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Dry-gel synthesis of Ti-beta for epoxidation of unsaturated fatty acid methyl esters (FAMEs)
(2026-09-01)
Yomthong, Krissanapat
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Saenluang, Kachaporn
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Soyphet, Asadawut
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Ittisanronnachai, Somlak
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Padchasri, Jintara
The Ti-beta was synthesized via a dry-gel conversion approach with the direct incorporation of titanium from titano-aluminosilicate nanobeads (Ti-SiAl-NB). At first, the Ti-SiAl-NB was prepared and employed as the precursor for zeolite crystallization. Powder XRD (PXRD) patterns confirm the amorphous nature of the nanobeads. These Ti-SiAl-NB precursors were subsequently converted to the Ti-beta zeolite via the dry-gel conversion approach. Structural characterization using PXRD, high-resolution TEM, and selected area electron diffraction (SAED) confirmed the formation of a beta zeolite framework, with dominant lattice planes indexed to (101) and (302). UV-vis DRS indicated that Ti existed as a tetrahedrally coordinated (TiIV) and non-framework Ti. Unfortunately, the as-synthesized Ti-beta exhibited a low catalytic activity in methyl oleate (MO) epoxidation, which is attributed to the prevalence of closed site TiIV [Ti(OSi)<inf>4</inf>] species that restrict substrate accessibility to active sites. To address this limitation, a post-synthetic treatment involving framework etching was applied to generate open site TiIV [Ti(OSi)<inf>3</inf>OH] species. As a result, MO conversion increased by approximately 2.73-fold, with epoxide selectivity up to 70%. Catalyst stability tests demonstrated sustained MO conversion of 65–72% and epoxide selectivity above 65% over several consecutive catalytic cycles. This work highlights a sustainable catalyst design strategy that combines the dry-gel conversion process with mild post-treatment to enhance active site accessibility and catalytic performance in the epoxidation of bulky molecules.
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Combination of natural silica and alumina sources for synthesis of MCM-22 zeolite
(2023-08-01)
Tanwongwan, Worapak
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Chollacoop, Nuwong
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Faungnawakij, Kajornsak
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Assabumrungrat, Suttichai
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Nakhanivej, Puritut
Zeolite has become a promising material that can potentially play a pivotal role in resolving environmental crises. Among zeolite families, MCM-22 zeolite shows outstanding intrinsic properties associated with the topology and porous structure, offering ion-exchange advantages for catalytic activity processes. The synthesis of MCM-22 zeolite becomes challenging when concerning the cost and catalytic performance. To overcome this bottleneck, we demonstrate a sustainable route of a hydrothermal process using natural resources as starting materials. Rice husk from agricultural waste was used as a silica source while natural clays (kaolin and bentonite) were applied as alumina sources. The products from natural sources were compared with the use of commercial starting materials, e.g., NaAlO<inf>2</inf> (for alumina) and Na<inf>2</inf>SiO<inf>3</inf> and TEOS (for silica), in points of crystal, compositional, and morphological views. We showed that the high purity of MCM-22 zeolite can be obtained from rice husk silica (RHS) and aluminosilicate gel (ASG) extracted from kaolin, while the use of ASG extracted from bentonite tended to be unsuitable to generate the zeolite formation. We also studied the effects of reaction time and the ratio of RHS/ASG on the crystallinity and surface area of MCM-22. The architecture and acidity of an optimal product were explored by Nuclear magnetic resonance spectroscopy and Temperature-programmed desorption of ammonia, demonstrating the success of achieving well acidity.
