研究者詳細 - 坪田　敏樹

論文 - 坪田　敏樹

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Characterization of the Electromagnetic Shielding Effectiveness of Biochar-Based Materials 査読有り

Nikolopoulos C.D., Baklezos A.T., Kapetanakis T.N., Vardiambasis I.O., Tsubota T., Kalderis D.

IEEE Access 11 6413 - 6420 2023年01月

記述言語：英語掲載種別：研究論文（学術雑誌）

Biochar and biochar-based composites are multi-functional materials with a wide range of environmental and other applications. A new and emerging application is in the field of modern communication systems as materials with significant electromagnetic shielding effectiveness. In this study, biochar was prepared from olive tree prunings which was subsequently used at various dosages to prepare composite samples with carbon black and polytetrafluoroethylene as binder. The electromagnetic shielding effectiveness of the samples were measured in the frequency range of 1-3 GHz, using a simple, user-friendly and reliable experimental set-up. The results showed that raw, unmodified biochar had a low shielding effectiveness in the range of 1.5-4 dB however, it slightly increased as the thickness of the sample increased from 0.1 to 0.5 mm. Modifying biochar with the 20 %w/w acetylene black largely increased its shielding effectiveness, reaching the value of 39 dB in the same frequency range. Our approach demonstrated that raw biochar can be used as a substrate to develop composite materials with significant shielding effectiveness and assess their performance with a quick and simple laboratory method.

DOI： 10.1109/ACCESS.2023.3237327

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Adsorption characteristics of ciprofloxacin and naproxen from aqueous solution using bamboo biochar 査読有り国際誌

Pham T.D., Nguyen D.T., Nguyen H.L., Nguyen M.Q., Tran T.M., Nguyen M.V., Nguyen T.L., Ngo T.M.V., Namakamura K., Tsubota T.

Biomass Conversion and Biorefinery 2023年01月

担当区分：最終著者記述言語：英語掲載種別：研究論文（学術雑誌）

Adsorption of the drugs ciprofloxacin (CFX) and naproxen (NPX) using bamboo biochar was systematically investigated. Bamboo biochar was characterized by SEM, TEM, FT-IR, BET, and ζ measurement. Bamboo biochar has a porous structure with high specific surface area and contains carboxyl groups with negative charge. Batch adsorption of CFX on bamboo biochar was optimal at pH 4, 7.5 g/L adsorbent dosage, and adsorbed in 90 min while the best conditions for NPX adsorption were pH 3, with 10 g/L and contact time 90 min. Adsorption isotherms of CFX and NPX on bamboo biochar surface at different ionic strengths were achieved with Freundlich better than Langmuir. Adsorption of CFX and NPX on bamboo biochar is controlled by electrostatic and non-electrostatics, while NPX adsorption is mainly controlled by electrostatic interactions. The CFX and NPX removal efficiencies were still greater than 60% after four regenerations, indicating that bamboo biochar is an excellent adsorbent for pharmaceutical contaminants removal in water. Graphical abstract: [Figure not available: see fulltext.].

DOI： 10.1007/s13399-023-05092-x

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Glycerol-Based Retrievable Heterogeneous Catalysts for Single-Pot Esterification of Palm Fatty Acid Distillate to Biodiesel 査読有り国際誌

Hazmi B., Beygisangchin M., Rashid U., Mokhtar W.N.A.W., Tsubota T., Alsalme A., Ngamcharussrivichai C.

