This document discusses membrane separation technology. It begins by defining membranes and the four types of separations they can perform. It then classifies membrane processes based on permeable species size into microfiltration, ultrafiltration, nanofiltration and reverse osmosis. Each process is described in terms of pore/molecular weight cutoff size and applications such as cell harvesting, virus removal, water purification. Finally, common membrane module configurations including flat plate, hollow fiber and spiral wound are outlined along with their uses in food/pharma processing, water treatment, and other industries.
This document discusses membrane separation processes. It defines membranes as thin layers that selectively control the transport of materials between phases. There are two main types of membranes: permeable and semipermeable. Membrane processes are classified based on the size of materials separated and the driving force used. Examples given include reverse osmosis and ultrafiltration in the dairy industry. Key concepts covered include transmembrane pressure, recovery percentage, molecular weight cutoff, and solute rejection coefficient. Advantages of membrane separation include energy savings, low temperature operation, and recovery of both concentrate and permeate.
This document discusses cross flow filtration, which separates solids from fluids using a semipermeable membrane while preventing filter cake formation. Cross flow filtration maintains a constant filtration rate by keeping the process feed in a mobile slurry form suitable for further processing. It allows for relatively high solids loads to be operated continuously without blinding the filter. The document outlines the principles, advantages over dead-end filtration, techniques to improve it like backwashing, and applications in reverse osmosis, nanofiltration, ultrafiltration, and microfiltration such as water treatment, sterilization, dairy processing, and more.
This is a descriptive note on Membrane separation. If you like this note or content please like comment and share. Your like inspires me very much .Thank you.
This presentation provides an overview of pervaporation. Pervaporation involves the partial vaporization of a liquid mixture through a nonporous membrane, driven by a concentration gradient. The membrane retains one component more strongly than the other, allowing separation. Common applications include dehydrating ethanol/water mixtures and removing organic solvents from wastewater. The presentation discusses the basic process, membrane types including organic and inorganic options, design of pervaporation modules, and mathematical models. Typical industrial uses aim to concentrate flavors or break azeotropes in distillation.
This document summarizes membrane separation processes. It describes that membrane separation uses a semi-permeable barrier to allow faster movement of some components over others. The retained part is called retentate and the passing part permeate. Membrane separation is desirable as it saves energy, has a long membrane life, is defect-free, compact and easily operated. The document discusses membrane materials, permeance factors, transport mechanisms including porous and non-porous membranes. It provides examples of industrial applications like dialysis, reverse osmosis, and pervaporation.
The document discusses ultrafiltration and reverse osmosis membrane filtration processes. Ultrafiltration uses semi-permeable membranes to separate solids and liquids based on particle size. It is used to purify water by removing bacteria, viruses and other pathogens. Reverse osmosis uses pressure to force water through a semi-permeable membrane, allowing pure water to pass while retaining dissolved ions and solutes. It has various industrial and domestic uses, including water purification, wastewater treatment and desalination. Both processes are effective at removing microorganisms and suspended particles from water and liquids.
This document discusses membrane separation technology. It begins by defining membranes and the four types of separations they can perform. It then classifies membrane processes based on permeable species size into microfiltration, ultrafiltration, nanofiltration and reverse osmosis. Each process is described in terms of pore/molecular weight cutoff size and applications such as cell harvesting, virus removal, water purification. Finally, common membrane module configurations including flat plate, hollow fiber and spiral wound are outlined along with their uses in food/pharma processing, water treatment, and other industries.
This document discusses membrane separation processes. It defines membranes as thin layers that selectively control the transport of materials between phases. There are two main types of membranes: permeable and semipermeable. Membrane processes are classified based on the size of materials separated and the driving force used. Examples given include reverse osmosis and ultrafiltration in the dairy industry. Key concepts covered include transmembrane pressure, recovery percentage, molecular weight cutoff, and solute rejection coefficient. Advantages of membrane separation include energy savings, low temperature operation, and recovery of both concentrate and permeate.
This document discusses cross flow filtration, which separates solids from fluids using a semipermeable membrane while preventing filter cake formation. Cross flow filtration maintains a constant filtration rate by keeping the process feed in a mobile slurry form suitable for further processing. It allows for relatively high solids loads to be operated continuously without blinding the filter. The document outlines the principles, advantages over dead-end filtration, techniques to improve it like backwashing, and applications in reverse osmosis, nanofiltration, ultrafiltration, and microfiltration such as water treatment, sterilization, dairy processing, and more.
This is a descriptive note on Membrane separation. If you like this note or content please like comment and share. Your like inspires me very much .Thank you.
This presentation provides an overview of pervaporation. Pervaporation involves the partial vaporization of a liquid mixture through a nonporous membrane, driven by a concentration gradient. The membrane retains one component more strongly than the other, allowing separation. Common applications include dehydrating ethanol/water mixtures and removing organic solvents from wastewater. The presentation discusses the basic process, membrane types including organic and inorganic options, design of pervaporation modules, and mathematical models. Typical industrial uses aim to concentrate flavors or break azeotropes in distillation.
This document summarizes membrane separation processes. It describes that membrane separation uses a semi-permeable barrier to allow faster movement of some components over others. The retained part is called retentate and the passing part permeate. Membrane separation is desirable as it saves energy, has a long membrane life, is defect-free, compact and easily operated. The document discusses membrane materials, permeance factors, transport mechanisms including porous and non-porous membranes. It provides examples of industrial applications like dialysis, reverse osmosis, and pervaporation.
The document discusses ultrafiltration and reverse osmosis membrane filtration processes. Ultrafiltration uses semi-permeable membranes to separate solids and liquids based on particle size. It is used to purify water by removing bacteria, viruses and other pathogens. Reverse osmosis uses pressure to force water through a semi-permeable membrane, allowing pure water to pass while retaining dissolved ions and solutes. It has various industrial and domestic uses, including water purification, wastewater treatment and desalination. Both processes are effective at removing microorganisms and suspended particles from water and liquids.
it is a mass transfer operation use in chemical industries
it is a simple diffusion of solid to liquid phase and foam a new concentrate liquid solution
it is base on simple diffusion how to work in industries this operation
it is use for pharma, seeds and oil industries.
