scholarly journals Effect of electric potential on the morphology and chemical composition of hollow fiber membrane surface in alkaline medium

2019 ◽  
Vol 4 (3) ◽  
pp. 117-121
Author(s):  
Nourhan A Shawky ◽  
Aly Abdallah SM ◽  
Mohamed H Sorour ◽  
Ahmed M Awad Abouelata ◽  
Mona A Abdel-Fatah
Keyword(s):  
Alkaline Medium ◽  
Hollow Fiber ◽  
Electric Potential ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Membrane Thickness ◽  
Stainless Steel Cathode ◽  
Conductive Additives ◽  
Maximum Decrease ◽  
The Impact

The impact of electric potential on the dimensional characteristics and membrane surface morphology was investigated in this work. Our study samples comprise hollow fiber (HF) Polysulfone (PS) membrane. Conductive additives have been incorporated within the membrane matrix at the desired predefined concentration. The DC operated electrochemical apparatus consists of graphite anode and stainless steel cathode. The voltage and current density ranges are 2 to 10volts and 0.01 to 1.4mA/mm2 respectively. These investigations have been conducted in alkaline medium at pH=8.5. The results of this work revealed essential changes of hollow fiber (HF) dimensions, including external (DO), internal (DI) and membrane thickness (t). The maximum decrease of DO, DI, and t were 13%, 15%, and 11% respectively at 5volts. EDX analysis showed the maximum sodium ions of about 0.84% on the membrane surface at 2.5volts after 1-hour treatment.

scholarly journals Numerical and experimental investigation for cleaning process of submerged outside-in hollow fiber membrane

2017 ◽  
Vol 76 (6) ◽  
pp. 1283-1299 ◽  
Author(s):  
Xingfei Guo ◽  
Yaowu Wang ◽  
Hongwei Zhang ◽  
Pengfei Li ◽  
Cong Ma
Keyword(s):  
Shear Stress ◽  
Hollow Fiber ◽  
Membrane Fouling ◽  
Cfd Simulation ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Experimental Studies ◽  
Membrane System ◽  
Fiber Membrane ◽  
The Impact

Membrane fouling has limited extensive applications for hollow fiber membranes in water treatment. Backwashing and air scouring can effectively solve this problem in the submerged outside-in hollow fiber membrane system. In this study, variation of the fouling layer on the membrane surface during backwashing and the impact of shear stress caused by air scouring on fouling removal were investigated through computational fluid dynamics (CFD) simulation. The backwashing and air scouring process were simulated using CFD and the results were verified by experimental studies. The results of experimental studies are in accordance with the simulation results. During the backwashing process, the velocity profile inside the reactor was presented, and visualization of the particle movement to illustrate the dynamic peeling process of the fouling layer on the membrane surface was also shown. The formation of uneven cleaning reveals that the upper region of the fibers has an excellent cleaning effect during backwashing. After that, the supporting role of air scouring was investigated in the study. It is concluded that the lower part and the middle region of the fibers suffer greater shear stress by analyzing the velocity contours and vectors, and the analysis results indicated that air scouring can further remove membrane fouling.

scholarly journals Applying a Hydrophilic Modified Hollow Fiber Membrane to Reduce Fouling in Artificial Lungs

Separations ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 113
Author(s):  
Nawaf Alshammari ◽  
Meshari Alazmi ◽  
Vajid Nettoor Veettil
Keyword(s):  
Gas Exchange ◽  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Artificial Lung ◽  
Hollow Fiber Membranes ◽  
Fiber Membrane ◽  
Hydrophilic Modification ◽  
Protein Fouling ◽  
Time Periods

Membranes for use in high gas exchange lung applications are riddled with fouling. The goal of this research is to create a membrane that can function in an artificial lung until the actual lung becomes available for the patient. The design of the artificial lung is based on new hollow fiber membranes (HFMs), due to which the current devices have short and limited periods of low fouling. By successfully modifying membranes with attached peptoids, low fouling can be achieved for longer periods of time. Hydrophilic modification of porous polysulfone (PSF) membranes can be achieved gradually by polydopamine (PSU-PDA) and peptoid (PSU-PDA-NMEG5). Polysulfone (PSU-BSA-35Mg), polysulfone polydopamine (PSUPDA-BSA-35Mg) and polysulfone polydopamine peptoid (PSU-PDA-NMEG5-BSA35Mg) were tested by potting into the new design of gas exchange modules. Both surfaces of the modified membranes were found to be highly resistant to protein fouling permanently. The use of different peptoids can facilitate optimization of the low fouling on the membrane surface, thereby allowing membranes to be run for significantly longer time periods than has been currently achieved.

