A review on membrane applications and transport mechanisms in vacuum membrane distillation

2017 ◽  
Vol 34 (1) ◽  
Author(s):  
Rakesh Baghel ◽  
Sushant Upadhyaya ◽  
Kailash Singh ◽  
Satyendra P. Chaurasia ◽  
Akhilendra B. Gupta ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Separation ◽  
Critical Evaluation ◽  
Experimental Studies ◽  
Membrane Distillation ◽  
Permeate Flux ◽  
Separation Processes ◽  
Vacuum Membrane Distillation ◽  
Polarization Coefficient ◽  
The Impact

AbstractThe main aim of this article is to provide a state-of-the-art review of the experimental studies on vacuum membrane distillation (VMD) process. An introduction to the history of VMD is carried out along with the other membrane distillation configurations. Recent developments in process, characterization of membrane, module design, transport phenomena, and effect of operating parameters on permeate flux are discussed for VMD in detail. Several heat and mass transfer correlations obtained by various researchers for different VMD modules have been discussed. The impact of membrane fouling with its control in VMD is discussed in detail. In this paper, temperature polarization coefficient and concentration polarization coefficient are elaborated in detail. Integration of VMD with other membrane separation processes/industrial processes have been explained to improve the performance of the system and make it more energy efficient. A critical evaluation of the VMD literature is incorporated throughout this review.

Characteristic and Performance of Polyvinylidene Fluoride Membranes Blended with Lithium Chloride in Direct Contact Membrane Distillation

2014 ◽  
Vol 69 (9) ◽  
Author(s):  
S. O. Lai ◽  
K. C. Chong ◽  
K. M. Lee ◽  
W. J. Lau ◽  
B. S. Ooi
Keyword(s):  
Lithium Chloride ◽  
Direct Contact ◽  
Polyvinylidene Fluoride ◽  
Membrane Separation ◽  
Polymeric Materials ◽  
Membrane Distillation ◽  
Inversion Method ◽  
Permeate Flux ◽  
Separation Processes ◽  
Direct Contact Membrane Distillation

Membrane distillation (MD) is one of the recent rising membrane separation techniques adopted in the desalination and wastewater treatment. Unlike other pressure-driven separation processes such as reverse osmosis and nanofiltration, MD is a thermal-driven process which involves vapor pressure difference across the feed and permeates solutions. As such, MD requires low energy consumption. Hydrophobic polymeric materials such as polyvinylidene fluoride (PVDF) are frequently used in direct contact membrane distillation (DCMD) due to low surface energy and promising thermal resistance. In this study, the DCMD hollow fiber membranes were separately prepared with PVDF and PVDF blended with lithium chloride (LiCl) through dry/wet phase inversion method. Subsequently, the membranes were used in a DCMD process to remove sodium chloride (NaCl) under different feed inlet temperatures to examine the effect of LiCl additives on the neat membrane. The result showed that by adding LiCl into the neat membrane solution, the finger-like structure was change to a sponge-like structure with microvoids. Furthermore, the performance of the LiCl additive membrane in term of permeate flux was found to be 20% higher compared to that of the neat membrane. Other results of the membrane characteristics were also discussed.      

scholarly journals Recent Developments in Nanomaterials-Modified Membranes for Improved Membrane Distillation Performance

Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 140 ◽  
Author(s):  
Saikat Sinha Ray ◽  
Harshdeep Singh Bakshi ◽  
Raghav Dangayach ◽  
Randeep Singh ◽  
Chinmoy Kanti Deb ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Separation ◽  
Interfacial Polymerization ◽  
Comprehensive Evaluation ◽  
Dip Coating ◽  
Membrane Distillation ◽  
Volatile Constituent ◽  
Volatile Components ◽  
Permeate Flux ◽  
Hydrophobic Membrane

Membrane distillation (MD) is a thermally induced membrane separation process that utilizes vapor pressure variance to permeate the more volatile constituent, typically water as vapor, across a hydrophobic membrane and rejects the less volatile components of the feed. Permeate flux decline, membrane fouling, and wetting are some serious challenges faced in MD operations. Thus, in recent years, various studies have been carried out on the modification of these MD membranes by incorporating nanomaterials to overcome these challenges and significantly improve the performance of these membranes. This review provides a comprehensive evaluation of the incorporation of new generation nanomaterials such as quantum dots, metalloids and metal oxide-based nanoparticles, metal organic frameworks (MOFs), and carbon-based nanomaterials in the MD membrane. The desired characteristics of the membrane for MD operations, such as a higher liquid entry pressure (LEPw), permeability, porosity, hydrophobicity, chemical stability, thermal conductivity, and mechanical strength, have been thoroughly discussed. Additionally, methodologies adopted for the incorporation of nanomaterials in these membranes, including surface grafting, plasma polymerization, interfacial polymerization, dip coating, and the efficacy of these modified membranes in various MD operations along with their applications are addressed. Further, the current challenges in modifying MD membranes using nanomaterials along with prominent future aspects have been systematically elaborated.