Cross Flow or Tangential Flow Membrane Filtration (TFF) to Enable High Solids...njcnews777
Cross Flow or Tangential Flow Filtration (TFF) Membrane Plants are used in Desalination, Brackish Groundwater Treatment, High Chloride Surface Water Treatment, Waste Water Treatment Plant Effluent Reuse, Biopharmaceutical, Food & Protein Applications for removal of undesired constituents and harvesting of desireable products. Cross flow membrane filtration technology has been used widely in industry globally. Filtration membranes can be polymeric or ceramic, depending upon the application. The principles of cross-flow filtration are used in reverse osmosis, nanofiltration, ultrafiltration and microfiltration. When purifying water, it can be very cost effective in comparison to the traditional evaporation methods. Techniques to improve performance of cross flow filtration include:
Backwashing: In backwashing, the transmembrane pressure is periodically inverted by the use of a secondary pump, so that permeate flows back into the feed, lifting the fouling layer.
Clean-in-place: Clean-in-place systems are typically used to remove fouling from membranes after extensive use. The CIP process may use detergents, reactive agents such as sodium hypochlorite and acids and alkalis such as citric acid and sodium hydroxide.
Concentration: The volume of the fluid is reduced by allowing permeate flow to occur. Solvent, solutes, and particles smaller than the membrane pore size pass through the membrane, while particles larger than the pore size are retained, and thereby concentrated. In bioprocessing applications, concentration may be followed by diafiltration.
Diafiltration: In order to effectively remove permeate components from the slurry, fresh solvent may be added to the feed to replace the permeate volume, at the same rate as the permeate flow rate, such that the volume in the system remains constant. This is analogous to the washing of filter cake to remove soluble components. Dilution and re-concentration is sometimes also referred to as "diafiltration."
Tangential flow filtration (TFF) is a type of filtration where feed flows parallel to the filter membrane rather than perpendicular. It can be used to purify components by size, concentrate solutions by reducing volume, and perform buffer exchange or diafiltration. Some applications of TFF include separating biomolecules, purifying plasmid DNA, harvesting cells, reducing bioburden in solutions, and recovering viruses. It uses various filters based on pore size for different separations.
The rotary drum filter uses a rotating metal drum covered with a filter cloth to continuously filter liquids. As the drum rotates through four sections - cake formation, washing, drying, and cake removal - liquids are vacuumed through the cloth and a solid cake is formed, washed, dried, and then scraped off in the cake removal zone. Rotary drum filters are commonly used for continuous, high-volume filtration applications in industries like wallboard production.
Leaching is a solid-liquid operation where a solute diffuses from a solid into a liquid. It is used widely in industries like food processing, pharmaceuticals, and metals processing. There are two main types of leaching - unsteady state operations like heap leaching where solids are piled up, and steady state continuous operations using equipment like agitated vessels, thickeners, and continuous countercurrent decantation systems. Selection of leaching equipment depends on factors like nature of solids, solvent used, and whether a batch or continuous process is required.
The document discusses various methods for cell disruption, which is the process of breaking open cells to release intracellular components. It describes both physical methods like bead mills, homogenizers, and ultrasonication as well as chemical/enzymatic methods like using detergents or osmotic shock. The ideal large-scale cell disrupter must disrupt tough organisms, have a well-understood and controllable mechanism, be sterilizable, economical, and amenable to automation. The choice of disruption method depends on factors like the cell type, product stability, and desired scale of production. Understanding the mechanisms of disruption helps control and validate the process.
This document discusses various mechanisms and equipment used in filtration. It provides details on:
1) Common filtration mechanisms including clarifiers, cake filters, and cartridge filters.
2) Equipment for conventional filtration such as plate and frame filters, horizontal plate filters, and rotary vacuum filters.
3) Pretreatment methods to improve filtration including heating, coagulation, flocculation, and the use of filter aids.
4) General theories for filtration including Darcy's law and equations for incompressible cake buildup.
5) Examples calculating specific cake resistance, filter area needed, and time required for filtration.
This document discusses different membrane separation techniques including reverse osmosis, dialysis, and electrodialysis. Reverse osmosis uses pressure to force purified water through a semi-permeable membrane, leaving dissolved ions behind. Dialysis relies on diffusion across a semi-permeable membrane to remove low molecular weight solutes from fluids. Electrodialysis transports ions through ion exchange membranes under an applied electric potential to purify solutions.
Microfiltration is a membrane solids separation technique used to remove particles and suspended solids from colloidal and suspended solutions with particle sizes ranging from 0.05-10 microns. There are two main types of microfiltration systems - cross flow microfiltration and dead end microfiltration. Microfiltration membranes are made from materials like ceramics, metals, and polymers and are commonly used to remove microorganisms, particulates, and reduce turbidity from water and other liquids.
Trickle-bed reactors are solid-liquid-gas contacting devices where liquid flows downward over a packed bed of catalyst particles. Gas can flow concurrently or countercurrently through the bed. Liquid forms thin films over catalyst particles. Species transport and reaction involve multiple steps: from gas to liquid interface, interface to bulk liquid, bulk liquid to catalyst surface, diffusion within catalyst pellet. Trickle beds are useful for three-phase reactions like hydrodesulfurization but can develop hot spots or channeling.
This presentation related to molecular diffusion of molecules in gases and liquids. Also includes inter-phase mass transfer and various theories related to it like two film theory, penetration theory and surface renewal theory.