Performance of Photocatalytic Microfiltration with Hollow Fiber Membrane

2007 ◽  
Vol 544-545 ◽  
pp. 95-98 ◽  
Author(s):  
Jong Tae Jung ◽  
Jong Oh Kim ◽  
Won Youl Choi
Keyword(s):  
Heavy Metals ◽  
Humic Acid ◽  
Rate Constant ◽  
Hollow Fiber ◽  
Reaction Rate ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Reaction Rate Constant ◽  
Operational Parameters ◽  
Tio2 Particles

The purpose of this study is to investigate the effect of the operational parameters of the UV intensity and TiO2 dosage for the removal of humic acid and heavy metals. It also evaluated the applicability of hollow fiber microfiltration for the separation of TiO2 particles in photocatalytic microfiltration systems. TiO2 powder P-25 Degussa and hollow fiber microfiltration with a 0.4 μm nominal pore size were used for experiments. Under the conditions of pH 7 and a TiO2 dosage 0.3 g/L, the reaction rate constant (k) for humic acid and heavy metals increased with an increase of the UV intensity in each process. For the UV/TiO2/MF process, the reaction rate constant (k) for humic acid and Cu, with the exception of Cr in a low range of UV intensity, was higher compared to that of UV/TiO2 due to the adsorption of the membrane surface. The reaction rate constant (k) increased as the TiO2 dosage increased in the range of 0.1~0.3 g/L. However it decreased for a concentration over 0.3 g/L of TiO2. For the UV/TiO2/MF process, TiO2 particles could be effectively separated from treated water via membrane rejection. The average removal efficiency for humic acid and heavy metals during the operational time was over 90 %. Therefore, photocatalysis with a membrane is believed to be a viable process for humic acid and heavy metals removal.

Steady three-dimensional flows past hollow fiber membrane arrays – cross flow arrangement

2018 ◽  
Vol 96 (12) ◽  
pp. 1272-1287 ◽  
Author(s):  
Mustafa Usta ◽  
Michael Morabito ◽  
Mohammed Alrehili ◽  
Alaa Hakim ◽  
Alparslan Oztekin
Keyword(s):  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Flow Behavior ◽  
Membrane Surface ◽  
Three Dimensional ◽  
Cross Flow ◽  
Coefficient Of Performance ◽  
Fiber Membrane ◽  
Cfd Simulations ◽  
Flow Configuration

Hollow fiber membrane (HFM) modules are among the most common separation devices employed in membrane separation applications. Three-dimensional steady-state computational fluid dynamics (CFD) simulations are carried out to study flow past hollow fiber membrane banks (HFMB). The current study investigates the effects of flow behavior on membrane performance during binary mixture separations. Carbon dioxide (CO2) removal from methane (CH4) is examined for various arrangements of HFMs in staggered and inline configurations. The common HFM module arrangement is the axial flow configuration. However, this work focuses on the radial cross-flow configuration. The HFM surface is a functional boundary where the suction rate and concentration of each species are coupled and are functions of the local partial pressures, the permeability, and the selectivity of the HFM. CFD simulations employed the turbulent k–ω shear stress transport (SST) model to study HFM performance for Reynolds numbers, 200 ≤ Re ≤ 1000. The efficiency of the inline and staggered arrangements in the separation module is evaluated by the coefficient of performance and the rate of mass flow per unit area of CO2 passing across the membrane surface. This work demonstrates that the module with staggered arrangement outperforms the module with the inline arrangement.

scholarly journals Modification of porous polyetherimide hollow fiber membrane by dip-coating of Zonyl® BA for membrane distillation of dyeing wastewater

2021 ◽  
Author(s):  
S. A. Mousavi ◽  
Z. Arab Aboosadi ◽  
A. Mansourizadeh ◽  
B. Honarvar
Keyword(s):  
Pore Size ◽  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Pure Water ◽  
Dip Coating ◽  
Membrane Distillation ◽  
Permeate Flux ◽  
Fiber Membrane ◽  
Air Gap Membrane Distillation

