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Microwave-activated reduced graphene oxide composite with hydrothermally treated corn husk activated carbon as an active electrode for high electrochemical performance in symmetrical carbon-based supercapacitor devices
(2026-07-01)
Srakaew, Khattiya
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Ratchayotee, Pornthip
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Janorat, Phattharawadee
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Phrompet, Chaiwat
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Kitiwan, Mettaya
This work applies microwaves for synthesizing reduced graphene oxide (rGO) and waste material corn husk activated carbon composites as active electrode materials for symmetric supercapacitors. The rGO is activated by microwave treatment and corn husk carbon by KOH in processed hydrothermal activation, followed by compositing at various weight ratios. Among all compositions, rGO:H_Corn_C (90:10) is reported with the best properties, with a specific surface area of 314.2 m2/g and a high specific capacitance of 1152 F/g at 0.1 A/g. The optimized composite also delivered increasing energy and power densities of up to 160 Wh/kg and 9.68 × 102 W/kg, respectively, within a 1 V operating window. In an experiment by assembling a symmetric coil cell supercapacitor, the device showed a specific capacitance of 142.23 F/g at 0.1 A/g, cycling stability with 98.8% capacitance retention after 1000 cycles of charge-discharge, and peak energy and power densities of 40.68 Wh/kg and 5.74 × 102 W/kg. Overall, the composite material with a high content of rGO and corn husk-derived activated carbon prepared by the hydrothermal method exhibits high-performance for the material in supercapacitor applications.
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Extraction of Chitin, Chitosan, and Calcium Acetate from Mussel Shells for Sustainable Waste Management
(2025-08-01)
Seangarun, Chaowared
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Seesanong, Somkiat
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Boonchom, Banjong
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Laohavisuti, Nongnuch
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Rungrojchaipon, Pesak
In this paper, mussel shells were used to produce chitin, chitosan, and calcium acetate using chemical processes, searching for an alternative environmentally friendly biopolymer and calcium source. Mussel shells were treated with acetic acid as a demineralizing agent, resulting in separate solid fractions and calcium solution. The solid was further purified to produce chitin by deproteinization and decolorization processes, and then the deacetylation process was used to obtain chitosan. The calcium solution was evaporated to produce calcium acetate powder. The yields of extracted chitin, chitosan, and calcium acetate from 100 g of mussel shells were 2.98, 2.70, and 165.23 g, respectively. The prepared chitin, chitosan, and calcium acetate were analyzed by Fourier transform infrared (FTIR) spectrophotometry, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscope (SEM) to confirm the chemical and physical properties. The analysis results of chitin and chitosan revealed the similarity to chitosan derived from crustaceans and insects in terms of functional group, structure and morphologies. The prepared calcium acetate shows FTIR and XRD data corresponding to calcium acetate monohydrate (Ca(CH<inf>3</inf>COO)<inf>2</inf>·H<inf>2</inf>O) similar to synthesized calcium acetate in previous research. In addition, the mineral contents of calcium acetate identified by X-ray fluorescence (XRF) analysis exhibit 97.8% CaO with non-toxic impurities. This work demonstrated the potential of the production process of chitin, chitosan, and calcium acetate for the development of a sustainable industrial process with competitive functional performance against the commercial chitin and chitosan production process using crustacean shells and supported the implementation of a circular economy.
