105 research outputs found
Bead-Containing Superhydrophobic Nanofiber Membrane for Membrane Distillation
No full textThis study introduces an innovative approach to enhancing membrane distillation (MD) performance by developing bead-containing superhydrophobic sulfonated polyethersulfone (SPES) nanofibers with S-MWCNTs. By leveraging SPES's inherent hydrophobicity and thermal stability, combined with a nanostructured fibrous configuration, we engineered beads designed to optimize the MD process for water purification applications. Here, oxidized hydrophobic S-MWCNTs were dispersed in a SPES solution at concentrations of 0.5% and 1.0% by weight. These bead membranes are fabricated using a novel electrospinning technique, followed by a post-treatment with the hydrophobic polyfluorinated grafting agent to augment nanofiber membrane surface properties, thereby achieving superhydrophobicity with a water contact angle (WCA) of 145 +/- 2 degrees and a higher surface roughness of 512 nm. The enhanced membrane demonstrated a water flux of 87.3 Lm-2 h-1 and achieved nearly 99% salt rejection efficiency at room temperature, using a 3 wt% sodium chloride (NaCl) solution as the feed. The results highlight the potential of superhydrophobic SPES nanofiber beads in revolutionizing MD technology, offering a scalable, efficient, and robust membrane for salt rejection
New generation washable PES membrane face mask for virus filtration
No full textMembrane materials might be used for face protection because they can decontaminate the inhaled air from particle pollution and viruses like the SARS-Cov0-2 which damages our respiration system. In this study, plyethersulfone membranes (PES) were synthesized with green solvent at room temperature and its filtration effectiveness was investigated against nano-bacteria (size 0.05 to 0.2 µm) by measuring their Bacterial Filtration Efficiency (BFE) and micro aerosol size (0.3 µm), and Particulate Filtration Efficiency (PFE). The average SARS-CoV-2 diameters are between 50 nm to 160 nm. A series of experiments were performed to accomplish between 0.03 to 0.21 µm PES sponge like diameters so that can be used for SARS-CoV-2 filtration. Results showed that nanofiltration/ultrafiltration could filter 99.9% of bacteria and aerosol from contaminated air the size of the Covid-19 molecule.</p
Ag nanoparticles immobilized sulfonated polyethersulfone/polyethersulfone electrospun nanofiber membrane for the removal of heavy metals
No full textIn this work, Eucommia ulmoides leaf extract (EUOLstabilized silver nanoparticles (EUOL@AgNPs) incorporated sulfonated polyether sulfone (SPES)/polyethersulfone (PES) electrospun nanofiber membranes (SP ENMs) were prepared by electrospinning, and they were studied for the removal of lead (Pb(II)) and cadmium (Cd(II)) ions from aqueous solutions. The SP ENMs with various EUOL@AgNPs loadings were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscope, thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and contact angle (CA) measurements. The adsorption studies showed that the adsorption of Cd(II) and Pb(II) was rapid, achieved equilibrium within 40 min and 60 min, respectively and fitted with non-linear pseudo-second-order (PSO) kinetics model. For Cd(II) and Pb(II), the Freundlich model described the adsorption isotherm better than the Langmuir isotherm model. The maximum adsorption capacity for Cd(II) and Pb(II) was 625 and 370.37 mg g-1 respectively at neutral pH. Coexisting anions of fluoride, chloride, and nitrate had a negligible influence on Cd(II) removal than the Pb(II). On the other hand, the presence of silicate and phosphate considerably affected Cd(II) and Pb(II) adsorption. The recyclability, regeneration, and reusability of the fabricated EUOL@AgNPs-SP ENMs were studied and they retained their high adsorption capacity up to five cycles. The DFT measurements revealed that SP-5 ENMs exhibited the highest adsorption selectivity for Cd(II) and the measured binding energies for Cd(II), Pb(II), are 219.35 and 206.26 kcal mol-1, respectively. The developed ENM adsorbent may find application for the removal of heavy metals from water.</p
Chitosan-functionalized sodium alginate-based electrospun nanofiber membrane for As (III) removal from aqueous solution
No full textEnvironment-friendly chitosan-modified-poly(vinyl alcohol) or (PVA)/sodium alginate (SA) electrospun nanofiber membrane (ENM) adsorbent was prepared for the removal of As(III) from an aqueous solution. The chitosan(CS)-functionalized-PVA/SA ENM (CS-f-PVA/SA) was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and X-Ray diffraction (XRD). The CS-f-PVA/SA ENM showed the maximum As (III) adsorption capacity at neutral pH (540.40 mg g-1). The adsorption experiments were conducted by varying the initial pH of the arsenic solutions and also in the presence of different coexisting anions, such Cl- and F-, SO42−, and PO43−. Moreover, the kinetic studies were performed to depict the rate of As(III) sorption onto CS-f-PVA/SA ENM. The As(III) adsorption