scholarly journals Verification of a Combined Fouling Model to Predict Flux Decline during Ultrafiltration of Organic Solutes

2018 ◽  
Vol 22 (2) ◽  
Author(s):  
I. N. H. M. Amin ◽  
A. W. Mohammad
Keyword(s):  
Early Stage ◽  
Membrane Surface ◽  
Organic Solutes ◽  
Filtration Time ◽  
Pvdf Membrane ◽  
Flux Decline ◽  
Cake Formation ◽  
Pore Blockage ◽  
Pes Membrane ◽  
Two Stages

Studies were conducted to investigate the blocking mechanism and flux decline behavior while treating organic solutes contained in glycerin-water solutions (triglycerides, TG and fatty acid, FA). Two ultrafiltration membranes were tested, polyethersulphone (PES 25 kDa) and polyvinylidenfluoride (PVDF 30 kDa) membranes. Influence of TG and its combination (TG-FA mixtures) as foulant models, pH of feed solutions (3–10) and membrane surface chemistry were investigated. Combined blocking model was applied and the fitting were discriminate that the flux decline of PES membrane was dominated by pore blockage at the early stage and later by cake resistance during the entire filtration time. However, for PVDF membrane, cake formation mechanism was acknowledged as the major contributor to the fouling mechanism for all the parameters tested. On the other hand, the model predicts there are two stages of filtration appeared to occur, involving pore blockage at the early stage followed by cake formation.

Ultrafiltration Behavior of Organic Mixtures Simulating Sweetwater Solutions: Influence of Membrane Surface and Feed Chemistry

2013 ◽  
Vol 65 (4) ◽  
Author(s):  
Indok Nurul Hasyimah Mohd Amin ◽  
Abdul Wahab Mohammad
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Glycerol Water ◽  
Pvdf Membrane ◽  
Organic Mixtures ◽  
Rich Solution ◽  
Organic Solute ◽  
Pes Membrane

One of the major drawbacks for the successful of ultrafiltration (UF) during pretreatment of glycerin-rich solution is membrane fouling due to the deposition of triglycerides (TG) and fatty acids (FA). In the present study, attempts were made to examine the filtration behaviour of organic mixtures (oleic acid-triglycerides) compared to single organic solute (triglycerides) contained in synthetic glycerol-water solutions (known as sweetwater). Furthermore, the rejections of individual solutes were studied. The TG-FA mixtures permeated preferentially when compared with single TG which is mainly due to the solubility as well as diffusivity of small fatty acid in the TG-FA mixtures. Furthermore, PVDF membrane provided higher fluxes and experienced less fouling than PES membrane for both cases. In case of PVDF membrane, the rejection of fatty acid was 6.20% while oil rejection in glycerol-water plus TG and TG-FA mixtures was 82.42% and 84.67%, respectively. However, PES membrane underwent higher fatty acid rejection (20.93%) as well as oil rejection in single TG (94.70%) and TG-FA mixtures (91.08%). It is noteworthy that the nature of the membrane and the feed characteristics had a significant effect on the fouling potential and filtration performance.

scholarly journals Influence of nanoparticles on filterability of fruit-juice industry wastewater using submerged membrane bioreactor

2017 ◽  
Vol 76 (3) ◽  
pp. 705-711 ◽  
Author(s):  
Guler Turkoglu Demirkol ◽  
Nadir Dizge ◽  
Turkan Ormanci Acar ◽  
Oyku Mutlu Salmanli ◽  
Nese Tufekci
Keyword(s):  
Membrane Bioreactor ◽  
Fruit Juice ◽  
Membrane Surface ◽  
Glass Container ◽  
Submerged Membrane Bioreactor ◽  
Flux Decline ◽  
Coated Membranes ◽  
Pes Membrane ◽  
Coated Membrane ◽  
Industry Wastewater

In this study, polyethersulfone (PES) ultrafiltration membrane surface was modified with nano-sized zinc oxide (nZnO) and silver (nAg) to improve the membrane filterability of the mixed liquor and used to treat fruit-juice industry wastewater in a submerged membrane bioreactor (MBR). The nAg was synthesized using three different methods. In the first method, named as nAg-M1, PES membrane was placed on the membrane module and nAg solution was passed through the membrane for 24 h at 25 ± 1 °C. In the second method, named as nAg-M2, PES membrane was placed in a glass container and it was shaken for 24 h at 150 rpm at 25 ± 1 °C. In the third method, named as nAg-M3, Ag nanoparticles were loaded onto PES membrane in L-ascorbic acid solution (0.1 mol/L) at pH 2 for 24 h at 150 rpm at 25 ± 1 °C. For the preparation of nZnO coated membrane, nZnO nanoparticles solution was passed through the membrane for 24 h at 25 ± 1 °C. Anti-fouling performance of pristine and coated membranes was examined using the submerged MBR. The results showed that nZnO and nAg-M3 membranes showed lower flux decline compared with pristine membrane. Moreover, pristine and coated PES membranes were characterized using a permeation test, contact angle goniometer, and scanning electron microscopy.