Abstract Wetting and fouling have significantly affected the application of membrane distillation (MD). In this work, a dip-coating method was used for improving surface hydrophobicity of the polyetherimide (PEI) hollow fiber membrane. An air gap membrane distillation (AGMD) process was applied for treatment of the methylene blue (MB) solution. The porous PEI membrane was fabricated by a dry-wet spinning process and the hydrophobic 2-(Perfluoroalkyl) ethanol (Zonyl® BA) was used as the coating material. From FESEM, the modified PEI-Zonyl membrane showed an open structure with large finger-like cavities. The modified membrane displayed a narrow pore size distribution with mean pore size of 0.028 μm. The outer surface contact angle of the PEI-Zonly membrane increased from 81.3° to 100.4° due to the formation of an ultra-thin coated layer. The pure water flux of the PEI-Zonyl membrane was slightly reduced compared to the pristine PEI membrane. The permeate flux of 6.5 kg/m2 h and MB rejection of 98% was found for the PEI-Zonyl membrane during 76 h of the AGMD operation. Adsorption of MB on the membrane surface was confirmed based on the Langmuir isotherm evaluation, AFM and FESM analysis. The modified PEI-Zonyl membrane can be a favorable alternative for AGMD of dyeing wastewaters.

Hydrophilic Modification of PES Hollow Fiber Membrane via Surface-Initiated Atom Transfer Radical Polymerization

2010 ◽  
Vol 150-151 ◽  
pp. 565-570 ◽  
Author(s):  
Yong Bo Shen ◽  
Ya Tao Zhang ◽  
Jian Hua Qiu ◽  
Yan Wu Zhang ◽  
Hao Qin Zhang
Keyword(s):  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Hollow Fiber ◽  
Polymer Brushes ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Pure Water ◽  
Average Molecular Weight ◽  
Atom Transfer ◽  
Fiber Membrane

Hydrophilic poly((poly(ethylene glycol) methyl ether methacrylate) (P(PEGMA)) brushes were grafted from chloromethylated polyethersulfone (CMPES) hollow fiber membrane surface by surface-initiated atom transfer radical polymerization(SI-ATRP) to improve the membrane’s hydrophilic property. The CMPES hollow fiber membrane was prepared by phase inversion process. The benzyl chloride groups on the CMPES membrane surface could afford effective macroinitiators for grafting the well-defined polymer brushes. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy confirmed the grafting of P (PEGMA) chains. Field emission scanning electron microscopy (FESEM) was used to characterize the surface morphology of the CMPES membrane and modified membrane. The grafting yield of P (PEGMA) was determined by weight gain measurement. The results showed that the number-average molecular weight (Mn) of P (PEGMA) increased with the polymerization time. It was found that the grafting of P (PEGMA) brought higher pure water flux, improved water uptake ratio and better anti-protein absorption ability to CMPES membrane after modification.

Preparation and Characterization of Negatively Charged Polysulfone Hollow Fiber Membrane by UV-Photografting Polymerization of AMPS

2010 ◽  
Vol 129-131 ◽  
pp. 295-300
Author(s):  
Xiao Lei Wang ◽  
Jun Fu Wei ◽  
Yan Ming Yang ◽  
Huan Zhang ◽  
Guo Yang Shi
Keyword(s):  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Morphological Changes ◽  
Membrane Surface ◽  
Streaming Potential ◽  
Attenuated Total Reflection ◽  
Water Contact ◽  
Potential Measurement ◽  
Uf Membranes ◽  
Surface Modified

Polysulfone (PSf) hollow fiber ultrafiltration (UF) membranes were surface-modified by the UV-induced graft polymerization of 2-acrylamido-2-methylpropanesulfonic acid (AMPS). Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and scanning electron microscope (SEM) were employed to characterize the structural and morphological changes on the membrane surface. Water contact angle of PSf-g-AMPS membrane surface decreased to 15.45° when AMPS concentration was 2 wt.%, which was nearly 35° lower than that of the unmodified membrane. The results of streaming potential measurement at different pressures implied the negatively charged characteristic of the PSf-g-AMPS membrane. The flux of PSf-g-AMPS membrane increased about 60% as compared to original PSf membrane and the rejection of heparin sodium for PSf-g-AMPS membrane achieved 78%, which was about 4 times that of PSf membrane at 0.04 MPa.

scholarly journals Effects of various chemical cleaning conditions for pressured MF process