Molecules 27 ( 20 ) 2022年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

The by-product of the previous transesterification, glycerol was utilised as an acid catalyst precursor for biodiesel production. The crude glycerol was treated through the sulfonation method with sulfuric acid and chlorosulfonic acid in a reflux batch reactor giving solid glycerol-SO3H and glycerol-ClSO3H, respectively. The synthesised acidic glycerol catalysts were characterised by various analytical techniques such as thermalgravimetric analyser (TGA), infrared spectroscopy, surface properties adsorption-desorption by nitrogen gas, ammonia-temperature programmed desorption (NH3-TPD), X-ray diffraction spectroscopy (XRD), elemental composition analysis by energy dispersive spectrometer (EDX) and surface micrographic morphologies by field emission electron microscope (FESEM). Both glycerol-SO3H and glycerol-ClSO3H samples exhibited mesoporous structures with a low surface area of 8.85 mm2/g and 4.71 mm2/g, respectively, supported by the microscopic image of blockage pores. However, the acidity strength for both catalysts was recorded at 3.43 mmol/g and 3.96 mmol/g, which is sufficient for catalysing PFAD biodiesel at the highest yield. The catalytic esterification was optimised at 96.7% and 98.2% with 3 wt.% of catalyst loading, 18:1 of methanol-PFAD molar ratio, 120 °C, and 4 h of reaction. Catalyst reusability was sustained up to 3 reaction cycles due to catalyst deactivation, and the insight investigation of spent catalysts was also performed.

DOI： 10.3390/molecules27207142

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Environmentally Safe Magnetic Nanocatalyst for the Production of Biodiesel from Pongamia pinnata Oil 査読有り国際誌

Sami H.Q.u.A., Hanif M.A., Rashid U., Nisar S., Bhatti I.A., Rokhum S.L., Tsubota T., Alsalme A.

Catalysts 12 ( 10 ) 2022年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

Biodiesel is an alternative fuel in many developing and developed countries worldwide. Biodiesel has significant and numerous economic, environmental, and social benefits. However, the problem with conventional biodiesel production is the high industrial production cost, mainly contributed by the raw materials. Therefore, catalysts and feedstock are essential in increasing total biodiesel production rates and minimizing production costs. Magnetic nano-catalysts play a crucial role in heterogeneous catalysis due to their easy recovery, recyclability, excellent selectivity, and fast reaction rates, owing to their larger surface area. This research activity used heterogeneous magnetic nano-catalysts of ICdO, ISnO, and their modified form, to produce biodiesel. The synthesized nano-catalysts were made through co-precipitation and found quite efficient for transesterifying Pongamia pinnata oil. The effect of various parameters on biodiesel yield in the presence of prepared magnetic nano-catalysts has been studied. In the transesterification supported by ISnO, high yield, i.e., 99%, was achieved after 2 h of reaction time at 60 °C. The nano-catalysts were magnetically recovered and reused 4–5 times without any change in their activity. All the synthesized magnetic nano-catalysts performed SEM analysis. Each fraction of the produced biodiesel was assessed for different quality parameters, and the results were per ASTM standards. The components present in biodiesel produced from Pongamia pinnata oil were determined by GCMS.

DOI： 10.3390/catal12101266

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A Heterogeneous Bifunctional Carbon Nanocatalyst from Plastic Waste to Efficiently Catalyze Waste Cooking Oil into Biodiesel 査読有り国際誌

Hazmi B., Rashid U., Kawi S., Mokhtar W.N.A.W., Ahangar F.A., Yaw T.C.S., Tsubota T., Alharthi F.A., Ngamcharussrivichai C.

Catalysts 12 ( 8 ) 2022年08月

記述言語：英語掲載種別：研究論文（学術雑誌）

In this study, black carbon derived from polyethylene terephthalate (PET) wastes was utilized as the precursor for heterogeneous bifunctional nanocatalyst, which successively catalyzed waste cooking oil into biodiesel. The nano-sized catalysts were prepared by impregnation method with different heat treatment techniques, such as reflux, hydrothermal, and microwave solvothermal, to provide good distribution of K2O and NiO particles on PET activated carbon mesoporous surface. The sample treated with microwave solvothermal technique (MAC-K2O-NiO) exhibited a high surface area of 120 m2/g with good dispersion of nanoparticles, as shown by FESEM image, large crystallite size of 62.2 nm, and consisted of a highest density of basicity (2.58 mmol/g) and acidity (1.79 mmol/g) for improving transesterification to a maximum yield. The catalytic transesterification of MAC-K2O-NiO was optimized with 3 wt.% of catalyst loading, 18: 1 methanol-oil molar ratio, 65 °C for 3 h of reaction, with a maximum yield of 97.2%. The catalyst reusability was performed, and it was found to maintain the catalytic activity up to six reaction cycles, with a yield of 72.9%. The physiochemical quality of the optimized biodiesel was examined in accordance with the American Society for Testing and Materials, ASTM D6751 testing method.

