Oil Drop Method Research Articles

Влияние температуры стадии формования и нейтрализации на свойства сферического носителя катализаторов риформинга, получаемого методом масляного формования

The work is devoted to the study of an oil-drop method for the production of spherical alumina used as a carrier for reforming catalysts with continuous regeneration. The mechanism of transformations occurring during spherical alumina forming by the oil-drop method from mixture of aluminum oxychloride and urotropin used as a gelling agent is proposed. The semi-quantitative composition of spheres after the neutralization stage is calculated on the basis of physicochemical methods of analysis. The possibility of obtaining spherical alumina with different physicochemical properties by varying temperature of the forming and neutralization stage is shown. Increasing the temperature of the neutralization stage leads to a narrower pore size distribution - the formation of more uniform pores with a smallercontribution of pores with a diameter greater than 170 angstroms. The strength of the obtained alumina is significantly affected: the strength increases several times with increasing the temperature of the neutralization stage.

Технология приготовления сферического носителя для катализатора непрерывного риформин

The paper presents the technology of spherical alumina production by oil-drop method developed at RN-RDC, LLC. Alumina is modified by tin oxide and is used for the synthesis of reforming catalysts with continuous catalyst regeneration.

Liquid seal for compact micropiston actuation at the capillary tip.

Actuators at the tip of a submillimetric catheter could facilitate in vivo interventional procedures at cellular scales by enabling tissue biopsy and manipulation or supporting active micro-optics. However, the dominance of frictional forces at this scale makes classical mechanism problematic. Here, we report the design of a microscale piston, with a maximum dimension of 150 μm, fabricated with two-photon lithography onto the tip of 140-μm-diameter capillaries. An oil drop method is used to create a seal between the piston and the cylinder that prevents any leakage below 185-mbar pressure difference while providing lubricated friction between moving parts. This piston generates forces that increase linearly with pressure up to 130 μN without breaking the liquid seal. The practical value of the design is demonstrated with its integration with a microgripper that can grasp, move, and release 50-μm microspheres. Such a mechanism opens the way to micrometer-size catheter actuation.

Effect of Aging Temperature of Support on Catalytic Performance of PtSnK/Al2O3 Propane Dehydrogenation Catalyst

Catalytic dehydrogenation of propane to propylene is one of the vital processes in the petrochemical industry, primarily because of the extensive use of propylene as one of the most crucial building blocks for the production of a wide range of essential chemicals and polymers. In this study, the nano-structural PtSnK was supported on an alumina carrier prepared by an environmentally friendly modified oil-drop method. By adjusting the aging temperature of the alumina carrier, the physical and chemical structural properties of the catalyst can be modulated, and then affect the propane dehydrogenation performance of the catalyst. The effects of aging temperature on the structure and chemical properties of the support and catalyst were studied by N2 sorption, XRD, TEM, TG, NH3-TPD, H2-TPR, CO pulse adsorption, and XPS techniques. As the aging temperature increases, the spherical particles gradually changed from a worm-like structure to a needle or rod-like structure. At the same time, the pore size and volume increase, the pore size distribution becomes wider. Besides, the aging temperature also affects the interaction between the supported metal and the alumina support. The higher aging temperature can inhibit the reduction of SnOx species and enhance the interaction between Sn species and the alumina support. All these features together ensure excellent propane dehydrogenation performance and high stability of the catalyst. When the aging temperature is 140 °C, the PtSnK/Al2O3 catalyst exhibits excellent catalytic propane dehydrogenation performance, with an average propane conversion of 36.5%, average propylene selectivity of 96.5% during 50 h reaction. We reported the modulation of the aging temperature on the physical and chemical properties of the PtSnK/Al2O3 propane dehydrogenation catalyst when the alumina carrier is prepared by the oil-drop method. In order to obtain an optimal propane dehydrogenation catalyst, an optimum aging temperature is preferred to provide a catalyst with high propane conversion, propylene selectivity and catalyst stability.