scholarly journals Engineered polyethersulfone membrane for well-dispersed silver nanoparticle impregnation at high loading: high water permeate flux and biofouling prevention

2021 ◽  
Author(s):  
Mohana Mukherjee ◽  
Rajdip Bandyopadhyaya
Keyword(s):  
Membrane Surface ◽  
Water Flux ◽  
High Water ◽  
High Loading ◽  
Permeate Flux ◽  
Ag Nps ◽  
Pore Blockage ◽  
Mean Size ◽  
Pes Membrane ◽  
20 Nm

Abstract We present a new method for impregnation of silver nanoparticles (Ag NPs) at high loading on PES membrane's external surface, simultaneously retaining native membrane's porosity – to achieve a high water permeate flux without biofouling. This was possible by PES membrane's surface modification with acrylic acid (AA), finally leading to AA-Ag-PES membrane. AA-Ag-PES had a high (9.04%) Ag-NP loading selectively on membrane surface, as discrete, smaller (mean size: 20 nm) NPs. In nonfunctionalized Ag-PES, aggregated (mean size: 70 nm) NPs, with lower Ag loading (0.73 wt.%) was obtained, with NP being present both on membrane surface and inside pores. Consequently, AA-Ag-PES could maintain similar water permeability and porosity (10,153.05 Lm−2 h−1bar−1 and 69.98%, respectively), as in native PES (11,368.74 Lm−2 h−1bar−1 and 68.86%, respectively); whereas both parameters dropped significantly for Ag-PES (4,869.66 Lm−2 h−1bar−1 and 49.02%, respectively). AA-Ag-PES also showed least flux reduction (7.7%) due to its anti-biofouling property and high flux recovery after usage and cleaning, compared to native PES and Ag-PES membrane's much higher flux reduction (54.29% and 36.7%, respectively). Hence, discrete NP impregnation, avoiding pore blockage, is key for achieving high water flux and anti-biofouling properties (in AA-Ag-PES), compared to non-functionalized Ag-PES, due to aggregated Ag-NPs inside its pores.

scholarly journals Interdependence of Contributing Factors Governing Dead-End Fouling of Nanofiltration Membranes

Membranes ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 47
Author(s):  
Oranso Themba Mahlangu ◽  
Bhekie Brilliance Mamba
Keyword(s):  
Membrane Surface ◽  
Contact Angles ◽  
Permeate Flux ◽  
Contributing Factors ◽  
Pore Blocking ◽  
Dead End ◽  
Flux Decline ◽  
Cake Formation ◽  
Affinity Interaction

Cake-enhanced concentration polarization (CECP) has been ascribed as the main cause of flux decline in dead-end filtration. An unfamiliar approach was used to investigate the role of CECP effects in the fouling of a nanofiltration membrane (NF-270) that poorly reject salts. Membrane–foulant affinity interaction energies were calculated from measured contact angles of foulants and membrane coupons based on the van der Waals/acid–base approach, and linked to resistance due to adsorption (Ra). In addition, other fouling mechanisms and resistance parameters were investigated using model organic and colloidal foulants. After selection, the foulants and membranes were characterized for various properties, and fouling experiments were conducted under controlled conditions. The fouled membranes were further characterized to gain more understanding of the fouling layer properties and flux decline mechanisms. Sodium alginate and latex greatly reduced membrane permeate flux as the flux declined by 86% and 59%, respectively, while there was minor flux decline when aluminum oxide was used as model foulant (<15% flux decline). More flux decline was noted when fouling was conducted with a combination of organic and colloidal foulants. Contrary to other studies, the addition of calcium did not seem to influence individual and combined fouling trends. Foulants adsorbed more on the membrane surface as the membrane–foulant affinity interactions became more attractive and pore blocking by the foulants was not important for these experiments. Hydraulic resistance due to cake formation (Rc) had a higher contributing effect on flux decline, while CECP effects were not substantial.

scholarly journals Preparation of alkali-resistant PVDF membranes via immobilization of sodium lauryl sulfate (SDS) on surface

2021 ◽  
Vol 11 (3) ◽  
Author(s):  
Gongpu Wen ◽  
Kun Chen ◽  
Yanhong Zhang ◽  
Yue Zhou ◽  
Jun Pan ◽  
...  
Keyword(s):  
Sodium Lauryl Sulfate ◽  
Alkali Treatment ◽  
Membrane Surface ◽  
Alkali Resistance ◽  
Lauryl Sulfate ◽  
Uv Curable ◽  
Pvdf Membrane ◽  
Glycol Diacrylate ◽  
Polyester Acrylate ◽  
Uv Curable Resin