DOI： 10.3390/catal12080874

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Comparison of consecutive impacts of wood and rice husk gasification biochars with nitrogen fertilizer on soybean yield 査読有り国際誌

Hien T.T.T., Tsubota T., Taniguchi T., Shinogi Y.

Paddy and Water Environment 20 ( 3 ) 303 - 313 2022年07月

記述言語：英語掲載種別：研究論文（学術雑誌）

Demand for gasification biochar is expected to increase, owing to the bioenergy requirements of a sustainable society. Here, we assessed the applicability of gasification biochars from cedar wood (W) and rice husk (R) for the agricultural soil amendment and compared their ability in enhancing soybean yield in two consecutive cropping cycles. The pot experiment included four treatments: F0 (control 1), without both nitrogen fertilizer (Nfer) and biochar, F (control 2), using only Nfer, W–F, using W with Nfer, and R–F, using R with Nfer. Both gasification biochars had higher pH, CEC, and greater nitrogen retention than the soil. In the first cropping cycle, the W application showed an immense impact on some soil physical properties, including bulk density reduction (12%) and water-holding capacity increment (25%) while the R amendment significantly increased exchangeable K (45%) and soil pH. In addition, other changes in soil chemical due to W and R applications included enhancement of available phosphorus (P, 8–14%) and reduction of ammonium content (12–21%). After two consecutive cropping cycles, W–F indicated the largest content of soil available P and the highest soil pH. Ultimately, the co-application with Nfer of W and R had the same significant impact on soybean yield compared with control 1 in the first and two consecutive cropping cycles. In addition, the W application specifically recorded a significantly higher soybean yield than control 2 in the first and two cropping cycles, unlike the R amendment.

DOI： 10.1007/s10333-021-00875-2

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Numerical analysis of the micropore structure of activated carbons focusing on optimum CO<inf>2</inf> adsorption 査読有り国際誌

Kwiatkowski M., Kalderis D., Tono W., Tsubota T.

Journal of CO2 Utilization 60 2022年06月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

In this work, the porous structure of activated carbons prepared from Moso bamboo were mathematically analysed. At first, the raw material was subjected to two-stage activation process i.e. in the first stage, phosphoric acid or zinc chloride was used followed by second stage physical activation or chemical activation with potassium hydroxide. Then, nitrogen and carbon dioxide adsorption isotherms were determined. Subsequently, a novel, clustering-based adsorption analysis method was applied, combined with a numerical procedure for the fast multivariant identification of adsorption systems. The mentioned method takes into consideration the heterogeneity of the adsorbent surface and allows the determination of the adsorption energy as well as the shape and size of the clusters of adsorbate molecules formed in the pores of the analysed material. Additionally, the Quenched Solid Density Functional Theory was selected to determine the cumulative pore volume, pore size distributions and other micropore parameters. The analyses revealed a considerable degree of complexity of the carbons’ porous structure, including differences in the adsorption of CO2 and N2. The complementarity of the applied methods leads to the reliable determination of the optimum activated carbon for CO2 adsorption and assists reverse engineering approaches in the production and activation stage.

DOI： 10.1016/j.jcou.2022.101996

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Towards sustainable biomass gasification: Evolution of bagasse char characteristics throughout gasification 査読有り国際誌

Nguyen H.N., Khuong D.A., Tran-Nguyen P.L., Tsubota T.

