scholarly journals Intermittent Ultrasound-Assisted Ceramic Membrane Fouling Control in Ultrafiltration

2021 ◽  
Author(s):  
Kyu Min Lee ◽  
Farhad Ein-Mozaffari
Keyword(s):  
Flow Rate ◽  
Membrane Fouling ◽  
Ceramic Membrane ◽  
Membrane Surface ◽  
Operating Cost ◽  
Feed Solution ◽  
Time Interval ◽  
Short Time Interval ◽  
Feed Concentration ◽  
Power Intensity

Ultrafiltration is one of the most promising membrane technologies for liquid purification due to its high economic efficiency in the industries. However, it has been faced with a critical problem, called fouling. The contaminants in feed solution tend to accumulate on the membrane surface, hindering permeate solution to pass through the porous spaces. Among the various solutions, application of ultrasound has been considered as the most popular method since it does not suffer a disadvantage of downtime and the filtration process does not need to be stopped for the removal of foulants. In this study, control of ceramic membrane fouling by an on-line intermittent ultrasound system was being investigated. The experiment focused on obtaining optimal operating ultrasonic condition. Frequency (20, 28, and 40 kHz), power intensity (1.44, 2.88, and 5.76W/cm2 ), and time interval of intermittent ultrasound (1, 1.5, and 2 minutes) were the parameters of interest. The effect of feed concentration was also analyzed at optimal ultrasonic condition. The quality and flow rate of the permeate streams were monitored for the evaluation of the process performance. The optimal condition of intermittent ultrasound was found at the frequency of 28 kHz and the power intensity of 2.88 W/cm2 ; and then, the application of intermittent ultrasound with short time interval successfully reduced the operating cost of ultrafiltration process while maintaining acceptable quality and flow rate of permeate solution. There was increase in efficiency of intermittent ultrasound at lower feed concentration.

scholarly journals Intermittent Ultrasound-Assisted Ceramic Membrane Fouling Control in Ultrafiltration

2021 ◽  
Author(s):  
Kyu Min Lee ◽  
Farhad Ein-Mozaffari
Keyword(s):  
Flow Rate ◽  
Membrane Fouling ◽  
Ceramic Membrane ◽  
Membrane Surface ◽  
Operating Cost ◽  
Feed Solution ◽  
Time Interval ◽  
Short Time Interval ◽  
Feed Concentration ◽  
Power Intensity

Ultrafiltration is one of the most promising membrane technologies for liquid purification due to its high economic efficiency in the industries. However, it has been faced with a critical problem, called fouling. The contaminants in feed solution tend to accumulate on the membrane surface, hindering permeate solution to pass through the porous spaces. Among the various solutions, application of ultrasound has been considered as the most popular method since it does not suffer a disadvantage of downtime and the filtration process does not need to be stopped for the removal of foulants. In this study, control of ceramic membrane fouling by an on-line intermittent ultrasound system was being investigated. The experiment focused on obtaining optimal operating ultrasonic condition. Frequency (20, 28, and 40 kHz), power intensity (1.44, 2.88, and 5.76W/cm2 ), and time interval of intermittent ultrasound (1, 1.5, and 2 minutes) were the parameters of interest. The effect of feed concentration was also analyzed at optimal ultrasonic condition. The quality and flow rate of the permeate streams were monitored for the evaluation of the process performance. The optimal condition of intermittent ultrasound was found at the frequency of 28 kHz and the power intensity of 2.88 W/cm2 ; and then, the application of intermittent ultrasound with short time interval successfully reduced the operating cost of ultrafiltration process while maintaining acceptable quality and flow rate of permeate solution. There was increase in efficiency of intermittent ultrasound at lower feed concentration.

Characterization of Fouled Flat Sheet Membranes by Infrared Thermography

2014 ◽  
Author(s):  
Kennethrex O. Ndukaife ◽  
George Agbai Nnanna
Keyword(s):  
Surface Temperature ◽  
Infrared Thermography ◽  
Spectral Power ◽  
Membrane Surface ◽  
Infrared Camera ◽  
Feed Solution ◽  
Feed Concentration ◽  
Ir Camera ◽  
Measure Surface Temperature

