scholarly journals Characterization of the Initial Fouling Layer on the Membrane Surface in a Membrane Bioreactor: Effects of Permeation Drag

Membranes ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 121
Author(s):  
Shengli Wang ◽  
Xin Lu ◽  
Lanhe Zhang ◽  
Jingbo Guo ◽  
Haifeng Zhang
Keyword(s):  
Zeta Potential ◽  
Electron Donor ◽  
Energy Barrier ◽  
Polyvinylidene Fluoride ◽  
Membrane Bioreactor ◽  
Membrane Surface ◽  
Permeate Flux ◽  
Pvdf Membrane ◽  
Operating Modes

In this study, the properties of the initial fouling layer on the membrane surface of a bioreactor were investigated under different operating modes (with or without permeate flux) to improve the understanding of the effect of permeation drag on the formation of the initial fouling layer. It was found that protein was the major component in the two types of initial fouling layers, and that the permeation drag enhanced the tryptophan protein-like substances. The attraction of the initial foulants to the polyvinylidene fluoride (PVDF) membrane was ascribed to the high zeta potential and electron donor component (γ−) of the membrane. Thermodynamic analyses showed that the permeation drag-induced fouling layer possessed high hydrophobicity and low γ−. Due to permeation drag, a portion of the foulants overcame an energy barrier before they contacted the membrane surface, which itself possessed a higher fouling propensity. A declining trend of the cohesive strength among the foulants was found with the increasing development of both fouling layers.

scholarly journals Fabrication and Characterization of Nanofibers Membranes using Electrospinning Technology for Oil Removal

2021 ◽  
Vol 18 (4) ◽  
pp. 1338
Author(s):  
Amer Naji Al-Naemi ◽  
Mohammed Amer Abdul-Majeed ◽  
Mustafa H. Al-Furaiji ◽  
Inmar N Ghazi
Keyword(s):  
Polyvinylidene Fluoride ◽  
Membrane Surface ◽  
Water Flux ◽  
Oil Removal ◽  
Nanofiber Membrane ◽  
Pvdf Membrane ◽  
Electrospinning Method ◽  
Average Water ◽  
Graphene Membranes

Oily wastewater is one of the most challenging streams to deal with especially if the oil exists in emulsified form. In this study, electrospinning method was used to prepare nanofiberous polyvinylidene fluoride (PVDF) membranes and study their performance in oil removal. Graphene particles were embedded in the electrospun PVDF membrane to enhance the efficiency of the membranes. The prepared membranes were characterized using a scanning electron microscopy (SEM) to verify the graphene stabilization on the surface of the membrane homogeneously; while FTIR was used to detect the functional groups on the membrane surface. The membrane wettability was assessed by measuring the contact angle. The PVDF and PVDF / Graphene membranes efficiency was tested in separation of emulsified oil from aqueous solutions. The results showed that PVDF-Graphene nanofiber membrane exhibited better performance than the plain PVDF nanofiber membrane with average water flux of 210 and 180 L.m-2.h-1, respectively. Both membranes showed high oil rejection with more than 98%.

scholarly journals Characterization of Mussel Inspired Surface Modified and Metal Chelated Polymer Membrane

2020 ◽  
Vol 9 (3) ◽  
pp. 2847-2852
Keyword(s):  
Polyvinylidene Fluoride ◽  
Membrane Surface ◽  
Chelating Agent ◽  
Flux Analysis ◽  
Permeate Flux ◽  
Functional Protein ◽  
Metal Chelating ◽  
Coating Absorption ◽  
Surface Modified

