scholarly journals How does porosity heterogeneity affect the transport properties of multibore filtration membranes?

2021 ◽  
Author(s):  
Matthias Wessling
Keyword(s):  
Pure Water ◽  
Skin Layer ◽  
Membrane Properties ◽  
Porous Media Flow ◽  
Micro Computed Tomography ◽  
Water Permeation ◽  
Spatially Distributed ◽  
Porosity And Permeability ◽  
Dynamics Simulations ◽  
Spatially Varying

The prediction of pressure and flow distributions inside porous membranes is important if the geometry deviates from single- bore tubular geometries. This task remains challenging, especially when considering local porosity variations caused by lumen- and shell-side membrane skins and macro- and micro-void structures, all of them present in multibore membranes.This study analyzes pure water forward and reverse permeation and backwashing phenomena for a polymeric multibore membrane with spatially-varying porosity and permeability properties using computational fluid dynamics simulations. The heterogeneity of porosity distribution is experimentally characterized by scanning electron microscopy scans and reconstructed cuboids of X-ray micro-computed tomography scans. The reconstructed cuboids are used to determine porosity, pore size distribution, and intrinsic permeability in the membrane’s porous structure in all spatial directions. These position-dependent properties are then applied to porous media flow simulations of the whole membrane domain with different properties for separation layer, support structure, and outside skin layer. Various cases mimicking the pure water permeation, fouling, and backwashing behavior of the membrane are simulated and compared to previously obtained MRI measurements.This work reveals (a) anisotropic permeability values and isoporosity in all directions and (b) differing contributions of each lumen channel to the total membrane performance, depending on the membrane-skin’s properties. This study encourages to pertain the quest of understanding the interaction of spatially distributed membrane properties and the overall membrane module performance of multibore membranes.

Influence of the Coagulation-Bath Temperature on Membrane Formation Mechanism and Properties of PVDF/TA-ATP Hybrid Membrane

2015 ◽  
Vol 713-715 ◽  
pp. 2723-2726
Author(s):  
Yue Rong Shi ◽  
Gui Fang Zhang ◽  
Xing Tian Liu ◽  
Xue Tao Tian ◽  
Yi Ping Zhao ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
Vinylidene Fluoride ◽  
Pure Water ◽  
Water Flux ◽  
Bath Temperature ◽  
Time Domain Reflectometry ◽  
Coagulation Bath ◽  
Membrane Formation ◽  
Water Permeation ◽  
Ultrasonic Time

In this study, poly (vinylidene fluoride) (PVDF) hybrid membranes were prepared from polymeric blend of PVDF/tannic acid (TA)-Attapulgite (ATP)/PEG system via phase inversion induced by immersion precipitation in water coagulation bath. The membrane formation mechanism of PVDF/TA-ATP/PEG casting solutions in water bath thermodynamics at different temperatures and the process of membrane formation were investigated via cloud point determination and ultrasonic time-domain reflectometry (UTDR). The structures and properties of the membrane were characterized by scanning electron microscopy (SEM), and water permeation experiment, respectively. It was found that the rate of precipitation controlled by the Coagulation-Bath thermodynamics. With the coagulation temperature increasing, the gelation line was moved to non-solvent axis and the pure water flux were decreased.

Molecular Dynamics Simulations to Elucidate Translocation and Permeation of Active from Lipid Nanoparticle to Skin: Complemented with Experiments

Nanoscale ◽  
2021 ◽  
Author(s):  
Krishna M. Gupta ◽  
Surajit Das ◽  
Pui Shan Chow
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Molecular Level ◽  
Skin Layer ◽  
Lipid Nanoparticle ◽  
Dynamics Simulations

One of the most realistic approaches that could deliver actives (pharmaceuticals/cosmetics) deep into skin layer is encapsulation into nanoparticles (NP). Nonetheless, molecular-level understanding into the mechanism of active delivery from...

