation. Although cefepime is a broad spectrum antibiotic, it has various adverse effects and a significant degradation rate. Thus, the preparation and physico-chemical characterization of nanomaterials able to intercalate this drug is an important study for medical and pharmaceutical field. The antibiotic inclusion into LDHs nanostructure was confirmed by advanced characterization techniques and the release profile of cefepime was analysed with the respect to pH of the simulated media.

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