Preparation of porous alumina adsorbent from kaolin using acid leach method: studies on removal of fluoride toxic ions from an aqueous system

In the present study, feasibility of the porous alpha alumina beads for the removal of fluoride has been investigated. The porous alumina beads were fabricated by choosing the low-cost method i.e., oil drop method through extraction of alumina from kaolin. Extraction of alumina from kaolinite is a well-defined process from long decade. After preparation, alumina beads were characterized using powder X-ray diffractometer (XRD) which shows major phase as alpha alumina (α-Al2O3) with minor phase of theta alumina (θ-Al2O3) at 1050 °C. Further these beads were examined through scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) using N2 adsorption–desorption isotherm. The specific surface area of 54.54 m2/g was estimated through BET experiment. Alumina beads were then used to eliminate the fluoride toxic ions from the aqueous system using adsorption process. Further, the adsorbent dose and kinetics parameters were thoroughly studied to achieve the maximum removal in the aqueous system. The microstructural analysis was carried out before and after the adsorption process using SEM with EDX to compare the surface morphology of the alumina beads. Batch adsorption study show the mechanism and adsorption capacity of the porous alpha alumina beads which suggests the Freundlich adsorption i.e., heterogeneous behavior of fluoride ions towards alumina surface. Through batch adsorption study it was clearly observed that adsorption belongs to pseudo second order kinetic with inter particle diffusion. At initial fluoride concentration of 10 mg/L (adsorbent dose = 3 g/L; pH 6.7 ± 0.3; time = 48 h) the defluoridation efficiency was 26% with Freundlich adsorption capacity kf = 0.91795 (mg/g) (L/mg)1/n.

A new approach for the fabrication of porous alumina beads using acid leachate of kaolin

Abstract In the present study, alumina beads; both in the α (alpha) phase and γ (gamma) phase; were prepared using the acid leachate of kaolinite as a starting solution by an oil-drop method. Size of the alumina beads prepared by this method was 6 mm–8 mm. The effect of different parameters on the formation, morphology and stability of the alumina beads were studied. Both α phase and γ phase were characterized by powder X-ray diffractometer (XRD), thermogravimetry (TG), differential scanning calorimeter (DSC), Fourier transforms infrared spectrophotometer (FTIR), field emission scanning electron microscope (FESEM), N2 adsorption-desorption surface area analyser and a pore size analyser. The porous nature of the beads was confirmed by the pore size distribution study as per the Barrett, Joyner, and Halenda (BJH) method and FESEM images. The γ alumina beads were found to have a higher surface area and porosity than α alumina beads. The unimodal distribution of pores in the mesoporous region of γ alumina beads suggests the possible application of these beads in the adsorption process.

Strength statistics for porous alumina

The mechanical strength statistics for porous spherical alumina based on the large sample size is considered. The Weibull and Gamma distributions have been used to describe mechanical strength of uniform alumina granules obtained by the oil-drop method. The suitability of distributions for the mechanical strength of spherical alumina has been verified by two goodness-of-fit tests: Lilliefors-corrected Kolmogorov-Smirnov and Pearson's chisquared test. Distribution parameters were calculated by the maximum likelihood estimation. It has been demonstrated that the Weibull distribution should not be employed for a statistical description of the mechanical strength of porous alumina. The alumina mechanical strength appear to follow the Gamma distribution. Advantages of using the Gamma distribution have been discussed. The main recommendations have been formulated when using a statistical approach for describing a strength of catalysts and supports based on alumina.