Biomass and Bioenergy 158 2022年03月

記述言語：英語掲載種別：研究論文（学術雑誌）

The development of a sustainable bagasse gasification system using bagasse as feedstock could be realized if a complete understanding of bagasse gasification was established. In this study, the evolution of the char characteristics throughout the gasification process was deeply investigated. The low ash content, high heating value, and fast char conversion rate highlighted the suitability of bagasse for gasification. The char morphology underwent significant changes with rupture of beehive-like structures that make up the char when conversion X [0, 1] is higher than 0.5. On the contrary, changes in carbon structures were observed more clearly at the beginning of char conversion (X < 0.5). The gasified chars had high porosity made of micro-mesoporous structures, and the maximum value of total specific surface area (SBET = 877 m2 g−1) and total pore volume (VBET = 0.49 cm3 g−1) were observed at X = 0.75. The high values of SBET and VBET - even when gasification is nearing its end - highlighted the potential of using residues after gasification as an alternative to expensive commercial activated carbons. The results of this study would contribute to forming solutions for some challenges for the industrialization of biomass gasification, such as the formation of soot and tar, or the treatment/reuse of post-gasification residues.

DOI： 10.1016/j.biombioe.2022.106384

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Thermal induced changes of rice straw phytolith in relation to arsenic release: A perspective of rice straw arsenic under open burning 査読有り国際誌

Nguyen M.N., Nguyen A.T.Q., Dultz S., Tsubota T., Duong L.T., Nguyen A.M., Pham N.T.T.

Journal of Environmental Management 304 2022年02月

記述言語：英語掲載種別：研究論文（学術雑誌）

On-site open burning is a common practice for handling rice straw, but its negative impacts, e.g., biomass loss and air pollution, are largely debated worldwide. To address the negative effects of open burning, many efforts have been made to ‘ignite’ worldwide bans. However, these bans are likely based on a singular view in which some positive aspects of open burning are overlooked. In this study, we aimed to determine the thermal-induced changes of straw and straw arsenic (As) under open burning and heat-treatments (in the temperature range from 300 to 900 °C). It was found that silica phase in rice straw (so-called phytolith) can encapsulate As in its structure. Open burning or heat-treatment of straw resulted in a tighter association of As and phytolith, thereby reducing dissolution of As. We proposed an opinion that open burning causes air pollution, but it can increase the activity of phytolith in sequestrating As, enabling delayed As cycle in rice ecosystems. The combat of on-site open burning of rice straw to reduce air pollution will alter straw handling routines, thereby changing the cycle of straw phytolith and the route of straw As.

DOI： 10.1016/j.jenvman.2021.114294

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Potential heterogeneous nano-catalyst via integrating hydrothermal carbonization for biodiesel production using waste cooking oil 査読有り国際誌

Abdullah R.F., Rashid U., Hazmi B., Ibrahim M.L., Tsubota T., Alharthi F.A.

Chemosphere 286 2022年01月

記述言語：英語掲載種別：研究論文（学術雑誌）

Hydrothermal carbonization (HTC) provides alternatives technique to produce a nanosize activated carbon from biomass with a high surface area. Herein, this study we prepared empty fruit bunch-based activated carbon (EFBHAC) using HTC technique. The activated carbon was then functionalized with K2CO3 and Cu(NO3)2 to produce bifunctional nano-catalyst for simultaneous esterification-transesterification of waste cooking oil (WCO). The physicochemical properties were performed i.e. N2 sorptions analysis, TPD-CO2/NH3, FESEM, EDX, FTIR and XRD analysis. The results revealed that produced EFBHAC possessed a BET surface area of 4056.17 m2 g−1, with pore volume of 0.827 cm3 g−1 and 5.42 nm of pore diameter resulting from hydrolysis, dehydration decarboxylation, aromatization and re-condensation during HTC process. Impregnation of EFBHAC with K2CO3 and Cu(NO3)2 granted a high amount of basicity and acidity of 9.21 mmol g−1 and 31.41 mmol g−1, respectively, accountable to high biodiesel yield of 97.1%, produced at the optimum condition of 5 wt% of catalyst loading, 12:1 of methanol to oil molar ratio at 70 °C for 2 h. More than 80% of biodiesel was produced after the 5th cycle depicted the good reusability. The transformations from WCO to biodiesel was confirmed via 1H NMR, FTIR and TGA analysis. Fuel properties revealed kinematic viscosity of 3.3 mm2 s−1, cetane number of 51, flash point of 160.5 °C, cloud and pour point of 11 °C and −3 °C, respectively. These results show the excellent potential of waste materials to prepare bifunctional nano-catalysts to produce higher biodiesel yield which has potential to be commercialized.

