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Optimization of hydrothermal carbonization of Rhizoclonium riparium macroalgae using response surface methodology for high-performance solid biofuel production
(2026-01-01)
Chanpee, Sirayu
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Jadsadajerm, Supachai
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Manatura, Kanit
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Wongrerkdee, Sutthipoj
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Eiad-ua, Apiluck
Hydrothermal carbonization (HTC) was adopted as a promising approach for improving fuel quality for several high-moist biomass. In this study, the Rhizoclonium riparium macroalgae (RMA), an abundant marine alga in an aquaculture pond, was successfully converted into hydrochars as a sustainable solid biofuel. The Box Behnken design (BBD) was applied for the HTC experiment to investigate the individual and interactive effects of operating parameters, including HTC temperature, reaction time, and water ratio, on hydrochar physicochemical characteristics and fuel properties. The response surface optimization (RSM) revealed maximum mass yield (MY) of 79.1%, higher heating value (HHV) of 23.6 MJ/kg, and energy yield (EY) of 94.4%. The RSM-BBD of process parameters and their HTC effects showed that the decreasing MY and EY were significantly due to the HTC temperature and residence time. From ANOVA analysis, temperature, time, and water ratio were the most significant parameters responding to MY, HHV, and EY. The optimal conditions for hydrothermal carbonization (HTC) of RMA as a solid biofuel were determined to be a temperature of 200 °C, a duration of 2 h, and a water-to-biomass ratio of 1:1, producing the highest energy yield (EY) of 95.3%. Utilizing RSM-BBD to investigate HTC parameters for hydrochar production is a suitable effort for technical scalability.
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Oil palm leaf-derived nanoporous carbon via hydrothermal carbonization combined with NaOH microwave activation for tetracycline adsorption
(2025-11-01)
Chanpee, Sirayu
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Apinyakul, Naruemon
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Kaewtrakulchai, Napat
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Khemasiri, Narathon
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Eiad-ua, Apiluck
Generally, the increase in pharmaceutical industrial activities has led to a corresponding rise in water resource contamination. Efforts have been dedicated to addressing the urgent challenge of waste biomass disposal by developing recycling methods capable of producing bio-adsorbents. Adsorption is a promising approach for removing tetracycline contaminants, owing to its simplicity, stability, and cost-effectiveness. In this study, a low-cost activated biochar was successfully developed using oil palm leaf (OPL) via hydrothermal carbonization (HTC) combined microwave-assisted pyrolysis system (MAPS) using sodium hydroxide (NaOH). The HTC and MAPS processes enhanced high mass yield, porosity, energy efficiency, and reduced reaction time. NaOH treatment improved the porosity of the activated biochar derived from OPL, resulting primarily in a mesoporous structure. However, NaOH treatment via the MAPS process increased surface area and porosity. Among the samples tested, OPLC-NaOH-1:1 exhibited the largest surface area and highest porosity, making it the chosen candidate for further TC adsorption tests. The adsorption experiments revealed that the Langmuir isotherm model and the pseudo-second-order kinetic model accurately matched the experimental data, suggesting a mono-layered adsorption mechanism due to micropores and chemisorption interactions. Additionally, thermodynamic analysis indicated an endothermic and spontaneous reaction during the adsorption process. The adsorption of nanoporous carbon for TC was primarily regulated by pore filling, hydrogen bonding, electrostatic effects, and π-π interactions also playing a significant role. Overall, this study highlights the potential of utilizing OPL waste as a sustainable material for producing nanoporous carbon and underscores the effectiveness of nanoporous carbon for adsorbing antibiotics.
