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Efficient and selective electrosynthesis of 4-aminophenol at circumneutral pH from the electrocatalytic reduction of nitrophenol over the nickel-iron phosphide modified electrode
(2023-12-01)
Ong, Papontee Sae
;
Huang, Shih Ching
;
Lin, Chia Yu
;
Lerkkasemsan, Nuttapol
The efficient and sustainable synthesis of 4-aminophenol (4-AP) from the electrocatalytic reduction of 4-nitrophenol (e-NPR) with water as the proton source relies on the development of robust electrocatalysts that readily expedite the kinetics of e-NPR and generate 4-AP with high selectivity at environmentally-benign conditions. In this study, we report on the efficient and sustainable electrosynthesis of 4-AP at circumneutral pH using the micro-structured nickel-iron phosphide modified electrode (CP|microNiFeP). The effects of the iron content of the prepared CP|microNiFeP electrodes as well as electrolysis conditions, including the electrolyte pH, applied potential, and electrolysis duration, on the electrosynthesis of 4-AP were thoroughly examined through a series of controlled-potential electrolyses (CPEs). Under optimal conditions, the CP|microNiFeP electrode exhibited a turnover frequency of 7.25 ± 0.05 h−1 for the generation of 4-AP at 0.0 V vs. RHE and achieved a high 4-NP conversion of 92.29 ± 1.47% with high selectivity for 4-AP generation (S<inf>A</inf><inf>P</inf>:85.77 ± 2.21%) after 8-h CPE at −0.15 V vs. RHE in the H-cell. In addition, the scale-up electrosynthesis of 4-AP with a flow-type electrolyzer was also demonstrated. The 3-h electrolysis using the flow-type electrolyzer resulted in a high 4-NP conversion (93.84 ± 0.84%) with a high S<inf>AP</inf> (86.32 ± 1.05%). The possible reaction pathways of e-NPR have been proposed, and 4,4′-dihydroxyazobenzene and dimers were identified as the main side products.
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Study of kinetic model for fungal spore germination under dynamic conditions: Case study on germination of Penicillium expansum spores
(2023-12-01)
Boonruang, Panuluk
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Lerkkasemsan, Nuttapol
The germination of fungal spores under non-isothermal conditions has been studied for several years, however, no mathematical model has been able to describe them suitably. Therefore, in this paper, we developed a new model to clarify the understanding of fungal spore germination under non-isothermal conditions by considering the effects of magnitude of condition change and difference in phase of spore during condition change on kinetic parameters, i.e., the mean rate of germination (μ) and the time that half of spores had germinated (t<inf>h</inf>). To combine both effects into our new model, it was necessary to develop other two new models. The first model was used for estimating the swelling time of spores. The second model was the relationship between t<inf>h</inf> vs μ. After we had completed both models and successfully combined both effects into the new model for fungal spore germination under non-isothermal conditions, the new model was validated against experimental data on germination of Penicillium expansum spores in the literature. The prediction results showed that the new model well described the germination of this fungus under non-isothermal conditions.
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Mn-Fe Prussian blue analogue as low-cost robust cathode for non-aqueous Zn-ion batteries
(2023-03-01)
Yimtrakarn, Trakarn
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Liao, Yi Chih
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MV, Ahmed Sanin
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Chen, Jeng Lung
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Chuang, Yu Chun
Zn-ion batteries (ZIBs) are one of the most promising alternatives for large-scale energy storage systems due to two-electron transfer capability, safety, low toxicity, and low cost. However, most of the cathode materials reported for non-aqueous ZIBs still show unsatisfactory electrochemical performance. To overcome this, factors such as type of crystal structure, transition metal-ion coordination, and nature of the d orbitals being filled must be taken into consideration in the design of suitable host materials. Herein, we report the use of a Prussian blue analogue, sodium manganese hexacyanoferrate (NaMnFe-PB), as cathode in ZIBs. Its ease of synthesis, rigid open framework, and compositional and electrochemical tunability make this low-cost Mn-Fe-based compound highly attractive. The strong interactions among the two redox centers MnIII/MnII, FeIII/FeII, and C[tbnd]N- ligand allow two close voltage plateaus at ∼1.50 V vs Zn/Zn2+, delivering a capacity of 89.5 mAh g-1. Ex-situ X-ray absorption and diffraction techniques confirm the high redox reversibility and structural stability of NaMnFe-PB upon divalent guest insertion. The Fe(CN)<inf>6</inf> vacancies and coordinated water in the host lattice are believed to facilitate cation diffusion. The insight gained in this work may pave the way for the design of low-cost cathode materials for next-generation large-scale energy storage systems.