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DFT Investigation of the catalytic conversion of acetic acid to acetone on the zeolite H-ZSM5
(2022-12-01)
Konsue, Adchatawut
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Gleeson, M. Paul
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Gleeson, Duangkamol
Biomaterials processing has become increasingly important in the chemical industry. Identification and optimization of processes to facilitate biomass conversion is therefore recognized as being of great importance. Carboxylic acids derived from biomaterials are important building blocks that can be used in a wide variety of industrial applications. As such, methods to process them in an efficient and cost-effective manner are highly desirable. In this study we report the use of theoretical methods to explore the catalytic conversion of acetic acid to acetone on the zeolite H-ZSM5. We have employed a 46T DFT cluster model to explore mechanistic proposals reported in the literature. We investigate the relative energetics associated with the formation of the proposed intermediates, including acyl-zeolite complexes, enols, acylium cations, ketenes, anhydrides, and beta-keto acids, that could potentially connect acetic acid to the desired product, acetone. This assessment would allow us to identify the most probable mechanism connecting the reactant to products. We predict a low energy pathway starting with the generation of a surface acyl, followed by an anhydride, with the rate determining step involving methyl group migration. The reaction is predicted to be bi-molecular and involves C-C bond formation, in line with proposals based on isotopic labelling experiments.
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Direct Synthesis of Liquefied Petroleum Gas from Carbon Dioxide Using a Copper/Zinc Oxide/Zirconia/Alumina and HY Zeolite Hybrid Catalyst
(2021-07-27)
Natakaranakul, Jaru
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Thongkam, Montree
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Li, Hangjie
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Suchamalawong, Phorndranrat
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Tsubaki, Noritatsu
Conversion of CO<inf>2</inf> to lower hydrocarbons (HCs) is a high potential process that could reduce and sustainably control this greenhouse gas. In accord with The Sustainable Development Goal from The United Nation Development Program, liquefied petroleum gas (LPG) is viewed as environmentally friendly and is widely used. Small HCs can be directly synthesized from CO<inf>2</inf> hydrogenation over a hybrid catalyst. The main purpose of this study was to investigate the direct synthesis of LPG from CO<inf>2</inf> hydrogenation using a copper/zinc oxide/zirconium/alumina (CZZA) mixed metal and HY zeolite as a hybrid catalyst. The study was conducted in a fixed bed reactor using hydrogen/CO<inf>2</inf>/carbon monoxide as the reactant gas and evaluating four types of production condition, method of catalyst combination, reaction temperature, CZZA/HY zeolite mass ratio, and catalyst weight/volume flow rate. The mixing type between the CZZA and HY zeolite catalysts markedly influenced the HC selectivity with strong suppression of reverse water gas shift reaction. At the optimum condition, a 27.39 % CO<inf>2</inf> conversion level and a high HC (98.70 %) and LPG (66.56 %) selectivity were obtained.
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Pressure Swing Absorption Oxygen Concentrator equipped with Remote Monitoring Pulse Oximeter
(2021-01-01)
Ongtrakul, Salila
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Thitiratannapong, Anyarin
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Pintavirooj, Chuchart
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Treebupachatsakul, Treesukon
The new COVID-19 disease was first identified in China at the end of 2019 and has spread rapidly all over the world. It has been projected that, by March 2021, the number of infections could reach 300 million cases and over two million deaths. One of the main implications for COVID-19 patients is pneumonia where the lung is infected, hence patients suffering from insufficient oxygen in the blood. As the number of COVID-19 cases have significantly increased, the demand for oxygen generators have also skyrocketed. This research concerns the design and construction of emergency low-cost oxygen concentrators used for mild COVID-19 symptoms, of which are forced to be treated at home. Our absorption-based oxygen concentrator uses zeolite packed in a sieve canister. An Oil-free compressor is then used to pump air in. Zeolite will absorb nitrogen from the air leaving oxygen free to travel towards the outlet. To evaluate the treatment, we have equipped the system with a pulse oximeter to measure the percent saturation oxygen, pulse rate and temperature. To prevent COVID-19 infections between patients and caretakers, we have designed an android application to remotely control the oxygen concentrator. Experiment has shown that our emergency low-cost oxygen concentrator can supply oxygen with an 85% purity rate.