2016 ◽  
Vol 75 (5) ◽  
pp. 1063-1070
Author(s):  
Chang-Kyu Lee ◽  
Chansoo Park ◽  
June-Seok Choi ◽  
Jong-Oh Kim
Keyword(s):  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Pilot Scale ◽  
Second Step ◽  
Fiber Membrane ◽  
Bag Filter ◽  
Chemical Cleaning ◽  
Pilot Plant Process ◽  
The Impact ◽  
Plant Process

A pilot-scale pressured hollow-fiber microfiltration (MF) process as pretreatment for the reverse osmosis process was studied and operated under various conditions to assess the relative influence of backwashing, chemical enhanced backwashing (CEB), and bag filter application. The pilot plant process consisted of backwashing but without the CEB or the bag filter as the first step of the research. As the second step of the research, the impact of the backwashing on permeability recovery was assessed at different intervals followed by the influence of CEB on flowrate recovery. Results from operating the pilot-scale hollow-fiber membrane modules for more than 1 year have demonstrated that the appropriate pore size of bag filters was 25–50 μm and the optimized backwashing process was every 30 minutes with 25 mg/L of NaOCl, and CEB with an interval of 10 cycles with the use of 100 mg/L NaOCl.

Numerical Simulation of Hollow Fiber Ultrafiltration Membrane

2009 ◽  
Author(s):  
Nina Zhou ◽  
A. G. Agwu Nnanna
Keyword(s):  
Numerical Model ◽  
Hollow Fiber ◽  
Membrane Fouling ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Operating Conditions ◽  
Permeate Flux ◽  
High Productivity ◽  
Design And Optimization ◽  
Membrane Performance

Low pressure driven ultrafiltraion (UF) processes has been applied in various industries due to its economical and easy operated benefits. Hollow fiber membrane is one of the most used membrane configuration in industry, membrane fouling is the major challenge for widely usage. Most of the investigation of UF was carried out by experiments to determine the effect of different operating conditions on permeate flux. However, experiments provide limited insight information on the membrane performance. In addition, the prediction of permeate flux under different operating conditions is necessary for experimental design and optimization. The purpose of the present study is to develop a numerical model to simulate the UF process and investigate the UF mechanism. A numerical model was developed using commercial CFD package (FLUENT). The effects of various operating conditions on permeate flux were determined by experiments and simulations, the comparison of the experimental and CFD results shows good agreements. Controlling membrane fouling will maintain a high productivity. The simulations were carried out to investigate the efficiency of removing accumulated particles on membrane surface by installing spacer filaments in membrane channels. The results suggested that the zigzag type spacer has d/h = 0.5 and l/h = 5 is more economical and efficient in reducing fouling.

scholarly journals Preparation of Hollow Fiber Membrane Containing ZnO Nanoparticles to Remove Natural Organic Matter

2021 ◽  
Vol 8 (2) ◽  
pp. 11-20
Author(s):  
Abdullah Adnan Abdulkarim ◽  
Yosra Mohammed Mahdi ◽  
Haider Jasim Mohammed
Keyword(s):  
Zinc Oxide ◽  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Pure Water ◽  
Water Flux ◽  
Sem Analysis ◽  
Inversion Method ◽  
Fiber Membrane ◽  
Modified Membrane

Polyethersulfone/zinc oxide mixed matrix hollow fiber membrane was fabricated using dry/wet phase inversion method. Zinc oxide nanoparticles (2 wt.%) were dispersed in N,N-dimethylacetamide (DMAc) solvent in the present of polyvinylepyrrolidene. The dope solution speed and take up speed was similar with performing the spinning process at room temperature. The produced membranes were characterized using scanning electron microscope (SEM), atomic force microscope (AFM), and Fourier transform infrared (FTIR) analysis. Membrane performance was evaluated using pure water flux (PWF), relative flux ration (RFR), and total organic carbon (TOC) removal efficiency. From SEM analysis, it was found that the nanoparticles were well dispersed in the polymeric matrix. From AFM results, it was observed that the modified membrane has higher surface roughness. The PWF of the modified membrane was enhanced, while the RFR showed to increase due to rougher membrane surface. The NOM remaoval of PES/ZnO membrane was higher than that of PES membrane and reached to 27% compared to only 16.9 % for pristine PES.

Sign in / Sign up

Export Citation Format

Share Document