Sooknoi, Tawan

Preferred name

Sooknoi, Tawan

Alternative Name

Sooknoi, T.

Main Affiliation

School of Science

tawan.so@kmitl.ac.th

Now showing 1 - 10 of 104

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Enhanced CO2/CH4 Permselectivity in Partially Hydrolyzed EVA Membranes via Synergistic PEG Plasticization and Amine-Functionalized Silica Incorporation
(2026-03-27)
Ritvirulh, Chonlada
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Wisatsuvan, Patchnakan
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Sooknoi, Tawan
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Rukchonlatee, Suparat
The separation of carbon dioxide (CO2) from methane (CH4) in biogas is essential for increasing the fuel quality. However, conventional membrane-based separation under high pressure is not suitable for household biogas systems due to operational cost and complexity. This study aims to develop low-pressure gas separation membranes based on partially hydrolyzed ethylene vinyl acetate (p-E) copolymers by incorporating poly(ethylene glycol) (PEG) as a plasticizer and amine-functionalized silica (APTES-modified SiO2) as a polar filler. The hydrolysis of EVA improves mechanical strength by increasing hydrogen bonding. PEG addition enhances the free volume and CO2 affinity, while the well-dispersed surface-treated SiO2 increases membrane polarity and suppresses CH4 permeation. Among the tested membranes, the optimal formulation (p-EP400(15)-S0.6) containing 15 wt % PEG400 and 0.6 wt % APTES-SiO2 achieves the highest CO2/CH4 selectivity (∼22) and a high CO2 permeability (∼1400 g/m2·day). These findings demonstrate a promising strategy to develop effective membranes for biogas upgrading under ambient conditions.
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Hydroxylamine intermediate governs selectivity in nitrite hydrogenation on Pd-based catalysts for sustainable water treatment
(2026-05-07)
Betting, Janek
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Preedawichitkun, Yardthip
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Sooknoi, Tawan
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Lefferts, Leon
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Faria Albanese, Jimmy A.
Catalytic hydrogenation of nitrate (NO<inf>3</inf>−) and nitrite (NO<inf>2</inf>−) is a promising route for drinking water purification and rebalancing the global nitrogen cycle. Recently, hydroxylamine (NH<inf>2</inf>OH) was detected as a persistent reaction intermediate although ammonium (NH<inf>4</inf>+) and dinitrogen (N<inf>2</inf>) were assumed to be the only significant reaction products for several decades. In this work, we systematically investigate NO<inf>2</inf>− hydrogenation over Pd/Al<inf>2</inf>O<inf>3</inf> and SnPd/Al<inf>2</inf>O<inf>3</inf> while explicitly quantifying NH<inf>2</inf>OH under various conditions, including changes in H<inf>2</inf> partial pressure, the initial NO<inf>2</inf>− concentration, and reaction temperature, and through co-feeding of NH<inf>2</inf>OH. We reveal that NH<inf>4</inf>+ selectivity depends strongly on the NO<inf>2</inf>− conversion level, reflecting shifts in surface coverages as the reaction progresses. Suppression of both NH<inf>2</inf>OH and NH<inf>4</inf>+ formation is only achievable under H<inf>2</inf>-deficient conditions, though this comes at the expense of lower overall hydrogenation activity. Elevated temperatures enhance NH<inf>2</inf>OH decomposition and thereby promote NH<inf>4</inf>+ formation, while leaving N<inf>2</inf> selectivity largely unaffected. Co-feeding experiments further show that externally introduced NH<inf>2</inf>OH does not influence the NO<inf>2</inf>− hydrogenation rate. We critically reviewed prior mechanistic studies on NO<inf>2</inf>− hydrogenation and propose a refined Langmuir–Hinshelwood scheme that explicitly incorporates NH<inf>2</inf>OH as a desorbed intermediate. This work highlights the importance of NH<inf>2</inf>OH in the reaction network and underscores the need to include it in the assessment of the reaction selectivity.
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Synthesis, preparation and catalytic activities of V-doped TiO2 gel coating on porous α-Al2O3 beads
(2007-01-01)
Jaroenworaluck, A.
