Pore size assessment of nanoporous alumina using absorption of laser light

2021 ◽  
Author(s):  
Abdulaziz M. Aljalal ◽  
Ahmed Al-Saudi ◽  
Khaled Gasmi ◽  
Watheq Al-Basheer ◽  
Samer Qari
Keyword(s):  
Pore Size ◽  
Laser Light ◽  
Nanoporous Alumina

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 Fabrication of Nanoporous Alumina Ultrafiltration Membrane with Tunable Pore Size Using Block Copolymer Templates

2017 ◽  
Vol 27 (34) ◽  
pp. 1701756 ◽  
Author(s):  
Chun Zhou ◽  
Tamar Segal-Peretz ◽  
Muhammed Enes Oruc ◽  
Hyo Seon Suh ◽  
Guangpeng Wu ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Pore Size ◽  
Ultrafiltration Membrane ◽  
Nanoporous Alumina

Photoluminescent Silicon in Nanoporous Aluminium Oxide

1997 ◽  
Vol 486 ◽  
Author(s):  
Andreas Heilmann ◽  
Peter Jutzi ◽  
Andreas Klipp ◽  
Uwe Kreibig ◽  
Rolf Neuendorf ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Pore Size ◽  
Aluminium Oxide ◽  
Silicon Nanostructures ◽  
Pore Surface ◽  
Nanoporous Alumina ◽  
Inner Pore

AbstractThermal decomposition of a metastable silane in nanoporous alumina leads to the formation of luminescent silicon nanostructures. While varying the pore size of the transparent membranes the luminescence can be shifted from 504 nm up to 537 nm by building up a sheet-like structure of siloxene on the inner pore surface.

scholarly journals Evolution of the Pore Size Distribution in Nanoporous Alumina Membranes with Anodization Voltage in Oxalic Acid

2015 ◽  
Vol 5 (6) ◽  
Author(s):  
Mesbah Elyaagoubi ◽  
Youssef Najih ◽  
Mohyeddine Khadiri ◽  
Amane. Oueriagli ◽  
Abdelkader Outzourhitb ◽  
...  
Keyword(s):  
Oxalic Acid ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Anodization Voltage ◽  
Nanoporous Alumina ◽  
Alumina Membranes

Highly Ordered Nanoporous Alumina Films: Effect of Pore Size and Uniformity on Sensing Performance

2002 ◽  
Vol 17 (5) ◽  
pp. 1162-1171 ◽  
Author(s):  
Oomman K. arghese ◽  
Dawei Gong ◽  
Maggie Paulose ◽  
Keat G. Ong ◽  
Craig A. Grimes ◽  
...  
Keyword(s):  
Pore Size ◽  
Average Pore Size ◽  
High Sensitivity ◽  
Water Layer ◽  
Adsorbed Water ◽  
Average Pore ◽  
Nanoporous Alumina ◽  
Wide Range ◽  
Anodization Process ◽  
Measured Impedance

The effect of pore size and uniformity on the humidity response of nanoporous alumina, formed on aluminum thick films through an anodization process, is reported. Pore sizes examined range from approximately 13 to 45 nm, with a pore size standard deviations ranging from 2.6 to 7.8 nm. The response of the material to humidity is a strong function of pore size and operating frequency. At 5 kHz an alumina sensor with an average pore size of 13.6 nm (standard deviation 2.6 nm) exhibits a well-behaved change in impedance magnitude of 103 over 20% to 90% relative humidity. Increasing pore size decreases the humidity range over which the sensors have high sensitivity and shifts the operating range to higher humidity values. Cole–Cole plots of 5 to 13 MHz measured impedance spectra, modeled using equivalent circuits, are used to resolve the effects of water adsorption and ion migration within the adsorbed water layer. The presence of impurity ions within the highly ordered nano-dimensional pores, accumulated during the anodization process, appear highly beneficial for obtaining a substantial variation in measured impedance over a wide range of humidity values.

scholarly journals Optical and Electrochemical Characterization of Nanoporous Alumina Structures: Pore Size, Porosity, and Structure Effect

2020 ◽  
Vol 10 (14) ◽  
pp. 4864
Author(s):  
Ana Laura Cuevas ◽  
A. Silvia González ◽  
Víctor Vega ◽  
Víctor M. Prida ◽  
Juana Benavente
Keyword(s):  
Pore Size ◽  
Near Infrared ◽  
Electrochemical Characterizations ◽  
Refraction Index ◽  
Solution Concentration ◽  
Asymmetric Structure ◽  
Transport Numbers ◽  
Optical Parameters ◽  
Nanoporous Alumina ◽  
Charge Concentration

Three nanoporous alumina structures (NPASs) obtained by the two-step anodization method were optically and electrochemically characterized. Two of the structures were symmetric (NPAS-Sf and NPAS-Ph) and one was asymmetric (NPAS-And); pore size ranged from 10 nm to 100 nm and porosity was 12% in the case of the symmetrical NPAS and 23% and 30% for each surface of the asymmetric structure NPAS-And(A) and (B), respectively. Optical parameters of the studied samples (refraction index and extinction coefficient) were obtained from ellypsometric spectroscopy measurements carried out for wavelengths ranging between 250 nm and 1700 nm (visible and near infrared regions), with the total average refraction indices being 1.54, 1.52, 1.14, and 1.05 for NPAS-Sf, NPAS-Ph, NPAS-And(A), and NPAS-And(B), respectively, which indicates porosity control of refraction index values. Electrochemical characterizations (concentration potential and impedance spectroscopy measurements) were performed with NaCl solutions, and they allowed us to estimate samples of effective fixed charge concentration (1.22 × 10−2 M, 1.13 × 10−3 M, and 1.15 × 10−3 M), ion transport numbers, permselectivity (33.0%, 3.1%, and 9.6%), and the electrical resistance of each solution/sample system as well as the interfacial effects associated to solution concentration–polarization, which seems to be mainly controlled by pore size and sample symmetry.

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