scholarly journals Slip Casting of Alumina for Membrane Application

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
B. Darunee ◽  
B. Tripob
Keyword(s):  
Porous Alumina ◽  
Pure Water ◽  
Slip Casting ◽  
Casting Process ◽  
Linear Shrinkage ◽  
Porous Membrane ◽  
Alumina Matrix ◽  
Alumina Membrane ◽  
Alumina Membranes ◽  
Different Temperatures

Porous alumina membranes were prepared from alumina matrix, polyvinyl alcohol binder (1–5%) and calcium carbonate additive (0–3%). The disc–shaped alumina samples were fabricated by slip casting process. The alumina paste was sintered at different temperatures of 1100, 1200, 1300 and 1400°C. The results showed that the porosity of the porous membrane reached 45%–46% at 1300°C sintering for the mixtures of alumina matrix with 3% PVA and alumina matrix with 2% CaCO3 plus 3% PVA. The water permeability was 150 L/m2.h at 20 kPa and the hydraulic conductivity coefficient was 1.06 × 10–9 – 2.43 × 10–9 ms–1Pa–1. The density, linear shrinkage water absorption and mechanical strength were ca. 3.92 g/cm3, 1.61–1.71% and 20.45–21.92%, 17.26–21 MPa, respectively. The SEM micrographs of alumina membrane using PVA binder showed a dense surface layers. An increase of the PVA binder resulted in a higher pure water fluxes and bigger pore sizes. An increase of CaCO3 in a 3% PVA binder mixtures resulted in a little decrease of porosity but increase in linear shrinkage from 1.57 to 2.04% at 1300°C sintering.

Fabrication and Characterization of Highly Ordered Porous Alumina Templates by a Two-Step Anodization Process

2013 ◽  
Vol 755 ◽  
pp. 75-81
Author(s):  
C.A. León-Patiño ◽  
E.A. Aguilar-Reyes ◽  
C. Ruiz-Aguilar
Keyword(s):  
Porous Alumina ◽  
Porous Membrane ◽  
Interpore Distance ◽  
Alumina Membranes ◽  
Single Side ◽  
Anodic Porous Alumina ◽  
20 Nm ◽  
Ordered Porous ◽  
Through Hole

Highly ordered through-hole anodic porous alumina membranes were fabricated by electrochemical oxidation of aluminum in a controlled two-step process. A teflon dispositive was used to ensure single side anodization. Under the most appropriate condition for the fabrication of ideally ordered anodic aluminum oxide (AAO), the voltage used was 15 V during 24 h in a 15 % w/v sulfuric acid solution. SEM, TEM and FESEM characterization shows that the as-fabricated AAO film has a defect-free array of straight parallel channels perpendicular to the surface. The thickness of the porous membrane is 20 microns, approximately. The ordered channels are formed in a honey comb arrange with a pore diameter in the range 20-30 nm, wall thickness of 10-20 nm, interpore distance of 40 nm, and high aspect ratio of 850. The pore density, quantified by image analysis, is 5.4×1010 pore/cm2; perfect ordering was maintained in the full depth of the membrane. Dimensions of this porous structure provide a convenient way to precision engineer the nanoscale morphology.

SiO2-Coated Porous Anodic Alumina Membrane for Electroosmotic Pumping

2006 ◽  
Author(s):  
Saumitra K Vajandar ◽  
Dongyan Xu ◽  
Deyu Li ◽  
Dmitry Markov ◽  
John Wikswo ◽  
...  
Keyword(s):  
Flow Rate ◽  
Porous Alumina ◽  
Sol Gel ◽  
Glass Frit ◽  
Electrochemical Anodization ◽  
High Porosity ◽  
Alumina Membrane ◽  
Alumina Membranes ◽  
Electroosmotic Pumping ◽  
Compact Design