reached equilibrium within 90 min, which well fitted to the pseudo-second-order kinetic model. The initial pH of arsenic solutions greatly affected the adsorption efficiency but the presence of competing anions in arsenic solutions showed a moderate effect on the arsenic adsorption. The FTIR and XRD analyses suggest that–NH2, –OH, and C–O functional groups of CS-f-PVA/SA ENM are responsible for As(III) uptake. The prepared CS-f-PVA/SA ENM can be easily regenerated using 0.003 M NaOH, and the As(III) removal rate was still above 90% to 50% after ten successive adsorption-desorption cycles. Thus, such a nanofiber-based adsorbent is quite promising for the removal of As(III) from potable water and can be beneficial in combating the current challenges of arsenic pollution
Liu Jishan xin xing lun tan wei: wei Mou Zongsan de "yi xin zhe xing" zuo bian hu
No full textM.Phil.In this thesis, I will focus on the discussion of Liu Jishan (Liu Zongzhou)’s theory of heart-mind and nature, based on the outcome of contemporary studies. The reason for investigating Liu’s theory is that he had developed a unique and complicated theory of heart-mind and nature based on the late Ming development of Confuciansim, which making him “The Last Neo-Confucian”. Due to the historical background and the complicity of his theory, Liu’s system is difficult to understand and opens for different interpretations. In my opinion, Mou Zongsan’s theory of “manifest nature by heart-mind” is the best interpretation to grasp Liu’s insight among the contemporary studies. Therefore, this thesis argues for Mou’s interpretation to Liu’s theory by analyzing Liu’s text and defending contemporary criticisms to Mou.This thesis includes four parts: First, it analyzes Liu’s problematic from the historical background of late Ming Confucian thoughts. Second, it illustrates Mou’s view in detail and explains why his interpretation fitting into Liu’s thought. Third, it analyzes the contemporary studies of Liu to see their understanding and criticisms to Mou. Finally, it defends for Mou’s view, by arguing Mou’s view grasping Liu’s insight by developing a system of covering both the subjective-moral aspect and the objective-ontological aspect, in order to solve the difficulties of moral practices caused by the School of Heart-mind.這篇論文的工作是在建基於當代研究的視野下，對明末大儒劉蕺山（宗周）的心性論作進一步的討論。以蕺山為研究對像的原因，是由於他在修正明末各種思潮的脈絡下發展出一套較為複雜的心性論系統。他在心性論上的創穫，使他獲得「宋明理學殿軍」之美譽。但亦因為蕺山在思想背景及其心性論系統上的複雜性，這使得他的系統艱澀難懂外，亦引不少詮釋上的爭議。而筆者認為，在當代研究之中，最能說明和闡發蕺山的心性論的洞見者當屬牟宗三的以心著性系統。故本文的目的在於疏解蕺山的心性論文字的同時論證牟宗三的以心著性是對蕺山最佳的解讀，並嘗試為牟宗三的觀點辯護，以回應當代學界的批評。為此，本篇論文主要處理四項工作：一、從明末思潮的脈絡梳理蕺山的問題意識。二、對牟宗三的以心著性觀點作出詳細的分析，並解釋此觀點何以契合蕺山的文字。三、分析當代蕺山研究中贊同及反對牟說的觀點，以說明當代學界對於以心著性的理解。四、為牟說作出辯護，論證以心著性系統以分言主觀道德面與客觀存有面的方式堵塞心學工夫的流弊是最能把握蕺山心性論洞見的說法。筆者希望著此來說明一套主客兼備的心性論系統在宋明理學中的哲學洞見。張鴻辰."2019年7月".Thesis M.Phil. Chinese University of Hong Kong 2019.Includes bibliographical references (leaves 246-256).Abstracts in Chinese and English.Title from PDF title page (viewed on February 23, 2022).Zhang Hongchen
Thermophilic and Halophilic Extremophiles in Eurasian Environments
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
Fabrication of a polyethersulfone/polyethyleneimine porous membrane for sustainable separation of proteins in water media
No full textThis paper aims to establish a new sustainable membrane with antifouling properties by developing a structured porous membrane with a honeycomb-like surface fabricated by blending polymers and additives via immersion precipitation and using a thermally induced phase inversion method coupled with exposure time to vapor. The hydrophilic properties, surface charge, and pore size of the membrane were dependent on controlling the blending ratio of polyethersulfone (PES), polyethyleneimine (PEI), and polyvinylpyrrolidone (PVP). The properties of the membranes were characterized, including physical properties, morphology, contact angle, mechanical properties, porosity, and pore size distribution. The membrane filtration performance was evaluated by examining the water permeation, antifouling, and hydrophilic properties of the membranes. The hydrophilic nature of the PES/PEI membrane increased the filtration performance and created a smooth surface that exhibited excellent antifouling ability. Finally, the separation capability of the membranes was evaluated using bovine serum albumin (BSA) and Angelica gigas Nakai (AGN) root solutions. An almost 99.9% rejection rate was achieved for BSA and AGN at 1 bar pressure. The optimized membrane outperforms the commercial membrane with analogous characteristics on both the water flux and molecular weight cut-off (MWCO) of polyethylene glycol (PEG). Due to the controlled pore size (0.0032 to 0.0041 μm) of the honeycomb-like surface, it may be possible to separate pharmacodynamic macromolecules (such as berberine, baicalin, geniposide, and palmatine) for future applications.</p
Multiferroic CoFe2O4-BiFeO3 core-shell nanofibers and their nanoscale magnetoelectric coupling