DOI： 10.1016/j.chemosphere.2021.131913

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Low-cost novel nano-constructed granite composites for removal of hazardous Terasil dye from wastewater 査読有り国際誌

Khalil M., Hanif M.A., Rashid U., Ahmad J., Alsalme A., Tsubota T.

Environmental Science and Pollution Research 30 ( 34 ) 81333 - 81351 2022年01月

担当区分：最終著者記述言語：英語掲載種別：研究論文（学術雑誌）

The hazardous dyes on mixing with water resources are affecting many life forms. Granite stone is popular worldwide for decorating floors, making other forms of decorative materials and items. Granite stone powder waste can be obtained free of cost from marble factories as factories spend on the disposal of this waste. In the present study, novel granite stone powder waste composite has been prepared and utilized for the effective removal of Terasil dye. Two types of granite including gray granite and white granite were used in pure, calcinized, and chemically modified forms. Freundlich adsorption isotherm model best explained the adsorption mechanism of dye removal using granite composites as compared to other adsorption isothermal models. Characterization techniques like scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used for the determination of morphological features and functional groups of granite composites. The obtained results were statistically analyzed using analysis of variance (ANOVA) along with the post hoc Tukey test. An extraordinarily high Terasil dye uptake capacity (more than 400 mg/g) was exhibited by granite composites prepared using sodium metasilicate. The synthesized novel nano-constructed composites provided a viable strategy as compared to the pure granite stone for dye removal from wastewater water. Graphical abstract: [Figure not available: see fulltext.]

DOI： 10.1007/s11356-022-21367-8

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Physicochemical Properties of Waste Palm-Based Catalysts Synthesized from Pyrolyzed and Hydrothermalized Chars for Biodiesel Production 査読有り国際誌

Rashid U., Hazmi B., Abdullah R.F., Ibrahim S.F., Alsalme A., Tsubota T.

Topics in Catalysis 66 ( 9-12 ) 723 - 739 2022年01月

担当区分：最終著者記述言語：英語掲載種別：研究論文（学術雑誌）

Carbon precursor derived from biomass waste gained significant interest as a component of heterogeneous catalysts that can be functionalized with active groups and provides the advantage of separating the catalyst from reactant and products, unlike common homogeneous catalyst. In this study, palm kernel shell (PKS) based char was developed by pyrolysis and hydrothermal carbonization methods and subsequently utilized for synthesizing bifunctional carbon catalyst. The wet impregnation method by loading K2CO3 and CuO provided bi-functional characteristics to the produced chars for conversion into efficient catalysts, which were suitable for concurrent esterification and transesterification processes. The prepared catalysts were characterized by BET, XRD, FESEM, FTIR, TGA, and CO2/NH3 TPD analysis. The report showed that the sample of hydrothermal-assisted carbonization (HTC) treatment possessed higher surface area (4056 m2/g) due to the steady degradation of lignocellulosic composition, thus improving the porous quality of carbon structure compared to normal pyrolytic carbon (2658 m2/g). Additionally, the PKSHAC@K2CO3-CuO catalyst sample embraced more potent acid-basic properties than PKSAC@K2CO3-CuO, yielding 98.4% and 96.7% of FAME respectively, at optimized reaction conditions, the temperature of 65 °C for 3 h, with 15:1 molar ratio of methanol to WCO with 3 wt% of catalysts loading.The reusability test showed that PKSHAC@K2CO3-CuO could catalyse up to 80.1% of FAME, while PKSAC@K2CO3-CuO recorded a yield of 60.1%. The biodiesel from waste cooking oil was analyzed to meet the ASTM D6751 standard for diesel fuel. The synthesized heterogeneous catalysts using different chars might be widely suitable for low-cost oil feedstocks used for biodiesel production. Graphical Abstract: [Figure not available: see fulltext.].