Modification of a membrane surface is critical to help further functional protein binding on the membrane. Mussel inspired modification and metal chelating agent grafting on the polyvinylidene fluoride (PVDF) is proposed to increase the hydrophilicity, stability, and functionality of the membrane. This study carried out a four steps modification including polymerization of dopamine, grafting with poly (ethyleneimine) (PEI) and metal chelating agent and finally metal (ZnO) coupling. Characterization of the modified membrane was carried out using contact angle observation, permeate flux analysis, FT-IR spectrum and FESEM analysis. The results show a successful PDA and PEI deposition on PVDF membrane with significant improvement of the membrane hydrophilicity and wettability. Permeate flux analysis showed blockage on membrane surface due to the successful coating. Absorption peak increased slightly showing the deposition of PDA/PEI. Successful Zn2+ ion coupling can be seen clearly from the FESEM analysis

Submerged Ultrafiltration for Minimizing Energy Process of Refinery Wastewater Treatment

2013 ◽  
Vol 789 ◽  
pp. 531-537
Author(s):  
Erna Yuliawati ◽  
Ahmad Fauzi Ismail
Keyword(s):  
Wastewater Treatment ◽  
Polyvinylidene Fluoride ◽  
Membrane Surface ◽  
Suspended Solid ◽  
Hollow Fibers ◽  
Refinery Wastewater ◽  
Permeate Flux ◽  
Energy Process ◽  
Oil Refineries ◽  
And Performance

Refinery wastewater treatment is needed especially in the oil-producing arid regions such as oil refineries due to water scarcity. One of potentially applicable process to treat refinery wastewater is a submerged membrane technology. However, the application of submerged membrane systems for industrial wastewater treatment is still in its infancy due to significant variety in wastewater composition and high operational costs. Aim of this study was to investigate ultrafiltration (UF) membrane morphology and performance for refinery produced wastewater treatment. Submerged UF bundle was equipped using polyvinylidene fluoride (PVDF) hollow fibers, which added by dispersing lithium chloride monohydrate (LiCl.H2O) and titanium dioxide (TiO2). The comparison of morphological and performance tests was conducted on prepared PVDF ultrafiltration membranes. Distinctive changes were observed in membrane characteristics in term of membrane wettability, tensile testing and roughness measurement. Mean pore size and surface porosity were calculated based on permeate flux. Fouling characteristics for hydrophilic PVDF hollow fibers fouled with suspended solid matter was also investigated. Mixed liquor suspended solid (MLSS) of 3 g/L and 4.5 g/L were assessed by using submerged PVDF membrane with varied air bubble flow rates. Results showed that effect of air bubbles flow rate of 2.4 ml/min increased flux, total suspended solids (TSS) and sulfide removal of 148.82 L/m2h, 99.82 % and 89.2%, respectively due to increase of turbulence around fibers, which exerts shear stress to minimize particles deposited on membrane surface. It was concluded that submerged ultrafiltration is an available option to minimize energy process for treating such wastewater solution.

Preparation and Characterization of Hydrophilic PVDF Membrane via Graft Modification by Maleic Anhydride

2011 ◽  
Vol 295-297 ◽  
pp. 286-291
Author(s):  
Li Guo Wang ◽  
Xiao Guang Zhang ◽  
Shu Fang Hou ◽  
Xiu Ju Wang ◽  
Ai Min Wang ◽  
...  
Keyword(s):  
Maleic Anhydride ◽  
Polyvinylidene Fluoride ◽  
Pure Water ◽  
Water Flux ◽  
Pvdf Membrane ◽  
Technical Parameters ◽  
Pure Water Flux ◽  
Flat Membranes ◽  
Better Than

Hydrophilic polyvinylidene fluoride (PVDF) flat ultrafiltration membranes were prepared by wet-spinning method. The effects of technical parameters of maleic anhydride grafted onto PVDF on the performance of hydrophilic PVDF membranes were investigated, the preparation technical parameters were determined, and the hydrophilic PVDF flat membranes were prepared. Then, hydrophilic PVDF membranes were characterized in terms of pure water flux, contact angle, infrared spectroscopic analysis and scanning electron microscope(SEM). The results showed that maleic anhydride had been grafted onto PVDF, and the hydrophilic performance of the modified membrane was better than the traditional one.

