scholarly journals Fabrication of a High Water Flux Conductive MWCNTs/PVC Composite Membrane with Effective Electrically Enhanced Antifouling Behavior

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1548
Author(s):  
Xi Chen ◽  
Jiabin Gao ◽  
Yunchang Song ◽  
Yaping Gong ◽  
Meng Qi ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Composite Membrane ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Water Flux ◽  
Pvc Membrane ◽  
Filtration Process ◽  
Electrically Conductive ◽  
Electrically Assisted ◽  
Conductive Membrane

Membrane fouling is a major issue that deteriorates the performance of membrane filtration systems. The electrically assisted membrane filtration process is proven to be effective for alleviating membrane fouling. In this study, we synthesized an electrically conductive membrane by incorporating multiwalled carbon nanotubes (MWCNTs) into polyvinyl chloride (PVC). The synthesized membranes have larger porosity than the PVC membrane (incorporating polyethylene glycol (PEG)), and thus possess much higher water flux under the same testing conditions. The initial and stable water fluxes are 2033 L/(m2·h) and 750 L/(m2·h), respectively, which are much higher than that of the pure PVC membrane. More importantly, the membrane has higher surface charge density and excellent electrical conductivity, but the surface hydrophilicity and toughness decreased with the addition of the MWCNTs. The 25 wt % MWCNTs/PVC composite membrane possesses suitable electrical conductivity of 0.128 S/m. The same membrane shows electro-enhanced antifouling performance during the antifouling test with yeast as a model foulant because the external electric field (−2 V) impulses a strong repulsion force while producing some micro bubbles to repel the foulant; thus, the membrane fouling is suppressed. In the current study, we develop a simple method to fabricate the electrically conductive membrane for application in the electrically assisted membrane filtration process.

scholarly journals Antifouling Polyethersulfone-Petrol Soot Nanoparticles Composite Ultrafiltration Membrane for Dye Removal in Wastewater

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 361
Author(s):  
Nkechi P. Nwafor ◽  
Richard M. Moutloali ◽  
Keneiloe Sikhwivhilu ◽  
Oluwole B. Familoni ◽  
Luqman A. Adams
Keyword(s):  
Composite Membrane ◽  
Membrane Filtration ◽  
Dye Removal ◽  
Pure Water ◽  
Water Flux ◽  
Composite Membranes ◽  
Water Remediation ◽  
Blue Dye ◽  
Phase Inversion Technique ◽  
Pure Water Flux

Engineered nanoparticles are known to boost membrane performance in membrane technology. Hitherto, tunable properties that lead to improved hydrophilicity due to increased surface oxygen functionalities upon oxidation of petrol soot have not been fully exploited in membrane filtration technology. Herein, the integration of oxidized petrol soot nanoparticles (PSN) into polyethersulfone ultrafiltration membranes produced via phase inversion technique for dye removal in wastewater is reported. The nanoparticles, as well as the composite membranes, were characterized with diverse physicochemical methods, particularly TEM, SEM, BET, AFM, contact angle, etc. The effect of varying the ratio of PSN (0.05–1.0 wt %) on the properties of the composite membrane was evaluated. The composite membranes displayed increased hydrophilicity, enhanced pure water flux, and antifouling properties relative to the pristine membrane. For example, the obtained pure water flux increased from 130 L·m−2·h−1 for base membrane to 265 L·m−2·h−1 for the best composite membrane (M4). The best flux recovery ratio (FRR) observed for the membranes containing PSN was ca. 80% in contrast to 49% obtained with the pristine membrane indicative of the positive influence of PSN on membrane antifouling behavior. Furthermore, the PSN composite membranes displayed relatively selective anionic dye rejection of ˃95% for Congo red and between 50–71% for methyl orange compared with 42–96% rejection obtained for cationic methylene blue dye with increasing PSN content. The successful fabrication of polyethersulfone–PSN composite membranes by a simple blending process opens a novel route for the preparation of economical, functional, and scalable water purification membranes capable of addressing the complex issue of water remediation of organic azo dyes.