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Panyathanmaporn, T.
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Soontornworajit, B.
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Supothina, S.
;
Tawkaew, S.
TiO<inf>2</inf> and V-doped TiO<inf>2</inf> gel were synthesized and coated onto porous α-Al<inf>2</inf>O<inf>3</inf> beads to study the thermal catalytic activities of oxidation reactions. Titanium isopropoxide (Ti(OPr) <inf>4</inf>) and 1,2-butadiol(Bu(OH)<inf>2</inf>) were used as starting chemicals for preparation of TiO<inf>2</inf> gel without V-doping. After aging at ambient temperature for one week, a TiO<inf>2</inf> gel was obtained. The concentration of Ti(OPr)<inf>4</inf> was varied, 0.2, 0.3, 0.7 and 2.4 M was used. For V-doping of the TiO<inf>2</inf> gel, 0.05, 0.20 and 0.75 mole% of V was prepared by ultrasonically dissolving vanadium acetylacetone (V(acac) <inf>2</inf>) in 1,2-butadiol. The solutions were then added to Ti(OPr) <inf>4</inf>. Finally, the mixed solutions were kept under ambient temperature for one week to form the V-doped TiO<inf>2</inf> gel. TiO<inf>2</inf> and V-doped TiO<inf>2</inf> were calcined at 300, 400, 500, 600, 700, and 800°C. XRD analysis, SEM and TEM in conjunction with EDS analysis were used to identify the phases present, grain size and morphology. The TiO<inf>2</inf> grains have a particle size in the nano-scale range. Doping TiO<inf>2</inf> with V could retard growth of the TiO<inf>2</inf> particles and affect phase transformation at higher calcination temperatures. Both the TiO<inf>2</inf> and V-doped TiO<inf>2</inf> gels were prepared and coated onto α-Al <inf>2</inf>O<inf>3</inf> beads to test oxidation reactions in a purpose-designed reactor. The results of the catalytic reactions indicated that V-doped TiO<inf>2</inf> had a higher oxidation activity than the undoped TiO<inf>2</inf> gel. The content of vanadium was related to the reaction efficiency.
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Oxidation of tetrahydrofuran to butyrolactone catalyzed by iron-containing clay
(2015-01-01)
Ausavasukhi, Artit
;
Sooknoi, Tawan
Thermally treated iron-containing clay was used as a greener oxidation catalyst for the conversion of tetrahydrofuran (THF) to butyrolactone (BTL). Mild liquid phase reactions were tested at 50-66 °C using hydrogen peroxide (H<inf>2</inf>O<inf>2</inf>) as an oxidizing agent. XRD, TGA, ESR, DR-UV, and FTIR revealed the dislodged iron oxide species formed by treating at ≥500 °C. Formation of active oxidizing species on the surface occurs on contact the dislodged Fe(III) oxide with H<inf>2</inf>O<inf>2</inf>. Such active species can promote the oxidation of THF, giving high yield and selectivity of BTL, whereas the iron-containing clay treated at lower temperatures (<500 °C) perform Fenton-like oxidation with lower THF conversions and non-selective products. 2-Hydroxytetrahydrofuran (THF-2-ol) was primarily produced and further oxidized to BTL with a small amount of 4-hydroxybutyric acid as a minor product. Minimal H<inf>2</inf>O<inf>2</inf>/THF ratio of 1.0 is sufficient for the production of BTL. Deactivation can be observed presumably due to deposition of the products despite slight leaching of the active iron species.
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Rational Design of Isolated Tetrahedrally Coordinated Ti(IV) Sites in Zeolite Frameworks for Methyl Oleate Epoxidation
(2024-10-16)
Klinyod, Sorasak
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Yomthong, Krissanapat
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Iadrat, Ploychanok
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Kidkhunthod, Pinit
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Choojun, Kittisak
