scholarly journals Design and Modeling of Novel Low-Pressure Nanofiltration Hollow Fiber Modules for Water Softening and Desalination Pretreatment

2018 ◽  
Author(s):  
Omar Labban
Keyword(s):  
Hollow Fiber ◽  
Transport Model ◽  
High Surface ◽  
Scale Up ◽  
High Surface Area ◽  
Volume Ratio ◽  
Low Pressure ◽  
System Level ◽  
Great Promise ◽  
Module Design

Given its high surface area to volume ratio and desirable mass transfer characteristics, the hollow fibermodule configuration has been central to the development of RO and UF technologies over the past fivedecades. Recent studies have demonstrated the development of a novel class of low-pressure nanofiltration(NF) hollow fiber membranes with great promise for scale-up implementation. Further progress on large-scaledeployment, however, has been restrained by the lack of an accurate predictive model, to guide module designand operation. Earlier models targeting hollow fiber modules are only suitable for RO or UF. In this work,we propose a new modeling approach suitable for NF based on the implementation of mass and momentumbalances, coupled with a validated membrane transport model based on the extended Nernst-Planck equationto predict module performance at the system-level. Modeling results are validated with respect to syntheticseawater experiments reported in an earlier work. A preliminary module design is proposed, and parametricstudies are employed to investigate the effect of varying key system parameters and elucidate the tradeoffsavailable during design. The model has significant implications for low-pressure nanofiltration, as well ashollow fiber NF module design and operation.

Biosynthesis of silver nanoparticles by natural precursor from clove and their antimicrobial activity

Biologia ◽  
2013 ◽  
Vol 68 (6) ◽  
Author(s):  
Harpreet Kaur ◽  
Simerjit Kaur ◽  
Minni Singh
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
High Surface ◽  
Scale Up ◽  
High Surface Area ◽  
Volume Ratio ◽  
Syzygium Aromaticum ◽  
Extracellular Biosynthesis ◽  
Vis Spectroscopy ◽  
Average Size

AbstractSilver nanoparticles (AgNPs) have attracted the attention of researchers because of their unique properties and applications in various fields, such as medicine, catalysis, textile engineering, and pollution treatment. The green synthesis of AgNPs has many advantages, such as less time requirement, highly stable AgNPs, better control over crystal growth, morphology, ease for scale up, and economic viability. Syzygium aromaticum (clove) was used for the extracellular biosynthesis of AgNPs. Eugenols are the active biomolecules present in clove, responsible for the bioreduction of AgNO3 (Ag+) leading to the formation and capping of AgNPs (Ag0). One molecule of eugenol releases two electrons and these two electrons will be taken by 2 Ag+ ions and these will get reduced to 2 Ag0. The synthesis of AgNPs was confirmed by the appearance of brown colour. The synthesized AgNPs were characterised by various techniques, such as UV-VIS spectroscopy, transmission electron microscopy, X-ray diffraction and Fourier transformed infrared spectroscopy. The synthesised AgNPs have λ max of 440 nm. It was evaluated that the AgNPs were biphasic in nature (cubic + hexagonal) with an average size of 50.0 nm. The synthesized AgNPs showed significant antimicrobial activity against Bacillus cereus NCDC 240 as they are nano-sized and have high surface area to volume ratio. AgNPs inhibit the growth of bacteria by various ways, such as by disrupting the cell membrane of bacteria, uncoupling the oxidative phosphorylation, inhibiting the DNA replication, forming free radicals and affecting the cellular signalling of bacteria leading to cell death.

scholarly journals Electrochemical Response of Glucose Oxidase Adsorbed on Laser-Induced Graphene

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1893
Author(s):  
Sónia O. Pereira ◽  
Nuno F. Santos ◽  
Alexandre F. Carvalho ◽  
António J. S. Fernandes ◽  
Florinda M. Costa
Keyword(s):  
Electron Transfer ◽  
Glucose Oxidase ◽  
Ph Dependence ◽  
High Surface ◽  
High Surface Area ◽  
Cost Effective ◽  
Great Promise ◽  
Glucose Detection ◽  
Half Wave ◽  
Electrochemical Transducers