Filtration of crude canola oil miscella utilizing PVDF membrane: the effects of pretreatments and operating conditions

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Razieh Niazmand ◽  
Reza Farhoosh ◽  
Seyed Mohammad Ali Razavi
Keyword(s):  
Canola Oil ◽  
Polyvinylidene Fluoride ◽  
Operating Conditions ◽  
Operating Pressure ◽  
Permeate Flux ◽  
Pvdf Membrane ◽  
Flat Membrane ◽  
Temperature And Pressure ◽  
Increasing Temperature ◽  
Membrane Cell

Abstract This study was conducted on adding chemical agents (aqueous solutions of CaCl2, EDTA and SDS) to crude canola oil miscella before ultrafiltration through polyvinylidene fluoride (PVDF) membrane with MWCO 50 kDa in a magnetically stirred flat membrane cell. Operating conditions including pressures 2-5 bar and temperatures 25-55 °C were employed. Permeate flux of pretreated oil samples exhibited sharp risings with increasing temperature and pressure. Except for the oils pretreated with SDS, the rejection of free fatty acids (FFAs) decreased in all oil samples. Increasing the operating pressure to 4 bar decreased the rejection of FFAs. Pretreatment of the oils with SDS and EDTA resulted in higher amounts of phosphorous rejection, while increasing temperature decreased it. Reduction of color values (L, a, and b) of the oil samples was not considerable through the PVDF membrane.

A real trial of a long-term non-fouling membrane bioreactor for saline sewage treatment

2011 ◽  
Vol 63 (7) ◽  
pp. 1519-1523 ◽  
Author(s):  
Peng Bai ◽  
Jin Wang ◽  
Guang-Hao Chen
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Membrane Surface ◽  
Pilot Trial ◽  
Sewage Treatment ◽  
Power Source ◽  
Permeate Flux ◽  
Mixing Condition ◽  
Water Ratio

This paper reports on a pilot trial of a novel MBR developed with coarse-pore membrane module by the authors. The plant was operated for 370 days with up to 7 m3/d raw saline sewage after 3-mm screening. The plant performed successfully without membrane fouling for 270 days except an accidental power source failure for 30 h, during which membrane was fouled under no aeration and mixing condition. EPS increases in both the reactor and the bio-cake on the membrane surface explained this fouling. The average TSS, COD and TKN removal efficiency were 92, 90, and 93%, respectively, under a high effective permeate flux of 4.8 m/d and a low air-to-water ratio of 15.

scholarly journals Membrane distillation crystallization using PVDF membrane incorporated with TiO2 nanoparticles and nanocellulose

2020 ◽  
Vol 20 (5) ◽  
pp. 1629-1642 ◽  
Author(s):  
Hoi-Fang Tan ◽  
Why-Ling Tan ◽  
N. Hamzah ◽  
M. H. K. Ng ◽  
B. S. Ooi ◽  
...  
Keyword(s):  
Pore Size ◽  
Tio2 Nanoparticles ◽  
Polyvinylidene Fluoride ◽  
Phase Inversion ◽  
Membrane Distillation ◽  
Coagulation Bath ◽  
Membrane Thickness ◽  
Permeate Flux ◽  
Sem Images ◽  
Pvdf Membrane

Abstract Polyvinylidene fluoride (PVDF) membrane was improved using TiO2 nanoparticles and nanocellulose for membrane distillation crystallization in this work. Besides the addition of TiO2 nanoparticles and nanocellulose, PVDF membrane was post-modified with octadecyltrichlorosilane after phase inversion using a dual coagulation bath. The addition of hydrophilic TiO2 nanoparticles and nanocellulose reduced membrane hydrophobicity, but the dispersed TiO2 nanoparticles assisted silane modification to improve surface hydrophobicity. Besides reducing the agglomeration of TiO2 nanoparticles, nanocellulose induced the formation of larger pore size and higher porosity as proven in SEM images and gravimetric measurement, respectively. The abundant moieties of nanocellulose accelerated the exchange between solvent and non-solvent during phase inversion for the formation of large pore size and porosity, but membrane thickness increased due to the thickening effects. The modified membrane showed higher water permeate flux in membrane distillation with salt rejection greater than 97%. Severe fouling in membrane distillation crystallization was not observed.