Influence of Hydrophilic Polymer on Pure Water Permeation, Permeability Coefficient, and Porosity of Polysulfone Blend Membranes

2014 ◽  
Vol 931-932 ◽  
pp. 168-172 ◽  
Author(s):  
Asmadi Ali ◽  
Mohamad Awang ◽  
Ramli Mat ◽  
Anwar Johari ◽  
Mohd Johari Kamaruddin ◽  
...  
Keyword(s):  
Permeability Coefficient ◽  
Pure Water ◽  
Polymer Concentration ◽  
Water Flux ◽  
Hydrophilic Polymer ◽  
Hydrophobic Property ◽  
Water Permeation ◽  
Blend Membranes ◽  
Wet Phase Inversion ◽  
Pure Water Flux

It is well known that membrane with hydrophobic property is a fouling membrane. Polysulfone (PSf) membrane has hydrophobic characteristic was blended with a hydrophilic polymer, cellulose acetate phthalate (CAP) in order to increase hydrophilicity property of pure PSf membrane. In this study, membrane casting solutions containing 17 wt% of polymer was prepared via wet phase inversion process. The pure PSf membrane was coded as PC-0. PSf/CAP blend membranes with blend composition of 95/5, 90/10, 85/15 and 80/20 wt% of total polymer concentration in the membrane casting solutions were marked as PC-5, PC-10, PC-15 and PC-20 respectively. All of the membranes were characterized in terms of pure water flux and permeability coefficient in order to study their hydrophilicity properties. The investigated results shows that increased of CAP composition in PSf blend membranes has increased pure water flux, permeability coefficient and porosity of the blend membrane which in turn formed membrane with anti-fouling property.

scholarly journals Preparation and Characterization of MWCNTs/PVDF Conductive Membrane with Cross-Linked Polymer PVA and Study on Its Anti-Fouling Performance

Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 703
Author(s):  
Yi Ding ◽  
Zhansheng Guo ◽  
Xinan Dong ◽  
Hong You ◽  
Junxue Mei ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Mass Loss Rate ◽  
Pure Water ◽  
Water Flux ◽  
Membrane Properties ◽  
Elongation Ratio ◽  
Functional Layer ◽  
Conductive Membranes ◽  
Pure Water Flux ◽  
Conductive Membrane

Based on carboxylated multi-walled carbon nanotubes (MWCNTs-COOH), a MWCNTs/PVDF conductive membrane was prepared by a vacuum filtration cross-linking method. The surface compositions and morphology of conductive membranes were studied by X-ray photoelectron spectroscopy and high-resolution field emission scanning electron microscopy, respectively. The effects of cross-linked polymeric polyvinyl alcohol (PVA) on the conductive membrane properties such as the porosity, pore size distribution, pure water flux, conductivity, hydrophilicity, stability and antifouling properties were investigated. Results showed that the addition of PVA to the MWCNTs/PVDF conductive membrane decreased the pure water flux, porosity and the conductivity. However, the hydrophilicity of the modified MWCNTs/PVDF conductive membrane was greatly improved, and the contact angle of pure water was reduced from 70.18° to 25.48° with the addition of PVA contents from 0 wt% to 0.05 wt%. Meanwhile, the conductive membranes with higher content had a relatively higher stability. It was found that the conductive functional layer of the conductive membrane had an average mass loss rate of 1.22% in the 30 min ultrasonic oscillation experiment. The tensile intensity and break elongation ratio of the conductive membrane are improved by the addition of PVA, and the durability of the conductive membrane with PVA was superior to that without PVA added. The electric assisted anti-fouling experiments of modified conductive membrane indicated that compared with the condition without electric field, the average flux attenuation of the conductive membrane was reduced by 11.2%, and the membrane flux recovery rate reached 97.05%. Moreover, the addition of PVA could accelerate the clean of the conductive membranes.

Performance and sensitivity of a spatially distributed hydrological conceptual flood model with snow components.

2021 ◽  
Author(s):  
François Colleoni ◽  
Catherine Fouchier ◽  
Pierre-André Garambois ◽  
Pierre Javelle ◽  
Maxime Jay-Allemand ◽  
...  
Keyword(s):  
Significant Proportion ◽  
Slow Flow ◽  
Modeling Tools ◽  
Snow Modeling ◽  
Distributed Modelling ◽  
Distributed Framework ◽  
Mountainous Catchments ◽  
Spatially Distributed ◽  
Flow Components ◽  
Spatially Varying

