受賞区分：国内学会・会議・シンポジウム等の賞  受賞国：日本国

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）   出版者・発行元：Colloids and Surfaces A: Physicochemical and Engineering Aspects  

Nanofibrous membranes have garnered significant interest in membrane filtration due to their high porosity, small pore sizes, and complex interconnected pore structures. Although many studies focus on size exclusion in surface filtration, the filtration behavior and mechanisms for particles smaller than the pore size have been relatively underexplored. In this study, membrane filtration using nanofibrous membranes was employed to elucidate the filtration behavior and mechanisms for polystyrene latex suspensions with particles smaller than the pore size. The results indicated that reducing fiber diameter decreases the pore size and enhances particle rejection, with particle retention occurring within the intricate three-dimensional nanofiber pore network. In contrast, the effect of the membrane's basis weight was less significant compared to fiber diameter. This observation can be attributed to the concept of effective thickness; once this thickness is exceeded, particles are prevented from penetrating deeper into the membrane. The filtration model was analyzed using Hermans-Bredée blockage filtration theory and cake filtration theory, considering the mass of trapped particles within the membranes. The model characterizes the filtration process as initially following standard blocking, progressing to cake filtration once a sufficient number of pores become clogged.

DOI： 10.1016/j.colsurfa.2024.135270

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人 日本繊維機械学会  

DOI： 10.4188/jte.240409a

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Sensors and Actuators B: Chemical  

Monitoring volatile organic compounds (VOCs), the majority of which are toxic and carcinogenic and pose serious threats to human health and the environment, provides diverse environmental data from industrial and biological processes. In this study, a sensor for the detection of refractive index (RI) and N,N-dimethylformamide (DMF) vapors was developed by electrospinning polyacrylonitrile (PAN) and Ti3C2 MXene/TiO2 hybrid materials onto a U-shaped evanescent optical fiber (UOFEs). UOFEs coated with PAN/Ti3C2 MXene/TiO2 films exhibited a 7-fold increase in RI sensitivity, with a maximum RI response value of 540 %/RI unit when compared to bare fibers. The UOFEs exhibited a limit of detection for DMF in the gas of 5.33 ppm at 25 °C. The proposed sensor works on the principle that DMF, which has a high RI, binds to PAN, which is rich in binding sites, via high compatibility and strong dipole–dipole interactions, increasing the RI of the films.

DOI： 10.1016/j.snb.2024.136143

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Colloids and Surfaces A: Physicochemical and Engineering Aspects  

The presence of oil-in-water (O/W) emulsions poses a serious threat to the equilibrium of aquatic ecosystems, contaminates potable water resources, and disrupts the structure of soil layers. Consequently, there is an urgent need for effective and economically viable methods for removing emulsified oil droplets from water. The coalescence method has been proposed as an effective means of separating O/W emulsions. In this study, we developed an in situ growth strategy to decorate zeolitic imidazolate framework-8 (ZIF-8) on electrospun polyacrylonitrile (PAN) nanofibers for coalescence separation. The in situ growth process commenced with pretreatment to activate the PAN membrane, creating anchor sites for zinc ions, which was followed by immersion in precursors of ZIF-8 particles. The incorporation of ZIF-8 enhanced amphiphilicity, and roughness, and imparted a positive charge to the membrane, which was anticipated to effectively demulsify and coalesce oil droplets with a negative charge. The ZIF-8/PAN nanofiber membrane obtained a separation ratio exceeding 99.9 % for surfactant-free emulsions and 97.1 % for surfactant-stabilized emulsions. It also demonstrated an ultra-high permeation flux of 21,177 L m−2 h−1 and 14,118 L m−2 h−1, respectively, in a long-term continuous separation process.

DOI： 10.1016/j.colsurfa.2024.133681

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Separation and Purification Technology  

Membrane separation has emerged as a prominent method for the removal of undesirable particles from wastewater in the field of water treatment. However, classification of particles with varying sizes by membrane is still poorly understood, warranting further exploration. This study is to investigate the wet classification behaviors of polydisperse particles using a nanofibrous membrane that features a complex three-dimensional network structure and high porosity. The experimental results demonstrate that the nanofibrous membrane is effective in retaining larger particles, while its high porosity facilitates the smooth passage of smaller particles. To clarify the classification mechanism, we analyzed the filtration model and employed SEM images taken at different stages of the process to investigate the retention behavior of larger particles. The filtration of larger particles through microfiltration membrane exhibited a cake filtration model. The blockage of large particles on the membrane surface formed a cake layer, significantly reducing the filtration rate. Conversely, the nanofibrous membrane exhibited continuous intermediate blocking filtration at pH 11, resulting in effective retention of larger particles inside the membrane rather than solely on membrane surface. This enabled better utilization of the pore space within the nanofibrous membrane, thus highlighting it as a potential area for future research.

DOI： 10.1016/j.seppur.2023.125658

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