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Effect of different heat treatments on oxidation-bonded SiC membrane for water filtration
Bukhari, Syed Zaighum Abbas,Ha, Jang-Hoon,Lee, Jongman,Song, In-Hyuck Elsevier 2018 Ceramics international Vol.44 No.12
<P><B>Abstract</B></P> <P>The porous SiC-based membrane has proved its validity in microfiltration membrane fabrication, but application is limited due to its high fabrication cost. In this study, the oxidation-bonding technique was used to fabricate a SiC microfiltration membrane. The oxidation behaviour exhibited during different thermal treatments was related to pore morphology, and ultimately membrane permeance. Corrosion properties of the oxidation-bonded SiC specimens were also studied. We have found that a membrane made by coating an oxidation-bonded SiC layer over a clay-bonded SiC support and sintered at 1000 °C for 3 h could make a defect-free, corrosion resistant microfiltration membrane with pure water membrane permeance above 700 LMH per bar over the 1 h operation time. The membrane has a narrow pore size distribution, with an average pore size of 78 nm.</P>
Viscosity Study to Optimize a Slurry of Alumina Mixed with Hollow Microspheres
Syed Zaighum Abbas Bukhari,Jang-Hoon Ha,이정만,송인혁 한국세라믹학회 2015 한국세라믹학회지 Vol.52 No.6
Porous alumina ceramics are involved in many industrial applications due to the exceptional properties of these products. This study addresses the preparation of porous alumina ceramics using hollow microspheres as a pore-forming agent and slip casting as a green-body-forming technique. A uniform distribution of pores is a basic requirement of a porous material. This study investigates three different slurry systems, i.e., as-prepared alumina slurry, alumina slurry electrostatically dispersed by hydrochloric acid (HCl), and slurry dispersed by the commercial dispersant ‘Darvan C-N’. At a low viscosity, the hollow microspheres in the slurry tend to float, which causes a non-uniform pore distribution. To avoid this phenomenon, the viscosity of the slurry was increased to the extent that the movement of hollow microspheres ceased in the slurry. As a result, a uniform pore distribution was achieved.
Viscosity Study to Optimize a Slurry of Alumina Mixed with Hollow Microspheres
Bukhari, Syed Zaighum Abbas,Ha, Jang-Hoon,Lee, Jongman,Song, In-Hyuck The Korean Ceramic Society 2015 한국세라믹학회지 Vol.52 No.6
Porous alumina ceramics are involved in many industrial applications due to the exceptional properties of these products. This study addresses the preparation of porous alumina ceramics using hollow microspheres as a pore-forming agent and slip casting as a green-body-forming technique. A uniform distribution of pores is a basic requirement of a porous material. This study investigates three different slurry systems, i.e., as-prepared alumina slurry, alumina slurry electrostatically dispersed by hydrochloric acid (HCl), and slurry dispersed by the commercial dispersant 'Darvan C-N'. At a low viscosity, the hollow microspheres in the slurry tend to float, which causes a non-uniform pore distribution. To avoid this phenomenon, the viscosity of the slurry was increased to the extent that the movement of hollow microspheres ceased in the slurry. As a result, a uniform pore distribution was achieved.
MF 필터를 위한 저가의 탄화규소계 세라믹 분리막의 최적화
송인혁,Syed Zaighum Abbas Bukhari,하장훈,이종만 한국막학회 2017 한국막학회 총회 및 학술발표회 Vol.2017 No.11
Ceramic membranes can be applied under extreme operating conditions such as low pH, high pressure and high temperature. In particular SiC has excellent mechanical properties and also has excellent properties related to membrane performance. However, high processing temperature increases cost of SiC products and thus limit’s its use. In this study oxidation bonding technique was used to fabricate cost-effective SiC microfiltration membrane at low temperature. The oxidation behavior at different thermal treatments was related with pore morphology and ultimately the membrane permeability. We have found that the membrane made by coating of oxidation bonded SiC layer over clay-bonded SiC support, sintered at 1000-1100°C could make a defect-free microfiltration membrane with pure water permeability above 700 LMH per bar. The membrane has narrow pore size distribution with average pore size about 0.1 μm.