The rational design of isolated metals containing zeolites is crucial for the catalytic conversion of biomass-derived compounds. Herein, we explored the insertion behavior of the isomorphic substitution of Ti(IV) in different zeolite frameworks, including ZSM-35 (FER), ZSM-5, and BEA. The different aluminium topological densities of each zeolite framework lead to the creation of different degrees of vacant sites for hosting the tetrahedrally coordinated Ti(IV) active sites. These observations show the precise control of the degree of four-coordinated Ti(IV) sites in a zeolite framework, especially in BEA topology, by tuning the degree of unoccupied sites in the host zeolite structure via dealumination. Interestingly, the more vacancies in the host zeolite structure, the more isolated tetrahedrally coordinated Ti(IV) can be increased, eventually enhancing the catalytic performance in methyl oleate (MO) epoxidation for producing methyl-9,10-epoxystearate (EP). The engineered Ti-β exhibits outstanding performances in bulky MO epoxidation with the amount of produced EP per number of Ti sites up to 17.1±1.8 mol mol−1. This observation discloses an alternative strategy for optimizing catalyst efficiency in the rational design of the Ti-embedding zeolite catalyst, endeavoring to reach highly efficient catalytic performance.
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Production of liquid fuel from palmitic acid over nanocrystalline CeO2-based catalysts with minimal use of H2
(2017-01-01)
Maluangnont, Tosapol
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Dararat, Chalinee
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Kulrat, Teerapong
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Soontontaweesub, Surachet
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Anothaiwalaikul, Thitima
The deoxygenation of palmitic acid into diesel-range hydrocarbons can be promoted over nanocrystalline ceria-based catalysts under atmospheric N<inf>2</inf> or 10% H<inf>2</inf>/N<inf>2</inf> in a fixed-bed flow reactor at 400 °C. Oxygen vacancy sites are active for ketonization of palmitic acid to C<inf>31</inf> ketone and also subsequent cracking of the formed ketone to hydrocarbons. The 22–31% selectivity of C<inf>9</inf> to C<inf>17</inf> liquid hydrocarbons can be achieved at 100% palmitic acid conversion. The deoxygenation under N<inf>2</inf> can be facilitated, presumably by hydrogen transfer from coke precursors. Catalytic activity of ceria-based catalysts can be tuned by pretreatment conditions, type of a carrier gas, or lattice modification.
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Effect of metal dispersion and support structure of Ni/silicalite-1 catalysts on non-thermal plasma (NTP) activated CO2 hydrogenation
(2020-09-05)
Chen, Huanhao
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Goodarzi, Farnoosh
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Mu, Yibing
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Chansai, Sarayute
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Mielby, Jerrik Jørgen
Non-thermal plasma (NTP) activated heterogeneous catalysis is a promising alternative to thermal catalysis for enabling many challenging reactions (e.g. catalytic CO<inf>2</inf> hydrogenation) under mild conditions. However, the mechanistic insight into the interaction between highly energetic electrons and vibrationally-exited reactive species with metal catalyst is still lacking. Here, catalytically active Ni nanoparticles supported on silicalite-1 zeolites with different configurations regarding the location of Ni active sites and support pore structures were comparably investigated using catalytic CO<inf>2</inf> hydrogenation under the thermal and NTP conditions. Experimental results revealed that the performance of the NTP-catalysis depends on the configuration of the catalysts significantly. Specifically, catalysts with Ni active sites sit on the outer surface of zeolite crystals (i.e. microporous Ni/S1 and Ni/M-S1@Shell with steam-assisted recrystallised micro-meso-porous structure) showed relatively good catalytic performance at a low applied voltage of 6.0 kV. Conversely, the encapsulated catalyst with hierarchical meso-micro-porous structure (i.e. Ni/D-S1) which has relatively small (i.e. average Ni particle sizes of 2.8±0.7 nm) and dispersed Ni nanoparticles (i.e. Ni dispersion of ca. 2.5 %) demonstrated comparatively the best catalytic performance (i.e. CO<inf>2</inf> conversion of ca. 75 %) at 7.5 kV. Additionally, under the NTP conditions studied, Ni on carbon-templated mesoporous silicalite-1 (Ni/M-S1) showed the worst selectivity to CH<inf>4</inf>, which was attributed to the poor accessibility of Ni active sites encapsulated in the enclosed mesopores. This study demonstrated the crucial role of catalyst design in NTP activated catalysis.