An Infrared thermography (IRT) technique for characterization of fouling on membrane surface has been developed. The emitted spectral power from the fouled membrane is a function of emissivity and surface morphology. In this work, a FLIR A320 IR camera was used to measure surface temperature and emissivity. The surface temperature and the corresponding emissivity value of various areas on the fouled membrane surface is measured by the infrared camera and recorded alongside its thermogram. Different fouling experiments were performed using different concentrations of aluminum oxide nanoparticle mixed with deionized water as feed solution (333 ppm, 1833 ppm and 3333 ppm) so as to investigate the effect of feed concentration on the degree of fouling and thus its effect on the emissivity values measured on the membrane surfaces. Surface plots in 3D and Line plots are obtained for the measured emissivity values and thickness of the fouling deposit on the membrane surface respectively. The results indicate that the IRT technique is sensitive to changes that occur on the membrane surface due to deposition of contaminants on the membrane surface and that emissivity is a function of temperature, surface roughness and thickness of the specimen under investigation.

scholarly journals Diethylene Glycol-Assisted Organized TiO2 Nanostructures for Photocatalytic Wastewater Treatment Ceramic Membranes

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 750 ◽  
Author(s):  
Ahmad ◽  
Kim ◽  
Kim ◽  
Kim
Keyword(s):  
Wastewater Treatment ◽  
Diethylene Glycol ◽  
Membrane Fouling ◽  
Ceramic Membrane ◽  
Membrane Surface ◽  
Ceramic Membranes ◽  
Tio2 Nanorods ◽  
Hydrolysis Rate ◽  
Capping Agent ◽  
Alumina Support

A high-performance photocatalytic ceramic membrane was developed by direct growth of a TiO2 structure on a macroporous alumina support using a hydrothermal method. The morphological nanostructure of TiO2 on the support was successfully controlled via the interaction between the TiO2 precursor and a capping agent, diethylene glycol (DEG). The growth of anatase TiO2 nanorods was observed both on the membrane surface and pore walls. The well-organized nanorods TiO2 reduced the perturbation of the alumina support, thus controlling the hydrolysis rate of the TiO2 precursor and reducing membrane fouling. However, a decrease in the amount of the DEG capping agent significantly reduced membrane permeability, owing to the formation of nonporous clusters of TiO2 on the support. Distribution of the organized TiO2 nanorods on the support was very effective for the improvement of the organic removal efficiency and antifouling under ultraviolet illumination. The TiO2 nanostructure associated with the reactive crystalline phase, rather than the amount of layered TiO2 formed on the support, which was found to be the key to controlling photocatalytic membrane reactivity. These experimental findings would provide a new approach for the development of efficacious photocatalytic membranes with improved performance for wastewater treatment.

scholarly journals Oil Deposition on Polymer Brush-Coated NF Membranes

Membranes ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 168 ◽  
Author(s):  
Anh Vu ◽  
Naama Segev Mark ◽  
Guy Z. Ramon ◽  
Xianghong Qian ◽  
Arijit Sengupta ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Surface ◽  
Polymer Brush ◽  
Operating Mode ◽  
Feed Solution ◽  
Polymer Chains ◽  
Membrane Properties ◽  
Solution Temperature ◽  
Oil Droplets ◽  
Grafted Polymer

Membrane-based processes are attractive for treating oily wastewaters. However, membrane fouling due to the deposition of oil droplets on the membrane surface compromises performance. Here, real-time observation of the deposition of oil droplets by direct confocal microscopy was conducted. Experiments were conducted in dead-end and crossflow modes. Base NF 270 nanofiltration membranes as well as membranes modified by grafting poly(N-isopropylacrylamide) chains from the membrane surface using atom transfer radical polymerization were investigated. By using feed streams containing low and high NaCl concentrations, the grafted polymer chains could be induced to switch conformation from a hydrated to a dehydrated state, as the lower critical solution temperature for the grafted polymer chains moved above and below the room temperature, respectively. For the modified membrane, it was shown that switching conformation of the grafted polymer chains led to the partial release of adsorbed oil. The results also indicate that, unlike particles such as polystyrene beads, adsorption of oil droplets can lead to coalescence of the adsorbed oil droplets on the membrane surface. The results provide further evidence of the importance of membrane properties, feed solution characteristics, and operating mode and conditions on membrane fouling.

scholarly journals Ozone Chemically Enhanced Backwash for Ceramic Membrane Fouling Control in Cyanobacteria-Laden Water

Membranes ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 213
Author(s):  
Stéphane Venne ◽  
Onita D. Basu ◽  
Benoit Barbeau
Keyword(s):  
Surface Water ◽  
Surface Waters ◽  
Membrane Fouling ◽  
Ceramic Membrane ◽  
Membrane Surface ◽  
Operating Costs ◽  
Fouling Control ◽  
Dead End ◽  
Cake Layer ◽  
Flow Experiments