DOI： 10.1007/s11244-022-01736-w

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Dependence of pore structure of activated carbon on the performance of electrical double layer capacitor with NaCl aqueous electrolyte 査読有り国際誌

Onodera H., Tsubota T.

Journal of Porous Materials 30 ( 4 ) 1101 - 1108 2022年01月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

In this study, electric double layer capacitors (EDLC) were fabricated as laminate type by using NaCl aqueous solution, which should be relatively safe electrolyte against environments and biological objects, for the investigation of the performance from a practical point of view. The capacitance value of the cell depended on the kind of activated carbon used as electrodes. The capacitance values of the EDLCs fabricated from the best activated carbon were ca. 38 F g− 1 at 0.36 mA cm− 2 of discharging current value and at 1.2 V of charging voltage. The capacitance value should be equivalent to commercial EDLCs although the charging voltage is smaller. The relationship between the properties related to pores of activated carbon and the capacitance value was examined. The enumerated values obtained from the Dubinin-Astakhov (DA) method for the activated carbons of this study were between 1 and 2, which could indicate that the micropore distribution of the activated carbons used in this study was heterogeneous. The capacitance value was found to be strongly related to the micropore volume calculated by the DA method from the adsorption isotherm of CO2 at 298 K. That is, the micropore volume estimated from the DA method should be used as the indicator for the selection of high-performance activated carbon for electrode of EDLC containing NaCl aqueous solution electrolyte.

DOI： 10.1007/s10934-022-01407-x

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Evolution of physico-chemical properties of Dicranopteris linearis-derived activated carbon under various physical activation atmospheres 査読有り

Mai N.T., Nguyen M.N., Tsubota T., Nguyen P.L.T., Nguyen N.H.

Scientific Reports 11 ( 1 ) 2021年12月

記述言語：英語掲載種別：研究論文（学術雑誌）

This work emphasizes the effect of the physical activation using CO2 and steam agents on the physicochemical properties of activated carbon produced from Dicranopteris linearis (D. linearis), a fern species widely distributed across tropic and subtropic ecoregions. The D. linearis-derived chars produced under pyrolysis at 400 °C for 1 h were activated in various CO2-steam proportions. As revealed by the IR and Raman spectra, the structure of the activated chars was heavily dependent on the relative proportion of CO2 and steam. The total specific surface area (SSA) of the activated chars proportionally increased with the increase in steam proportion and was comparable to the values of commercial activated char products. Specifically, the activation under CO2− and steam-saturated conditions has correspondingly resulted in SSA increasing from 89 to 653 m2g−1 and from 89 to 1015 m2g−1. Steam also enhanced the development of mesoporous structures of the D. linearis-derived char products, thereby extending their potential applications, particularly for industries that require high rigidity in the product such as pharmaceutical and cosmetic sectors.

DOI： 10.1038/s41598-021-93934-x

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Fungicide application can intensify clay aggregation and exacerbate copper accumulation in citrus soils 査読有り

Dao T.T., Tran T.T.T., Nguyen A.M., Nguyen L.N., Pham P.T.M., Tsubota T., Nguyen M.N.

