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Study on Fouling and Cleaning of PVDF Membrane  [cached]
Bofeng Zhang,Shihu Ma
Modern Applied Science , 2009, DOI: 10.5539/mas.v3n11p52
Abstract: The effects of different water sources on the fouling of PVDF membrane are different. On the basis of the scientific appraisal, the correct cleaning process and cleaning reagent are selected to recover the flux and other performances of PVDF membrane. The results indicate that the TMP (transmembrane pressure) of PVDF membrane can be effectively recovered by CIP (clean-in-place) process, and almost reaches the initial level even under the circumstance that PVDF membrane has been used for a certain time and its TMP can not be recovered by either physical cleaning process or CEB (chemically enhanced backwashes).
Use of Ultrasonic Sensors for Characterization of Membrane Fouling and Cleaning  [PDF]
Elmira Kujundzic, Ph.D.,Keith Cobry,Alan R. Greenberg, Ph.D.,Mark Hernandez, Ph.D.
Journal of Engineered Fibers and Fabrics , 2008,
Abstract: The modern challenges for membrane separations in a wide range of processes require more sophisticated approaches for the detection and remediation of fouling, i.e., the association of solutes, particulate matter, and colloids on and/or within a membrane. Most commonly, fouling is assessed from inferred measurements of permeation rate and/or permeate quality. The use of acoustic techniques for direct observations of membrane fouling was introduced over 10 years ago. We summarize here, recent developments in ultrasonic reflectometry that use both time-domain and frequency-domain spectra for noninvasive, real-time assessments of fouling in a variety of module configurations and geometries. In addition, we describe recent developments and applications of scanning acoustic microscopy (SAM) for post-mortem characterization of membranes with particular emphasis on biofouling.
Experimental Study of Fouling and Cleaning of Sintered Stainless Steel Membrane in Electro-Microfiltration of Calcium Salt Particles  [PDF]
Frank G. F. Qin,John Mawson,Xin An Zeng
Membranes , 2011, DOI: 10.3390/membranes1020119
Abstract: Sintered stainless steel (SSS) microfiltration membranes, which served as electrode directly, were used for the experiment of separating Alamin, a calcium salt and protein containing particles, found in dairy processing. Fouling and cleaning of the SSS membranes under the application of an external electric field were studied. The imposed electric field was found, diverging the pH of permeate and retentate. This in turn altered the solubility of the calcium salt and impacted the performance of electro microfiltration membrane. Using electric field as an enhanced cleaning-in-place (CIP) method in back flushing SSS membrane was also studied.
Fouling Reasons and Cleaning Methods of Nanofiltration Membrane Filtrated with the Effluent of Membrane Bioreactor

CHEN Jian-hua,HUANG Xia,

环境科学 , 2008,
Abstract: In order to investigate the fouling reasons and cleaning methods of nanofiltration membrane fouled with the effluent of membrane bioreactor (MBR), FEG-SEM-EDS, FTIR, AFM and contact angle system, were applied to analyze the membrane fouling layer. The results showed that, the foulants included both organic and inorganic substances, which contained phosphorous (P) and magnesium (Mg). After investigations of membrane surfaces through different cleaning steps, it was showed that critic acid cleaning could remove Mg and most of P, which were inorganic; and subsequent sodium hydroxide cleaning could remove the residual P, which probably came from organic acid, organic phosphorous or protein. The roughness increased from 79.5 nm to 111.2 nm with fouling, but the hydrophilicity didn't change obviously according to the contact angle from 55.6° to 62.1°. But after acid cleaning, the roughness decreased to 51.9 nm and the contact angle changed to be 96.0°, which showed the organic foulants were exposed and the surface changed to be hydrophobic. And after subsequent alkali cleaning, the roughness and the hydrophilicity were both close to those of the new membrane. These results concluded that acid cleaning followed by alkali cleaning could remove most of the foulants. It was also suggested that organic matters fouled the membrane in the initial stage, and inorganic matters aggravated the membrane fouling subsequently.
Crude Oil Fouling: A Review  [PDF]
U.B. Deshannavar,M.S. Rafeen,M. Ramasamy,D. Subbarao
Journal of Applied Sciences , 2010,
Abstract: Fouling in crude preheat train heat exchangers in refineries is a complex phenomenon. Crude oil fouling undergoes different mechanisms at different stages of preheating. Understanding the fouling mechanisms is essential in formulating appropriate fouling mitigation strategies. The use of the concept of threshold fouling conditions is one of the approaches for mitigating fouling through operating conditions. In this study, an attempt has been made to review the various fouling models available in literature, their advantages and limitations.
Microbial Relevant Fouling in Membrane Bioreactors: Influencing Factors, Characterization, and Fouling Control  [PDF]
Bing Wu,Anthony G. Fane
Membranes , 2012, DOI: 10.3390/membranes2030565
Abstract: Microorganisms in membrane bioreactors (MBRs) play important roles on degradation of organic/inorganic substances in wastewaters, while microbial deposition/growth and microbial product accumulation on membranes potentially induce membrane fouling. Generally, there is a need to characterize membrane foulants and to determine their relations to the evolution of membrane fouling in order to identify a suitable fouling control approach in MBRs. This review summarized the factors in MBRs that influence microbial behaviors (community compositions, physical properties, and microbial products). The state-of-the-art techniques to characterize biofoulants in MBRs were reported. The strategies for controlling microbial relevant fouling were discussed and the future studies on membrane fouling mechanisms in MBRs were proposed.
Study on RO membrane fouling in landfill leachate treatment