Carbon-based electrodes have demonstrated great promise as electrochemical transducers in the development of biosensors. More recently, laser-induced graphene (LIG), a graphene derivative, appears as a great candidate due to its superior electron transfer characteristics, high surface area and simplicity in its synthesis. The continuous interest in the development of cost-effective, more stable and reliable biosensors for glucose detection make them the most studied and explored within the academic and industry community. In this work, the electrochemistry of glucose oxidase (GOx) adsorbed on LIG electrodes is studied in detail. In addition to the well-known electroactivity of free flavin adenine dinucleotide (FAD), the cofactor of GOx, at the expected half-wave potential of −0.490 V vs. Ag/AgCl (1 M KCl), a new well-defined redox pair at 0.155 V is observed and shown to be related to LIG/GOx interaction. A systematic study was undertaken in order to understand the origin of this activity, including scan rate and pH dependence, along with glucose detection tests. Two protons and two electrons are involved in this reaction, which is shown to be sensitive to the concentration of glucose, restraining its origin to the electron transfer from FAD in the active site of GOx to the electrode via direct or mediated by quinone derivatives acting as mediators.

scholarly journals Developing Eco-Friendly and Cost-Effective Porous Adsorbent for Carbon Dioxide Capture

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1962
Author(s):  
Mahboubeh Nabavinia ◽  
Baishali Kanjilal ◽  
Noahiro Fujinuma ◽  
Amos Mugweru ◽  
Iman Noshadi
Keyword(s):  
Carbon Dioxide ◽  
Surface Area ◽  
Co2 Capture ◽  
High Surface ◽  
Scale Up ◽  
Polymer Networks ◽  
High Surface Area ◽  
Excellent Thermal Stability ◽  
Doped Polymers ◽  
Metal Doped

To address the issue of global warming and climate change issues, recent research efforts have highlighted opportunities for capturing and electrochemically converting carbon dioxide (CO2). Despite metal doped polymers receiving widespread attention in this respect, the structures hitherto reported lack in ease of synthesis with scale up feasibility. In this study, a series of mesoporous metal-doped polymers (MRFs) with tunable metal functionality and hierarchical porosity were successfully synthesized using a one-step copolymerization of resorcinol and formaldehyde with Polyethyleneimine (PEI) under solvothermal conditions. The effect of PEI and metal doping concentrations were observed on physical properties and adsorption results. The results confirmed the role of PEI on the mesoporosity of the polymer networks and high surface area in addition to enhanced CO2 capture capacity. The resulting Cobalt doped material shows excellent thermal stability and promising CO2 capture performance, with equilibrium adsorption of 2.3 mmol CO2/g at 0 °C and 1 bar for at a surface area 675.62 m2/g. This mesoporous polymer, with its ease of synthesis is a promising candidate for promising for CO2 capture and possible subsequent electrochemical conversion.

scholarly journals Electrospun Nanofibers for Sensing and Biosensing Applications—A Review

2021 ◽  
Vol 22 (12) ◽  
pp. 6357
Author(s):  
Kinga Halicka ◽  
Joanna Cabaj
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Toxic Metal ◽  
Volume Ratio ◽  
Electrospun Nanofibers ◽  
Clinical Diagnostics ◽  
Loading Capacity ◽  
Electrospun Nanofiber ◽  
Sensing Platforms ◽  
Different Types

