Kitiwan, Mettaya

Preferred name

Kitiwan, Mettaya

Alternative Name

Kitiwan, M.

Main Affiliation

School of Science

mettaya.ki@kmitl.ac.th

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Effects of AlN on the reactive sintering of porous Al2TiO5composites
(2020-01-01)
Kitiwan, Mettaya
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Kongsak, Mongkol
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Atong, Duangduen
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Wakui, Yoshito
The porous Al2TiO5/Al2O3 composites were fabricated by reactive sintering at 1500-1700 °C in nitrogen atmosphere. The starting materials Al2O3 and TiO2 were mixed in an equimolar ratio and the addition of AlN was 5-40 mol%. The effects of AlN content and sintering temperature on phase composition, linear shrinkage, pore sized distribution, porosity and microstructure were investigated. The XRD results showed that the composites mainly consist of Al2TiO5 while the peak intensity of Al2O3 increased with AlN content. The median pore sizes decreased with increasing AlN content and were in the range of 2- 6 lm, 1-2 lm, 0.4-0.7 lm, and 0.3-0.5 lm for composites using 10, 20, 30, 40 mol% AlN, respectively. The porosities of ATN10 and ATN20 were from 20% to 10% at 1600 °C to 1700 °C while the porosities of ATN30 and ATN40 were almost constant in between 11 and 13%. The addition of AlN effectively decrease the grain size of Al2TiO5 and led to reduce microcrack at the grain boundary.
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Effect of AlN addition on the reaction sintering of Al2TiO5 composites fabricated by spark plasma sintering
(2023-01-01)
Kitiwan, Mettaya
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Atong, Duangduen
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Endo, Fumio
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Goto, Takashi
Fully dense Al<inf>2</inf>TiO<inf>5</inf>–Al<inf>2</inf>O<inf>3</inf>–TiN (ATN) composites were fabricated by reactive sintering using spark plasma sintering at 1400°C for 5 min under 100 MPa in vacuum. An equimolar ratio of Al<inf>2</inf>O<inf>3</inf>:TiO<inf>2</inf> was used as the starting powder, while the addition of 0–36 mol% AlN was investigated. The thermodynamic calculation indicates that the initial reaction was that of TiO<inf>2</inf> and AlN, forming TiN and Al<inf>2</inf>O<inf>3</inf>, and then the remaining TiO<inf>2</inf> reacted with Al<inf>2</inf>O<inf>3</inf> to produce Al<inf>2</inf>TiO<inf>5</inf>. With the increase in AlN precursor, Al<inf>2</inf>TiO<inf>5</inf> gradually decreased, while Al<inf>2</inf>O<inf>3</inf> and TiN increased. The lattice parameters of Al<inf>2</inf>TiO<inf>5</inf> were enlarged with AlN addition, implying the incorporation of N atoms in the Al<inf>2</inf>TiO<inf>5</inf> unit cell. The addition of AlN effectively produced fully densified bodies with small grain size, and microcrack-free, which therefore enhanced the mechanical properties of ATN composites. At 36 mol% AlN addition, the composite shows Vickers hardness and fracture toughness of 16.26 ± 1.61 GPa and 5.20 ± 0.46 MPa.m1/2, respectively.
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Modification of Al2O3-Based Membranes with Carbon Black for Enhanced Hydrogen Permeation
(2025-11-01)
Hankoy, Montree
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Rodchom, Mana
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Vichaphund, Supawan
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Atong, Duangduen
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Zhang, Jianfeng
This work presents the development and characterization of alumina–carbon black (ACB) composite membranes for enhanced hydrogen separation performance. A series of membranes containing 0–3.0 wt.% carbon black was fabricated via high-temperature sintering and systematically investigated with respect to their structural, morphological, mechanical, and gas separation properties. The addition of carbon black significantly influenced membrane microstructure, promoting pore network formation, increasing specific surface area, and enhancing gas transport. Gas permeation tests using H<inf>2</inf> and N<inf>2</inf> revealed that all ACB membranes exhibited higher hydrogen permeance than the pure Al<inf>2</inf>O<inf>3</inf> membrane. Notably, the ACB3.0 specimen demonstrated the highest H<inf>2</inf> permeance of 508 × 10−6 mol m−2 s−1 Pa−1 at 303 K, which is nearly four times greater than the unmodified membrane. At an elevated temperature (773 K), H<inf>2</inf>/N<inf>2</inf> selectivity improved with increasing carbon black content, with ACB3.0 achieving a maximum selectivity of 3.82, exceeding the theoretical Knudsen value, suggesting a synergistic contribution of Knudsen diffusion and surface diffusion. These results demonstrate that carbon black is a cost-effective and versatile additive for modifying ceramic membranes, offering a promising route for advancing hydrogen purification technologies in industrial applications.
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Enhancing the hydrogen permeation of alumina composite porous membranes via graphene oxide addition
(2023-01-12)
Hankoy, Montree
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Phrompet, Chaiwat
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Ruttanapun, Chesta
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Kaewpengkrow, Prangtip Rittichote