No full textMultiferroic CoFe2O4-BiFeO3 (CFO-BFO) core-shell nanofibers were synthesized by coaxial electrospinning. The spinel structure of CFO and perovskite structure of BFO were confirmed by x-ray diffraction and high-resolution transmission electron microscopy. The core-shell configuration of nanofibers was verified by scanning electron microscopy and transmission electron microscopy images. The macroscopic ferromagnetic property of core-shell nanofibers was demonstrated by magnetic hysteresis loop. The local magnetoelectric (ME) coupling was confirmed by using dual frequency piezoresponse force microscopy (PFM) under an external magnetic field, showing magnetically induced evolution of piezoresponse and domain structure. The ferroelectric characteristics are demonstrated by the switching spectroscopy PFM. From PFM hysteresis and butterfly loops, it is observed that the piezoresponse amplitude is reduced while coercive voltage increased under external in-plane magnetic field, induced through the mechanical interactions between magnetostrictive CFO and piezoelectric BFO, from which the lateral ME coupling can be estimated quantitatively. The nanofibers thus can find a variety of applications as a one-dimensional multiferroic material
Development of an apparent face-shear mode (d(36)) piezoelectric transducer for excitation and reception of shear horizontal waves via two-dimensional antiparallel poling
No full textThe non-dispersive fundamental shear horizontal (SH0) wave is extremely useful in guided-wave-based inspection techniques. However, the generation or reception of the SH0 wave by using a piezoelectric transducer is always a challenge. In this work, first, we realized the apparent face-shear (d(36)) mode in PbZr1-xTixO3 (PZT) ceramics via two-dimensional antiparallel poling. Then, we demonstrated via finite element simulations that the apparent d(36) mode PZT wafer can behave as both a SH0 wave actuator and a SH0 wave sensor. Next, by using the apparent d(36) PZT wafer as an actuator and a face-shear d(36) 0.72[Pb(Mg1/3Nb2/3)O-3]-0.28[PbTiO3] crystal as the sensor, almost a pure SH0 wave with a high signal-to-noise ratio was successfully excited in an aluminum plate from 180 kHz to 200 kHz. Later, experiments showed that the proposed apparent d(36) PZT wafer can also serve as a sensor to detect the SH0 wave over a wide frequency range (160 kHz to 230 kHz). Finally, the amplitude directivity of the SH0 wave generated by the apparent d(36) PZT wafer was also investigated. The wave amplitude reaches its maxima at the main direction (0 degrees and 90 degrees) and then decreases monotonically when the propagation direction deviates from the main directions, with the symmetric axis along the 45 degrees direction. The proposed apparent d(36) PZT wafer is very suitable for severing as SH0 wave actuators and sensors in structural health monitoring systems. Published by AIP Publishing.National Natural Science Foundation of China [11422216, 11672003, 11521202]SCI(E)[email protected]
Identifying a suitable revegetation technique for soil restoration on water-limited and degraded land: Considering both deep soil moisture deficit and soil organic carbon sequestration
No full textRevegetation is an important means to improve the ecosystem services delivered by degraded land; however, inappropriate revegetation can result in severe soil desiccation and ecosystem degradation in water-limited regions. Here we evaluated seven common revegetation techniques by considering both deep soil moisture deficit and soil organic carbon (SOC) sequestration on the Loess Plateau of China, attempting to identify a suitable method for soil restoration of severely degraded ecosystems. The seven revegetation techniques considered were: two single-species shrub plantations (Caragana korshinskii and Hippophae rhamnoides), two single species tree plantations (Platycladus orientalis with terracing and Robinia pseudoacacia), and three mixed plantations (P. orientalis/H. rhamnoides with terracing, R. pseudoacacia/H. rhamnoides, R. pseudoacacia/P. orientalis). A 12-year-old abandoned cropland served as the control. The results showed that the single-species plantation of P. orientalis with terracing had the lowest soil moisture deficit in deep layers (200-800 cm) but also had the lowest SOC sequestration. In contrast, the mixed plantation of R. pseudoacacia/H. rhamnoides had the highest SOC sequestration but also had significant deep soil moisture deficit. In contrast, the mixed plantation of P. orientalis/H. rhamnoides with terracing showed near-zero deep soil moisture deficit and significant, positive SOC sequestration. Therefore, this mixed plantation was identified as representing a suitable revegetation technique for this region. The results here suggest that appropriate mixed tree/shrub plantations with appropriate land engineering measures could deliver effective soil restoration in such environments. Our results provide an insight into revegetation in areas with degraded land
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