Flexible route to fabricate excellent adsorbents for vitamin B 12 by specially designed oil‐drop process

This work presented the preparation of an excellent adsorbent composed of carbon nanotubes (CNTs) and activated carbon (AC) with hierarchical porous structure by specially designed oil-drop process. In this process, CNTs were pre-dispersed in the ethanol diluted phenolic formaldehyde resin and subsequently, the uniform suspension was injected dropwise into the stratified liquids. These liquids were composed of paraffin, polydimethyl siloxane and poly(ethylene glycol) (PEG)-6000 aqueous solution with different densities. After being semi-cured in the three-layered liquids at 70°C, the spheres were carbonised at 600°C and further activated at 800°C with steam. Scanning electron microscope observations indicated that compared with those prepared by two-layered oil bath in the authors’ previous work, the CNTs/phenolic resin spheres acquired by the modified oil-drop method would absorb PEG-6000 instead of polydimethyl siloxane and hence no residue of silica spheres produced in the final CNTs/AC spheres. Meanwhile, pore structure analyses indicated that the average diameter of the pores in the CNTs/AC spheres increased from 8.1 to 23.3 nm, which could be ascribed to the pore forming effect of PEG-6000. The adsorption capacity for vitamin B12 by the porous CNTs/AC spheres reached 52.98 mg/g, which was much higher than commercial AC beads and macroporous resin spheres. This implied that the CNTs/AC spheres could have potential applications in hemoperfusion.

Fabrication of uniform porous CNTs/activated carbon composite spheres by oil-drop method in stratified oils and their adsorption of VB12

Uniform porous CNTs/activated carbon composite spheres were prepared by oil-drop method followed by gradual suspension curing in stratified oils.

Highly dispersed Pd catalyst for anthraquinone hydrogenation supported on alumina derived from a pseudoboehmite precursor

Pseudoboehmite was synthesized using the separate nucleation and aging steps (SNAS) method for the first time. An alumina support (Al2O3(PB)) was then prepared by extrusion method using the synthesized pseudoboehmite as precursor. Compared with spherical alumina (Al2O3(OD)) prepared by the conventional oil-drop method, Al2O3(PB) exhibits higher surface area, more regular pore structure and narrower pore size distribution. Al2O3(PB) and Al2O3(OD) were used as supports to prepare Pd catalysts. The catalytic performance of the two Pd catalysts was investigated in the catalytic hydrogenation of 2-ethylanthraquinone (EAQ) to 2-ethylanthrahydroquinone, a key step in the anthraquinone process for the manufacture of hydrogen peroxide. Compared with Pd/Al2O3(OD) catalyst, Pd/Al2O3(PB) catalyst showed higher Pd dispersion and thinner Pd penetration depth which resulted in more catalytically active site and easier diffusion of the reactants, and consequently Pd/Al2O3(PB) catalyst exhibited higher anthraquinone hydrogenation activity and better selectivity.

Effect of Polyethylene Glycol on the Properties of γ-Al2O3 Formation by Polyaluminum Chloride

A polyaluminium chloride solution with high Al13 content self-prepared was used as material for preparing the spherical γ-Al2O3 by the sol-gel and oil-drop method. Polyethylene glycol with different molecular mass was used as surfactant to investigate the effect on property of γ-Al2O3. The physical property was characterized by 27Al NMR (nuclear magnetic resonance) spectra, X-ray diffraction, FT-IR (Fourier transform infrared spectroscopy) and TG-DTA (thermogravimetric-differential thermal analysis). The results showed that surface area, pore volume and pore size of γ-Al2O3 all increased with the increase of polyethylene glycol molecular mass in the experimental research range, and polyethylene glycol 10000 was the most suitable pore forming additive. γ-Al2O3 with surface area of 339 m2·g−1, pore volume of 0.59 cm3·g−1 and pore diameter of 6.9 nm were obtained at 450 °C.