Electroosmotic pumping has been extensively used in biomedical lab-on-a-chip devices and micropumps for critical applications such as microelectronic cooling. In many applications, a high flow rate is a key requirement in desired performance so constant efforts have been made to increase the pumping flow rate through unit area to achieve the compact design. We report here an attempt of using SiO2-coated anodic porous alumina membrane as the material to achieve high electroosmotic pumping flow rate. High quality porous alumina membranes of controllable pore diameter in the range of 20-300 nm and pore length of 60 - 100 μm have been fabricated with electrochemical anodization. The pores are uniform and hexagonally packed with a high porosity of up to 50% and a tortuosity of a bare minimum of unity. In addition, the inner surface of the pores could be conformally coated with a thin layer (~ 5 nm) of SiO2 with sol-gel chemistry to achieve a high zeta potential. Scanning electron microscopy of the cross section of the membrane verified these facts. Electroosmotic pumping performance of these membranes has been investigated using standard relevant aqueous electrolyte buffer solutions and results showed that SiO2-coated porous alumina could achieve a higher flow rate compared with other microporous materials such as glass frit and porous silicon reported in the literature.

Electrochemical Fabrication of InSb Nanowires using Porous Alumina Membrane and their Characterization

2008 ◽  
Vol 1080 ◽  
Author(s):  
Muhammad Ibrahim Khan ◽  
Xu Wang ◽  
Krassimir N. Bozhilov ◽  
Cengiz S. Ozkan
Keyword(s):  
Electron Microscopy ◽  
Porous Alumina ◽  
Growth Direction ◽  
Anodic Alumina ◽  
Alumina Membrane ◽  
Alumina Membranes ◽  
Transmission Electron ◽  
Dependent Behavior ◽  
Conductivity Increase ◽  
Insb Nanowires

ABSTRACTAmong various ways to produce nanowires; anodic alumina membrane (AAM) based synthesis has constantly received much attention because AAM possess a uniform and parallel porous structure which makes them an ideal template material for creating highly ordered nanostructures. In this paper we report fabrication of InSb nanowire arrays with diameter of 200 nm and 30 nm by direct current electrodeposition inside the nanochannels of anodic alumina membranes without subsequent annealing. The nanowires have four major growth direction, [220] being the most dominant with structure defects such as twins. The transmission electron microscopy (TEM) and scanning electron microscopy (SEM) results demonstrate that these InSb nanowires are uniform with diameters about 200 nm and 30 nm, corresponding to the pore diameter of the AAMs. The nanowires also conduct almost no current in the dark, but when hit with light, they conduct 10,000 times more current. This photoconduction property could lead to a variety of tiny optoelectronic devices potentially useful in future generations of nanoelectronics and chemical sensors. The light-induced conductivity increase and the temperature dependent behavior of the nanowires are also reported.

scholarly journals Stimulated Emission Depletion Microscopy Resolves Nanoparticle Assembly on a Porous Membrane Surface

2016 ◽  
Vol 17 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Bhanu Bhakta Neupane
Keyword(s):  
Self Assembly ◽  
Polymeric Nanoparticles ◽  
Membrane Surface ◽  
Porous Alumina ◽  
Porous Membrane ◽  
Stimulated Emission ◽  
Alumina Membrane ◽  
Experimental Conditions ◽  
Wet Condition ◽  
Stimulated Emission Depletion

Stimulated emission depletion microscopy—depending on the nature of fluorophore and sample, depletion laser power, and other experimental conditions—provides diffraction unlimited lateral resolution in the range of 20- 100 nm. In this paper, a detailed description of such a microscope along with one of the possible imaging schemes is provided. Application of such a microscope in resolving self assembly of polymeric nanoparticles on porous alumina membrane in wet condition is demonstrated. STED microscopy resolves formation of loose linear to quasi polygonal self-assembly patterns on the membrane surface. Possible reasons for the formation of such self assembly patterns are provided.

Effect of Sintering Temperature on Properties of Setiu Clay Sediments

2020 ◽  
Vol 1010 ◽  
pp. 206-210
Author(s):  
Mohd Al Amin Muhamad Nor ◽  
Noor Asliza Ismail Adnen ◽  
Mohamad Zaky Noh ◽  
A.R.M. Warikh ◽  
Julie Juliewatty Mohamed
Keyword(s):  
Sintering Temperature ◽  
Slip Casting ◽  
Casting Process ◽  
Production Costs ◽  
Ceramic Samples ◽  
Before And After ◽  
Different Temperatures ◽  
Clay Sediment ◽  
Quality Of Products ◽  
Increasing Temperature