Anwar Muhammad Shoaib,Bukhari Syed Zaighum Abbas,Ha Jang-Hoon,Lee Jongman,송인혁 한국세라믹학회 2022 한국세라믹학회지 Vol.59 No.6
An electrically conductive mullite-bonded porous SiC-based Mn 3O4–Ni system was designed, which provided low-temperature sintering and excellent extrudability into complex shapes. Each designed composition contained kaolin (30 wt%) and Mn3O4 (10 wt%) as sintering aids. The combination of Ni (0–20 wt%) and sintering temperature (1100–1300 °C) regulated the electrical resistivity (5.5 × 10 7–3.4 × 10 –1 Ω cm) and flexural strength (33 ± 2–59 ± 3 MPa) of the sintered samples. Inter- face reactions formed secondary phases [e.g. nickel silicide (Ni 2Si) and manganese silicate (MnSiO 3)], which decreased the electrical resistivity. The in situ formation of mullite and an increased amount of Ni collectively improved the flexural strength. The sample with 15 wt% Ni sintered at 1200 °C in argon fl ow had a low electrical resistivity of 5.6 × 10 –1 Ω cm and a good flexural strength of 51 ± 4 MPa. The same composition was extruded to form a square honeycomb structure to verify the large-scale viability of the developed composition.
Ha, Jang-Hoon,Abbas Bukhari, Syed Zaighum,Lee, Jongman,Song, In-Hyuck,Park, Chanhyuk Elsevier 2016 CERAMICS INTERNATIONAL Vol.42 No.12
<P><B>Abstract</B></P> <P>Recently, porous ceramic membranes have become a subject of significant interest due to their outstanding thermal and chemical stability. To reduce the high manufacturing costs of these porous ceramic membranes, recent research has focused on the utilization of inexpensive natural materials. However, there have not been any well-established direct comparisons of the membrane properties between typical alumina-based membranes and novel natural material-based membranes. Therefore, we compared alumina-coated alumina support layers (with average pore sizes ranging from 0.10µm ~0.18µm), alumina-coated diatomite-kaolin composite support layers (with an average pore size of 0.12µm), and alumina-coated pyrophyllite-diatomite composite support layers (with an average pore size of 0.11µm) via the dip-coating method and subsequent heat treatment ranging from 1200°C–1400°C for 1h. The pure water permeability of the alumina-coated diatomite-kaolin composite support layer and the alumina-coated pyrophyllite-diatomite composite support layer was found to be approximately 2.0×10<SUP>2</SUP> Lm<SUP>−2</SUP> h<SUP>−1</SUP> bar<SUP>−1</SUP>, which is similar to that of an alumina-coated alumina support layer. Therefore, we suggest that the average pore size of an alumina-coated natural material-based support layer can be effectively controlled while exhibiting acceptable water permeability.</P>
Ha, Jang-Hoon,Lee, Sujin,Abbas Bukhari, Syed Zaighum,Lee, Jongman,Song, In-Hyuck Elsevier 2017 Ceramics international Vol.43 No.1
<P><B>Abstract</B></P> <P>Porous ceramic membranes are a current research focus because of their outstanding thermal and chemical stabilities. Recent research has utilized inexpensive natural materials such as pyrophyllite and diatomite to reduce the expense of these porous ceramic membranes. However, insufficient data exist for microfiltration applications using pyrophyllite-based membranes. We compared the measured membrane properties of alumina-coated alumina support layers and alumina-coated pyrophyllite-diatomite composite support layers. These experiments were used to determine whether we could effectively reduce the average pore size with acceptable water permeability by controlling the thickness of the alumina coating layer. The membrane properties of the alumina-coated alumina support layers and alumina-coated pyrophyllite-diatomite composite support layers were examined using scanning electron microscopy, mercury porosimetry, and a dead-end microfiltration system.</P>