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Re-parameterization of the asymmetric model for fungal spore germination
(2023-01-02)
Boonruang, Panuluk
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Lerkkasemsan, Nuttapol
The asymmetric model (Dantigny et al., 2011, A new model for germination of fungi, International Journal of Food Microbiology, 146, 176–181) is capable to fit both symmetric and asymmetric curves of fungal spore germination. However, the shape parameter in the asymmetric model must be derived from a regression of the model with experimental data of fungal spore germination, thus the asymmetric model can fit spore germination under tested conditions only. In this paper, to solve this limitation, the previously proposed shape parameter-based asymmetric model has been replaced by using the pure biological parameter-based asymmetric model as: [Formula presented], where P is the percentage of germinated spores at time t, P<inf>max</inf> is the maximum percentage of germinated spores, τ is the germination time (the time that P = 0.5P<inf>max</inf>), and μ is the slope of fungal spore germination at t = τ, representing the rate of fungal spore germination. The modified asymmetric model was validated against the germination data of six fungal species collected from the literature. The results showed that the modified asymmetric model described the spore germination of all fungi studied well. Moreover, the τ and μ in the modified asymmetric model at various environmental conditions were estimated properly via the Cardinal Model with Inflection. This solved the limitation of the previous asymmetric model. So, it can be concluded that the modified asymmetric model is an improvement over the previous asymmetric model for predicting fungal spore germination.
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Solvent Selection for Mitragynine Extraction by Hansen Solubility Parameter
(2023-01-01)
Ditthapornset, Sirawich
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Lerkkasemsan, Nuttapol
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Areerat, Surat
Mitragyna speciosa (Korth.) Havil., commonly known as “Kratom” has a wide range of therapeutic benefits. In this research study the solvents that can be used to extract Mitragynine from kratom leaves. To predict solubility parameters, Hansen solubility parameters were employed. Then analyzing the solubility parameters using the ProCAPE application However, Mitragynine cannot directly determine the solubility. Instead, a method for evaluating the solubility from derivatives of Mitragynine was used in this study. A ternary graph shows the solubility of the derivatives and solvents. The solvents selected were considered for safety from the GSK’s Solvent Selection Guide. From the results, it was found that several types of solvents which that were dissolved derivatives of Mitragynine better than conventional solvents. Additionally, while using ProCAPE, the solubility parameters were predicted from extraction-related research was applied, and the results were shown as ternary graphs. The graphs were confirmed to be in accordance with the experimental data from the research that was collected.
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Application of Endoxylanases of Bacillus halodurans for Producing Xylooligosaccharides from Empty Fruit Bunch
(2023-01-01)
Thirametoakkhara, Chanakan
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Hong, Yi Cheng
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Lerkkasemsan, Nuttapol
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Shih, Jian Mao
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Chen, Chien Yen
Endo-1,4-β-xylanase catalyzes the random hydrolysis of β-1,4-D-xylosidic bonds in xylan, resulting in the formation of oligomers of xylose. This study aims to demonstrate the promise of endoxylanases from alkaliphilic Bacillus halodurans for the production of xylooligosaccharides (XOS) from oil palm empty fruit bunch (EFB) at high pH. Two enzyme preparations were employed: recombinant endoxylanase Xyn45 (GH10 xylanase) and nonrecombinant endoxylanases, a mixture of two extracellular endo-1,4-β-xylanases Xyn45 and Xyn23 (GH11 xylanase) produced by B. halodurans. EFB was first treated with an alkaline solution. Then, the dissolved xylan-containing fraction was retained, and a prepared enzyme was added to react at pH 8 to convert xylan into XOS. Compared with the use of only Xyn45, the combined use of Xyn45 and Xyn23 resulted in a higher yield of XOS, suggesting the synergistic effect of the two endoxylanases. The yield of XOS obtained from EFB was as high as 46.77% ± 1.64% (w/w), with the xylobiose-to-xylotriose ratio being 6:5. However, when the enzyme activity dose was low, the product contained more xylotriose than xylobiose. Four probiotic lactobacilli and bifidobacteria grew well on a medium containing XOS from EFB. The presence of XOS increased cell mass and reduced pH, suggesting that XOS promoted the growth of probiotics.