Membrane fouling in surface waters impacted by cyanobacteria is currently poorly controlled and results in high operating costs. A chemically enhanced backwash (CEB) is one possible strategy to mitigate cyanobacteria fouling. This research investigates the potential of using an ozone CEB to control the fouling caused by Microcystis aeruginosa in filtered surface water on a ceramic ultrafiltration membrane. Batch ozonation tests and dead-end, continuous flow experiments were conducted with ozone doses between 0 and 19 mg O3/mg carbon. In all tests, the ozone was shown to react more rapidly with the filtered surface water foulants than with cyanobacteria. In addition, the ozone CEB demonstrated an improved mitigation of irreversible fouling over 2 cycles versus a single CEB cycle; indicating that the ozone CEB functioned better as the cake layer developed. Ozone likely weakens the compressible cake layer formed by cyanobacteria on the membrane surface during filtration, which then becomes more hydraulically reversible. In fact, the ozone CEB reduced the fouling resistance by 35% more than the hydraulic backwash when the cake was more compressed.

Integration of ceramic membrane and compressed air-assisted solvent extraction (CASX) for metal recovery

2010 ◽  
Vol 62 (6) ◽  
pp. 1274-1280 ◽  
Author(s):  
Chi-Wang Li ◽  
Chun-Hao Chiu ◽  
Yu-Cheng Lee ◽  
Chia-Hao Chang ◽  
Yu-Hsun Lee ◽  
...  
Keyword(s):  
Solvent Extraction ◽  
Removal Efficiency ◽  
Membrane Fouling ◽  
Water Solubility ◽  
Ceramic Membrane ◽  
Metal Removal ◽  
Membrane Surface ◽  
Extraction Process ◽  
Compressed Air ◽  
Dead End

In our previous publications, compressed air-assisted solvent extraction process (CASX) was developed and proved to be kinetically efficient process for metal removal. In the current study, CASX with a ceramic MF membrane integrated for separation of spent solvent was employed to remove and recover metal from wastewater. MF was operated either in crossflow mode or dead-end with intermittent flushing mode. Under crossflow mode, three distinct stages of flux vs. TMP (trans-membrane pressure) relationship were observed. In the first stage, flux increases with increasing TMP which is followed by the stage of stable flux with increasing TMP. After reaching a threshold TMP which is dependent of crossflow velocity, flux increases again with increasing TMP. At the last stage, solvent was pushed through membrane pores as indicated by increasing permeate COD. In dead-end with intermittent flushing mode, an intermittent flushing flow (2 min after a 10-min or a 30-min dead-end filtration) was incorporated to reduce membrane fouling by flush out MSAB accumulated on membrane surface. Effects of solvent concentration and composition were also investigated. Solvent concentrations ranging from 0.1 to 1% (w/w) have no adverse effect in terms of membrane fouling. However, solvent composition, i.e. D2EHPA/kerosene ratio, shows impact on membrane fouling. The type of metal extractants employed in CASX has significant impact on both membrane fouling and the quality of filtrate due to the differences in their viscosity and water solubility. Separation of MSAB was the limiting process controlling metal removal efficiency, and the removal efficiency of Cd(II) and Cr(VI) followed the same trend as that for COD.

Water Permeates in Ceramic Membrane Modified with Nano Inorganic Coating

2011 ◽  
Vol 239-242 ◽  
pp. 27-30
Author(s):  
Jian Er Zhou ◽  
Qi Bing Chang ◽  
Ying Chao Dong ◽  
Xue Bing Hu ◽  
Yong Qing Wang ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Ceramic Membrane ◽  
Membrane Surface ◽  
Molecular Layer ◽  
Pore Wall ◽  
Boundary Slip ◽  
Membrane Pore ◽  
Nano Coating ◽  
Inorganic Coating ◽  
Modified Membrane

Membrane surface modification is the important method to decrease membrane fouling. The hydrophilic modification of ceramic membrane with nano-sized inorganic coating is prepared by the wet chemical methods. The thin nano coating is not a separating top layer but distributes uniformly on the surface of the membrane pore wall. The coating does not change the structure of the membrane pores. Therefore, water flows on not the pore wall but the nano coating surface. The results show that the water flux of the modified membrane is higher than that of the unmodified membrane despite that the mean pore size of the modified membrane decreases. The “boundary slip” is used to explain this special phenomenon. What generates the slippage? The slippage is relative with the molecular layer adhered tightly on the hydrophilic pore wall, the roughness and the surface charge of the nano coating, the interaction between the ions in water and the nano coating, et al.