scholarly journals A Comprehensive Review on Membrane Fouling: Mathematical Modelling, Prediction, Diagnosis, and Mitigation

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1327
Author(s):  
Nour AlSawaftah ◽  
Waad Abuwatfa ◽  
Naif Darwish ◽  
Ghaleb Husseini
Keyword(s):  
Membrane Fouling ◽  
Membrane Separation ◽  
Diagnostic Techniques ◽  
Mitigation Strategies ◽  
Special Focus ◽  
Permeate Flux ◽  
Separation Processes ◽  
Improved Performance ◽  
Inducing Factors ◽  
Prediction Techniques

Membrane-based separation has gained increased popularity over the past few decades, particularly reverse osmosis (RO). A major impediment to the improved performance of membrane separation processes, in general, is membrane fouling. Fouling has detrimental effects on the membrane’s performance and integrity, as the deposition and accumulation of foulants on its surface and/or within its pores leads to a decline in the permeate flux, deterioration of selectivity, and permeability, as well as a significantly reduced lifespan. Several factors influence the fouling-propensity of a membrane, such as surface morphology, roughness, hydrophobicity, and material of fabrication. Generally, fouling can be categorized into particulate, organic, inorganic, and biofouling. Efficient prediction techniques and diagnostics are integral for strategizing control, management, and mitigation interventions to minimize the damage of fouling occurrences in the membranes. To improve the antifouling characteristics of RO membranes, surface enhancements by different chemical and physical means have been extensively sought after. Moreover, research efforts have been directed towards synthesizing membranes using novel materials that would improve their antifouling performance. This paper presents a review of the different membrane fouling types, fouling-inducing factors, predictive methods, diagnostic techniques, and mitigation strategies, with a special focus on RO membrane fouling.

scholarly journals Investigation of Membrane Fouling in Vacuum Membrane Distillation (VMD) Using Blocking Filtration Laws

2022 ◽  
Vol 12 (1) ◽  
pp. 82
Author(s):  
Wajeeha Bibi ◽  
Muhammad Asif ◽  
Jawad Rabbi
Keyword(s):  
Membrane Fouling ◽  
Lower Energy ◽  
Constant Pressure ◽  
Membrane Distillation ◽  
Low Grade ◽  
Permeate Flux ◽  
Cake Layer ◽  
Vacuum Membrane Distillation ◽  
Critical Problems ◽  
Drinking Water Purification

VMD is one of the desalination technologies used for drinking water purification because of it higher permeate flux and lower energy consumption, and it uses low grade energy for operation. However, there are some critical problems related to VMD, one of which is membrane fouling. In the present study, the fouling phenomenon in VMD is investigated using constant pressure-blocking filtration laws. The results of constant pressure-blocking filtration law indicated that the permeate flux was initially unaffected by the cake layer, but with the passage of time as the pores began to constrict, a formation of a relatively thick cake layer was observed, which resulted in the decrease of permeate flux.

scholarly journals Review of New Approaches for Fouling Mitigation in Membrane Separation Processes in Water Treatment Applications

Separations ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Mervette El Batouti ◽  
Nouf F. Alharby ◽  
Mahmoud M. Elewa
Keyword(s):  
Membrane Fouling ◽  
New Technologies ◽  
Membrane Separation ◽  
Control Strategies ◽  
Membrane Surface ◽  
Membrane Distillation ◽  
Separation Processes ◽  
Term Operation ◽  
Fouling Control ◽  
Inorganic Matter

This review investigates antifouling agents used in the process of membrane separation (MS), in reverse osmosis (RO), ultrafiltration (UF), nanofiltration (NF), microfiltration (MF), membrane distillation (MD), and membrane bioreactors (MBR), and clarifies the fouling mechanism. Membrane fouling is an incomplete substance formed on the membrane surface, which will quickly reduce the permeation flux and damage the membrane. Foulant is colloidal matter: organic matter (humic acid, protein, carbohydrate, nano/microplastics), inorganic matter (clay such as potassium montmorillonite, silica salt, metal oxide, etc.), and biological matter (viruses, bacteria and microorganisms adhering to the surface of the membrane in the case of nutrients) The stability and performance of the tested nanometric membranes, as well as the mitigation of pollution assisted by electricity and the cleaning and repair of membranes, are reported. Physical, chemical, physico-chemical, and biological methods for cleaning membranes. Biologically induced biofilm dispersion effectively controls fouling. Dynamic changes in membrane foulants during long-term operation are critical to the development and implementation of fouling control methods. Membrane fouling control strategies show that improving membrane performance is not only the end goal, but new ideas and new technologies for membrane cleaning and repair need to be explored and developed in order to develop future applications.