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Study of Lignin Extracted from Rubberwood Using Microwave Assisted Technology for Fuel Additive
(2022-02-01)
Yimtrakarn, Trakarn
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Kaveevivitchai, Watchareeya
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Lee, Wen Chien
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Lerkkasemsan, Nuttapol
Lignin is the most abundant natural aromatic polymer, especially in plant biomass. Lignin-derived phenolic compounds can be processed into high-value liquid fuel. This study aimed to determine the yield of lignin by the microwave-assisted solvent extraction method and to characterize some essential properties of the extracted lignin. Rubberwood sawdust (Hevea brasiliensis) was extracted for lignin with an organic-based solvent, either ethanol or isopropanol, in a microwave oven operating at 2450 MHz. Two levels of power of microwave, 100 W and 200 W, were tested as well as five extraction times (5, 10, 15, 20, 25, and 30 min). The extracted lignin was characterized by Klason lignin, Fourier transform infrared spectroscopy (FT-IR), 2D HSQC NMR, Ultraviolet-visible spectrophotometry (UV-vis), and Bomb calorimeter. The results showed that the yield of extracted lignin increased with the extraction time and power of the microwave. In addition, the extraction yield with ethanol was higher than the yield with isopropanol. The highest yield was 6.26 wt.%, with ethanol, 30 min extraction time, and 200 W microwave power.
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A study of eutectic temperature of sugar mixture for thermal energy storage
(2021-08-02)
Wisutthimateekorn, Suchanun
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Lerkkasemsan, Nuttapol
We studied Phase Change Materials (PCMs), which can be used as thermal energy storage for temperatures lower than 120◦C: They can store both sensible heat from a changing temperature and latent heat from changing the state of a substance. The advantage of storing energy in a PCM is that it can be reused continuously, without the degradation of efficiency. Here, the PCM mixture consists of fructose and xylitol and thus, this PCM can be used to store energy below 120◦C. The calculated Excess Gibbs Energy and activity coefficient of xylitol and fructose decreased as the fraction of xylitol increased. We tested a system, which included an evacuated tubular collector and—fructose mixtures. The system with the PCM maintained a water temperature ~14◦C higher than water without the PCM. This PCM system could store 248 kJ/kg. The xylitol—fructose mixture had a market price ~$US 4.62 $/kg (2018 price), so compared to other PCMs, xylitol-fructose was cheap and store energy efficiently.
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Kinetic Study of Steam Gasificaiton of Palm Kernel Shell Char
(2020-05-27)
Lerkkasemsan, Nuttapol
In this work, we investigate the reaction mechanism of steam gasification reaction of palm kernel shell char. The experiment results which are used in this work are carried on at temperature of 1123, 1173, and 1223K. The isothermal steam gasification of palm kernel shell char is described by mathematic models including volumetric model (VM), grain model (GM), random pore model (RPM), and modified random pore model (mRPM). From results, we found that the RPM model can predict gasification of palm kernel shell char better than other models. The RPM model considers the overlapping of pore surfaces, which results in the reduction of surface area available for the reaction. The activation energy of gasification reactivity of palm kernel shell char is 152.63 kJ/mol for RPM model. The coefficient of determination of RPM model are 0.9920, 0.9995, and 0.9907 at 1123, 1173, and 1223 K respectively.
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Life cycle assessment of diuron from cradle to grave: case study in agave farm
(2019-11-01)
Thirametoakkhara, Chanakan
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Lerkkasemsan, Nuttapol
Diuron is a herbicide commonly used in agriculture to control and kill pre-emergent weeds. Extensive use of the chemical nonetheless harms the environment and human health. This research thus investigates the cradle-to-grave environmental impacts and risks to human health and ecosystem of diuron production, consumption, and disposal using life cycle assessment. The research focused on five production schemes (schemes A–E) of varying origins of raw materials and countries. Simapro 8.5 was used to simulate the environmental impacts (midpoint impacts) and risks to human health and ecosystem (endpoint impacts). The results revealed a positive correlation between overall environmental impact and transportation distance, rendering scheme C the most environmentally-friendly option due to the shortest transportation distance. Likewise, the endpoint-impact results indicated scheme C as the most favorable scheme, given the lowest overall human health risk and ecosystem damage.

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