scholarly journals A Simple Method to Identify the Dominant Fouling Mechanisms during Membrane Filtration Based on Piecewise Multiple Linear Regression

Membranes ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 171 ◽  
Author(s):  
Hao Xu ◽  
Kang Xiao ◽  
Jinlan Yu ◽  
Bin Huang ◽  
Xiaomao Wang ◽  
...  
Keyword(s):  
Linear Regression ◽  
Multiple Linear Regression ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Model Fitting ◽  
Multiple Linear Regression Model ◽  
Cake Filtration ◽  
Filtration Process ◽  
Simple Method

Membrane fouling is a complicated issue in microfiltration and ultrafiltration. Clearly identifying the dominant fouling mechanisms during the filtration process is of great significance for the phased and targeted control of fouling. To this end, we propose a semi-empirical multiple linear regression model to describe flux decline, incorporating the five fouling mechanisms (the first and second kinds of standard blocking, complete blocking, intermediate blocking, and cake filtration) based on the additivity of the permeate volume contributed by different coexisting mechanisms. A piecewise fitting protocol was established to distinguish the fouling stages and find the significant mechanisms in each stage. This approach was applied to a case study of a microfiltration membrane filtering a model foulant solution composed of polysaccharide, protein, and humic substances, and the model fitting unequivocally revealed that the dominant fouling mechanism evolved in the sequence of initial adaptation, fast adsorption followed by slow adsorption inside the membrane pores, and the gradual growth of a cake/gel layer on the membrane surface. The results were in good agreement with the permeate properties (total organic carbon, ultraviolet absorbance, and fluorescence) during the filtration process. This modeling approach proves to be simple and reliable for identifying the main fouling mechanisms during membrane filtration with statistical confidence.

scholarly journals Modeling of submerged membrane filtration processes using recurrent artificial neural networks

2020 ◽  
Vol 9 (1) ◽  
pp. 155
Author(s):  
Zakariah Yusof ◽  
Norhaliza Abdul Wahab ◽  
Syahira Ibrahim ◽  
Shafishuhaza Sahlan ◽  
Mashitah Che Razali
Keyword(s):  
Neural Network ◽  
Dynamic Behavior ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Dynamic Models ◽  
Transmembrane Pressure ◽  
Permeate Flux ◽  
Filtration Process ◽  
Absolute Deviation ◽  
Auto Regressive

<span lang="EN-US">The modeling of membrane filtration processes is a challenging task because it involves many interactions from both biological and physical operational behavior. Membrane fouling behaviour in filtration processes is complex and hard to understand, and to derive a robust model is almost not possible. Therefore, it is the aim of this paper to study the potential of time series neural network based dynamic model for a submerged membrane filtration process. The developed model that represent the dynamic behavior of filtration process is later used in control design of the membrane filtration processes. In order to obtain the dynamic behaviour of permeate flux and transmembrane pressure (TMP), a random step was applied to the suction pump. A recurrent neural network (RNN) structure was employed to perform as the dynamic models of a filtration process, based on nonlinear auto-regressive with exogenous input (NARX) model structure. These models are compared with the linear auto-regressive with exogenous input (ARX) model. The performance of the models were evaluated in terms of %<em>R<sup>2</sup></em>, mean square error (MSE,) and a mean absolute deviation (MAD). For filtration control performance, a proportional integral derivative (PID) controller was implemented. The results showed that the RNN-NARX structure able to model the dynamic behavior of the filtration process under normal conditions in short range of the filtration process. The developed model can also be a reliable assistant for two different control strategies development in filtration processes.</span>

scholarly journals Development of Magnetite Nano–composite Membrane for Membrane Defouling

2017 ◽  
Vol 15 (1) ◽  
Author(s):  
N. A. Azmi ◽  
Q. H. Ng ◽  
A. L. Ahmad ◽  
S. C. Low
Keyword(s):  
Humic Acid ◽  
Composite Membrane ◽  
Membrane Fouling ◽  
Electrostatic Interactions ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Ammonium Hydroxide ◽  
Polymeric Membrane ◽  
Precipitation Method ◽  
Nano Composite

