Study of Backwashing Process for Ceramic Micro-Filtration Membranes Used in Pretreatment of DMF Wastewater

2011 ◽  
Vol 418-420 ◽  
pp. 1980-1983
Author(s):  
Peng Wei Xu ◽  
Wei Qiu Huang ◽  
Qi Zhang ◽  
Bao Zhu Yang ◽  
Jing Zhong
Keyword(s):  
Membrane Fouling ◽  
Reverse Flow ◽  
Average Pore Size ◽  
Membrane Surface ◽  
Permeate Flux ◽  
Average Pore ◽  
Filtration Membranes ◽  
Membrane Flux ◽  
In Series ◽  
Flow Through

DMF wastewater from the PU synthetic leather industries was filtrated by ZrO2 micro-filtration membranes with an average pore size of 0.2μm. The membrane fouling mechanism was analyzed by resistance-in series model. The results indicated that the resistance from the particles sedimentation on membrane surface accounting for 76% of the total resistances. The technology of backwashing was a stable, valid and reusable method to recover the membrane flux in the micro-filtration. During backwashing, the reverse flow through the membrane removes the concentration polarization and cake or gel layers from the membrane surface. The effect of the backwashing conditions on the flux was studied. The obtained optimization conditions were as follows: backwashing pressure 0.6 MPa, backwashing time 5s and the backwashing interval 20min. The permeate flux could be raised about 50% compared with that without backwashing.

scholarly journals Reduction of Biofouling of a Microfiltration Membrane Using Amide Functionalities—Hydrophilization without Changes in Morphology

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1379
Author(s):  
Daniel Breite ◽  
Marco Went ◽  
Andrea Prager ◽  
Mathias Kühnert ◽  
Agnes Schulze
Keyword(s):  
Membrane Fouling ◽  
Average Pore Size ◽  
Membrane Surface ◽  
Aqueous Media ◽  
Soxhlet Extraction ◽  
Hydrophobic Membrane ◽  
Average Pore ◽  
Water Contact ◽  
Microfiltration Membrane ◽  
Membrane Performance

A major goal of membrane science is the improvement of the membrane performance and the reduction of fouling effects, which occur during most aqueous filtration applications. Increasing the surface hydrophilicity can improve the membrane performance (in case of aqueous media) and decelerates membrane fouling. In this study, a PES microfiltration membrane (14,600 L m−2 h−1 bar−1) was hydrophilized using a hydrophilic surface coating based on amide functionalities, converting the hydrophobic membrane surface (water contact angle, WCA: ~90°) into an extremely hydrophilic one (WCA: ~30°). The amide layer was created by first immobilizing piperazine to the membrane surface via electron beam irradiation. Subsequently, a reaction with 1,3,5-benzenetricarbonyl trichloride (TMC) was applied to generate an amide structure. The presented approach resulted in a hydrophilic membrane surface, while maintaining permeance of the membrane without pore blocking. All membranes were investigated regarding their permeance, porosity, average pore size, morphology (SEM), chemical composition (XPS), and wettability. Soxhlet extraction was carried out to demonstrate the stability of the applied coating. The improvement of the modified membranes was demonstrated using dead-end filtration of algae solutions. After three fouling cycles, about 60% of the initial permeance remain for the modified membranes, while only ~25% remain for the reference.

Investigation Into the Crossflow Microfiltration Process Utilizing Ceramic Membrane Applied to Bacteria Reduction and Clarifying of Ac¸ai Juice

2008 ◽  
Author(s):  
Renata Natsumi Haneda ◽  
Se´rgio Rodriques Fontes
Keyword(s):  
Pore Size ◽  
Ceramic Membrane ◽  
Average Pore Size ◽  
Membrane Surface ◽  
Polymeric Membrane ◽  
Euterpe Oleracea ◽  
Permeate Flux ◽  
Average Pore ◽  
The Difference ◽  
Crossflow Microfiltration