Filtration
0 INTRODUCTION
1 The Theory Underlying Filtration Processes
1.1 The Mechanism of Simple Filtration Systems
1.1.2 Cake Filtration
1.1.3 Complete Blocking
1.1.4 Standard Blocking
1.1.5 Intermediate Blocking
1.2 Cake Filtration – Models and Mechanisms
1.2.1 Classical Theory for the Permeability of Porous Cakes and Beds
1.2.2 The Rate of Filtration through a Compressible Cake – The Standard Filtration Equation
1.2.3 The Compression or Consolidation of Filter Cakes – Ultimate degree of dewatering
1.2.4 The Rate of Consolidation
1.2.5 Useful Semi-Empirical Relations for Constant Pressure and Constant Rate Cake Filtration
1.2.6 Constant Pressure Filtration
1.2.7 Constant Rate Filtration
1.2.8 Multiphase Theory of Filtration
1.3 Crossflow Filtration
2 The Range and Selection of Filtration Equipment Technology
2.1 Scale
2.2 Solids Recovery, Liquids Clarification or Feed stream Concentration
2.3 Rate of Sedimentation
2.4 Rate of Cake Formation and Drainage
2.5 Batch vs Continuous Operation
2.6 Solids Loading
2.7 Further Processing
2.8 Aseptic or “Hygienic” Operation
2.9 Miscellaneous
2.10 Shear versus Compressional Deformation
2.11 Pressure versus Vacuum
3 Suspension Conditioning Prior to Filtration
3.1 Simple Filtration Aids
3.2 Mechanical Treatments
4 Post-Filtration Treatments and Further Downstream Processing
4.1 Washing
4.1.1 Air-Blowing
4.1.2 Drying
5 Testing and Characterization of Suspensions
5.1 Introduction – Suspension
5.2 Properties relevant to Filtration Performance
5.2.1 Pre-Filtration Properties of Suspension
5.2.2 Properties of Filter Cake
5.2.3 Laboratory Scale Filtration Rigs
5.3 Means of Monitoring Flocculant Dosage
5.4 Filter Cake Testing
5.4.1 Strength Testing (See also piston press described earlier)
5.4.2 Cake Permeability or Resistance
5.4.3 Rate of Cake Formation
6 Examples of the Application of the Forgoing Principles
6.1 Dewatering of Calcium Carbonate Slurries
6.2 Dewatering of Organic Products – Procion Dyestuffs
6.3 Filtration of Biological Systems – Harvesting a Filamentous Organism
References
Tables
Figures
Dialysis is a process that uses a semi-permeable membrane to selectively remove small molecules from a sample based on size. The membrane allows small molecules like salts to diffuse out of a dialysis bag containing the sample solution and into the surrounding buffer solution. This process is used to desalt and purify protein solutions by removing salts and other small contaminants from the sample inside the dialysis bag until equilibrium is reached. The rate of dialysis is affected by factors like temperature, concentration gradient, membrane thickness, and solvent used.
This document discusses various types of filtration processes. It begins by defining filtration as the separation of solids from a liquid suspension using a porous medium. It then describes different filter media types, including cake filters, clarifying filters, cross-flow filters, and ultrafilters. The document provides equations for calculating pressure drop and flow rate during batch and continuous filtration. It also discusses specific cases like constant pressure/rate filtration of compressible vs incompressible cakes. Finally, it describes common industrial filtration equipment like plate and frame filter presses, rotary drum filters, and shell and leaf filters.
The document discusses characterization methods for filtration membranes. It describes that membrane characterization helps choose the right membrane and understand selectivity and fouling mechanisms. Methods examine both structural/chemical properties and functional properties like permeability. Structural analysis techniques include microscopy, liquid displacement, and tracer retention methods. Microscopy provides information on surface topology and pore size, while displacement and tracer techniques assess pore size distribution and selectivity curves. The document outlines various characterization techniques and how they provide insights into membrane performance and properties.
These slides use concepts (e.g., scaling) from my (Jeff Funk) course entitled analyzing hi-tech opportunities to analyze how membranes have and are becoming more economically feasible for one application, pervaporation. The economic feasibility of pervaporation is improved as temperatures and pressures of the systems are increased, which are facilitated by larger scale, and as the membranes are improved. Membranes become cheaper as they are made thinner (example of scaling) and they become better as the pore size is made both smaller and is designed for allowing specific molecules to pass through the pores.
Slides for the eLearning course Separation and purification processes in biorefineries (https://open-learn.xamk.fi) in IMPRESS project (https://www.spire2030.eu/impress).
Section: Mass transfer processes
Subject: 2.2 Molecular diffusion
This document discusses membrane filtration technology. It covers topics such as membrane classification based on pore size and pressure range, common membrane processes like microfiltration and reverse osmosis, factors that affect membrane performance like fouling, and advantages of membrane filtration over conventional processes like sand filtration. The document also describes strategies to mitigate fouling, such as pretreatment, operation techniques like crossflow filtration, and chemical cleaning methods. Maintaining membrane integrity is also addressed.
This document provides an overview of membrane separation processes. It discusses different types of membranes based on their structure like dense/non-porous, porous, asymmetric, composite and electrically charged membranes. It also describes various membrane separation techniques like microfiltration, ultrafiltration, reverse osmosis, dialysis, electrodialysis and pervaporation. Key applications and theoretical principles of each process are outlined. The document provides a comprehensive introduction to membrane separation technology.
Membrane separation process and its applications in food processingPriya darshini
This document summarizes key concepts in membrane separation processes used in food engineering applications. It defines membrane separation as selectively separating materials through a semi-permeable barrier based on molecule size and properties. It then discusses membrane transport mechanisms and important membrane properties like permeability and retention. Finally, it provides examples of membrane processes and materials commonly used in food industries like dairy, fruit juice, sugar, and brewing.
it is a mass transfer operation use in chemical industries
it is a simple diffusion of solid to liquid phase and foam a new concentrate liquid solution
it is base on simple diffusion how to work in industries this operation
it is use for pharma, seeds and oil industries.
Cross Flow or Tangential Flow Membrane Filtration (TFF) to Enable High Solids...njcnews777
Cross Flow or Tangential Flow Filtration (TFF) Membrane Plants are used in Desalination, Brackish Groundwater Treatment, High Chloride Surface Water Treatment, Waste Water Treatment Plant Effluent Reuse, Biopharmaceutical, Food & Protein Applications for removal of undesired constituents and harvesting of desireable products. Cross flow membrane filtration technology has been used widely in industry globally. Filtration membranes can be polymeric or ceramic, depending upon the application. The principles of cross-flow filtration are used in reverse osmosis, nanofiltration, ultrafiltration and microfiltration. When purifying water, it can be very cost effective in comparison to the traditional evaporation methods. Techniques to improve performance of cross flow filtration include:
Backwashing: In backwashing, the transmembrane pressure is periodically inverted by the use of a secondary pump, so that permeate flows back into the feed, lifting the fouling layer.
Clean-in-place: Clean-in-place systems are typically used to remove fouling from membranes after extensive use. The CIP process may use detergents, reactive agents such as sodium hypochlorite and acids and alkalis such as citric acid and sodium hydroxide.
Concentration: The volume of the fluid is reduced by allowing permeate flow to occur. Solvent, solutes, and particles smaller than the membrane pore size pass through the membrane, while particles larger than the pore size are retained, and thereby concentrated. In bioprocessing applications, concentration may be followed by diafiltration.