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Coconut Residue-Derived Nanoporous Carbon via Hydrothermal Carbonization for Nanoporous Carbon-Based Supercapacitor Electrodes
(2025-07-01)
Ruenroengrit, Kemchat
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Kunyuan, Jumpon
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Ruttanadech, Nuttapong
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Kaewtrakulchai, Napat
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Puengjinda, Pramote
The increasing demand for sustainable and cost-effective energy storage solutions has driven interest in biomass-derived carbon materials for supercapacitor electrodes. This study explores the valorization of coconut residue (CR), an abundant agricultural waste, as a carbon precursor for nanoporous carbon (NPC) production. NPC was synthesized via hydrothermal carbonization (HTC) of CR, followed by chemical activation using potassium hydroxide (KOH) at varying temperatures (700, 800, and 900 °C). The effects of activation temperature on the structure and electrochemical performance of the NPC were systematically investigated. The activated materials exhibited amorphous, highly porous structures, with surface areas increasing alongside activation temperature—reaching a maximum of 1969 m2 g−1 at 900 °C. Electrochemical characterization was conducted using a three-electrode setup through cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) in a 1 M Na<inf>2</inf>SO<inf>4</inf> electrolyte. The sample activated at 900 °C with a CR:KOH weight ratio of 1:2.5 achieved the highest specific capacitance of 52 F g−1 at a specific current of 1 A g−1. These findings underscore the potential of CR as a low-cost and sustainable raw material for fabricating efficient electrode materials in energy storage applications.
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NiO-YSZ anode composite material derived from mechano-chemical for solid oxide fuel cells application
(2025-06-01)
Srisuwan, Thanakorn
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Puengjinda, Pramote
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Kaewtrakulchai, Napat
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Chanpee, Sirayu
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Jadsadajerm, Supachai
This study investigates the effects of calcination time, milling duration, and sintering temperature on the properties of Nickel oxide and Yttria-stabilized zirconia (NiO-YSZ) anode composite materials for solid oxide fuel cell (SOFC) applications. NiO nanoparticles were synthesized from nickel (II) sulfate (Ni(II)SO<inf>4</inf>), with X-ray diffraction (XRD) confirming a face-centered cubic (FCC) structure. The crystallite size (21 nm) was achieved after 8 hours of calcination, while prolonged durations caused particle agglomeration. Ball-milling for 12 hours produced comparatively fine particles with an average of 706 nm, though extended milling led to grain growth and aggregation. Scanning electron microscopy (SEM) revealed nano aggregation. Sintering at 1200 °C improved the densification of the NiO-YSZ layer while increasing its porosity, which enhanced the reduction of NiO to metallic nickel (Ni). Electrochemical Impedance Spectroscopy (EIS) demonstrated lower impedance and improved electrochemical performance for cells cold-sintered at 1200 °C. These findings show the importance of optimizing processing conditions to enhance the performance of NiO-YSZ anode for SOFCs, offering valuable insights for advanced energy conversion technologies.
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Physicochemical properties and hydrophobicity enhancement of water-washed durian peel by oxidative torrefaction at 250 °C
(2025-01-01)
Kaewtrakulchai, Napat
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Soukaew, Nuttawan
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Phongaksorn, Monrudee
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Wisetsai, Awat
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Pimsamarn, Jindarat
Durian peel presents disposal challenges but offers potential as a renewable biofuel feedstock. However, high ash content, hygroscopicity, and low energy density limit its direct application. This study examined the effects of oxidative torrefaction at 250 °C (0–21 vol% O₂) combined with water washing pre-treatment on the physicochemical and hydrophobic properties of durian peel. Fuel quality was evaluated by proximate and ultimate analyses, HHV, EMC, water contact angle, FTIR, and SEM. Water washing reduced ash content by ~80%. Increasing oxygen concentration promoted devolatilization and carbonisation, with carbon content rising above 55 wt% and HHV reaching 22.34 MJ/kg. The lowest EMC (7.25%) and hydrophobic stability were obtained for washed samples at 5 vol% O₂. SEM revealed porous carbon-rich structures, while FTIR confirmed the removal of hydrophilic groups. The combined method improved energy density, minimised ash, and significantly enhanced hydrophobicity, producing coal-like biofuel suitable for storage, transportation, and co-firing applications.
