Ritvirulh, Chonlada

Preferred name

Ritvirulh, Chonlada

Alternative Name

Ritvirulh, C.

Main Affiliation

School of Science

chonlada.ri@kmitl.ac.th

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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
;
Wisatsuvan, Patchnakan
;
Sooknoi, Tawan
;
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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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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Reversible Hydrogenation-Dehydrogenation of Acetylpyridine-Pd-MIL-101(Cr) for Chemical Hydrogen Storage
(2020-10-07)
Makmeesub, Nuttapong
;
Ritvirulh, Chonlada
;
Choojun, Kittisak
;
Chen, Teng Hao
;
Poo-Arporn, Yingyot
3-Acetylpyridine (AcP), as an organic hydrogen carrier, and Pd nanoparticles, as a catalyst, were incorporated into MIL-101(Cr) for chemical hydrogen storage. AcP was first grafted into MIL-101(Cr), and then Pd (0.5-4.0 wt %) was encapsulated by a double-solvent adsorption process. Thermogravimetric analysis, inductively coupled plasma-optical emission spectrometry, X-ray photoelectron spectroscopy, transmission electron microscopy, in situ X-ray adsorption near-edge structure analysis, 1H nuclear magnetic resonance (NMR), and elemental analysis suggested the existence of AcP and Pd nanoparticles (NPs) inside the MIL-101(Cr) cages. The chemical hydrogen storage of samples was evaluated by H2 temperature-programmed reaction. In situ Fourier transform infrared and 1H NMR techniques verified the hydrogenated and dehydrogenated forms of AcP upon hydrogen uptake. Reversible hydrogenation/dehydrogenation can be readily regulated by H2 partial pressure and temperature. The chemical hydrogen storage could be accomplished only when AcP and Pd NPs were adjacently present. The chemical hydrogen storage was enhanced with an increased Pd loading up to 0.33 mmol H2·g-1 per cycle. With the manipulation of hydrogenation and dehydrogenation temperatures at 150 °C, the chemical hydrogen storage can be maintained for up to 10 cycles. The material reported herein is one of the noncryogenic chemical hydrogen storages that can be operated at constant temperature and atmospheric pressure.
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Highly stable Pd2+ species anchoring on ethylenediamine-grafted-MIL-101(Cr) as a robust oxidation catalyst†
(2022-02-01)
Makmeesub, Nuttapong
;
Ritvirulh, Chonlada
;
Choojun, Kittisak
;
Sattayaporn, Suchinda
;
Resasco, Daniel E.
Highly stable Pd2+ species were anchored on ethylenediamine-grafted MIL-101(Cr). Ethylenediamine (0.3-1.2 mmol g−1) was first grafted onto MIL-101(Cr), then Pd2+ (0.03-0.2 mmol Pd per g) was incorporated by double-solvent adsorption. Fourier transform infrared, inductively coupled plasma-optical emission spectroscopy, transmission electron microscopy and CHN analysis confirmed the incorporation of ethylenediamine and Pd2+ in MIL-101(Cr). X-ray photoelectron and Raman spectroscopy suggested that one amino moiety of ethylenediamine coordinated with the Cr3+ nodes of MIL-101(Cr). The other served as an anchoring site for the incorporated Pd2+ species. In situ X-ray absorption near-edge structure analysis showed that the strong interaction between Pd2+ and ethylenediamine, within the confinement of the MIL-101(Cr) structure, effectively prevented reduction to Pd0, even in the presence of H<inf>2</inf> at 150 °C. At relatively low temperatures, the catalysts with ethylenediamine : Pd2+ molar ratios of 10 provided a higher activity for styrene oxidation (TOF ∼30 h−1), as compared to previous reports. The presence of ethylenediamine as an anchoring ligand also inhibited the reduction of Pd2+ by the feed (styrene) and minimized leaching of the active Pd2+ species under oxidizing and acidic conditions. The Pd2+ species anchoring on ethylenediamine-grafted-MIL-101(Cr) exhibited an improved catalytic activity and stability, as compared to typical liquid-phase oxidation catalysts.
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Selective Hydrogenation of Polyunsaturated Fatty Acid Methyl Esters over Bifunctional Ligand-Modified Pd/MIL-101(Cr) Catalysts
(2025-09-22)
Khenkhom, Phuwadon
;
Ritvirulh, Chonlada
;
Choojun, Kittisak
;
Preedawichitkun, Yardthip
;
Chanlek, Narong
Highly dispersed palladium nanoparticles (Pd NPs) were incorporated into MIL-101(Cr) frameworks functionalized with bifunctional ligands for the liquid-phase hydrogenation of polyunsaturated fatty acid methyl esters (FAMEs). A series of amino- and carboxylic-acid-containing ligands─ethylenediamine (en), diethylenetriamine (DET), alanine (AN), 4-aminobutyric acid (ABA), 5-aminovaleric acid (AVA), glutamic acid (GA), and adipic acid (AA)─were grafted onto MIL-101(Cr), followed by Pd loading (0.5 wt %). Spectroscopic and structural analyses confirmed ligand coordination to both Cr nodes and Pd species. Catalysts bearing ABA, AVA, and GA exhibited Pd0dispersion (<1 nm), yielding high turnover frequencies (up to ∼15,400  h–1) and >94% selectivity for monounsaturated FAMEs. In contrast, strong Pd–N interactions in en- and DET-grafted materials suppressed Pd0formation, reducing activity. Hot filtration and recyclability tests confirmed high catalyst stability and negligible Pd leaching. The bifunctional ligand architecture effectively tunes Pd speciation and activity, providing a robust platform for selective and reusable hydrogenation catalysts.
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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.

Ritvirulh, Chonlada

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