scholarly journals Energy evaluation and treatment efficiency of vacuum membrane distillation for brackish water desalination

2014 ◽  
Vol 5 (2) ◽  
pp. 119-131
Author(s):  
Mohammad Ramezanianpour ◽  
Muttucumaru Sivakumar
Keyword(s):  
Brackish Water ◽  
Potable Water ◽  
Membrane Separation ◽  
Rapid Development ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Treated Wastewater ◽  
Permeate Flux ◽  
Effective Parameters ◽  
Vacuum Membrane Distillation

Strict environmental regulations have led to the rapid development of membrane separation technologies for the production of potable water, for industrial water supply, and for the reuse and discharge of treated wastewater. Promotion of water recycling and the provision of potable water from brackish water prevent significant negative effects on the environment and drinking water supplies. This study is intended to describe and compare a sustainable technology for brackish water treatment. Among the four configurations of the membrane distillation process, vacuum membrane distillation (VMD) produces higher flux and results in a low fouling rate. It comprises evaporation and condensation that mimics what occurs in nature. Mathematical models proposed for the VMD transport mechanisms are incorporated to predict the actual experimental flux. The response of the flux rate to various process operating parameters is demonstrated. Variation of effective parameters is investigated in terms of energy consumption. The data indicate that the permeate flux is highly responsive to the variation of pressure and temperature. VMD enables the removal of 99.9% of total dissolved solids from natural and contaminated water sources. The findings are that the quality of the permeate water from all sources was at acceptable standards for potable use.

scholarly journals Sonicated membrane separation

2018 ◽  
Vol 14 (s1) ◽  
pp. 89-99
Author(s):  
Balázs Lemmer ◽  
Szabolcs Kertész ◽  
Gábor Keszthelyi-Szabó ◽  
Kerime Özel ◽  
Cecilia Hodúr
Keyword(s):  
Membrane Fouling ◽  
Membrane Separation ◽  
Fermentation Broth ◽  
Membrane Surface ◽  
Permeate Flux ◽  
Separation Processes ◽  
Xylanase Enzyme ◽  
Stirred Cell ◽  
Hydrolysis Of

Membrane separation processes are currently proven technologies in many areas. The main limitation of these processes is the accumulation of matter at the membrane surface which leads to two phenomena: concentration polarization and membrane fouling. According to the publications of numerous authors permeate flux could be increased by sonication. Our work focuses on separation of real broth by sonicated ultrafiltration. The broth was originated from hydrolysis of grounded corn-cob by xylanase enzyme. The filtration was carried out in a laboratory batch stirred cell with a sonication rod sonicator. In our work the effect of the stirring, the intensity of sonication and the membrane-transducer distance was studied on the efficiency of the ultrafiltration and on the quality of separated enzymes. Results reveal that xylanase enzyme can be effectively separated from real fermentation broth by ultrafiltration and enzymes keep their activity after the process. Enzyme activity tests show that low energy sonication is not harmful to the enzyme.

scholarly journals Characterization of polymer membranes by contact angle goniometer

2014 ◽  
Vol 8 (2) ◽  
pp. 18-22 ◽  
Author(s):  
Szabolcs Kertész ◽  
T. B. De Freitas ◽  
Cecília Hodúr
Keyword(s):  
Contact Angle ◽  
Membrane Fouling ◽  
Water Droplet ◽  
Membrane Separation ◽  
Contact Angles ◽  
Permeate Flux ◽  
Separation Processes ◽  
Membrane Sample ◽  
Uf Membranes

The wider applications of all membrane separation processes have a main obstacle, namely the fouling phenomena, which have to be understood in more details. Surface properties, hydrophilic and hydrophobic characteristics of a polymer membrane can be determined by measuring the contact angle. The hydrophilicity of a membrane has an important influence on its performances, like permeate flux, membrane rejection or membrane fouling characteristics. In our work the contact angles of three kinds of typically commercial ultrafiltration (UF-PES-4), nanofiltration (NE-90) and reverse osmosis (LFC-30) membranes were firstly investigated and compared by contact angle goniometer measurements. The relationships between the contact angles were researched by well considering the effects of membrane sample pretreatments by distilled water prewetting and water droplet volume. Furthermore, the effects of prewetting, water droplet contact time on different molecular weight cut-off ultrafiltration membranes’ surface and droplet pH on the contact angle values were also investigated. Moreover, fresh, clean and dry, as well as pretreated, and fouled UF membranes were also measured and compared.