Novel amorphous microporous silica spheres for controlled release applications

A new synthesis route for large spherical particles of amorphous microporous silica (AMS) was developed. These novel spherical porous particles with diameter of around 100 µm and pore diameter smaller than 2 nm were prepared using an oil drop method. Molten ibuprofen was successfully loaded into the AMS pores. In vitro release experiments revealed that ibuprofen was released from the spheres via a slow pore diffusion process lasting up to 14 days. Experimentally determined diffusion coefficients of ibuprofen in the porous spheres were of the order of 10−15–10−16 m2 s−1. The present findings reveal the potential of AMS spheres for controlled release of small drug molecules over long time periods. The spherical shape of the AMS particles is advantageous in formulation processes as it provides adequate powder flow properties and reliable release profiles. © 2011 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:4295–4301, 2011

Synthesis of Cu/Fe/Ti/Al2O3 Composite Granules for SO3 Decomposition in SI Cycle

The present paper deals with the catalytic decomposition of SO3 reaction. Cu/Fe/Ti/Al2O3 composite granule catalysts prepared by a combination of Yoldas process and oil-drop method were studied in an attempt to find some suitable catalysts for the decomposition of sulfur trioxide as the oxygen-generating reaction in the thermo-chemical water splitting process. CuFe/Ti:Al-1:2 shows high SO3 conversion (69%) at 800 °C compared with other catalysts because of the high surface area and the support permitted a better dispersion of Ti.

Preparation and characterization of Fe/Cu/Al2O3-composite granules for SO3 decomposition to assist hydrogen production

In this work, the activity values of Cu/Al2O3-, Fe/Al2O3- and Cu/Fe/Al2O3-composite granule catalysts prepared by a combination of Yoldas-process and oil-drop method were studied in an attempt to find some suitable catalysts for the decomposition of sulfur trioxide as the oxygen-generating reaction in the thermo-chemical water splitting process. The SO3 decomposition was performed in the temperature range of 750–950 °C at a space velocity of 72,000 mL/g cat. h in a fixed bed reactor. The catalytic activity of Cu/Fe/Al2O3-composite granule catalyst was better than that of Cu/Al2O3- and Fe/Al2O3-composite granule catalysts. The composite of Cu and Fe in the alumina granules increased the catalytic activity and found the optimum ratio of [Cu]/[Fe] = 1/2 with [Cu] + [Fe] = 0.125 M.

Selective acetylene hydrogenation over core–shell magnetic Pd‐supported catalysts in a magnetically stabilized bed

AbstractA novel magnetic microspherical catalyst support with enough mechanical strength was prepared through coating Al2O3 on a magnetic core of NiFe2O4 spinel ferrite using the oil drop method to synthesize magnetic Pd‐supported catalyst for acetylene hydrogenation reaction. The synthesized core–shell composite Pd/Al2O3 catalyst shows high surface area and pore volume as well as sufficient saturated magnetization property, characterized by powder X‐ray diffraction, low‐temperature N2 adsorption–desorption analysis, and magnetic measurements. Catalytic performance of this magnetic Pd/Al2O3 catalyst was measured for acetylene hydrogenation reaction in a magnetically stabilized bed (MSB) reactor under different operation conditions. Under the optimal conditions of 353 K, 1.5 MPa and a gas hourly space velocity of 12,000 h−1, C2H2 conversion and C2H4 selectivity approximated 100% and 84%, respectively, over this magnetic Pd/Al2O3 catalyst in the MSB reactor, as a control over the commercial catalyst for hydrogenation reaction C2H2 conversion and C2H4 selectivity was near 37 and 64% under the similar conditions. Significant improvement of acetylene hydrogenation processes over this novel magnetic catalyst enlightens us a promising route to explore process intensification techniques through MSB. © 2008 American Institute of Chemical Engineers AIChE J, 2008

Search for Fractional-Charge Particles in Meteoritic Material

We have used an automated Millikan oil drop method to search for free fractional-charge particles in a sample containing in total 3.9 mg of pulverized Allende meteorite suspended in 259 mg of mineral oil. The average diameter of the drops was 26.5 microm with the charge on about 42 500 000 drops being measured. This search was motivated by the speculation that isolatable, fractional-charge particles produced in the early Universe and present in our Solar System are more likely to be accumulated in asteroids than on Earth's surface. No evidence for fractional-charge particles was found. With 95% confidence, the concentration of particles with fractional-charge more than 0.25 e (e being the magnitude of the electron charge) from the nearest integer charge is less than 1.3 x 10(-21) particles per nucleon in the meteoritic material and less than 1.9 x 10(-23) particles per nucleon in the mineral oil.

