Toward uniform pore-size distribution and high porosity of isotactic polypropylene microporous membrane by adding a small amount of ultrafine full-vulcanized powder rubber

Polymer ◽  
2016 ◽  
Vol 103 ◽  
pp. 405-414 ◽  
Author(s):  
Yanling Zhu ◽  
Yongsheng Zhao ◽  
Qiang Fu
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Isotactic Polypropylene ◽  
Microporous Membrane ◽  
High Porosity ◽  
Uniform Pore Size

Dehydrogenation of Propane to Propene over Mesoporous ZrO2-Supported VCrO Catalysts

2014 ◽  
Vol 1008-1009 ◽  
pp. 290-294
Author(s):  
Bao Agula ◽  
Si Qin Dalai ◽  
Yue Chao Wu
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Mesoporous Structure ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Size Distributions ◽  
Tem Analysis ◽  
Surfactant Assisted ◽  
Uniform Pore Size

Mesoporous ZrO2with narrow mesopore size distributions has been prepared by the surfactant-assisted method of nanoparticle assembly. A series of VCrO/ZrO2catalysts with different V/Cr molar ratio (0.3, 0.6, 1.0, 1.3 and 1.6) were prepared by the wetness impregnation method and characterized by XRD, N2adsorption and TEM techniques. N2adsorption and TEM analysis revealed that the surfactant-assisted method prepared VCrO/ZrO2catalysts have wormhole-like mesoporous structure with uniform pore size distribution. VCrO/ZrO2catalysts have been applied for direct dehydrogenation of propane to propene. The optimistic catalyst was V/Cr-0.6 with highest yield of 41.7% the corresponding conversion of propane was 44.1% and selectivity to propene was 94.5% at 550 °C.

scholarly journals Preparation of an Ultrafiltration (UF) Membrane with Narrow and Uniform Pore Size Distribution via Etching of SiO2 Nano-Particles in a Membrane Matrix

Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 150
Author(s):  
Bushra Khan ◽  
Sajjad Haider ◽  
Rooha Khurram ◽  
Zhan Wang ◽  
Xi Wang
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Nano Particles ◽  
Coagulation Bath ◽  
Inversion Method ◽  
Permeate Flux ◽  
Membrane Matrix ◽  
Etched Membrane ◽  
Uniform Pore Size

The UF membrane with a narrow and uniform pore size distribution and a low tendency to foul has significant applications in wastewater treatment. A major hindrance in the preparation of the UF membrane with these features is the lack of a scalable and economical membrane fabrication method. Herein, we devise a new strategy to prepare a high-quality polyvinylidene fluoride/polymethyl acrylate/cellulose acetate (PVDF/PMMA/CA) blend UF membrane via a combination of the etching mechanism with the traditional Loeb–Sourirajan (L-S) phase inversion method. Different concentrations of silicon dioxide (SiO2) nanoparticles (NP) in the membrane matrix were etched by using a 0.2 M hydrofluoric acid (HF) solution in a coagulation bath. This strategy provided the membrane with unique features along with a narrow and uniform pore size distribution (0.030 ± 0.005 μm). The etched membrane exhibits an increase of 2.3 times in pure water flux (PWF) and of 6.5 times in permeate flux(PF), with a slight decrease in rejection ratio (93.2% vs. 97%) when compared to than that of the un-etched membrane. Moreover, this membrane displayed outstanding antifouling ability, i.e., a flux recovery ratio (FRR) of 97% for 1000 mg/L bovine serum albumin (BSA) solution, a low irreversible fouling ratio of 0.5%, and highly enhanced hydrophilicity due to the formation of pores/voids throughout the membrane structure. The aforementioned features of the etched membrane indicate that the proposed method of etching SiO2 NP in membrane matrix has a great potential to improve the structure and separation efficiency of a PVDF/PMMA/CA blend membrane.

High Porosity SiC Ceramics with a Narrow Pore Size Distribution

2008 ◽  
Vol 368-372 ◽  
pp. 840-842 ◽  
Author(s):  
Li Min Shi ◽  
Hong Sheng Zhao ◽  
Ying Hui Yan ◽  
Chun He Tang
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Phenolic Resin ◽  
High Porosity ◽  
X Ray Diffraction ◽  
Narrow Pore Size Distribution ◽  
X Ray ◽  
Sic Ceramics ◽  
Porous Sic

Using the coat mix process, porous SiC ceramics are fabricated using commercially available silicon powders and phenolic resin as the starting materials. The phase composition, morphology, pore size and pore size distribution of the obtained products are characterized by X-ray diffraction, scanning electron microscopy and mercury intrusion porosimeter. The results show that high porosity SiC ceramics with a narrow pore size distribution can be fabricated at 1500°C in vacuum by the coat mix process. The open pore porosity can reach up to 60%. The pore size varies in the range of 1-6 'm.