Liu Yanping,Li Xiujin,

环境工程学报 , 2007,
Abstract: Prevention and control of membrane fouling is a major factor influencing membrane performance.Study on membrane fouling and chemical cleaning was carried out by analyzing Disc-tube RO membrane treating landfill leachate for more than one year.The study results indicated that membrane fouling layer was a complex system,in which organic substances played a major role in membrane fouling,containing Al and Si colloid,as well as Ca and Fe compound.The optimum method of chemical cleaning is alkali agents followed by acid agent,because organic substances act an important role in fouling layer formation.
Analysis of membrane fouling genesis in nanofiltration process for advanced treatment of dyeing and finishing wastewater

Cao Xiao-Bing,Li Tao,Zhou Liu,Yang Hai-Jun,Wang Xiao,
Cao XB
,Li T,Zhou L,Yang HJ,Wang X

环境科学 , 2012,
Abstract: In order to investigate the types and genesis of membrane fouling of nanofiltration desalination system treating dyeing and finishing wastewater of cotton knit textile, comprehensive analysis, using ICP-AES, SEM-EDX, FTIR, TGA, high optical microscope and XRF, was carried out based on tests of influent water quality, and tests of the membrane fouling states of different processes and tests of membrane cleaning. The results showed that the types of membrane fouling included inorganic fouling, organic fouling and microbial fouling. The mass percents of bound water, organic substance and inorganic substance of dry foulants, dried at 105 degrees C, were 8.2%, 41.0% and 50.8% respectively. Ferric salt was the most serious inorganic fouling salt, and the main functional groups, found from organic foulants, were -OH, -CH and -C =C. Several kinds of protozoa were found from the membrane foulants as well as metazoan. The analysis of short-term and long-term membrane fouling indicated that it need a long time cumulative effect for the formation of organic fouling and microbial fouling. The results of NF cleaning tests showed that the mainly reason lead to the decline of membrane flux were organic fouling and microbial fouling, which took 53.3%.
Hydrodynamic systems for assessing surface fouling, soil adherence and cleaning in laboratory installations  [PDF]
Detry JG.,Deroanne C.,Sindic M.
Biotechnologie, Agronomie, Société et Environnement , 2009,
Abstract: Five hydrodynamic systems are presented in this short review: the parallel plate flow cell, the impinging jet, the radial flow cell, the rotating disk and fluid dynamic gauging. These systems are of particular relevance to study surface fouling, surface cleaning or adhesion onto solid surfaces in laboratory environment. The key features of their hydrodynamics are given as well as their practical advantages and drawbacks. Examples of applications fields are also listed.
Analysis on ceramic membrane fouling procedure and optimization of membrane flushing method

Tian Yuelin,Yuan Dongdong,Li Ruqi,

环境工程学报 , 2013,
Abstract: The alkaline organic washing wastewater of high concentrations was treated by cross-flow filtration of ceramic membrane with a pore size of 50 nm. The decline regularity of membrane flux was studied and regenerating the fouled membrane with reverse pulse flushing was carried out in 9 running cycles. Then the total resistance of the membrane fouling and its composition were calculated. The results showed that the proportions of membrane intrinsic resistance and concentration polarization pollution were lower compared to others. The membrane fouling resistances of Rt, Rc plus Rirf were higher and remained stable during every cycle. Moreover, the membrane was both blocked in the forms of pore blocking and cake layer filtration. Finally, the cleaning of membrane fouling was conducted with the pulse duration and frequency of 3 s/5 s for 3 min by 0.1% of HCl or 0.2% of oxalic acid. The membrane fouling could be removed effectively.
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