Preparation of high purity spherical γ-alumina using a reduction-magnetic separation process

A purified alumina hydrosol has been prepared by removing metal impurities using a new reduction-magnetic separation process. The amount of iron in the alumina hydrosol was reduced by over 78% from 0.0094% to 0.0020%. As a result of co-crystallization, the copper content was simultaneously reduced from 0.0003% to 0.0001%. Spherical γ-alumina granules were prepared by the oil-drop method using the purified alumina hydrosol as starting material. The γ-alumina granules had a bulk density of about 0.50 g cm −3, crush strength of around 90N per granule, specific surface area of about 200 m 2 g −1 and pore volume of about 0.75 cm 3 g −1. The purification process employed during the preparation of the alumina hydrosol had no effect on the physical properties, pore structure and crystal structure of the final spherical alumina granules.

Synthesis of mesoporous TiO 2/γ-Al 2O 3 composite granules with different sol composition and calcination temperature

Mesoporous TiO 2/γ-Al 2O 3 composite granules were prepared by combining sol–gel method and oil-drop method. After calcination at 450 °C, the composite granules showed anatase and γ-Al 2O 3 phases with the specific surface area of 240–310 m 2/g. The phase composition and pore structure of the granules can be controlled by calcination temperature and the mixing ratio of boehmite sol and titania sol. The product granules can be used as a photocatalyst or adsorbent in moving or fluidized bed reactors.

Methane conversion over nanostructured Pt/γAl2O3 catalysts in dielectric-barrier discharge

Spherical nanostructured γ-Al2O3 granules were prepared by combining the modified Yoldas process and oil-drop method, followed by the Pt impregnation inside mesopores of the granules by incipient wetness method. Prepared Pt/γ-Al2O3 catalysts were reduced by novel method using plasma, which was named plasma assisted reduction (PAR), and then used for methane conversion in dielectric-barrier discharge (DBD). The effect of Pt loading, calcination temperature on methane conversion, and selectivities and yields of products were investigated. Prepared Pt/γ-Al2O3 catalysts were successfully reduced by PAR. The main products of methane conversion were the light alkanes such as C2H6, C3H8 and C4H10 when the catalytic plasma reaction was carried out with Pt/γ-Al2O3 catalyst. Methane conversion was in the range of 38–40% depending on Pt loading and calcination temperature. The highest yield of C2H6 was 12.7% with 1 wt% Pt/γ-Al2O3 catalysts after calcinations at 500 ‡C.

A Simple Laboratory Experiment to Measure e/k

The measurement of fundamental constants is common practice in instructional laboratories. A number of the equipment manufacturers have developed apparatus for such applications, e.g., the determination of e by the Millikan oil drop method or the determination of the speed of light with fiber optics. Other experiments determine not a single constant, but a combination of constants, e.g., e/m by electron beam deflection in a magnetic field or h/e by the photoelectric effect. About 30 years ago Carl E. Miller and I1 proposed a method of measuring e/k, the ratio of the electron charge to Boltzmann's constant, that was reasonably simple but not necessarily inexpensive because it involved the use of a sensitive electrometer. In recent years, however, inexpensive digital multimeters (DMM), many costing less than $30, have found their way into the physics laboratory. The purpose of this paper is to suggest the use of two DMMs, one operating as a voltmeter and the other as an ammeter, in a simple circuit involving a junction transistor and a variable potential source. Even the potential source can be quite simple, a 1.5-V battery and a 1-kΩ potentiometer, as shown in Fig. 1. If available, a variable dc power supply replacing the battery and potentiometer would be more convenient.