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Co-hydrothermal carbonization of polystyrene waste and maize stover combined with KOH activation to develop nanoporous carbon as catalyst support for catalytic hydrotreating of palm oil
(2024-12-01)
Kaewtrakulchai, Napat
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Chanpee, Sirayu
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Jadsadajerm, Supachai
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Wongrerkdee, Sutthipoj
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Manatura, Kanit
Plastic waste is massively generated daily from households, mainly as packaging material, causing serious surrounding ecological problems. The development of plastic waste for higher value-added applications instead of landfilling and incineration has received consideration interest in bioenergy and material science research. Herein, a nanoporous carbon support of nickel phosphide catalyst for palm oil hydrotreating was developed from blended polystyrene waste and maize stover via the Co-hydrothermal carbonization (HTC) coupled with the KOH activation process. The Co-HTC parameters, such as temperature, reaction time, and PS percentage, were studied on the properties of co-hydrochar feedstocks for further activation using the Box behnken design. From the comprehensive characterization results, response surface methodology (RSM) results showed that the rising polystyrene proportion significantly exhibited the higher production yield and fixed carbon of co-hydrochar products, an essential characteristic for porous carbon manufacturing. After activation step, the final nanoporous carbon derived from the co-hydrochar (PMPC) exhibited the highest specific surface area of 1033.58 m2/g with total pore volume of 0.45 cm3/g. Moreover, the PCMC-supported nickel phosphide catalysts were successfully synthesized and tested for the catalytic hydrotreating of palm oil as alternative catalyst. The NiP-PMPC catalyst represents an impressive liquid hydrocarbon yield of 74.68 % with a high green diesel selectivity of 85.92 % at 100 % palm oil conversion. The findings of this study might help develop and utilize blended plastic waste and agricultural waste as an alternate catalytic support for various processes in biofuel and biochemical synthesis.
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Nanoporous Carbon-Supported Bimetallic (Ni, Cu, and Fe)-Mo Catalysts for Partial Hydrogenation of Biodiesel
(2024-10-15)
Jaruwat, Dolrudee
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Kaewtrakulchai, Napat
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Siriorarnroj, Siwat
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Srifa, Atthapon
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Kiatkittipong, Worapon
Upgrading biodiesel or hydrogenated fatty acid methyl esters (H-FAMEs) by partial hydrogenation is a second-generation biofuel with high specific fuel characteristics, such as superior cold flow properties, higher oxidative stability, and lower hazardous gas emissions, allowing this biofuel to provide excellent fuel properties, over conventional biodiesel. This study assessed the potential of using nanoporous carbon produced from cattail leaves (CL) as an alternative catalyst support. We synthesized various catalysts including monometallic Mo/NPC, Ni/NPC, Ce/NPC, and Fe/NPC catalysts, as well as bimetallic molybdenum-based catalysts doped with nickel, copper, or iron for the partial hydrogenation of soybean biodiesel. The NPC support demonstrated a surface area (S<inf>BET</inf>) of approximately 1,323 m2g-1, which greatly increases the catalytic activity through the efficient dispersion of catalyst active sites. The partial hydrogenation reaction of soybean FAME over the MoNi/NPC catalyst obtained the highest catalytic activity with enhanced oxidation stability from 3 to 14 h, and the cloud point and pour point increased from 2 to 13 °C and −1 to 10 °C, respectively. Hence, the selection of catalysts is crucial due to their impact on the feasibility of the process and its economic viability. This article focuses on highlighting the effectiveness of a highly promising catalyst for partial hydrogenation as well as examining the variables that influence the primary reaction pathway.