Diafiltration: In order to effectively remove permeate components from the slurry, fresh solvent may be added to the feed to replace the permeate volume, at the same rate as the permeate flow rate, such that the volume in the system remains constant. This is analogous to the washing of filter cake to remove soluble components. Dilution and re-concentration is sometimes also referred to as "diafiltration."
Tangential flow filtration (TFF) is a type of filtration where feed flows parallel to the filter membrane rather than perpendicular. It can be used to purify components by size, concentrate solutions by reducing volume, and perform buffer exchange or diafiltration. Some applications of TFF include separating biomolecules, purifying plasmid DNA, harvesting cells, reducing bioburden in solutions, and recovering viruses. It uses various filters based on pore size for different separations.
The rotary drum filter uses a rotating metal drum covered with a filter cloth to continuously filter liquids. As the drum rotates through four sections - cake formation, washing, drying, and cake removal - liquids are vacuumed through the cloth and a solid cake is formed, washed, dried, and then scraped off in the cake removal zone. Rotary drum filters are commonly used for continuous, high-volume filtration applications in industries like wallboard production.
Leaching is a solid-liquid operation where a solute diffuses from a solid into a liquid. It is used widely in industries like food processing, pharmaceuticals, and metals processing. There are two main types of leaching - unsteady state operations like heap leaching where solids are piled up, and steady state continuous operations using equipment like agitated vessels, thickeners, and continuous countercurrent decantation systems. Selection of leaching equipment depends on factors like nature of solids, solvent used, and whether a batch or continuous process is required.
The document discusses various methods for cell disruption, which is the process of breaking open cells to release intracellular components. It describes both physical methods like bead mills, homogenizers, and ultrasonication as well as chemical/enzymatic methods like using detergents or osmotic shock. The ideal large-scale cell disrupter must disrupt tough organisms, have a well-understood and controllable mechanism, be sterilizable, economical, and amenable to automation. The choice of disruption method depends on factors like the cell type, product stability, and desired scale of production. Understanding the mechanisms of disruption helps control and validate the process.
This document discusses various mechanisms and equipment used in filtration. It provides details on:
1) Common filtration mechanisms including clarifiers, cake filters, and cartridge filters.
2) Equipment for conventional filtration such as plate and frame filters, horizontal plate filters, and rotary vacuum filters.
3) Pretreatment methods to improve filtration including heating, coagulation, flocculation, and the use of filter aids.
4) General theories for filtration including Darcy's law and equations for incompressible cake buildup.
5) Examples calculating specific cake resistance, filter area needed, and time required for filtration.
This document discusses different membrane separation techniques including reverse osmosis, dialysis, and electrodialysis. Reverse osmosis uses pressure to force purified water through a semi-permeable membrane, leaving dissolved ions behind. Dialysis relies on diffusion across a semi-permeable membrane to remove low molecular weight solutes from fluids. Electrodialysis transports ions through ion exchange membranes under an applied electric potential to purify solutions.
Microfiltration is a membrane solids separation technique used to remove particles and suspended solids from colloidal and suspended solutions with particle sizes ranging from 0.05-10 microns. There are two main types of microfiltration systems - cross flow microfiltration and dead end microfiltration. Microfiltration membranes are made from materials like ceramics, metals, and polymers and are commonly used to remove microorganisms, particulates, and reduce turbidity from water and other liquids.
Trickle-bed reactors are solid-liquid-gas contacting devices where liquid flows downward over a packed bed of catalyst particles. Gas can flow concurrently or countercurrently through the bed. Liquid forms thin films over catalyst particles. Species transport and reaction involve multiple steps: from gas to liquid interface, interface to bulk liquid, bulk liquid to catalyst surface, diffusion within catalyst pellet. Trickle beds are useful for three-phase reactions like hydrodesulfurization but can develop hot spots or channeling.
This presentation related to molecular diffusion of molecules in gases and liquids. Also includes inter-phase mass transfer and various theories related to it like two film theory, penetration theory and surface renewal theory.
Filtration
0 INTRODUCTION
1 The Theory Underlying Filtration Processes
1.1 The Mechanism of Simple Filtration Systems
1.1.2 Cake Filtration
1.1.3 Complete Blocking
1.1.4 Standard Blocking
1.1.5 Intermediate Blocking
1.2 Cake Filtration – Models and Mechanisms
1.2.1 Classical Theory for the Permeability of Porous Cakes and Beds
1.2.2 The Rate of Filtration through a Compressible Cake – The Standard Filtration Equation
1.2.3 The Compression or Consolidation of Filter Cakes – Ultimate degree of dewatering
1.2.4 The Rate of Consolidation
1.2.5 Useful Semi-Empirical Relations for Constant Pressure and Constant Rate Cake Filtration
1.2.6 Constant Pressure Filtration
1.2.7 Constant Rate Filtration
1.2.8 Multiphase Theory of Filtration
1.3 Crossflow Filtration
2 The Range and Selection of Filtration Equipment Technology
2.1 Scale
2.2 Solids Recovery, Liquids Clarification or Feed stream Concentration
2.3 Rate of Sedimentation
2.4 Rate of Cake Formation and Drainage
2.5 Batch vs Continuous Operation
2.6 Solids Loading
2.7 Further Processing
2.8 Aseptic or “Hygienic” Operation
2.9 Miscellaneous
2.10 Shear versus Compressional Deformation
2.11 Pressure versus Vacuum
3 Suspension Conditioning Prior to Filtration
3.1 Simple Filtration Aids
3.2 Mechanical Treatments
4 Post-Filtration Treatments and Further Downstream Processing
4.1 Washing
4.1.1 Air-Blowing
4.1.2 Drying
5 Testing and Characterization of Suspensions
5.1 Introduction – Suspension
5.2 Properties relevant to Filtration Performance
5.2.1 Pre-Filtration Properties of Suspension
5.2.2 Properties of Filter Cake
5.2.3 Laboratory Scale Filtration Rigs
5.3 Means of Monitoring Flocculant Dosage
5.4 Filter Cake Testing
5.4.1 Strength Testing (See also piston press described earlier)
5.4.2 Cake Permeability or Resistance
5.4.3 Rate of Cake Formation
6 Examples of the Application of the Forgoing Principles
6.1 Dewatering of Calcium Carbonate Slurries
6.2 Dewatering of Organic Products – Procion Dyestuffs
6.3 Filtration of Biological Systems – Harvesting a Filamentous Organism
References
Tables
Figures
Dialysis is a process that uses a semi-permeable membrane to selectively remove small molecules from a sample based on size. The membrane allows small molecules like salts to diffuse out of a dialysis bag containing the sample solution and into the surrounding buffer solution. This process is used to desalt and purify protein solutions by removing salts and other small contaminants from the sample inside the dialysis bag until equilibrium is reached. The rate of dialysis is affected by factors like temperature, concentration gradient, membrane thickness, and solvent used.