Environmental Pollution 288 2021年11月

記述言語：英語掲載種別：研究論文（学術雑誌）

Fungicide application for controlling fungal diseases can increase copper (Cu) accumulation in soil. More urgently, Cu released from fungicides can associate with soil clay and favour the mutual aggregation of Cu and soil clay, thereby potentially intensifying the accumulation of Cu. We investigated the effects of Cu salt and six common Cu-based fungicides on colloidal dynamics of a clay fraction from citrus cultivated soil. Batch experiments were carried out to provide the loading capacity of the clay fraction for Cu. The colloidal dynamic experiments were performed over a pH range from 3 to 8 following a test tube method, while surface charge, the key electrochemical factor of the solid-liquid interface, was quantified by a particle charge detector. It was found that all the studied fungicides, via releasing Cu2+, acted to effectively favour clay aggregation. The dissolved organic matter obtained from the dissolution of polymers in fungicides can theoretically stimulate clay dispersion. However, their effects were obscured due to the overwhelming effect of Cu2+. Therefore, Cu2+ appears as the most active agent in the fungicides that intensifies clay aggregation. These findings imply that the intensive application of fungicides for plant protection purposes can inadvertently reduce clay mobility, favour the co-aggregation of clay and fungicides, and hence potentially exacerbate the contamination of the citrus soil.

DOI： 10.1016/j.envpol.2021.117703

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Conversion of waste polyethylene terephthalate (Pet) polymer into activated carbon and its feasibility to produce green fuel 査読有り

Ahangar F.A., Rashid U., Ahmad J., Tsubota T., Alsalme A.

Polymers 13 ( 22 ) 2021年11月

記述言語：英語掲載種別：研究論文（学術雑誌）

In this study, a novel idea was proposed to convert the polyethylene terephthalate (PET) waste drinking-water bottles into activated carbon (AC) to use for waste cooking oil (WCO) and palm fatty acid distillate (PFAD) feasibility to convert into esters. The acidic and basic char were prepared by using the waste PET bottles. The physiochemical properties were determined by employing various analytical techniques, such as field emission scanning electron microscopy (FESEM), thermo-gravimetric analysis (TGA), Fourier transform infrared (FTIR), Brunauer–Emmett–Teller (BET) and temperature-programmed desorption – ammonia/carbon dioxide (TPD-NH3 /CO2 ). The prepared PET H3 PO4 and PET KOH showed the higher surface area, thus illustrating that the surface of both materials has enough space for impregnation of foreign precursors. The TPD-NH3 and TPD-CO2 results depicted that PET H3 PO4 is found to have higher acidity, i.e., 18.17 mmolg−1, due to the attachment of phosponyl groups to it during pretreatment, whereas, in the case of PET KOH, the basicity increases to 13.49 mmolg−1 . The conversion results show that prepared materials can be used as a support for an acidic and basic catalyst for the conversion of WCO and PFAD into green fuel.

DOI： 10.3390/polym13223952

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Assessment of biochar produced by flame-curtain pyrolysis as a precursor for the development of an efficient electric double-layer capacitor 査読有り

Tsubota T., Tsuchiya S., Kusumoto T., Kalderis D.

Energies 14 ( 22 ) 2021年11月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

Pine tree biochar produced by flame-curtain pyrolysis, an inexpensive and simple pyrolysis methodology, was used as the starting material for KOH-activated carbon. Flame-curtain pyrolysis is a simple, low-technology methodology that can be performed by non-specialized personnel. The elemental analysis of the biochars highlighted the high reproducibility of the process. The N2 adsorption isotherms indicated that KOH activation was effective for the preparation of high-surfacearea activated carbons from the biochar. The BET specific surface area increased with the quantity of KOH added in the activation process, achieving a maximum value of 3014 m2 g−1 at 85.7 wt.% of KOH addition. The adsorption isotherms of all samples were IUPAC type I, establishing their microporous nature. Results from the Mikhail–Brunauer (MP) method and αs plot indicated that the pore size distribution became wider and the pore volume increased as the KOH content increased. The measured capacitance values followed the same dependence on KOH content. The maximum capacitance value at 1 mV s−1 was determined as 200.6 F g−1 for the sample prepared at 75 wt.% of KOH addition. Therefore, pine tree biochar prepared by simple pyrolysis equipment is a suitable precursor for the development of an electric double-layer capacitor.