The effect of sintering temperature on physical properties of Setiu clay sediment was studied. The ceramic samples were prepared via slip casting method, and sintered at different temperatures ranging from 900 to 1100°C, with 2 hours soaking time. Morphologies of ceramic samples were characterized using Tabletop Microscope. Shrinkage was determined from measurement of samples before and after sintering process. A good ceramic sample without warping or cracks obtained after casting process and after sintered at different temperatures. The results show that sintering temperatures greatly influence morphology of samples. As sintering temperature increased the grain boundaries between particles become smoother and compacted while pores shrunk due to the densification behavior. A considerable increased in shrinkage from 5 to 20% were observed with increasing temperature from 900 to 1100°C. As conclusion, Setiu clay sediment are suitable for production ceramic products and 1000°C can be consider the best sintering temperature in terms of quality of products and production costs.

scholarly journals Nanoporous Alumina Membranes for Sugar Industry: An Investigation of Sintering Parameters Influence onUltrafiltration Performance

2021 ◽  
Vol 13 (14) ◽  
pp. 7593
Author(s):  
Farooq Khan Niazi ◽  
Malik Adeel Umer ◽  
Ashfaq Ahmed ◽  
Muhammad Arslan Hafeez ◽  
Zafar Khan ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Pore Size ◽  
Sugar Industry ◽  
Average Pore Size ◽  
Research Work ◽  
Homogeneous Distribution ◽  
Alumina Membrane ◽  
Average Pore ◽  
Nanoporous Alumina ◽  
Alumina Membranes

Ultrafiltration membranes offer a progressive and efficient means to filter out various process fluids. The prime factor influencing ultrafiltration to a great extent is the porosity of the membranes employed. Regarding membrane development, alumina membranes are extensively studied due to their uniform porosity and mechanical strength. The present research work is specifically aimed towards the investigation of nanoporous alumina membranes, as a function of sintering parameters, on ultrafiltration performance. Alumina membranes are fabricated by sintering at various temperatures ranging from 1200–1300 °C for different holding times between 5–15 h. The morphological analysis, conducted using Scanning electron microscopy (SEM), revealed a homogeneous distribution of pores throughout the surface and cross-section of the membranes developed. It was observed that an increase in the sintering temperature and time resulted in a gradual decrease in the average pore size. A sample with an optimal pore size of 73.65 nm achieved after sintering at 1250 °C for 15 h, was used for the evaluation of ultrafiltration performance. However, the best mechanical strength and highest stress-bearing ability were exhibited by the sample sintered at 1300 °C for 5 h, whereas the sample sintered at 1250 °C for 5 h displayed the highest strain in terms of compression. The selected alumina membrane sample demonstrated excellent performance in the ultrafiltration of sugarcane juice, compared to the other process liquids.

scholarly journals Gravity-Driven Separation of Oil/Water Mixture by Porous Ceramic Membranes with Desired Surface Wettability

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 457
Author(s):  
Chunlei Ren ◽  
Wufeng Chen ◽  
Chusheng Chen ◽  
Louis Winnubst ◽  
Lifeng Yan
Keyword(s):  
Porous Ceramic ◽  
Ceramic Membranes ◽  
Separation Performance ◽  
Water Mixture ◽  
Alumina Membrane ◽  
Water Separation ◽  
Alumina Membranes ◽  
Oil Water Separation ◽  
Gravity Driven ◽  
Oil Water

Porous Al2O3 membranes were prepared through a phase-inversion tape casting/sintering method. The alumina membranes were embedded with finger-like pores perpendicular to the membrane surface. Bare alumina membranes are naturally hydrophilic and underwater oleophobic, while fluoroalkylsilane (FAS)-grafted membranes are hydrophobic and oleophilic. The coupling of FAS molecules on alumina surfaces was confirmed by Thermogravimetric Analysis and X-ray Photoelectron Spectroscopy measurements. The hydrophobic membranes exhibited desired thermal stability and were super durable when exposed to air. Both membranes can be used for gravity-driven oil/water separation, which is highly cost-effective. The as-calculated separation efficiency (R) was above 99% for the FAS-grafted alumina membrane. Due to the excellent oil/water separation performance and good chemical stability, the porous ceramic membranes display potential for practical applications.

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