This paper reports the results of the crossflow microfiltration process applied to the reduction of bacteria and retention of particles in suspension of ac¸ai (Euterpe oleracea Mart.) juice. A commercial membrane of α-alumina (Al2O3) in the form of a tube with 1.2μm of average pore size was utilized to investigate the reduction of the bacteria of ac¸ai juice without using high temperatures (pasteurization). This pore size of the ceramic structure was utilized in an attempt to reduce the polarization phenomenon and improve the permeate flux without utilizing the usual enzymatic treatment made in the microfiltration processes that utilize polymeric membrane (Cianci et al., 2005 and Ushikubo et al., 2006). An anthocyanin concentration was also observed during the microfiltration process followed by suspended particles retention as an indicator of ac¸ai juice clarifying. The Scanning Electronic Microscopy (SEM) was utilized as an essential tool to characterize the morphology of the ceramic micro porous structure and to evaluate the formation of a polarization layer on the membrane surface, while the Optical Microscopy was used to analyze the difference in the characteristics between samples of concentrate and permeate.

scholarly journals ZnO Microfiltration Membranes for Desalination by a Vacuum Flow-Through Evaporation Method

Membranes ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 156 ◽  
Author(s):  
Shailesh Dangwal ◽  
Ruochen Liu ◽  
Lyndon D. Bastatas ◽  
Elena Echeverria ◽  
Chengqian Huang ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Surface ◽  
Water Flux ◽  
Atomic Layer ◽  
Rejection Rate ◽  
Contact Angles ◽  
Transfer Resistance ◽  
Membrane Pore ◽  
Evaporation Method ◽  
Flow Through

ZnO was deposited on macroporous α-alumina membranes via atomic layer deposition (ALD) to improve water flux by increasing their hydrophilicity and reducing mass transfer resistance through membrane pore channels. The deposition of ZnO was systemically performed for 4–128 cycles of ALD at 170 °C. Analysis of membrane surface by contact angles (CA) measurements revealed that the hydrophilicity of the ZnO ALD membrane was enhanced with increasing the number of ALD cycles. It was observed that a vacuum-assisted ‘flow-through’ evaporation method had significantly higher efficacy in comparison to conventional desalination methods. By using the vacuum-assisted ‘flow-through’ technique, the water flux of the ZnO ALD membrane (~170 L m−2 h−1) was obtained, which is higher than uncoated pristine membranes (92 L m−2 h−1). It was also found that ZnO ALD membranes substantially improved water flux while keeping excellent salt rejection rate (>99.9%). Ultrasonic membrane cleaning had considerable effect on reducing the membrane fouling.

Electroflocculation as potential pretreatment in colloid ultrafiltration

2006 ◽  
Vol 6 (1) ◽  
pp. 69-78 ◽  
Author(s):  
T. Harif ◽  
M. Hai ◽  
A. Adin
Keyword(s):  
Membrane Fouling ◽  
Colloidal Suspension ◽  
Membrane Surface ◽  
Constant Current ◽  
Permeate Flux ◽  
Batch Mode ◽  
Membrane Behavior ◽  
Flux Decline ◽  
Stainless Steel Cathode ◽  
Marginal Improvement

Electroflocculation (EF) is a coagulation/flocculation process in which active coagulant species are generated in situ by electrolytic oxidation of an appropriate anode material. The effect of colloidal suspension pretreatment by EF on membrane fouling was measured by flux decline at constant pressure. An EF cell was operated in batch mode and comprised two flat sheet electrodes, an aluminium anode and stainless steel cathode, which were immersed in the treated suspension, and connected to an external DC power supply. The cell was run at constant current between 0.06–0.2A. The results show that pre-EF enhances the permeate flux at pH 5 and 6.5, but only marginal improvement is observed at pH 8. At all pH values cake formation on the membrane surface was observed. The differences in membrane behavior can be explained by conventional coagulation theory and transitions between aluminium mononuclear species which affect particle characteristics and consequently cake properties. At pH 6.5, where sweep floc mechanism dominates due to increased precipitation of aluminium hydroxide, increased flux rates were observed. It is evident that EF can serve as an efficient pretreatment to ultrafiltration of colloid particles.