Sensors and biosensors have found applications in many areas, e.g., in medicine and clinical diagnostics, or in environmental monitoring. To expand this field, nanotechnology has been employed in the construction of sensing platforms. Because of their properties, such as high surface area to volume ratio, nanofibers (NFs) have been studied and used to develop sensors with higher loading capacity, better sensitivity, and faster response time. They also allow to miniaturize designed platforms. One of the most commonly used techniques of the fabrication of NFs is electrospinning. Electrospun NFs can be used in different types of sensors and biosensors. This review presents recent studies concerning electrospun nanofiber-based electrochemical and optical sensing platforms for the detection of various medically and environmentally relevant compounds, including glucose, drugs, microorganisms, and toxic metal ions.

scholarly journals Design Considerations for Borehole Thermal Energy Storage (BTES): A Review with Emphasis on Convective Heat Transfer

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-26 ◽  
Author(s):  
Helge Skarphagen ◽  
David Banks ◽  
Bjørn S. Frengstad ◽  
Harald Gether
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Theoretical Calculations ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Thermal Recovery ◽  
Conductive Heat ◽  
Geological Environment

Borehole thermal energy storage (BTES) exploits the high volumetric heat capacity of rock-forming minerals and pore water to store large quantities of heat (or cold) on a seasonal basis in the geological environment. The BTES is a volume of rock or sediment accessed via an array of borehole heat exchangers (BHE). Even well-designed BTES arrays will lose a significant quantity of heat to the adjacent and subjacent rocks/sediments and to the surface; both theoretical calculations and empirical observations suggest that seasonal thermal recovery factors in excess of 50% are difficult to obtain. Storage efficiency may be dramatically reduced in cases where (i) natural groundwater advection through the BTES removes stored heat, (ii) extensive free convection cells (thermosiphons) are allowed to form, and (iii) poor BTES design results in a high surface area/volume ratio of the array shape, allowing high conductive heat losses. The most efficient array shape will typically be a cylinder with similar dimensions of diameter and depth, preferably with an insulated top surface. Despite the potential for moderate thermal recovery, the sheer volume of thermal storage that the natural geological environment offers can still make BTES a very attractive strategy for seasonal thermal energy storage within a “smart” district heat network, especially when coupled with more efficient surficial engineered dynamic thermal energy stores (DTES).

Biological weathering in soil: the role of symbiotic root-associated fungi biosensing minerals and directing photosynthate-energy into grain-scale mineral weathering

2008 ◽  
Vol 72 (1) ◽  
pp. 85-89 ◽  
Author(s):  
J. R. Leake ◽  
A. L. Duran ◽  
K. E. Hardy ◽  
I. Johnson ◽  
D. J. Beerling ◽  
...  
Keyword(s):  
Carbon Allocation ◽  
High Surface ◽  
Turgor Pressure ◽  
High Surface Area ◽  
Volume Ratio ◽  
Mineral Weathering ◽  
Mycorrhizal Associations ◽  
P Content ◽  
Biological Weathering

AbstractBiological weathering is a function of biotic energy expenditure. Growth and metabolism of organisms generates acids and chelators, selectively absorbs nutrient ions, and applies turgor pressure and other physical forces which, in concert, chemically and physically alter minerals. In unsaturated soil environments, plant roots normally form symbiotic mycorrhizal associations with fungi. The plants provide photosynthate-carbohydrate-energy to the fungi in return for nutrients absorbed from the soil and released from minerals. In ectomycorrhiza, one of the two major types of mycorrhiza of trees, roots are sheathed in fungus, and 15—30% of the net photosynthate of the plants passes through these fungi into the soil and virtually all of the water and nutrients taken up by the plants are supplied through the fungi. Here we show that ectomycorrhizal fungi actively forage for minerals and act as biosensors that discriminate between different grain sizes (53—90 μm, 500—1000 μm) and different minerals (apatite, biotite, quartz) to favour grains with a high surface-area to volume ratio and minerals with the highest P content. Growth and carbon allocation of the fungi is preferentially directed to intensively interact with these selected minerals to maximize resource foraging.

scholarly journals Preparation and Characterization of Biocompatible Electrospun Nanofiber Scaffolds