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Vichaphund, Supawan
Graphene oxide (GO) membranes have attracted considerable interest for hydrogen (H<inf>2</inf>) purification applications. However, the addition of GO into matrix materials to enhance the efficiency of H<inf>2</inf> permeation remains a challenge. In this study, the fabrication of alumina/graphene oxide (AGO) composites containing varying contents of GO (0.5–3.0 wt.%) was investigated. The AGO composites were formed into pellets and sintered for 2 h at 1500 °C. Accordingly, the presence of GO in the membranes following sintering was confirmed by Raman spectroscopy. Additionally, the porosity of the AGO composites increased from 3.7% to 26.9% as the GO concentration increased from 0.5 wt.% to 3.0 wt.%. Furthermore, the average pore diameter of the AGO composites was in the range of 87–228 nm, and the pore size distribution was unimodal. The performance of the AGO membranes was investigated for the permeance of single gases H<inf>2</inf> and N<inf>2</inf> at 30–500 °C to evaluate their potential for H<inf>2</inf> separation applications. The AGO membranes with a GO addition of 2.5 and 3.0 wt.% exhibited a high hydrogen permeance of 232–410 × 10−6 mol m−2 s−1 Pa−1, which was approximately 10 times greater than that of pristine Al<inf>2</inf>O<inf>3</inf> membrane. Additionally, the ideal H<inf>2</inf>/N<inf>2</inf> selectivity values ranged from 4.02 to 4.20. Furthermore, gas permeation through the AGO membrane was observed to follow the Knudsen diffusion mechanism.
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EFFECT OF h-BN AS AN ADDITIVE ON PHYSICAL AND MECHANICAL PROPERTIES OF Al2TiO5 COMPOSITE
(2023-01-01)
Treetornkeerati, Paramapat
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Hankoy, Montree
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Kitiwan, Mettaya
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Rodchom, Mana
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Vichaphund, Supawan
Aluminum titanate (Al<inf>2</inf>TiO<inf>5</inf>) is a promising material for high-temperature applications due to its low thermal expansion, high melting point, and excellent corrosion resistance. In this study, the effect of h-BN addition on the properties of Al<inf>2</inf>TiO<inf>5</inf> composites was investigated. The composites were prepared by sintering a mixture of Al<inf>2</inf>O<inf>3</inf> and TiO<inf>2</inf> at a 1:1 molar ratio, with varying amounts of h-BN (5-20 mol%) added to the mixture. The samples were sintered at 1,500ºC for 4 h in N<inf>2</inf> atmosphere, and the bulk density, porosity, phase transition, microstructure, flexural strength, and hardness of the composites were investigated. XRD analysis confirmed the presence of Al<inf>2</inf>TiO<inf>5</inf>, Al<inf>2</inf>O<inf>3</inf>, and Al<inf>18</inf>B<inf>4</inf>O<inf>33</inf> phases in the composites. The addition of h-BN in increasing amounts from 5 to 20 mol% resulted in a gradual improvement in the bulk density, flexural strength, and hardness of the Al<inf>2</inf>TiO<inf>5</inf> composites. The composite with the highest h-BN content (20 mol%) exhibited a bulk density of 3.12 g/cm3, as well as the highest flexural strength and hardness values of 123.6±8.9 MPa and 11.2±4.1 GPa, respectively.
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Hydrogen Sulfide Adsorption on Alumina/Graphene Oxide Composites at Ambient Temperature
(2022-11-01)
Hankoy, Montree
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Kitiwan, Mettaya
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Phrompet, Chaiwat
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Ruttanapun, Chesta
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Kaewpengkrow, Prangtip Rittichote
Hydrogen sulfide (H<inf>2</inf>S) is one of the most common pollutants found in natural gas and industrial waste. Over the few decades, the removal of H<inf>2</inf>S has become a significant problem. In the field of a clean environment such as water purification and toxic gas removal, graphene oxide (GO) has been found to have advantages. In this study, the influence of GO on alumina (Al<inf>2</inf>O<inf>3</inf>) as an adsorbent of H<inf>2</inf>S was examined. A series of Al<inf>2</inf>O<inf>3</inf>/GO (AGO) composites with varying graphene oxide addition (0.5–3.0 wt%) were prepared using the high-temperature sintering method. The X-ray diffraction patterns indicate the primary phase of Al<inf>2</inf>O<inf>3</inf> with hexagonal crystal structure for all AGO composites. Raman spectrometry measurements confirmed that the GO particles were incorporated in AGO composites. The TEM image indicated that GO nanosheets were embedded between Al<inf>2</inf>O<inf>3</inf> grains. The efficiency of AGO adsorbent at ambient temperature was investigated and compared with the pristine Al<inf>2</inf>O<inf>3</inf> adsorbent. The AGO composites adsorbent demonstrated the H<inf>2</inf>S breakthrough capacity in the range of 0.07–0.43 mg/g, which is higher than that of pristine Al<inf>2</inf>O<inf>3</inf> (0.06 mg/g). Furthermore, the highest H<inf>2</inf>S breakthrough capacity of 0.43 mg/g was obtained from AGO containing 3.0 wt% GO. This investigation demonstrates that the AGO adsorbent fabricated using a simple method has the potential to be used for H<inf>2</inf>S removal at ambient temperature.

Kitiwan, Mettaya

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