A Wall Film Model for Membrane Fouling

2018 ◽  
Author(s):  
Sina Jahangiri Mamouri ◽  
Volodymyr V. Tarabara ◽  
André Bénard
Keyword(s):  
Multiphase Flow ◽  
Membrane Fouling ◽  
Oil And Gas ◽  
Membrane Separation ◽  
Film Formation ◽  
Membrane Surface ◽  
Permeate Flux ◽  
Water Separation ◽  
Wall Film ◽  
Oil Water

Deoiling of produced or impaired waters associated with oil and gas production represents a significant challenge for many companies. Centrifugation, air flotation, and hydrocyclone separation are the current methods of oil removal from produced water [1], however the efficiency of these methods decreases dramatically for droplets smaller than approximately 15–20 μm. More effective separation of oil-water mixtures into water and oil phases has the potential to both decrease the environmental footprint of the oil and gas industry and improve human well-being in regions such as the Gulf of Mexico. New membrane separation processes and design of systems with advanced flow management offer tremendous potential for improving oil-water separation efficacy. However, fouling is a major challenge in membrane separation [2]. In this study, the behavior of oil droplets and their interaction with crossflow filtration (CFF) membranes (including membrane fouling) is studied using computational fluid dynamics (CFD) simulations. A model for film formation on a membrane surface is proposed for the first time to simulate film formation on membrane surfaces. The bulk multiphase flow is modeled using an Eulerian-Eulerian multiphase flow model. A wall film is developed from mass and momentum balances [3] and implemented to model droplet deposition and membrane surface blockage. The model is used to predict film formation and subsequent membrane fouling, and allow to estimate the actual permeate flux. The results are validated using available experimental data.

Analysis of Physical Properties and Experimental Behaviour of High Turbulent Flow in Cross-Flow Microfiltration of Ac¸ai Juice

2009 ◽  
Author(s):  
Renata Natsumi Haneda ◽  
Se´rgio Rodrigues Fontes
Keyword(s):  
Pore Size ◽  
Average Pore Size ◽  
Cross Flow ◽  
Rheological Behaviour ◽  
Transmembrane Pressure ◽  
Euterpe Oleracea ◽  
Permeate Flux ◽  
Average Pore ◽  
Flow Behaviour Index ◽  
Transmembrane Flux

This paper presents an experimental investigation of the cross-flow microfiltration process applied to the clarifying of ac¸ai (Euterpe oleracea Mart.) juice. Ac¸ai juice is a complex fluid, similar to a suspension of particles (fibers and cellulose) mixed in water, which contains ions of iron, zinc, maganese and pigments, as anthocyanins. In this study, a commercial membrane of α-alumina (Al2O3) in the form of a tube with 1.2μm of average pore size was utilized to investigate the clarifying of juice. This pore size of the ceramic structure was utilized in an attempt to reduce the polarization phenomenon and improve the permeate flux without utilizing the usual enzymatic treatment made in the microfiltration processes. The rheological behaviour of the suspension was investigated in a cone/plate rheometer (model, DVIII-Ultra) and a cylindrical rheometer (model, DVIII+), both by Brookfield/USA, as the shear stress (τ) in function of shear rate (γ) was fitted and analyzed with the power-law and Herschel-Bulkley’s models. All the mixtures showed flow behaviour index values (n) near to one, characterizing Newtonian fluids (pseudo-plastic). The particle size distribution (PSD) of the samples of suspension and permeate were analyzed by APS100 (ultrasound spectroscopy) by Matec/USA. The analysis of the suspension showed the presence of particles of size equal 0.16micra, while the permeate did not present particles. The experiments were performed in a turbulent range higher than 2400 until 57500 and with variation to values of transmembrane pressure from 1 to 4bar; the usual and direct correlation between transmembrane flux and transmembrane pressure was not observed in the experiments and a new correlation to the dimensionless of TMP (trans-membrane pressure) and Reynolds (Re) was presented.