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Grain boundary, electrical transport and thermoelectric properties of the ultra-high rGO amount of C12A7-rGO composites
(2024-04-30)
Maneesai, Keerati
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Thongkam, Montree
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Sriwong, Chaval
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Ruttanapun, Chesta
The Ca<inf>12</inf>Al<inf>14</inf>O<inf>33</inf> ceramic (C12A7) and reduced graphene oxide (rGO) composite which an ultra-high amount (i.e., 40, 50, 60, and 70 wt%) of rGO (ultra-high amount C12A7/rGO composite) were synthesized by a solid-state reaction process. After the hydraulic press, the heat treatment in the temperature range of 773 K under the argon environment had been performed with the composite pellets for 30 min. XRD results of the C12A7 and all the ultra-high amount C12A7/rGO composites indicated a pure phase of C12A7 ceramic. Raman spectra confirmed the existence of rGO content in all the ultra-high amount C12A7/rGO composites. Raman peaks also suggested reduction of the free O<inf>2</inf>2− and O<inf>2</inf>− ions from the framework of the ultra-high amount C12A7/rGO composites. SEM image presented the homogeneous grain boundary interface after the heat treatment at 773 K of the C12A7 wrapped by the rGO sheet, the agglomerated rGO sheet, and the rough interface stack of rGO sheets. UV-VIS spectroscopy presented the absorption behavior, direct energy gap, and indirect energy gap modifications of the ultra-high amount C12A7/rGO composites. Electrical conductivity of the ultra-high amount C12A7/rGO composites illustrated larger than 108 times improvement with temperature independence. Range of −5 to −17 μV/K, temperature dependence, and increased with rGO content increasing Seebeck coefficient were reported. Thermal conductivity of the ultra-high amount C12A7/rGO composites was increased with the rGO content increasing. Both the Power factor (PF) and the figure of merit (ZT) of the ultra-high amount C12A7/rGO composites were temperature dependent and were increased with the rGO content increasing, within the range of 0.4 μW/m.K2 of PF and the range of 3x10−4 of ZT, respectively. These experimental results verified grain boundary, modified energy band, electrical transport properties and thermoelectric properties of C12A7/rGO composites loading with ultra-high content rGO
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Vitrimer-like of poly (glycerol sebacate) by using zinc acetate, zinc oxide and Amberlyst as catalysts
(2023-01-01)
Thongkam, Montree
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Saowsupa, Sairoong
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Rungrojchaipon, Pesak
Polyglycerol sebacate (PGS) is elastomeric biodegradable polymer with potential biomedical and green packaging applications. This study focuses on the synthesis of vitrimer-like PGS utilizing various catalysts, including Zinc acetate, Zinc oxide and Amberlyst-15. The investigation of vitrimer-like of PGS polymer by polycondensation of glycerol and sebacic acid with various molar ratio of 1:1, 1:1.25 and 1:1.5 will be studied. The synthetic time and temperature were controlled at 72 h, 120 °C, respectively. The prepolymer of PGS had a weight-average molecular weight (Mw.) of 1743. The result of functional group was confirmed by Fourier transforms Infrared spectroscopy (FTIR). The intense C[dbnd]O stretch at 1737 cm−1 confirms the formation of ester bonds. The intense OH stretch at 3454 cm−1 indicated hydroxyl groups from hydrogen bonded. When the quantity of catalyst is increased, the results of hardness are rising but swelling (%) becomes lower. The results showed a polymer network has higher cross-link when the catalyst increases. In addition, the proton nuclear magnetic resonance spectroscopy (1H NMR) analysis found that PGS using catalyst does not have peaks of glycerol.
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A Facile Method to Synthesize b-Oriented Silicalite-1 Thin Film
(2022-05-01)
Thongkam, Montree
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Woramongkolchai, Somsak
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Saowsupa, Sairoong
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Rungrojchaipon, Pesak
Silicalite-1 thin film was prepared with the following batch composition—3TPAOH:25TEOS: 1450H<inf>2</inf> O:100EtOH—and synthesized using the hydrothermal technique. Silicalite-1 colloidal crystals were successfully coated on the surface of the silica substrate by the dip-coating method. The investigation of silicalite-1 thin film with organic structure-directing agents (SDA), using a seeding technique with various colloidal seed concentrations, number of dip-coating steps, and crystallization time, were systematically discussed and obtained interesting results. Silicalite-1 powder and Silicalite-1 membrane, the patterns of which showed a unique characteristic crystallography of MFI topology, were characterized by XRD, which indicated the preferred orientation along the b-axis perpendicular to the substrate surface. The morphology and crystal size aspect of Silicalite-1 were also examined by a scanning electron microscope (SEM).