This research proposes to untangle the membrane fouling by introducing nanostructured magnetite (Fe3O4) colloids into the polymeric membrane. In present study, nanostructure magnetite nanoparticles (MNPs) were synthesized via co–precipitation method with ammonium hydroxide and sodium hydroxide as the precipitation agents at different pH condition. The synthesized MNPs were functionalized with poly(diallyldimethylammonium chloride) (PDDA) and then spin coated on the surface of the ultrafiltration cellulose acetate (CA) membrane. Intrinsic properties for this nano–composite membrane, in regards to the physical structures, surface negative charge density and the membrane filtration performance, on surface fouling by humic acid solutions were investigated. Experimental results demonstrated that, the nano–composite membrane has significantly reduced the humic acid fouling on the membrane surface. This could be explained by the electrostatic interactions between negatively charged humic acid molecules and the nano–composite membrane. Throughout the study, the results provide some fundamental insights into the physical interactions that governing the membrane fouling during filtration.

scholarly journals Performance Evaluation and Fouling Propensity of Forward Osmosis (FO) Membrane for Reuse of Spent Dialysate

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 438
Author(s):  
Chaeyeon Kim ◽  
Chulmin Lee ◽  
Soo Wan Kim ◽  
Chang Seong Kim ◽  
In S. Kim
Keyword(s):  
Active Layer ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Chronic Renal Disease ◽  
Membrane Surface ◽  
Water Flux ◽  
Forward Osmosis ◽  
Salt Flux ◽  
Future Research ◽  
Spent Dialysate

The number of chronic renal disease patients has shown a significant increase in recent decades over the globe. Hemodialysis is the most commonly used treatment for renal replacement therapy (RRT) and dominates the global dialysis market. As one of the most water-consuming treatments in medical procedures, hemodialysis has room for improvement in reducing wastewater effluent. In this study, we investigated the technological feasibility of introducing the forward osmosis (FO) process for spent dialysate reuse. A 30 LMH of average water flux has been achieved using a commercial TFC membrane with high water permeability and salt removal. The water flux increased up to 23% with increasing flowrate from 100 mL/min to 500 mL/min. During 1 h spent dialysate treatment, the active layer facing feed solution (AL-FS) mode showed relatively higher flux stability with a 4–6 LMH of water flux reduction while the water flux decreased significantly at the active layer facing draw solution (AL-DS) mode with a 10–12 LMH reduction. In the pressure-assisted forward osmosis (PAFO) condition, high reverse salt flux was observed due to membrane deformation. During the membrane filtration process, scaling occurred due to the influence of polyvalent ions remaining on the membrane surface. Membrane fouling exacerbated the flux and was mainly caused by organic substances such as urea and creatinine. The results of this experiment provide an important basis for future research as a preliminary experiment for the introduction of the FO technique to hemodialysis.

scholarly journals Fouling-free ultrafiltration for humic acid removal

RSC Advances ◽  
2018 ◽  
Vol 8 (44) ◽  
pp. 24961-24969 ◽  
Author(s):  
Hassan Younas ◽  
Jiahui Shao ◽  
Yiliang He ◽  
Gul Fatima ◽  
Syed Taseer Abbas Jaffar ◽  
...  
Keyword(s):  
Humic Acid ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Filtration Process

Membrane fouling is a serious concern that significantly affects the membrane filtration process.