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Deoxygenation of model biofuel compounds over CsNaX zeolite catalyst
(2008-12-01)
Danuthai, Tanate
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Peralta, Maria A.
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Sooknoi, Tawan
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Osuwan, Somchai
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Lobban, Lance L.
The deoxygenation of methyl octanoate and benzaldehyde over CsNaX zeolite catalyst has been investigated as a model for reactions for production of hydrocarbon fuels from bio-oxygenates. The CsNaX zeolite used in the study was prepared by ion exchange of NaX with a CsNO<inf>3</inf>/CsOH solution to a 50% exchange level. The decarbonylation activity, selectivity, and stability of the CsNaX catalyst were enhanced when methanol was co-fed for the reaction of methyl octanoate. TPD studies suggest that methyl octanoate first decomposes to an octanoate-like species. The decomposition of such species leads to the formation of heptenes and hexenes as major products. Octenes and hydrogenated products are formed in lesser amounts via hydrogenation / hydrogenolysis using hydrogen produced on the surface from methanol decomposition, but not from gas phase H<inf>2</inf>.
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Correction to “A Career in Catalysis: Daniel Resasco”
(2026-02-20)
Resasco, Joaquin
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Albanese, Jimmy Faria
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Alvarez, Walter
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Crossley, Steven
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Haller, Gary L.
In the original manuscript, José E. Herrera was inadvertently omitted from the author list. He contributed to the section on carbon nanotubes. The author list has been corrected to reflect his contribution.
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Local structure of stoichiometric and oxygen-deficient A 2Ti6O13 (A = Li, Na, and K) studied by X-ray absorption spectroscopy and first-principles calculations
(2018-10-21)
Kanchanawarin, Jarin
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Limphirat, Wanwisa
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Promchana, Pratya
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Sooknoi, Tawan
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Maluangnont, Tosapol
Oxygen vacancy defects (V<inf>O</inf>) in Ti-based oxides play important roles in catalytic processes despite limited knowledge regarding their formation and characterization. Here, we demonstrate the use of X-ray absorption spectroscopy (XAS) measurements to compare the relative proportion of V<inf>O</inf> defects in as-grown alkali hexatitanate A<inf>2</inf>Ti<inf>6</inf>O<inf>13</inf> (A = Li, Na, K). Both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) regions were studied. The similarity of measured XANES spectra of Ti K-edge in all samples indicates the presence of (Ti4+)O<inf>6</inf> units in good agreement with reported X-ray diffraction results. The small influence of cations A at the tunnel was observed and can be well reproduced in the simulated spectra. In addition, we present a semi-quantitative approach to intuitively determine the content of V<inf>O</inf> defects in oxygen-deficient K<inf>2</inf>Ti<inf>6</inf>O<inf>13-x</inf> by in situ time-resolved XAS measurements under reducing conditions (10%H<inf>2</inf>/Ar, 50-650 °C). The in situ XANES measurements indicate that the oxidation state of bulk Ti remains the same as the as-grown sample, i.e., 4+, at elevated temperatures. By in situ EXAFS measurements, the relative number of V<inf>O</inf> defects is highest at a reduction temperature of ∼550 °C and slightly decreases after that. To confirm the formation of V<inf>O</inf> defects, first-principles calculations were independently carried out using a 126-atom K<inf>2</inf>Ti<inf>6</inf>O<inf>13</inf> supercell with V<inf>O</inf> at various positions. Based on calculated EXAFS, the removal of the oxygen atom nearest to the tunnel, which is the lowest energy structure, provides a good match to the experimental spectra.

Sooknoi, Tawan

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