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Acid soil amendment by zeolite, sepiolite and diatomite
(2019-01-01)
Chaiyaraksa, Chompoonut
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Tumtong, Mintra
The aim of this research was to reduce the heavy metal movement to the biosystem using clay minerals including zeolite, sepiolite, and diatomite. The clay soil and sandy loam soil were made contaminated with 200, 350, 700, and 250 mg of Zn, Cu, Cr, and Ni per kg of soil, respectively. The ratio of clay minerals added to soils was 2.5%, 5%, and 7.5%. The determination of various forms of heavy metals bound to soil mixed with clay minerals and left for a period of 30 and 60 days was carried out using the sequential extraction method. The results indicated that Ni and Zn were mostly in an exchangeable form, while Cu and Cr were mostly in an oxide bound form and an organically bound form. The pH of the soils increased after adding clay minerals. Diatomite caused the smallest change in the pH value. Chromium had the best adsorption capacity by bonding with various elements in the soil, followed by Cu, Zn, and Ni, respectively. The addition of sepiolite caused more heavy metals in a stable form than adding zeolite and diatomite. When adding clay minerals to both types of soil, the highest impact was on Ni, followed by Zn, Cu, and Cr, respectively. The bioavailable index (BI) value was the least when adding sepiolite. The risk of heavy metals moving to the biosystem was lower when increasing the incubation time. Without adding any clay mineral, the BI value of metals in the sandy clay loam soil was higher than that in the clay soil.
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Improvement of water vapor permeability of LLDPE/EVA film with zeolite A as filler
(2017-01-01)
Rukchonlatee, Suparat
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Jaisomboon, Nattarika
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Sooknoi, Tawan
In this work, water vapor permeability of linear low density polyethylene (LLDPE)/ethylene vinyl acetate copolymer (EVA) film is improved by incorporation of zeolite A as filler (0-25%wt) for prolonging shelf-life of fresh produces. All films were characterized by SEM, DSC, tensile testing, contact angle measurement and tested for water vapor permeability (WVP). The shelf-life of Bird's eye chili in the film samples was also tested at 10°C for 21 days. It was found that zeolite A particles were virtually dispersed in EVA phase. Accordingly, crystallinity and tensile properties of LLDPE/EVA/Zeolite A films is independent to zeolite loading. Despite, when zeolite loading was increased, the dispersion became low. The film's wetting behavior was enhanced by increasing zeolite content in the LLDPE/EVA/Zeolite A films. The observed increase in the film's polarity significantly enhances the WVP. Therefore, less water condensed can be found inside the package made with LL80E20Ze25 film, as compared to LLDPE or LLDPE/EVA film. The LL80E20Ze25 also possesses comparable tensile properties to the commercial LLDPE film and hence can used as packaging for extending the shelf-life of fresh produces.
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Zeolite supported bimetallic catalyst system: The effect of metal loading for catalytic pyrolysis of jatropha residue
(2017-01-01)
Goodwin, Vituruch
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Amnaphiang, Phanwatsa
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Thungngern, Pimpreeya
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Kah Shin, Kong
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Udomsap, Parncheewa
Two transition metals were loaded on H-ZSM-5 zeolite to produce bimetallic zeolite supported catalysts for catalytic pyrolysis reaction. Ni and Co metal were loaded on H-ZSM-5 via wet impregnation method. The loading sequence was applied using one-step and two-step loading method. The different loading sequence affect surface properties of catalyst and catalytic activity in pyrolysis reaction. The bimetallic catalysts were prepared at Ni+Co metal loading content of 10+ 10 wt% (Ni:Co=1:1) to 10+20 wt% (Ni:Co=1:2 or 2:1). All bimetallic catalysts supported on H-ZSM-5 were calcined and characterized by X-ray Diffraction (XRD), Surface area analysis (BET) and Temperature Programmed Desorption of ammonia (NH3-TPD). The XRD patterns of bimetallic zeolite supported catalysts revealed that loading of two metals at high content affect crystalline structural of ZSM-5 support. All XRD patterns illustrated peaks characteristic of ZSM-5, cobalt oxide and nickel oxide. The NH3-TPD results showed number of acid sites of the catalyst which revealed that the acid sites of ZSM-5 support was weakened with transition metal added. The twostep loading of 10+20 wt% metals on ZSM-5 reduced the peak intensities of NH3 desorption due to the metal particles aggregate on acid sites of ZSM-5. The two-step 10+20 wt% bimetallic catalysts has the lowest surface acidity, followed by the one-step 10+20 wt%, the two-step 10+10 wt% and the one-step 10+10 wt% bimetallic catalysts, respectively. Jatropha residue was used for catalytic pyrolysis study. Jatropha residue and bimetallic catalyst was pyrolyzed at 500 °C in a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The product vapor was analyzed by GC/MS for the different groups of organic products such as fatty acid, aldehydes, ketones, aliphatic hydrocarbons, aromatic hydrocarbons and nitrogen compounds. The product from catalytic pyrolysis of jatropha residue with bimetallic zeolite supported catalysts enhance deoxygenation reaction that resulted in high aliphatic and aromatic hydrocarbons product. The one-step loading at ratio Ni:Co = 1:1 (10+10 wt%) gave the highest hydrocarbons product yield at 57.81%.