Separation of Biologically Active Compounds by Membrane Operations

2017 ◽  
Vol 23 (2) ◽  
pp. 218-230 ◽  
Author(s):  
Xiaoying Zhu ◽  
Renbi Bai
Keyword(s):  
Energy Consumption ◽  
Bioactive Compounds ◽  
Membrane Fouling ◽  
Membrane Separation ◽  
Separation Efficiency ◽  
High Energy ◽  
Separation Processes ◽  
Membrane Processes ◽  
Separation Technology ◽  
Pressure Driven

Background: Bioactive compounds from various natural sources have been attracting more and more attention, owing to their broad diversity of functionalities and availabilities. However, many of the bioactive compounds often exist at an extremely low concentration in a mixture so that massive harvesting is needed to obtain sufficient amounts for their practical usage. Thus, effective fractionation or separation technologies are essential for the screening and production of the bioactive compound products. The applicatons of conventional processes such as extraction, distillation and lyophilisation, etc. may be tedious, have high energy consumption or cause denature or degradation of the bioactive compounds. Membrane separation processes operate at ambient temperature, without the need for heating and therefore with less energy consumption. The “cold” separation technology also prevents the possible degradation of the bioactive compounds. The separation process is mainly physical and both fractions (permeate and retentate) of the membrane processes may be recovered. Thus, using membrane separation technology is a promising approach to concentrate and separate bioactive compounds. Methods: A comprehensive survey of membrane operations used for the separation of bioactive compounds is conducted. The available and established membrane separation processes are introduced and reviewed. Results: The most frequently used membrane processes are the pressure driven ones, including microfiltration (MF), ultrafiltration (UF) and nanofiltration (NF). They are applied either individually as a single sieve or in combination as an integrated membrane array to meet the different requirements in the separation of bioactive compounds. Other new membrane processes with multiple functions have also been developed and employed for the separation or fractionation of bioactive compounds. The hybrid electrodialysis (ED)-UF membrane process, for example has been used to provide a solution for the separation of biomolecules with similar molecular weights but different surface electrical properties. In contrast, the affinity membrane technology is shown to have the advantages of increasing the separation efficiency at low operational pressures through selectively adsorbing bioactive compounds during the filtration process. Conclusion: Individual membranes or membrane arrays are effectively used to separate bioactive compounds or achieve multiple fractionation of them with different molecule weights or sizes. Pressure driven membrane processes are highly efficient and widely used. Membrane fouling, especially irreversible organic and biological fouling, is the inevitable problem. Multifunctional membranes and affinity membranes provide the possibility of effectively separating bioactive compounds that are similar in sizes but different in other physical and chemical properties. Surface modification methods are of great potential to increase membrane separation efficiency as well as reduce the problem of membrane fouling. Developing membranes and optimizing the operational parameters specifically for the applications of separation of various bioactive compounds should be taken as an important part of ongoing or future membrane research in this field.

scholarly journals Organic Fouling Impact in a Direct Contact Membrane Distillation System Treating Wastewater: Experimental Observations and Modeling Approach

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 493
Author(s):  
Amine Charfi ◽  
Fida Tibi ◽  
Jeonghwan Kim ◽  
Jin Hur ◽  
Jinwoo Cho
Keyword(s):  
Particle Size ◽  
Membrane Fouling ◽  
Direct Contact ◽  
Feed Solution ◽  
Membrane Distillation ◽  
Mixed Solution ◽  
Permeate Flux ◽  
Direct Contact Membrane Distillation ◽  
Organic Fouling ◽  
Specific Cake Resistance

This study aims to investigate the effect of operational conditions on organic fouling occurring in a direct contact membrane distillation (DCMD) system used to treat wastewater. A mixed solution of sodium alginate (SA) and bovine serum albumin (BSA) was used as a feed solution to simulate polysaccharides and proteins, respectively, assumed as the main organic foulants. The permeate flux was observed at two feed temperatures 35 and 50 °C, as well as three feed solution pH 4, 6, and 8. Higher permeate flux was observed for higher feed temperature, which allows higher vapor pressure. At higher pH, a smaller particle size was detected with lower permeate flux. A mathematical model based on mass balance was developed to simulate permeate flux with time by assuming (i) the cake formation controlled by attachment and detachment of foulant materials and (ii) the increase in specific cake resistance, the function of the cake porosity, as the main mechanisms controlling membrane fouling to investigate the fouling mechanism responsible of permeate flux decline. The model fitted well with the experimental data with R2 superior to 0.9. High specific cake resistance fostered by small particle size would be responsible for the low permeate flux observed at pH 8.

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