DOI： 10.3390/en14227671

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85121049946&origin=inward

An easily fabricated palladium nanocatalyst on magnetic biochar for Suzuki-Miyaura and aryl halide cyanation reactions 査読有り

Turunç E., Akay S., Baran T., Kalderis D., Tsubota T., Kayan B.

New Journal of Chemistry 45 ( 28 ) 12519 - 12527 2021年07月

記述言語：英語掲載種別：研究論文（学術雑誌）

Biochar is a carbon-rich solid, the surface of which is covered with a high density of functional carbonyl, hydroxyl and carboxylic acid groups. In this work, palladium nanoparticles were embedded on magnetic biochar and a new reusable and environmentally-friendly catalyst was developed and applied for the promotion of Suzuki-Miyaura C-C coupling and cyanation reactions. The high-carbon (77%), low-ash content (5.8%) and the relatively high surface area (266 m2g−1) of pine tree biochar (PTB) suggested that it might be highly suitable as a catalyst substrate. The Fe3O4-Pd-biochar nanocomposite was successfully characterized using SEM, TEM, EDX, FT-IR, BET and XRD. Its catalytic role was initially evaluated usingp-NO2C6H4I as a model reactant (for both types of reactions) and later for the production of biaryls and benzonitriles from a wide range of aryl halides under mild reaction conditions. Biaryls and benzonitriles were characterized using GC-MS. In the case of the Suzuki-Miyaura reaction, the optimum yield of 98% was obtained with a catalyst concentration of 0.04 mol%, microwave irradiation of 400 W, and a residence time of 5 min, using K2CO3as the base. With respect to the cyanation reaction, dimethylformamide, Na2CO3and 6 h were the optimum solvent, base and reaction duration, respectively. Subsequently, the nanocatalyst showed excellent catalytic activity in both reactions, achieving >88% yields in most cases, regardless of the aryl iodide or bromide used and the type of substitution.

DOI： 10.1039/d1nj00941a

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85110723065&origin=inward

Towards engineered hydrochars: Application of artificial neural networks in the hydrothermal carbonization of sewage sludge 査読有り

Kapetanakis T.N., Vardiambasis I.O., Nikolopoulos C.D., Konstantaras A.I., Trang T.K., Khuong D.A., Tsubota T., Keyikoglu R., Khataee A., Kalderis D.

Energies 14 ( 11 ) 2021年06月

記述言語：英語掲載種別：研究論文（学術雑誌）

Sewage sludge hydrochars (SSHs), which are produced by hydrothermal carbonization (HTC), offer a high calorific value to be applied as a biofuel. However, HTC is a complex processand the properties of the resulting product depend heavily on the process conditions and feedstock composition. In this work, we have applied artificial neural networks (ANNs) to contribute to the production of tailored SSHs for a specific application and with optimum properties. We collected data from the published literature covering the years 2014–2021, which was then fed into different ANN models where the input data (HTC temperature, process time, and the elemental content of hydrochars) were used to predict output parameters ((higher heating value, (HHV) and solid yield (%)). The proposed ANN models were successful in accurately predicting both HHV and contents of C and H. While the model NN1 (based on C, H, O content) exhibited HHV predicting performance with R2 = 0.974, another model, NN2, was also able to predict HHV with R2 = 0.936 using only C and H as input. Moreover, the inverse model of NN3 (based on H, O content, and HHV) could predict C content with an R2 of 0.939.

DOI： 10.3390/en14113000

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85106932642&origin=inward

Correction to: Enhancing soil water holding capacity and provision of a potassium source via optimization of the pyrolysis of bamboo biochar (Biochar, (2021), 3, 1, (1-3), 10.1007/s42773-020-00075-x) 査読有り

Hien T.T.T., Tsubota T., Taniguchi T., Shinogi Y.

Biochar 3 ( 1 ) 2021年03月

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