Fabrication and Properties of Poly(Ether Imide)/Poly(Vinyl Alcohol) Composite Ultrafiltration Membrane

2012 ◽  
Vol 531-532 ◽  
pp. 18-21 ◽  
Author(s):  
Watchanida Chinpa
Keyword(s):  
Composite Membrane ◽  
Membrane Fouling ◽  
Vinyl Alcohol ◽  
Pure Water ◽  
Water Flux ◽  
Composite Membranes ◽  
Dip Coating ◽  
Poly Vinyl Alcohol ◽  
Phase Inversion Technique ◽  
Pure Water Flux

A poly(ether imide) (PEI) composite membrane was prepared by dip coating a PEI membrane pretreated with 2-aminoethanole (AEOH) into an aqueous solution of poly(vinyl alcohol) PVA and glutaraldehyde (GA). PEI membrane support was firstly prepared via phase inversion technique by casting a solution of PEI in N-methylpyrrolidone (NMP), using water as non-solvent. The hydrophilicity, permeability, anti-fouling and mechanical properties of unmodified PEI and PEI/PVA composite membranes were investigated. By comparison with the unmodified PEI membrane, the PEI/PVA composite membrane exhibited a higher pure water flux and an increase in its hydrophilicity. In addition, the flux recovery of the pure water flux of the composite PEI membrane was higher than that of the unmodified PEI membrane. This indicated that the obtained composite membrane could reduce the membrane fouling and improve its use for ultrafiltration.

scholarly journals Removal of Tetracycline Oxidation Products in the Nanofiltration Process

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 555
Author(s):  
Renata Żyłła ◽  
Stanisław Ledakowicz ◽  
Tomasz Boruta ◽  
Magdalena Olak-Kucharczyk ◽  
Magdalena Foszpańczyk ◽  
...  
Keyword(s):  
River Water ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Oxygen Demand ◽  
Oxidation Products ◽  
Amide Bond ◽  
Ozone Treatment ◽  
Xps Analysis ◽  
Filtration Process ◽  
H2o2 Oxidation

The possibility of removing tetracycline (TRC) from water in an integrated advanced oxidation and membrane filtration process was investigated. Ozonation and UV/H2O2 photooxidation were applied for the destruction of TRC. Six oxidation products (OPs) retaining the structural core of TRC have been identified. One new TRC oxidation product, not reported so far in the literature, was identified—ethyl 4-ethoxybenzoate. All identified OPs were effectively retained on the membrane in the nanofiltration process. However, chemical oxygen demand (COD) measurements of the filtrates showed that in the case of UV/H2O2 oxidation, the OPs passed through the membrane into the filtrate. Various water matrices were used in the research, including the river water untreated and after ozone treatment. It has been shown that organic matter present in surface water can improve pharmaceutical retention, although it contributes to significant membrane fouling. Pre-ozonation of the river water reduced the membrane fouling. The XPS analysis was used to show ozone and H2O2 influence on the top polymer layer of the membrane. It was shown that the oxidants can damage the amide bond of the polyamide.

Coagulation/flocculation/ultrafiltration for natural organic matter removal in drinking water production

2004 ◽  
Vol 4 (5-6) ◽  
pp. 215-222 ◽  
Author(s):  
A.R. Costa ◽  
M.N. de Pinho
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Water Production ◽  
Cellulose Acetate Membranes ◽  
Wide Range ◽  
Drinking Water Production

Membrane fouling by natural organic matter (NOM), namely by humic substances (HS), is a major problem in water treatment for drinking water production using membrane processes. Membrane fouling is dependent on membrane morphology like pore size and on water characteristics namely NOM nature. This work addresses the evaluation of the efficiency of ultrafiltration (UF) and Coagulation/Flocculation/UF performance in terms of permeation fluxes and HS removal, of the water from Tagus River (Valada). The operation of coagulation with chitosan was evaluated as a pretreatment for minimization of membrane fouling. UF experiments were carried out in flat cells of 13.2×10−4 m2 of membrane surface area and at transmembrane pressures from 1 to 4 bar. Five cellulose acetate membranes were laboratory made to cover a wide range of molecular weight cut-off (MWCO): 2,300, 11,000, 28,000, 60,000 and 75,000 Da. Severe fouling is observed for the membranes with the highest cut-off. In the permeation experiments of raw water, coagulation prior to membrane filtration led to a significant improvement of the permeation performance of the membranes with the highest MWCO due to the particles and colloidal matter removal.

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