Preparation of Mesoporous Alumina Using Hexamethyl Disilylamine as Substitute Solvent

2013 ◽  
Vol 773 ◽  
pp. 482-486 ◽  
Author(s):  
Su Min Cui ◽  
Li Li Ren ◽  
Feng Chao Cao
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Surface Area ◽  
Supercritical Drying ◽  
Mesoporous Alumina ◽  
Bet Surface Area ◽  
High Porosity ◽  
Drying Method

Mesoporous inorganic alumina with framework walls has been synthesized using a new and simple non-supercritical drying method. As a substitute solvent, hexamethyl disilylamine (HMDS) plays a definitive part for synthesis of the mesoporous alumina due to its special characters. The resulting alumina product shows high BET surface area, concentrated distribution of diameter and high porosity. The pore size distribution of alumina we prepared is concentrated around 11nm. Its structure still maintained stable and the BET surface area could reach up to 413.4593m2/g after being calcined at 800°C.

scholarly journals Innovative Material Can Mimic Coral and Boulder Reefs Properties

2021 ◽  
Vol 8 ◽  
Author(s):  
Lucia Margheritini ◽  
Per Møldrup ◽  
Rasmus Lund Jensen ◽  
Kirstine Meyer Frandsen ◽  
Yovko Ivanov Antonov ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Low Voltage ◽  
Artificial Reef ◽  
Total Porosity ◽  
Electrical Current ◽  
High Porosity ◽  
Mineral Deposition

Low-Voltage Mineral Deposition technology (LVMD), widely known as Biorock, has previously been suggested as support for coral reef restoration, as hypothesized high porosity, wide pore-size distribution and connectivity, and good strength properties may facilitate biological functions (for example larvae settlement) and durability. In this technology, very low voltage induces an electrical current that initiates precipitation and accretion of hard minerals (aragonite and calcite) on a metal in seawater. This technology has been discussed mainly for its biological value, while this paper wants to highlight also its engineering value as artificial reef material. Indeed, some of the properties that makes it valuable in one domain are also supporting its use in the other. Because the metal on which the precipitation takes place can be of any shape and size, so can the artificial reef and its mechanical strength characteristics are above the ones of corals and similar to concrete, indicating adequate durability. Coral and boulder reefs suffering from degradation have severe implications on biodiversity, protection from flooding, and cultural value and therefore understanding how to persevere and re-establish these ecosystems is central for sustainable intervention in the marine environment. By comparing chemical-physical characteristics of Coral Porites Exoskeleton (CPE), one typical reef building coral type, LVMD and High-Voltage Mineral Deposition (HVMD), we show that they possess highly similar properties including chemical composition, density, total porosity, pore-size distribution, physical and chemical heterogeneity, total and external surface areas, and comparable mechanical strength.

Preparation of Porous Polymer Membrane with Controllable Pore Size via Spray Spinning

2017 ◽  
Vol 909 ◽  
pp. 157-162
Author(s):  
Wen Ting Sun ◽  
Shuang Xi Liu ◽  
Xiao Yu Hu ◽  
Qiu Ying Jia ◽  
Ya Qin Shen ◽  
...  
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Polymer Membranes ◽  
Processing Parameters ◽  
Polymer Membrane ◽  
Water Soluble ◽  
Porous Polymer ◽  
The Novel ◽  
Uniform Pore Size

Polymer membranes with fixed pore size or narrow pore size distribution can be used for special separation. However, polymer membranes prepared by conventional method usually have wide pore size distribution and the pore size is hard to control. Here we prepared a porous polymer membrane with uniform pore size via spraying a blend of polystyrene (PS) and polyethylene oxide (PEO) on a filtration paper. Dissolving the water-soluble component (PEO) forms the pore and varying the ratios of PEO in the blend controls the pore size. The pore size and size distribution are also affected by processing parameters, such as the flow rate of solution and carrier gas, and gap length. The morphologies of the membrane are observed using scanning electron microscopy (SEM). The novel polymer membrane with controllable and uniform pore size will be used for the separation of solutes with predictable sizes.

Electron Microscopy of Porous Materials—The Structure of a Commercial Alumina Catalyst Support

1971 ◽  
Vol 29 ◽  
pp. 154-155
Author(s):  
D. Faulkner ◽  
N. H. Sagert ◽  
E. E. Sexton ◽  
R. C. Styles
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Catalyst Support ◽  
Chemical Properties ◽  
Carbon Substrate ◽  
High Porosity ◽  
Transmission Electron Micrograph ◽  
Electron Micrograph ◽  
Direct Technique

Many practical catalysts consist of a metal supported on a stable material. The activity of such a system depends not only on the chemical properties of the metal and support, but also on certain physical properties of the support such as surface area, pore volume and pore size distribution. Indirect information on the pore structure of the support material can be obtained from low-temperature nitrogen adsorption experiments, but a more direct technique for obtaining this information is to examine the material in the electron microscope.The material chosen for this study was a high porosity alumina obtained from Englehard. The pore size distribution as supplied by the manufacturer indicated 0.24 cc of pores/g in the range 0-100Å, and 0.16 cc/g > 100Å. Figure 1 is a scanning electron micrograph of the surface of the material. Although no great detail can be resolved, the surface is obviously uneven, and gives the impression of being somewhat fibrous in texture. Figure 2 is a transmission electron micrograph of the same material. This sample was prepared by crushing the material and dispersing the particles on a carbon substrate.

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