2018 ◽  
Vol 62 (4) ◽  
Author(s):  
Edit Hirsch ◽  
Márió Nacsa ◽  
Ferenc Ender ◽  
Miklós Mohai ◽  
Zsombor K. Nagy ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Surface Characteristic ◽  
Poly Lactic Acid ◽  
Nanofibrous Scaffolds ◽  
Plasma Surface Treatment ◽  
Nanoscale Fibers ◽  
Solution Electrospinning

Nanoscale fibers were prepared for the fabrication of scaffolds by using a strong electrostatic field on the polymer solution. Electrospinning is widely applied for production of drug delivery, tissue engineering, and regenerative medicine systems as well as biosensors and enzyme immobilization. Nanofibers, thanks to their high surface area to volume ratio, can also mimic the extracellular matrix, thus it has been recognized as a suitable technique for the fast fabrication of scaffolds. This article demonstrates the fabrication of several nanofibrous scaffolds from biopolymers such as polycaprolactone, poly(lactic acid), poly(lactide-co-glycolide), poly(lactide-co-caprolactone) and poly(hydroxybutyrate-co-hydroxy valerate). The characterization and comparison of the scaffolds were achieved based on the morphology and surface characteristic of the nanofibers. The samples showed hydrophobic characteristic, thus a plasma surface treatment was applied successfully to increase hydrophilicity and the effect of the treatment was evaluated based on the wettability and the change in elemental composition of the surface based on X-ray photoelectron spectroscopy.

Fabrication of Hybrid Cell-Microbead Constructs Using Laser Direct-Write of Alginate Microbeads and Adherent Breast Cancer Cells

2013 ◽  
Author(s):  
Andrew D. Dias ◽  
David M. Kingsley ◽  
Douglas B. Chrisey ◽  
David T. Corr
Keyword(s):  
Drug Delivery ◽  
Mammalian Cells ◽  
Hybrid Cell ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Direct Write ◽  
Cellular Interactions ◽  
Paracrine Signaling ◽  
Laser Direct Write

Microbeads are becoming popular tools in tissue engineering as 3D microstructure hydrogels. The gel nature of microbeads enables them to sequester soluble factors and mammalian cells, and their high surface area-to-volume ratio allows diffusion between the bead and the environment [1,2]. Microbeads are thus good systems for drug delivery and can serve as 3D microenvironments for cells. To fully maximize their potential as delivery systems and microenvironments, it is highly desirable to create spatially-precise hybrid cultures of microbeads and mammalian cells. Precise placement of microbeads in proximity to patterned cells will allow the study of spatial cellular interactions, paracrine signaling, and drug delivery.

scholarly journals Nanotechnology for Environmental Remediation: Materials and Applications

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1760 ◽  
Author(s):  
Fernanda Guerra ◽  
Mohamed Attia ◽  
Daniel Whitehead ◽  
Frank Alexis
Keyword(s):  
Organic Compounds ◽  
Environmental Remediation ◽  
Organophosphorus Compounds ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Chlorinated Organic Compounds ◽  
Environmental Media ◽  
Chlorinated Organic ◽  
Materials Used

Environmental remediation relies mainly on using various technologies (e.g., adsorption, absorption, chemical reactions, photocatalysis, and filtration) for the removal of contaminants from different environmental media (e.g., soil, water, and air). The enhanced properties and effectiveness of nanotechnology-based materials makes them particularly suitable for such processes given that they have a high surface area-to-volume ratio, which often results in higher reactivity. This review provides an overview of three main categories of nanomaterials (inorganic, carbon-based, and polymeric-based materials) used for environmental remediation. The use of these nanomaterials for the remediation of different environmental contaminants—such as heavy metals, dyes, chlorinated organic compounds, organophosphorus compounds, volatile organic compounds, and halogenated herbicides—is reviewed. Various recent examples are extensively highlighted focusing on the materials and their applications.

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