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Synergy of functionalized activated carbon and ZnO nanoparticles for enhancing photocatalytic degradation of methylene blue and carbaryl
(2024-10-01)
Rungsawang, Tipawan
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Krobthong, Sucheewan
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Paengpan, Krisanachai
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Kaewtrakulchai, Napat
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Manatura, Kanit
This study proposes preparing ZnO and ZnO/activated carbon (AC) for photocatalytic applications. ZnO and AC were synthesized using precipitation and carbonization processes, respectively. Particle sizes of ZnO and ZnO/AC were estimated at 121–135 nm. The crystalline structure analysis confirmed the presence of hexagonal wurtzite structures in ZnO. Microcrystalline graphite and amorphous carbon structures were observed in AC. The combination of these characteristics was observed in ZnO/AC. ZnO/AC exhibited an increase in surface area from 25.36 to 29.86 m2/g and a decrease in pore diameter from 5.66 to 4.31 nm. The chemical states of ZnO and AC remained unchanged. Therefore, the nanocompound structure of ZnO/AC can be inferred. The ZnO/AC nanocompounds were then employed to degrade methylene blue (MB) dye and carbaryl (CBR) insecticide, demonstrating excellent photocatalytic performance compared to pure ZnO. The apparent degradation rate constant reached an average value of 3.49 × 10−3 and 16.25 × 10−3 min−1 for MB and CBR, respectively. AC functions as carrier collectors in the ZnO/AC nanocompound structures due to the suitable energy band level for facilitating electron and hole transfers. This results in recombination suppression and prolonged lifetime, thus enhancing photocatalytic activity. The finding suggests the potential use of ZnO/AC nanocompounds to degrade agricultural chemicals in contaminated natural water under sunlight.
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Torrefaction of durian peel in air and N2 atmospheres: Impact on chemical properties and optimization of energy yield using multilevel factorial design
(2024-09-01)
Pimsamarn, Jindarat
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Kaewtrakulchai, Napat
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Wisetsai, Awat
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Mualchontham, Jomthong
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Muidaeng, Nattawut
This study investigated the torrefaction of durian peel using air and nitrogen as carrier gases. A multilevel factorial design coupled with response surface methodology (RSM) and ANOVA analysis was employed to analyze the impact of torrefaction parameters on chemical properties and energy yield. Durian peel, an agricultural waste product, was torrefied at temperatures ranging from 200 to 320 °C for residence times between 0 and 30 min. Results showed that air torrefaction significantly enhanced thermal decomposition, reducing mass yield from 94.65 % to 30.63 % as the temperature increased from 200 °C to 300 °C with a 30-min holding time. Air torrefaction also increased the higher heating value (HHV) from 19.02 MJ/kg to 35.26 MJ/kg at 300 °C, compared to nitrogen, which achieved a maximum HHV of 32.49 MJ/kg. ANOVA analysis revealed that torrefaction temperature and carrier gas significantly affect energy yield and chemical properties. Air torrefaction positively affected HHV while reducing mass yield compared to nitrogen. Low-temperature air torrefaction showed enhanced energy yield improvement. These findings provided insights for optimizing torrefaction processes enhancing utilization wasted durian peel as a sustainable bioenergy resource.
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A novel photocatalyst of Y2O3-BaO-ZnO ternary system for enhanced photocatalytic degradation of carbofuran insecticide
(2024-08-01)
Sujinnapram, Supphadate
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Krobthong, Sucheewan
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Moungsrijun, Sasimonton
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Boonruang, Chatdanai
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Kaewtrakulchai, Napat
A novel Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO ternary system was synthesized via precipitation of a mixture of Y(NO<inf>3</inf>)<inf>3</inf>.6 H<inf>2</inf>O:Ba(NO<inf>3</inf>)<inf>2</inf>:Zn(NO<inf>3</inf>)<inf>2</inf>.6 H<inf>2</inf>O using some Fibonacci sequences. The Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO was applied to the photocatalyst to investigate the degradation of carbofuran insecticide. The Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO prepared at the sequence ratio of 5:8:13 (YBZ5) exhibited the highest photocatalytic performance. Morphological characterization showed that the particle size of the YBZ5 sample was significantly smaller than that of ZnO by over half, possibly providing high surface areas. The crystalline structure, functional group, and surface chemical composition investigations confirmed the presence of Y<inf>2</inf>O<inf>3</inf>, BaO, and ZnO. The fluorescence study exhibited no difference. Based on band gap energy and energy band alignment analysis, the Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO ternary system demonstrated a well-aligned valence band. The energy band alignment analysis revealed a good alignment of the valence band for continuous hole transport in the Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO ternary system. The alignment induces charge separation which reduces recombination and provides efficient active carriers at the surfaces of the photocatalyst, allowing reactions with toxic molecules. Therefore, the synergistic function of high surface areas and appropriate energy band alignments of the novel Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO ternary system is considered the crucial factor in the enhancement of photocatalytic performance.

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