This document discusses various types of filtration processes. It begins by defining filtration as the separation of solids from a liquid suspension using a porous medium. It then describes different filter media types, including cake filters, clarifying filters, cross-flow filters, and ultrafilters. The document provides equations for calculating pressure drop and flow rate during batch and continuous filtration. It also discusses specific cases like constant pressure/rate filtration of compressible vs incompressible cakes. Finally, it describes common industrial filtration equipment like plate and frame filter presses, rotary drum filters, and shell and leaf filters.
The document discusses characterization methods for filtration membranes. It describes that membrane characterization helps choose the right membrane and understand selectivity and fouling mechanisms. Methods examine both structural/chemical properties and functional properties like permeability. Structural analysis techniques include microscopy, liquid displacement, and tracer retention methods. Microscopy provides information on surface topology and pore size, while displacement and tracer techniques assess pore size distribution and selectivity curves. The document outlines various characterization techniques and how they provide insights into membrane performance and properties.
These slides use concepts (e.g., scaling) from my (Jeff Funk) course entitled analyzing hi-tech opportunities to analyze how membranes have and are becoming more economically feasible for one application, pervaporation. The economic feasibility of pervaporation is improved as temperatures and pressures of the systems are increased, which are facilitated by larger scale, and as the membranes are improved. Membranes become cheaper as they are made thinner (example of scaling) and they become better as the pore size is made both smaller and is designed for allowing specific molecules to pass through the pores.
Slides for the eLearning course Separation and purification processes in biorefineries (https://open-learn.xamk.fi) in IMPRESS project (https://www.spire2030.eu/impress).
Section: Mass transfer processes
Subject: 2.2 Molecular diffusion
This document discusses membrane filtration technology. It covers topics such as membrane classification based on pore size and pressure range, common membrane processes like microfiltration and reverse osmosis, factors that affect membrane performance like fouling, and advantages of membrane filtration over conventional processes like sand filtration. The document also describes strategies to mitigate fouling, such as pretreatment, operation techniques like crossflow filtration, and chemical cleaning methods. Maintaining membrane integrity is also addressed.
This document provides an overview of membrane separation processes. It discusses different types of membranes based on their structure like dense/non-porous, porous, asymmetric, composite and electrically charged membranes. It also describes various membrane separation techniques like microfiltration, ultrafiltration, reverse osmosis, dialysis, electrodialysis and pervaporation. Key applications and theoretical principles of each process are outlined. The document provides a comprehensive introduction to membrane separation technology.
Membrane separation process and its applications in food processingPriya darshini
This document summarizes key concepts in membrane separation processes used in food engineering applications. It defines membrane separation as selectively separating materials through a semi-permeable barrier based on molecule size and properties. It then discusses membrane transport mechanisms and important membrane properties like permeability and retention. Finally, it provides examples of membrane processes and materials commonly used in food industries like dairy, fruit juice, sugar, and brewing.
Membrane based water purification technology(ultra filteration,dialysis and e...Sanjeev Singh
This is made by keeping in mind needy students who want to know water purification technology.This slide contain brief description about membrane,ultra filtration,dialysis,electro dialysis.For further topic check my updates regularly....... .At last i would like to thanks those students who downloaded this slide.
This document summarizes a seminar presentation on water purification using ultrafiltration methods. It begins with an introduction to water purification and different filtration types including ultrafiltration. It then discusses the working principles of ultrafiltration, including membranes used. It describes membrane fouling and various methods to reduce fouling, as well as cleaning techniques. Finally, it outlines applications of ultrafiltration in water treatment and other industries.
Membrane filters are composed of thousands of micropores that filter particles larger than the aperture. They are used to filter various solutions and remove bacteria and impurities. Membrane filters come in flat or curly styles and are made from materials like MCE, Nylon, PTFE, PES, CA, PVDF. They are classified based on pore size and can be MF, UF, NF or RO. Membrane filters are thin, brittle membranes usually made of cellulose derivatives and are available in sizes up to 60 cm2. They have uniform pores that occupy 80% of the filter volume and are used to sterilize aqueous and oily liquids through their ability to filter out
This document provides an introduction to membrane technology used in water production. It discusses what membranes are and some key advantages like energy savings, compact operation, and water reuse. It also reviews different membrane processes like microfiltration, ultrafiltration, nanofiltration, and reverse osmosis. These processes are distinguished by the sizes of particles they can remove. The document also discusses parameters like flux, rejection rate, and concentration polarization. It reviews membrane materials, structures, configurations and modules. In summary, the document provides a comprehensive overview of membrane technology fundamentals and applications in water treatment.
This document provides an overview of membrane technology. It defines membrane technology as processes that use semipermeable membranes to separate molecules and ions on a molecular level. The document then discusses various membrane separation processes like microfiltration, ultrafiltration, nanofiltration and reverse osmosis. It also covers membrane materials, modules, factors affecting performance, fouling, and applications of membrane technology in food processing industries like juice, dairy, fermented beverages and probiotic beverages. Emerging applications of membrane technology in novel food processing techniques and high-pressure processes are also mentioned.
This document summarizes membrane separation materials and modules. It discusses types of membranes including dense and microporous, as well as separation operations like reverse osmosis, ultrafiltration, and gas permeation. Common membrane materials are synthetic polymers like cellulose and rubber. Asymmetric polymer membranes have a thin selective layer supported by a porous layer. Membrane modules include flat sheet, tubular, spiral-wound and hollow fiber configurations to provide a large surface area. Characteristics like packing density, fouling resistance and cost vary between module types.