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Effects of Zinc and Aluminum on the CuO Crystalline Size for Direct Dimethyl Ether Synthesis from Syngas
(2021-09-01)
Thongkam, Montree
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Piyabunditgul, Nanchapak
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Trisupakitti, Somsuk
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Rungrojchaipon, Pesak
The effects of zinc and aluminum on the CuO crystalline size for direct dimethyl ether (DME) synthesis from syngas were investigated. Metal oxide catalysts were synthesized with various molar ratios of CuO by the precipitation method, and by the co-precipitation method with CuO/ZnO (CZ), CuO/ZnO/Al<inf>2</inf>O<inf>3</inf> (CZA), and CZA at ratios of 1:1, 2:2:1, and 6:3:1, respectively. The acid catalysts (γ-Al<inf>2</inf>O<inf>3</inf>, HZSM-5) were added to the metal oxide catalysts by physical mixing. The catalysts were characterized morphologically and their acidities were determined. Loading of zinc and aluminum at different ratios showed that CZA (2:2:1) gave the smallest CuO crystalline size, appropriate for the methanol synthesis reaction. γ-Al<inf>2</inf>O<inf>3</inf> has a weak to moderate acidity range, suitable for DME synthesis. Moreover, the bifunctional catalyst, CZA (2:2:1)/γ-Al<inf>2</inf>O<inf>3</inf>, had the highest surface area as well as the highest %CO conversion and %DME selectivity.
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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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Adsorption kinetic of direct dyes from aqueous solution on zeolite lta
(2021-01-01)
Thongkam, Montree
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Trisupakitti, Somsuk
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Palama, Thongsuk
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Senajuk, Watchara
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Nausri, Chompoo
The analysis of adsorption relies on the equilibrium state of the mass. It is the relationship between the concentration of the adsorbate in the liquid phase and the concentration of the adsorbate in the solid phase. The relationship is written as an isotherm of the adsorption graph. Zeolite LTA was used as adsorbent to remove dye from solution in a batch adsorption system. The adsorption isotherm showed that the Langmuir model was better than the Freundlich model. Adsorption of adsorbate consists of a diffusion process through the fluid layer around the adsorbent material and the diffusion in the cavity. This research found that a pseudo-second order model was a better fit to measured adsorption data.
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Simple and Rapid Synthesis of Calcium Acetate from Scallop Shells to Reduce Environmental Issues
(2021-01-01)
Thongkam, Montree
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Saelim, Jinnaput
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Boonchom, Banjong
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Seesanong, Somkiat
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Chaiseeda, Kittichai
The search for sustainable resources remains a subject of global interest. Calcium acetate used in many fields was prepared using waste scallop shell as a raw material, and its physicochemical properties were investigated. The waste scallop shells were transformed to calcium acetate compounds by reactions with four acetic acid concentrations at ambient temperature until the completely dried powder is obtained. The maximum yield of 87% with short reaction time at a low temperature was observed in the reaction of 60%w/w acetic acid with scallop shells. Thermal transformation reactions of all prepared calcium acetate samples revealed temperature conditions for heating to produce other advanced materials. FTIR and XRD results confirmed the purity and solid phase of all prepared calcium acetate samples, and they were compared with those of literatures and found to be well consistent. The obtained timber-like particles have different sizes depending on the acetic acid concentration. This work reports an easy and low-cost method with no environmental effect to produce cheap calcium products to be used in the industry.
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A Well-Defined Core–Shell-Structured Capsule Catalyst for Direct Conversion of CO2 into Liquefied Petroleum Gas
(2020-04-21)
Li, Hangjie
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Zhang, Peipei
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Guo, Lisheng
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He, Yingluo
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Zeng, Yan
A Pd/SiO<inf>2</inf>@S1@H-ZSM-5 capsule catalyst (Pd/SiO<inf>2</inf>–SZ) is fabricated through a dual-layer crystal growth method with an auxiliary hydrothermal reaction. The catalyst exhibits excellent selectivity to liquefied petroleum gas (LPG) in CO<inf>2</inf> hydrogenation reactions, which is attributed to the tandem reactions of methanol synthesis on the Pd/SiO<inf>2</inf> core catalyst and methanol dehydration to hydrocarbons on the H-ZSM-5 shell. The Pd/SiO<inf>2</inf>–SZ capsule catalyst has a similar mesoporous structure, narrow range of Pd particles size distribution, and consistent reduction characteristics to the Pd/SiO<inf>2</inf> core catalyst. It maintains the physical and chemical properties of the core catalyst throughout the H-ZSM-5 shell synthesis process. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy results reveal that the H-ZSM-5 zeolite shell completely encapsulates the Pd/SiO<inf>2</inf> core catalyst. Compared with the crushed capsule catalyst (Pd/SiO<inf>2</inf>–SZP), the well-defined-structured Pd/SiO<inf>2</inf>–SZ catalyst has a much higher LPG selectivity of 33.6 %, owing to the well-matched reactions at the Pd/SiO<inf>2</inf> core and H-ZSM-5 shell.

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