Influence of humic acid on the long-term performance of direct contact membrane distillation

2018 ◽  
Vol 30 (1) ◽  
pp. 109-120 ◽  
Author(s):  
Dong-Wan Cho ◽  
Gihoon Kwon ◽  
Jeongmin Han ◽  
Hocheol Song
Keyword(s):  
Humic Acid ◽  
Membrane Fouling ◽  
Coalbed Methane ◽  
Direct Contact ◽  
Membrane Surface ◽  
Membrane Distillation ◽  
Permeate Flux ◽  
Direct Contact Membrane Distillation ◽  
High Level

In this study, the influence of humic acid on the treatment of coalbed methane water by direct contact membrane distillation was examined with bench-scale test unit. During short-term distillation (1000 min), high level of humic acid above 50 ppm resulted in significant decrease in permeate flux, while low level of humic acid (∼2 ppm) had little influence on the flux. For the long-term distillation (5000 min), the flux decline began at 3400 min in the presence of 5 ppm humic acid and 5 mM Ca2+, and decreased to ∼40% of initial flux at 5000 min. The spectroscopic analysis of the membrane used revealed that the surface was covered by hydrophilic layers mainly composed of calcite. The membrane fouling effect of humic acid became more significant in the presence of Ca2+ due to more facile calcite formation on the membrane surface. It was demonstrated that humic acid enhanced CaCO3 deposition on the membrane surfaces, thereby expediting the scaling phenomenon.

Chemical pretreatment of feed water for membrane distillation

2008 ◽  
Vol 62 (1) ◽  
Author(s):  
Marek Gryta
Keyword(s):  
Membrane Fouling ◽  
Membrane Surface ◽  
Membrane Distillation ◽  
Feed Water ◽  
Chemical Pretreatment ◽  
Permeate Flux ◽  
Membrane Scaling ◽  
Water Pretreatment ◽  
Energy Dispersion Spectrometry ◽  
Process Operation

AbstractMembrane distillation was used to produce demineralized water from ground water. The influence of feed water pretreatment carried out in a contact clarifier (softening with Ca(OH)2 and coagulation with FeSO4 · 7H2O) followed by filtration, on the process effectiveness was evaluated. It was found that the chemical pretreatment decreased the membrane fouling; however, the degree of water purification was insufficient because precipitation of small amounts of deposit on the membrane surface during the process operation was still observed. The permeate flux was gradually decreasing as a result of scaling. The morphology and composition of the fouling layer were studied using scanning electron microscopy coupled with energy dispersion spectrometry. The presence of significant amounts of silica, apart from calcium and magnesium, was determined in the formed deposit. The removal of foulants by heterogeneous crystallization performed inside the filter (70 mesh), assembled directly at the module inlet, was found to be a solution preventing the membrane scaling.

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 Fabrication of Bentonite–Silica Sand/Suspended Waste Palm Leaf Composite Membrane for Water Purification

Membranes ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 290
Author(s):  
Saad A. Aljlil
Keyword(s):  
Contact Angle ◽  
Pore Size ◽  
Average Pore Size ◽  
Membrane Surface ◽  
Ceramic Membranes ◽  
Suspended Solid ◽  
Silica Sand ◽  
Distribution Analysis ◽  
Average Pore ◽  
Water Contact

In this study, a method for fabricating tubular ceramic membranes via extrusion using economical and locally available bentonite–silica sand and waste palm leaves was developed as a tool for conducting the necessary task of purifying water polluted with oil and suspended solid materials produced via various industrial processes. The developed tubular ceramic membranes were found to be highly efficient at separating the pollutants from water. The properties of the fabricated membrane were evaluated via mechanical testing, pore size distribution analysis, and contact angle measurements. The water contact angle of the fabricated membrane was determined to be 55.5°, which indicates that the membrane surface is hydrophilic, and the average pore size was found to be 66 nm. The membrane was found to demonstrate excellent corrosion resistance under acidic as well as basic conditions, with weight losses of less than 1% in each case. The membrane surface was found to be negatively charged and it could strongly repulse the negatively charged fine bentonite particles and oil droplets suspended in the water, thereby enabling facile purification through backwashing. The obtained ceramic membranes with desirable hydrophilic properties can thus serve as good candidates for use in ultrafiltration processes.

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