Size exclusion chromatography separates molecules based on their size, with larger molecules eluting from the column first. It uses a stationary phase of porous beads and an aqueous or organic mobile phase. Molecules smaller than the pore size penetrate the beads and take longer to elute, while larger molecules are excluded from the pores and elute more quickly. It is commonly used to determine the molecular weight distribution of polymers and to separate biomolecules like proteins.
Product polishing techniques in Downstream ProcessingErin Davis
This is a presentation based on gel permeation chromatography and dialysis.This mainly deals with the basic principle behind these techniques.and its working.The major components,advantages,disadvantages,applications are also mentioned in the same.Besides these the pictoric representation helps to understand the concept clearly.
This will be helpful to learn downstream processing techniques.
Downstream processing involves the separation, purification, and packaging of products after fermentation or bioconversion. It includes several stages: removal of insolubles by filtration, centrifugation, or flocculation; product isolation using liquid-liquid extraction, adsorption, or ultrafiltration; product purification using chromatography, crystallization, or fractional precipitation; and product polishing through additional processes prior to packaging. Key unit operations at each stage aim to separate and concentrate the target product while removing contaminants.
Membrane technology uses semi-permeable membranes to selectively separate substances through diffusion or filtration. It is widely used for water purification and in various industrial separation processes. There are two main types of membrane modules - tubular membranes located inside tubes, and plate and frame membranes consisting of membrane envelopes wrapped around a central drain. Membrane processes are classified based on the driving force used, such as pressure, concentration gradient, electric potential, or temperature difference. Common applications include microfiltration, ultrafiltration, nanofiltration, reverse osmosis, gas separation, and pervaporation.
Membrane separation uses membranes to selectively transport or reject substances between mediums through filtration or mechanical separation processes. Membrane technology is commonly used in industries like water treatment, chemicals, pharmaceuticals, and food processing. Separation occurs through either a solution-diffusion model where diffusion drives transport, or a hydrodynamic model where transport occurs convectively through membrane pores. Membrane operations can be pressure-driven like microfiltration, ultrafiltration, nanofiltration, reverse osmosis, and gas separation.
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This is for actual presentation for Membrane Separation Process. I hope I guided you better from skills. So keep learn about this slide. You basics already cleared from this presentations after reading. Many more things on this subject in Chemical Engineering. I will discuss with you about that remaining part. So Thank You.
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This document discusses various membrane separation techniques used in food processing, including reverse osmosis, ultrafiltration, and microfiltration. It explains the basic operation of these techniques, comparing how they separate molecules of different sizes. It also covers membrane materials and module designs, factors that influence separation efficiency like concentration polarization, and techniques for membrane cleaning. Finally, it discusses freeze concentration as another method for separating ice crystals from concentrated liquid food.
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8. Membrane preparation by casting
• Precipitation from vapour phase
– This is achieved by penetration of the precipitant through a polymeric
film from the vapour phase, which is saturated with the solvent used.
• Precipitation by evaporation
– The polymer is dissolved in a mixture of more volatile and less volatile
solvents. As the more volatile component evaporates, the polymer
precipitates to form the membrane.
• Immersion precipitation
– This involves immersion of the cast film in a bath of non-solvent for
coagulation of the membrane material.
• Thermal precipitation
– The polymer is precipitated from solution by a cooling step.
9. Other membrane making procedures
• Stretching:
– Involves stretching a polymer film
at normal or elevated temperature
in order to produce pores of
desired size.
• Sintering:
– Powdered material is sintered by
compression with/without heating
to give microporous membranes.
• Slip casting:
– Most inorganic membranes are
prepared using this method.
– The method involves coating
repeated layers of uniform particles
with decreasing sizes on porous
support.
10. Other membrane making procedures
• Leaching:
– Some inorganic membranes are
prepared by leaching technique.
– Isotropic glass membranes are
prepared by a combination of
phase separation and acid leaching.
• Track etching:
– A homogeneous polymer film is
exposed to laser beams or beams
of collimated charged particles.
– This breaks specific chemical bonds
in the polymer matrix.
– The film is then placed in an
etching bath to remove the
damaged sections thus giving rise
to monodisperse pores
14. Factors influencing the performance of a
membrane
• Mechanical strength
– Tensile strength, bursting pressure
• Chemical resistance
– pH range, solvent compatibility
• Permeability to different species
– Pure water permeability, sieving coefficient
• Average porosity and Pore size distribution
• Sieving properties
– Nominal molecular weight cut-off
• Electrical properties
– Membrane zeta potential
15. Driving force in membrane separation
• Transmembrane (hydrostatic) pressure (TMP)
• Concentration or electrochemical gradient
• Osmotic pressure
• Electrical field
• Partial pressure
• pH gradient
17. Membrane processes that separate based
on principles other than size
• Pervaporation
– Separates a volatile or
low-boiling-point liquid
from a non-volatile
liquid
– The driving force is a
vacuum on the
gaseous side of the
membrane
– Tool for separation of
liquid mixtures,
especially dehydration
of liquid hydrocarbons
18. Applications of pervaporation
• Dehydration of ethanol–water azeotrope
• Removal of water from organic solvents
• Removal of organics from water
19. Membrane processes that separate based
on principles other than size
• Electrodialysis (ED)
• Electrochemical process used to separate charged particles from an
aqueous solution or from other neutral solutes
• A stack of membranes is used, half of them passing positively charged
particles and rejecting negatively charged ones; the other half doing
the opposite.
• An electrical potential is imposed across the membranes and a
solution with charged particles is pumped through the system.