scholarly journals A Membrane Modified with Nitrogen-Doped TiO2/Graphene Oxide for Improved Photocatalytic Performance

2019 ◽  
Vol 9 (5) ◽  
pp. 855
Author(s):  
Tingting Li ◽  
Yong Gao ◽  
Junwo Zhou ◽  
Manying Zhang ◽  
Xiaofei Fu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Polyvinylidene Fluoride ◽  
Membrane Surface ◽  
Pure Water ◽  
Impregnation Method ◽  
Photocatalytic Efficiency ◽  
Pvdf Membrane ◽  
Microfiltration Membrane ◽  
Doped Tio2 ◽  
Nitrogen Doped

An improved photocatalytic microfiltration membrane was successfully prepared by the impregnation method with nitrogen-doped TiO2/graphene oxide (GO) (NTG). By utilizing the unique role of N and GO, the photocatalytic activity of the membrane in UV and sunlight was improved. Compared with the Polyvinylidene Fluoride (PVDF) microfiltration membrane which was modified by TiO2, N-TiO2 (NT) and TiO2-GO (TG), the NTG/PVDF membrane exhibited high photocatalytic efficiency and significantly improved photodegradation power to the methylene blue (MB) solution under ultraviolet light and sunlight, with the photocatalytic efficiency reaching 86.5% and 80.6%, respectively. Scanning electron microscopy (SEM), X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the morphology, crystal structure and chemical bonds of the membrane surface. The hydrophilicity of the modified PVDF microfiltration membrane was significantly improved, the flux of the pure water membrane reached 1672 Lm−2h−1, the flux of the MB solution was also significantly improved due to photodegradation. Therefore, the nitrogen-doped titanium dioxide graphene oxide PVDF microfiltration membrane (NTG/PVDF membrane) has great development prospects in sustainable water treatment.

PVDF MEMBRANE FOR OIL-IN-WATER SEPARATION VIA CROSS-FLOW ULTRAFILTRATION PROCESS

2015 ◽  
Vol 78 (1) ◽  
Author(s):  
A. Moslehyani ◽  
M. Mobaraki ◽  
A. F. Ismail ◽  
M. H. D. Othman ◽  
A. Mayahi ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Cross Flow ◽  
Permeate Flux ◽  
Thermal Stabilities ◽  
Water Separation ◽  
Pvdf Membrane ◽  
Membrane Matrix ◽  
Phase Inversion Technique ◽  
Oil In Water ◽  
Wet Phase Inversion

The objective of this study is to investigate the potential of ultrafiltration polyvinylidene fluoride (PVDF)-titanium dioxide (TiO2) membrane for oil-in-water separator. PVDF polymeric matrix membrane is excellent in term of chemical and thermal stabilities, which make it very promising to be used as a membrane matrix for water separation. However, poor hydrophilic property of the PVDF has led to the severe fouling during operation. Thus, current work was performed to investigate the effect of incorporation of two additives i.e. polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) in PVDF-TiO2 membrane, which fabricated using dry/wet phase inversion technique. Membranes characterizations were performed using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), contact angle and UV-vis spectrophotometer. Accordingly, modified PVDF membrane possessed good hydrophilicity property when the additives were added into PVDF-TiO2 membrane matrix. In term of filtration performance, the experimental results showed that oil rejection using PVDF-TiO2/PVP membrane were ~99.7%, which met the requirement for discharge. On the other hand, PVDF-TiO2/PEG membrane was shown more enhancement in terms of permeate flux by given over 64 (L/m2h) at pressure of 2 bar gauge.

Sign in / Sign up

Export Citation Format

Share Document