Sooknoi, Tawan

Preferred name

Sooknoi, Tawan

Alternative Name

Sooknoi, T.

Main Affiliation

School of Science

tawan.so@kmitl.ac.th

Now showing 1 - 7 of 7

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Surface hydrophobicity and catalytic performance of cerium incorporated HZSM-5 zeolite for conversion of bio-ethanol
(2024-05-01)
Ausavasukhi, Artit
;
Sooknoi, Tawan
Cerium incorporated HZSM-5 (CeHZSM-5) catalyst prepared by impregnation method was tested for aqueous ethanol conversion at 200–400 °C. The CeHZSM-5 catalyst was found to be very active (21.02 %Conversion), compared to the parent HZSM-5 catalyst (9.39 %Conversion), especially at low reaction temperatures (200 °C) and when fed with high water content (80 wt% ethanol). FTIR, FT-Raman, DR-UV, NH<inf>3</inf>-TPD, IPA-TPD, DSC and contact angle techniques reveal that the incorporation of cerium species into zeolites results in the acidity and hydrophilic/hydrophobic nature. Cerium species are thought to tend to migrate into ZSM-5 channels and associate with the zeolite framework. As a result, the net electrostatic charge decreases due to the presence of tetrahedral cerium atoms. Therefore, the CeHZSM-5 exhibits a hydrophobic character, compared to the parent one. The decrease in competitive adsorption of water versus ethanol feed at the Brønsted acid site may lead to an increase in CeHZSM-5 catalyst activity.
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Tubular EVA copolymer/SiO2/PEG composite membrane for CO2 removal from household biogas
(2025-03-01)
Watasit, Prachya
;
Ausavasukhi, Artit
;
Rukchonlatee, Suparat
;
Sooknoi, Tawan
;
Ritvirulh, Chonlada
The fuel efficiency of household biogas is generally regulated by its CO<inf>2</inf> content (25%–50%). To improve its heating value, atmospheric CO<inf>2</inf> removal of household biogas using a polymeric membrane was attempted to avoid a complicated separation process. A tubular membrane of poly(ethylene-co-vinyl acetate), composed of 28% and 18% vinyl acetate (E28 and E18) modified with SiO<inf>2</inf> and polyethylene glycol (PEG), was fabricated by blown film extrusion. Model biogas containing CO<inf>2</inf>/CH<inf>4</inf> (40/60 v/v) was separated in an in-house continuous gas separation module, in which CO<inf>2</inf> was mainly permeated out of the tubular membrane at atmospheric pressure. Blending the E28 matrix with E18 (10 wt%) improves the membrane processability and inhibits the CH<inf>4</inf> permeation, leading to enhanced CO<inf>2</inf>/CH<inf>4</inf> selectivity (from ~2.3 to 2.9). Well-dispersed SiO<inf>2</inf> particles (0.5 wt%) increase the membrane modulus and suppress CH<inf>4</inf> loss. However, adding more SiO<inf>2</inf> (0.75–1.0 wt%) leads to higher total gas permeation flux with lower CO<inf>2</inf>/CH<inf>4</inf> selectivity due to particle agglomeration. Incorporation of PEG (0.5–1.5 wt%) increased the membrane polarity and CO<inf>2</inf> permeability. The CO<inf>2</inf>/CH<inf>4</inf> selectivity was also improved (~5.3), only up to 1.0 wt% PEG content. Highlights: Composite EVA/SiO2/PEG membrane separates CO<inf>2</inf>/CH<inf>4</inf> at atmospheric pressure. The concentration gradient across the membrane drives CO<inf>2</inf>/CH<inf>4</inf> permeation. Adding SiO<inf>2</inf> hinders CH<inf>4</inf> permeability and enhances CO<inf>2</inf>/CH<inf>4</inf> selectivity. Increasing PEG content enhances membrane polarity and interaction with CO<inf>2</inf>.
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Synergistic effects of bimetallic Co-SnOx species in selective hydrogenation of methyl oleate: The crucial role of reduction characteristics
(2026-09-01)
Sooknoi, Tawan
;
Thainoi, Suwimon
;
Chanakha, Vichuda
;
Ausavasukhi, Artit
This study investigates the catalytic performance of bimetallic Co-Sn catalysts supported on alumina (Al<inf>2</inf>O<inf>3</inf>) for the selective hydrogenation of methyl oleate to oleyl alcohol. A strategic sequential reduction methodology, employing sodium borohydride followed by thermal hydrogen treatment (NaBH<inf>4</inf>-H<inf>2</inf>), was utilized to precisely tune the catalytic activity and chemoselectivity. Catalysts reduced solely with hydrogen at 300 °C exhibited limited efficiency, primarily favoring the formation of oleic acid via hydrogenolysis, which is attributed to the prevalence of cobalt oxide species. In contrast, the CoSnBH/Al<inf>2</inf>O<inf>3</inf> catalyst synthesized via a strategic sequential reduction methodology demonstrated a markedly enhanced selectivity toward oleyl alcohol, achieving a maximum selectivity of 54.1% at 270 °C and 8 MPa. Comprehensive characterization and kinetic analyses revealed that the superior performance stems from the synergistic coexistence of metallic cobalt (Co0) and low-valent tin oxides (SnO<inf>x</inf>), which form a bimetallic interface that preferentially polarizes the C=O bond. The catalytic efficiency was found to be highly sensitive to the nature of the support, the Co/Sn atomic ratio, and the total metal loading. Notably, turnover frequency (TOF) analysis indicated that while increased loading improves conversion, it may lead to site agglomeration and a reduction in surface-active concentration. Mechanistically, we propose that the CoSnBH/Al<inf>2</inf>O<inf>3</inf> system facilitates a direct hydrogenation pathway to oleyl alcohol, effectively bypassing the formation of heavy ester intermediates typically reported in literature.
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Hydrothermal sulfonation of palm kernel shells to produce a carbon-based solid acid catalyst for the glycerol etherification
(2025-04-01)
Ausavasukhi, Artit
;