• Positively charged particles migrate toward the negative electrode, but
are stopped by a positive-particle-rejecting membrane
• Negatively charged particles migrate in the opposite direction with
similar results
21. Flux
• Throughput of material
through a membrane
• Flux depends on
– Applied driving force
– Resistance offered by
membrane
• Fouling
– Increase in membrane
resistance during a process
– The decline in flux through a
membrane with time in a
constant force membrane
process is due to fouling
Flux
Time
Decline in flux due to fouling in a
constant driving force membrane
separation
Pressure
Time
Fouling in constant flux
membrane separation
23. Membrane element and module
Membrane element refers to the basic form of the
membrane:
• Flat sheet
• Hollow fibre
• Tubular
Membrane module refers to the device which houses
the membrane element:
• Stirred cell module
• Flat sheet tangential flow (TF) module
• Tubular membrane module
• Spiral wound membrane module
• Hollow fibre membrane module
24. Membrane
modules
Stirred cell unit Arrangement flat sheet TF module
Small scale flat sheet TF module
Pilot plant scale flat sheet TF module
26. Flat sheet tangential flow module
Feed Retentate
Permeate
Permeate
Membranes
•Similar plate and frame filter press
•Alternate layers of membranes, support
screens and distribution chambers
•Used for microfiltration and ultrafiltration
27. Spiral flow membrane module
•Flat sheet membranes are fused to form an envelop
•Membrane envelop is spirally wound along with a feed
spacer
•Filtrate is collected within the envelope and piped out
31. Tubular membrane module
Feed
Retentate
Permeate (flows radially)
•Cylindrical geometry; wall acts as the membrane
•Tubes are generally greater than 3 mm in diameter
•Shell and tube type arrangement is preferred
•Flow behaviour is easy to characterise
32. Tubular membranes are used for all types of pressure
driven separations
Tubular modules are widely used where it is advantageous
to have a turbulent flow regime
Advantages
1. Low fouling and hence relatively easy cleaning
2. Easy handling of suspended solids & viscous fluids
3. Ability to replace or plug a damaged membrane.
Disadvantages
1. High capital cost
2. Low packing density
3. High pumping costs
4. High dead volume
Tubular membrane module
34. Hollow fibre membrane module
•Similar to tubular membrane module
•Tubes or fibres are 0.25 - 2.5 mm in diameter
•Fibres are prepared by spinning and are potted within the module
•Straight through or U configuration possible
•Typically several fibres per module
36. Plate and
frame
Spiral wound Tubular Hollow fiber
Packing
density
30 – 500 200 – 800 30 – 200 500 – 9000
Resistance to
fouling
Good Moderate Very good Poor
Ease of
cleaning
Good Fair Excellent Poor
Relative cost High Low High Low
Main
Applications
D, RO, PV, UF,
MF
D, RO, GP, UF,
MF
RO, UF D, RO, GP, UF
Comparison of different membrane modules
37. Type
Fluid flow
regime
Membrane
area/module
volume
Mass
transfer
coefficient
Hold-up
volume
Special remarks
TF flat
sheet
Laminar-
turbulent
Low
Low to
moderate
Moderate
Can be dismantled
and cleaned easily
Spiral
wound
Laminar Moderate Low Low
High pressures
cannot be used
Hollow
fibre
Laminar-
turbulent
High
Low to
moderate
Low
Susceptible to fibre
blocking
Tubular Turbulent Low
Moderate to
high
Moderate
to high
Flow easy to
characterize
Excellently suited
for basic
membrane studies.
Operating characteristics of membrane modules
39. Membrane characterization
The performance of a membrane process depends on the
properties of the membrane:
• Mechanical strength
• Tensile strength, bursting pressure
• Chemical resistance
• pH range, compatibility with solvents
• Permeability to different species
• Pure water permeability, gas permeability
• Average porosity and pore size distribution
• Sieving properties
• Nominal molecular weight cut-off
• Electrical properties
• Membrane zeta potential
40. Ultrafiltration
General Industrial Uses:
Concentration of macromolecules
Purification of solvent by removal of solutes
Fractionation of macromolecules
Clarification
Retention of catalysts
Analysis of complex solutions for specific solutes
Bioprocess Applications:
Fractionation of biological macromolecules e.g. proteins, DNA
Concentration of polymer solutions
Removal of LMW solutes from protein solutions
Removal of cells and cell debris from fermentation broth
Virus removal from therapeutic products
Harvesting of biomass e.g., cells and sub-cellular products
Membrane bioreactors
Effluent treatment
41. Ultrafiltration membranes
•Pores: 10 to 1000 Angstroms
•Generally anisotropic (skin layer 0.2 to 10 micron thick)
•Properties of an ideal ultrafiltration membrane:
•High hydraulic permeability to solvent
•Sharp “retention cut-off” properties: The membrane must be
capable of retaining completely nearly all the solutes above some
specified value, known as the molecular cut-off (MWCO)
•Good mechanical durability
•Good chemical and thermal stability
•Excellent manufacturing reproducibility and ease of manufacture
43. Ultrafiltration: Pore flow model
p
p
m
v
l
P
d
J
32
2
Jv = Permeate flux
m =Membrane porosity
dp = Average pore diameter
P =Transmembrane pressure
=Viscosity
Lp =Average pore length
f
o
i
P
P
P
P -
+
2
Membrane
Retentate
Feed
Permeate/filtrate
Pi
Po
Pf
Hagen-Poiseuille’s law for permeate flux
of pure solvent
Pi and Po inlet and outlet pressures on
the feed side
Pf is the pressure on the filtrate side
The pressure drop for a
Cross flow membrane module
44. Ultrafiltration: Flux equations
Pore flow model: UF of solvent
p
p
m
v
l
P
d
J
32
2
Resistance model: UF of solvent
m
v
R
P
J
Osmotic pressure model: UF of solution
cp
m
v
R
R
P
J
+
-
g
cp
m
v
R
R
R
P
J
+
+
-
Rm = membrane hydraulic
resistance
Rcp = resistance due to concentration polarization
Rg = gel layer resistance
Rm = membrane hydraulic resistance
46. Concentration polarization model UF
of solution
-
-
p
b
p
w
v
C
C
C
C
k
J ln
0
v v p
dC
J C J C D
dx
- +
Material balance in a control volume
within the concentration polarization
layer at steady state
Upon integration with boundary conditions
C= Cw at x=0 and C=Cb at x=δb we get
concentration polarization equation for
partially rejected solutes
For total solute rejection i.e, Cp = 0 ln w
v
b
C
J k
C
When Cw is equal to the gelation concentration, there
will be no further increase in the value of Cw
Hence we write gel polarization equation as lim ln g
b
C
J k
C
47. Effect of transmembrane pressure
on permeate flux
Permeate
flux
Transmembrane pressure
Pressure
dependent
Pressure
independent
?
Limiting
flux
At constant TMP the
permeate flux decreases
as the feed concentration
increases
When Cw = Cg the
permeate flux is
independent of the TMP
48. Problem
A protein solution (conc, 4.4 g/l) is being ultrafiltered using a spiral
wound membrane module which totally retains the protein.
At a certain transmembrane pressure the permeate flux is
1.3x10-5 m/s. The diffusivity of the protein is 9.5 x 10-11 m2/s while
the wall concentration at this operating pressure is estimated to be
10 g/l.