Effects of gas adsorbed on solid surface during gas breakdown in electron cyclotron resonance discharge

2021 ◽  
Author(s):  
Sheng Hui Fu ◽  
Zhen- Feng Ding
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Electron Cyclotron Resonance ◽  
Vertical Component ◽  
Plasma Source ◽  
Time Interval ◽  
Short Time Interval ◽  
Gas Flow Rate ◽  
Ecr Plasma ◽  
Long Time

Abstract The microwave breakdown power (Pwb) in an ECR plasma source was not merely determined by pressure (gas flow rate), but found to vary with the time interval between two successive breakdowns. The measured Pwb dropped rapidly from a high value at a short time interval to a low level at a long time interval. The obtained dependence of Pwb on pressure (gas flow rate) exhibited distinct features: the normal monotonicity and abnormal non-monotonicity at the short and long time intervals, respectively. The effective zone in the antenna’s surface bombarded by hot electrons heated in the ECR layer was validated by (1) masking the antenna with a film having a variable radius; (2) calculating the distribution of the vertical component of the microwave electric field with respect to the static magnetic field; (3) imaging glows of transient breakdown discharges with a fast camera. The reduction in Pwb was mainly attributed to the enhanced emission of δ-electrons from the gas-adsorbed antenna under the bombardment of energetic electrons coming from the ECR layer.. The correlation between the dynamic gas coverage and the coefficient emission of δ-electrons was established to understand the abnormal ECR breakdown features.

scholarly journals Membrane Fouling – The Enemy of Forward Osmosis

2021 ◽  
Vol 25 (2) ◽  
pp. 73-88
Author(s):  
Z. H. Chang ◽  
Y. H. Teow ◽  
S. P. Yeap ◽  
J. Y. Sum
Keyword(s):  
Membrane Fouling ◽  
Membrane Separation ◽  
Membrane Surface ◽  
Forward Osmosis ◽  
Feed Solution ◽  
Separation Process ◽  
Nutrient Recovery ◽  
Water Reclamation ◽  
Water Permeation ◽  
Fouling Mechanism

Forward osmosis (FO) is an osmotically driven membrane separation process. It is potentially applied in various industries for nutrient recovery and water reclamation. Although FO showed a lesser fouling tendency than other pressure-driven membrane processes, the solutes in the feed solution would still deposit on the membrane surface, forming a fouling layer that resists water permeation. For that reason, fouling mitigation is a trending issue in the FO process. A better understanding of the fouling mechanism is required before opting for the appropriate strategy to mitigate it. This article describes the fouling mechanism based on different foulant presented in the feed, followed by a method in relieving fouling in the FO process.

scholarly journals Removal of Dyes from Wastewater by Ceramic Membrane

2019 ◽  
Vol 70 (5) ◽  
pp. 1715-1719
Author(s):  
Ramy Mohamed Jebir Al-Alawy ◽  
Baker M. Abod ◽  
Firas Hashim Kamar ◽  
Aurelia Cristina Nechifor
Keyword(s):  
Flow Rate ◽  
Ceramic Membrane ◽  
Cross Flow ◽  
Rejection Rate ◽  
Feed Flow Rate ◽  
Acid Orange 7 ◽  
Feed Concentration ◽  
Acid Orange ◽  
High Feed ◽  
Oil Concentration

The current study aimed to investigate the elimination of dyes from sewerage, using microfiltration membrane mechanism. Three dyes were applied, acid yellow-23, disperse blue -79 and acid orange -7. Experiments were performed with feed concentration (40 -120) ppm, feed flow rate (25 -65) l/h and time (0.25 -1.5) h. The membrane used ceramic membrane, constructed as a candle. It was discovered that water flow diminishes with an elevation in running time, feeding oil concentration and enhancing with elevation in the feed flow rate. In addition, it was determined that the elimination (rejection) rate of dyes enhances with elevation in the flow rate, and the elimination (rejection) rate diminishes as time passes. In cross flow microfiltration, the rejection concentration (concentrate) goes up as time passes, with high feed concentration and flow rate. It was also discovered that the modal infusion concentration declines with high feed concentration and working time. In addition, it was found that product rate goes down as time passes and with high feed concentration. Increasing feed concentration of dyes was associated with an increase in the concentration of rejecting solution. The highest elimination of disperse blue -79, Acid Yellow- 23 and acid orange -7, are 97%, 96.4% and 95.8%, respectively. The maximum recovery percentage of disperse blue - 79, acid yellow- 23 and acid orange -7are 57.7%, 58.5% and 59% respectively.

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