Sooknoi, Tawan
Carbon-based solid acid catalysts were successfully prepared by one-step hydrothermal sulfonation of palm kernel shells. Among the solid acids studied, the catalysts with acidity and hydrophobic/hydrophilic balance were found to be more selective and efficient catalytic systems for the conversion of glycerol to glycerol ethers. The stability of the carbon-based solid acid catalyst was confirmed by a regeneration test, which showed that no leaching of acid groups into solution occurs. In addition, the carbon-based solid acid catalyst prepared by one-step hydrothermal sulfonation at 160 °C exhibits good cyclability. The etherification of glycerol with tertiary butanol occurs in a truly heterogeneous process in the presence of such an acid carbon.
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Atmospheric CO2/CH4 permeability of EVA copolymer/SiO2 composite membrane for biogas purification
(2021-09-10)
Watasit, Prachya
;
Rukchonlatee, Suparat
;
Ausavasukhi, Artit
;
Ritvirulh, Chonlada
;
Sooknoi, Tawan
The CO<inf>2</inf> and CH<inf>4</inf> permeabilities of poly(ethylene-co-vinyl acetate) (EVA)/SiO<inf>2</inf> composite membrane were investigated at atmospheric pressure. The membranes were fabricated by compression molding and characterized by Fourier transformed infrared spectroscopy, differential scanning calorimetry, a universal testing machine, and a contact angle analyzer. The effect of vinyl acetate content (18–33 wt%) wasevaluated for both single-gas and mixed-gas permeation systems. A non-pressurized homemade-permeation cell was used for the single-gas permeation of CO<inf>2</inf> and CH<inf>4</inf>, while a tubular membrane was utilized for a continuous separation of CO<inf>2</inf>/CH<inf>4</inf> mixture. CO<inf>2</inf> flux was readily increased (from 0.7 to 2.0 ml/m2.s) with vinyl acetate content (18–33 wt%). The enhanced CO<inf>2</inf> permeability is attributed to the increase in polarity and also the decrease in crystallinity of the membrane. A satisfied gas separation selectivity (CO<inf>2</inf>/CH<inf>4</inf>) of 4.31 could be obtained from tubular membrane with 28 wt% VA content. The incorporation of SiO<inf>2</inf> as a filler (0.5–2.0 wt%) especially increased the membrane polarity and hence the CO<inf>2</inf> flux up to 6.0 ml/m2.s. However, the CH<inf>4</inf> flux was not affected by VA and SiO<inf>2</inf> contents.
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Water-tolerant cerium-modified zeolite catalyst for glycerol etherification
(2026-02-01)
Ausavasukhi, Artit
;
Thainoi, Suwimon
;
Krukrathok, Nattanitcha
;
Sooknoi, Tawan
The transformation of glycerol into alkyl ethers, which are utilized as oxygenated fuel additives, is the main topic of this study. Zeolite and cerium-modified zeolite catalysts were prepared and characterized, then evaluated for their efficacy in the etherification of glycerol with tertiary butanol. In comparison to the parent HBeta catalyst, the cerium-modified HBeta catalyst (CeHBeta), which was prepared by impregnation, demonstrated high catalytic performance in glycerol etherification, particularly at lower reaction temperatures. The cerium species can be present as charge-balancing cations and inserted into the framework. CeHBeta is therefore hydrophobic, unlike the parent catalyst. The CeHBeta catalyst may become more active if the water molecules preferentially occupying the Brønsted acid sites are reduced. While Brønsted acid sites are indispensable for the reaction, a synergistic effect with surface hydrophobicity significantly enhances catalytic performance, with CeHBeta exhibiting superior activity. Furthermore, the experiments show that a higher reaction time, molar ratio of glycerol to alcohol, reaction temperature and amount of catalyst lead to a higher selectivity for di-alkyl ether and a higher glycerol conversion.
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Tailoring the coordination environment of Co-Sn active sites via zinc aluminate spinel support for highly chemoselective hydrogenation of methyl oleate
(2027-01-01)
Sooknoi, Tawan
;
Chanakha, Vichuda
;
Wattanakul, Titiporn
;
Ausavasukhi, Artit
The chemoselective hydrogenation of methyl oleate to oleyl alcohol was investigated over Co-Sn catalysts supported on zinc aluminate (ZnAl<inf>2</inf>O<inf>4</inf>). The ZA-M support, synthesized via a methanol-mediated solvothermal route, provided a high specific surface area (296.8 m2/g) and an optimized mesoporous structure. Sequential NaBH<inf>4</inf> and H<inf>2</inf> reduction finely tuned the coordination of active sites, enabling the optimized 2Co4SnBH/ZA-M catalyst to achieve a superior oleyl alcohol yield (33.58%) and a high selectivity (65.39%) at a conversion level of 51.36% via a direct hydrogenation pathway. Based on bulk and surface characterizations, a fraction of cobalt was found to remain in a cationic state, stabilized within a network of interfacial Co-O-Sn complexes and framework CoAl<inf>2</inf>O<inf>4</inf>. These species are proposed to function as bifunctional active centers, where the Snn+/Sn0 species and neighboring Co2+ sites cooperatively enhance the chemoselectivity toward C=O reduction. Furthermore, the optimized catalyst demonstrated reasonable structural stability and reusability over four cycles, maintaining its catalytic viability despite a minor extent of metal leaching. These findings underscore the efficacy of spinel-supported ionic-metallic ensembles for the highly chemoselective and efficient hydrogenation of long-chain fatty acid methyl esters.
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Sooknoi, Tawan

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