<p>In France, flash floods are responsible for a significant proportion of damages caused by natural hazards, either human or material. Hence, advanced modeling tools are needed to perform effective predictions. However for mountainous catchments snow modeling components may be required to correctly simulate river discharge.</p><p>This contribution investigates the implementation and constrain of snow components in the spatially distributed SMASH* platform (Jay-Allemand et al. 2020). The goal is to upgrade model structure and spatially distributed calibration strategies for snow-influenced catchments, as well as to investigate parametric sensitivity and equifinality issues. First, the implementation of snow modules of varying complexity is addressed based on Cemaneige (Valery et al. 2010) in the spatially distributed framework. Next, tests are performed on a sample of 55 catchments in the French North Alps. Numerical experiments and global sensitivity analysis enable to determine pertinent combinations of flow components (including a slow flow one) and calibration parameters. Spatially uniform or distributed calibrations using a variational method (Jay-Allemand 2020) are performed and compared on the dataset, for different model structures and constrains. These tests show critical improvements in outlet discharge modeling by adding slow flow and snow modules, especially considering spatially varying parameters. Current and future works focus on testing and improving the constrains of snow modules and calibration strategy, as well as potential validation and multiobjective calibration with snow signatures gained from in situ or satellite data. </p><p>*SMASH: Spatially-distributed Modelling and ASsimilation for Hydrology, platform developped by INRAE-Hydris corp. for operational applications in the french flood forecast system VigicruesFlash</p>

Highly effective permeability and antifouling performances of polypropylene non-woven fabric membranes modified with graphene oxide by inkjet printing and immersion coating methods

2013 ◽  
Vol 67 (10) ◽  
pp. 2307-2313 ◽  
Author(s):  
Chuan-Qi Zhao ◽  
Xiao-Chen Xu ◽  
Rui-Yun Li ◽  
Jie Chen ◽  
Feng-Lin Yang
Keyword(s):  
Graphene Oxide ◽  
Inkjet Printing ◽  
Membrane Surface ◽  
Pure Water ◽  
Woven Fabric ◽  
Water Permeation ◽  
Lower Protein ◽  
Coating Methods ◽  
And Performance ◽  
The Impact

In the current study, graphene oxide (GO)-modified polypropylene non-woven fabric (PP-NWF) membranes were prepared via inkjet printing and immersion coating methods. Scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle measurements, pure water permeation (JPWP) and protein adsorption were tested to evaluate the impact of the GO nanosheet on the characteristics and performance of modified PP-NWF membranes. The results showed that the exfoliated GO nanosheets uniformly deposited on the membrane surface and firmly embedded into the interlaced fibers, resulting in the improvement of membrane hydrophilicity, permeability and antifouling properties comparing with original PP-NWF membranes. The GO-printed and GO-coated membranes had 113 and 188% higher fluxes, and 70.95 and 75.74% lower protein adsorptions than the original PP-NWF membranes, respectively. After cross-linked treatment, ultrasound processing was conducted to evaluate the stability of the modified PP-NWF membranes. The results demonstrated that there was almost no decrease in permeation after ultrasonic treatment indicating that the cross-linking treatment could enhance the immobilization of the GO nanosheets on and into the modified membranes.

Composite Membrane with a Calixarene-Containing Polyamide Functional Layer

2018 ◽  
Vol 71 (5) ◽  
pp. 360 ◽  
Author(s):  
Shun Ren ◽  
Dong-Qing Liu ◽  
Rui-Xiang Miao ◽  
Ze-Xian Zhu ◽  
Yu-Feng Zhang
Keyword(s):  
Composite Membrane ◽  
Photoelectron Spectroscopy ◽  
Interfacial Polymerization ◽  
Film Formation ◽  
Pure Water ◽  
Water Flux ◽  
Metal Cations ◽  
Heat Treating ◽  
Skin Layer ◽  
Functional Layer

Monolayer thin films were prepared at the interface of hexane and water to investigate the film formation ability of monomers through interfacial polymerization (IP). A tetra-calix[4]arene chloride derivative (CC) and a diamino-terminated PEG-1000 (DAP) produced a high strength membrane among the tested monomers. IP is consequently proposed to prepare a composite membrane with CC and DAP on a polysulfone (PSF) bulk membrane used for ultrafiltration. The top layer was cross-linked by heat-treating at 60°C for 2 min, with DAP (2 wt.-%) in water and CC (0.05 wt.-%) in hexane. Attenuated total reflectance (ATR)-FTIR and X-ray photoelectron spectroscopy data confirmed that a polyamide was formed on the surface of the PSF substrate. The skin layer was a 3 μm thick smooth thin-film as determined by field emission scanning electron microscopy (FE-SEM), and was also compact without gaps. Pure water flux was ~80.5 L m−2 h−1 under 0.5 MPa. Rejection of MgSO4 was round 22 %, since the calixarene-containing network was a sparse grid, and also had an affinity for metal cations. Although the skin of the composite membrane was compact under SEM, it was easy for metal cations to transfer through. This composite membrane might have good performance in other separation areas as a result of the special structure imparted by using the calixarenes as cross-linking knots.

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