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Effects of zeolite on seed quality of organic upland rice
(2014-01-01)
Nokkoul, Raumjit
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Wichitparp, Teerayut
The production of high quality seeds is an important strategy for organic seed producers. In particular, organic farming is a production system which avoids the use of synthetic fertilizers, insecticides and plant growth regulators. Alternative management organic farming system is reducing nutrient loss and improving soil quality. Zeolite is organic matter and alternative for organic upland rice production. Our objective was to determine the effects of zeolite on seed quality of organic upland rice varieties: Dokkam and Nangchuan. The study involved using Randomized Complete Block design (RCB) with four replications and four treatments: 1) Chemicals method by using fertilizer (15N-15P-15K) rated 4.80 kg/ha for control (T1) 2) Cattle manure rated 160 kg/ha (T2) 3) Zeolite rated 16 kg/ha (T3) 4) Zeolite rated 32 kg/ha (T4). The fertilizer was applied at the rate of 160 kg/ha of cow manure (T1 to T4) and were applied at the rated of 16 and 32 kg/ha of zeolite (T3 and T4), respectively, (mixing into the soil before growing). The experiment was done at the experimental plots of King Mongkut's Institute of Technology Ladkrabang, Prince of Chumphon Campus, Thailand during July to November, 2012. The results showed that both varieties of organic upland rice seed quality, all four treatments had high quality, which were not significantly different among the treatments. The 1,000-seed weight ranged from of 22.30 to 25.24 mg, standard germination of 91.50 to9 5. 50%, soil emergence of 90.00 to 94.00%, speed of germination index of 6.79 to 11.30, seedling dry weight of 4.38 to 5.88 mg/seeding, conductivity of 5.49 to 9.07 μmo/cm/gm and age acceleration of 92.00 to 99.00%. These results confirm that a zeolite could replace the application of chemical fertilizers which could be used to produce agricultural products to satisfy the needs of the consumers who want to consume safe food, besides minimizing pollution of agricultural environment and economic costs.
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A double-shell capsule catalyst with core-shell-like structure for one-step exactly controlled synthesis of dimethyl ether from CO2 containing syngas
(2011-08-10)
Yang, Guohui
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Thongkam, Montree
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Vitidsant, Tharapong
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Yoneyama, Yoshiharu
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Tan, Yisheng
A zeolite capsule catalyst Cr/ZnO-S-Z was prepared successfully by a novel dual-layer method, in which one layer of neutral Silicalite-1 zeolite shell was first synthesized on the bimetallic Cr/ZnO core catalyst, acting as the intermediate layer for the following H-type H-ZSM-5 zeolite shell direct synthesis on its surface. By using this dual-layer method, it can be easily realized that the formation of H-ZSM-5 zeolite membrane on the millimeter-sized bimetallic substrates. Direct synthesis of dimethyl ether (DME) from syngas at higher reaction temperature was the application of this zeolite capsule catalyst to test its catalytic performance. In reaction, this zeolite capsule catalyst could realize the exactly controlled synthesis of DME, suppressing the formation of other alkane/alkene by-products simultaneously, demonstrating its exclusive ability for the selective synthesis of target product compared with the conventional hybrid catalyst. © 2011 Elsevier B.V. All rights reserved.

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