AbstractA novel strategy was proposed to fabricate alkali-resistant PVDF membrane via sodium lauryl sulfate (SDS) attached to the surface of membrane and immobilized by UV-curable polyester acrylate and tri(propylene glycol) diacrylate (TPGDA). The attached anionic surfactant, SDS, on the membrane surface can resist the alkali corrosion by NaOH, and the curing of the resin can immobilize the SDS on the membrane firmly. Due to the unique alkali resistance of SDS and resin formed, the UV-curable resin-modified PVDF membrane showed greatly enhanced alkali-resistant ability. Characterization of SEM and FTIR showed that polyester acrylate and TPGDA were cured successfully under the action of 1-hydroxycyclohexyl phenyl ketone (184) and ultraviolet light. Whiteness, differential scanning calorimeter and X-ray photoelectron spectrometer characterization showed that the modified PVDF membrane had a lower degree of dehydrofluorination than the pristine PVDF membrane after alkali treatment. Results of the detailed alkali-resistant analysis indicated that the F/C ratio of the UV-curable resin-modified PVDF membrane decreased by 2.6% after alkali treatment compared to pristine PVDF membrane decreased by 19.28%. The alkali-resistant performance was mainly attributed to the immobilized SDS. This study provided a facile and scalable method for designing alkali-resistant PVDF membrane, which shows a promising potential in the treatment of alkaline wastewater and alkaline-cleaning PVDF membrane.

scholarly journals Influence of bulk concentration on the organisation of molecules at a membrane surface and flux decline during reverse osmosis of an anionic surfactant

2016 ◽  
Vol 499 ◽  
pp. 257-268 ◽  
Author(s):  
Zhaohuan Mai ◽  
Vincent Butin ◽  
Mohammed Rakib ◽  
Haochen Zhu ◽  
Murielle Rabiller-Baudry ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Anionic Surfactant ◽  
Membrane Surface ◽  
Bulk Concentration ◽  
Flux Decline

scholarly journals High Fat Diet Induces Adhesion of Platelets to Endothelium in Two Models of Dyslipidemia

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Jaime Gonzalez ◽  
Wendy Donoso ◽  
Natalia Díaz ◽  
María Eliana Albornoz ◽  
Ricardo Huilcaman ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Early Stage ◽  
Endothelial Activation ◽  
Mice Model ◽  
High Fat ◽  
Early Stages ◽  
Endothelial Surface ◽  
Two Stages ◽  
Adhesion Of Platelets

Cardiovascular diseases (CVD) represent about 30% of all global deaths. It is currently accepted that, in the atherogenic process, platelets play an important role, contributing to endothelial activation and modulation of the inflammatory phenomenon, promoting the beginning and formation of lesions and their subsequent thrombotic complications. The objective of the present work was to study using immunohistochemistry, the presence of platelets, monocytes/macrophages, and cell adhesion molecules (CD61, CD163, and CD54), in two stages of the atheromatous process. CF-1 mice fed a fat diet were used to obtain early stages of atheromatous process, denominated early stage of atherosclerosis, and ApoE−/−mice fed a fat diet were used to observe advanced stages of atherosclerosis. The CF-1 mice model presented immunostaining on endothelial surface for all three markers studied; the advanced atherosclerosis model in ApoE−/−mice also presented granular immunostaining on lesion thickness, for the same markers. These results suggest that platelets participate in atheromatous process from early stages to advance d stages. High fat diet induces adhesion of platelets to endothelial cellsin vivo. These findings support studying the participation of platelets in the formation of atheromatous plate.

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.

scholarly journals Influence of Membrane Vibration on Particles Rejection Using a Slotted Pore Membrane Microfiltration

Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 709
Author(s):  
Asmat Ullah ◽  
Kamran Alam ◽  
Saad Ullah Khan ◽  
Victor M. Starov
Keyword(s):  
Membrane Fouling ◽  
Produced Water ◽  
Separation Efficiency ◽  
Membrane Surface ◽  
Water Separation ◽  
Oil Droplet ◽  
Pore Blockage ◽  
Oil Water Separation ◽  
Microfiltration Membranes ◽  
Membrane Vibration

A new method is proposed to increase the rejection in microfiltration by applying membrane oscillation, using a new type of microfiltration membrane with slotted pores. The oscillations applied to the membrane surface result in reduced membrane fouling and increased separation efficiency. An exact mathematical solution of the flow in the surrounding solution outside the oscillating membrane is developed. The oscillation results in the appearance of a lift velocity, which moves oil particles away from the membrane. The latter results in both reduced membrane fouling and increased oil droplet rejection. This developed model was supported by the experimental results for oil water separation in the produced water treatment. It was proven that the oil droplet concentration was reduced notably in the permeate, due to the membrane oscillation, and that the applied shear rate caused by the membrane oscillation also reduced pore blockage. A four-times lower oil concentration was recorded in the permeate when the membrane vibration frequency was 25 Hz, compared to without membrane vibration. Newly generated microfiltration membranes with slotted pores were used in the experiments.

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