Predict the thickness of the boundary layer.
If the permeate flux is increased to 2.6 x 10-5 m/s while maintaining
the same hydrodynamic conditions within the membrane module,
what is the new wall concentration?
49. Where there is total retention we can use the equation
This equation can be written as
The mass transfer coefficient is given by
Therefore
When Jv is increased to 2.6 x 10-5 m/s and k remains the same, the wall
concentration can be obtained from the concentration polarization equation for
totally retained solute
ln w
v
b
C
J k
C
5
5
1.3 10
1.584 10 /
10
ln
ln
4.4
v
w
b
J
k m s
C
C
-
-
b
D
k
d
11
6
5
9.5 10
5.99 10
1.584 10
b m m
d
-
-
-
6
5
2.6 10
exp 4.4 exp / 22.727 /
1.584 10
w b
Jv
C C g l g l
k
-
-
50. Effect of feed concentration on
permeate flux
TMP
Jv
Cb
Jlim
ln Cb
Cs or Cg
k
For a given feed concentration,
the limiting flux increases with
increases in mass transfer
coefficient
Permeate flux decreases as the feed
concentration is increased
51. Mass transfer coefficient (k)
Affects back-diffusion of accumulated solute
Measure of the hydrodynamic conditions within the module
k = (D/db)
Mass transfer coefficient can be measured experimentally
•Plot of limiting flux versus log of feed concentration
•Plot of sieving parameter versus (Jv/k)
Mass transfer coefficient can be estimated using heat-mass
transfer analogy
•Dimensionless equations: Sherwood number as function of Reynolds
number and Schmidt number
52. Schmidt number = Momentum transfer/Mass transfer
kd
Sh
D
Reynolds number = Inertial forces/Viscous forces
Sherwood number = Total mass transfer/Diffusive mass transfer
Re
du du
v
Sc
D D
Mass transfer correlations
Peclet number = Convective mass transfer / Diffusive mass transfer h
d
Pe
D
Grashof number = Gravitational forces/ Viscous forces
3 2
2
'
L B g t
Gr
Froude number = Interial forces/ Gravitational forces
2
v
Fr
gL
53. Mass transfer correlations
Fully developed laminar flow (i.e. Re < 1000) in tubular
membrane 0.33
0.33 0.33
1.62 Re
t
d
Sh Sc
l
Turbulent flow (i.e. Re > 2000) in tubular
membrane 33
.
0
8
.
0
Re
023
.
0 Sc
Sh
Graetz-Leveque
Dittus-Boelter
Fully developed laminar
flow
33
.
0
67
.
0
33
.
0
816
.
0 -
t
L
D
k Porter
Shear rate at the wall = 8 ul / d for tubes
= 6 ul / b for rectangular channels (b = channel depth)
54. Problem: Shear-Induced Diffusivity
Shear-induced diffusivity is 3 x 10-7 cm2/s.
Hydrodynamic diffusivity is 2 x10-9 cm2/s.
Shear-induced diffusivity is about 150 times larger.
6 A A
RT
D
R N
2
s w
D a
Compare hydrodynamic and shear-induced diffusivity values for
a 1-mm particle at a shear rate of 1,000 s-1. Assume the value of
α to be 0.03 for ultra filtration processes
55. 0.8 0.33
0.023 Re
Sh Sc
Problem:
Calculate the mass transfer coefficient for ultrafiltration of milk at
50oC employing tubular membrane system with the following
configurations:
Pore diameter of 1.25 cm; Length = 240 cm;
Number of channels = 18;
superficial velocity = 200 cm/sec;
Pressure drop over length = 2 kg/cm2.
The physical properties of milk are as follows:
Density = 1.03 g/ml;
viscosity 0.008 g/cm/sec;
Diffusivity = 7.0 x 10-7 cm2/sec.
The bulk protein concentration is 3.1% and the gel protein
concentration is 22%. Assume turbulent regime for the process and
make use of Dittus-Boelter correlation
56. 3
1.25( ) 200( / sec) 1.03( / )
Re
0.008( / / sec)
du du cm cm g cm
g cm
= 32188
3 7 2
0.008( / / sec)
1.03( / ) 7 10 ( / sec)
v g cm
Sc
D D g cm cm
-
= 11096
For calculating Sherwood number in turbulent flow regime (i.e. Re >
2000) in tubular membrane, Dittus-Boelter correlation can be used
0.8 0.33 0.8 0.33
0.023 Re 0.023 (32188) (11096)
Sh Sc
= 2008
57. kd
Sh
D
Now for calculating mass transfer coefficient k we will make use of the
Sherwood number
7 2
2 2 2
2008 7 10 ( / sec)
1.25( )
0.0011( / / sec) 60 10 ( / / )
DSh cm
k
d cm
cm cm litre m hr
-
-
To calculate the flux for the process
2 2
22
ln 60 10 ln 79.3654 / /
3.1
g
b
C
J k litre m hr
C
-
58. Calculate the mass transfer coefficient for ultrafiltration of milk at
50oC employing tubular membrane system with the following
configurations:
Pore diameter of 1.25 mm; Length = 240 cm;
Number of channels = 18;
superficial velocity = 200 cm/sec;
Pressure drop over length of tube = 2 kg/cm2
Shear rate at wall = 7272.0 /sec
The physical properties of milk are as follows:
Density = 1.03 g/ml;
viscosity 0.008 g/cm/sec;
Diffusivity = 7.0 x 10-7 cm2/sec.
The bulk protein concentration is 3.1% and the gel protein
concentration is 22%. Assume turbulent regime for the process and
make use of Dittus-Boelter correlation
59. Effect of hydrodynamic parameters
on permeate flux
Crossflow velocity
Permeate
flux
Mass
transfer
coefficient
Reynolds number
Turbulent
Laminar
60. Enhancement of permeate flux
• By increasing the cross-flow rate
• By creating pulsatile flow
• By pressure pulsing
• By creating oscillatory flow
• By flow obstruction using baffles
• By generating Dean vortices
• By generating Taylor vortex
• By gas-sparging into the feed
61. Dean vortices
• Dean vortices are helicoidal flows created by
centrifugal forces in curved channels
– Coiled or helically twisted tubular membranes
• Enhance solute back transfer away from the
membrane
• Effective for enhancing permeate flux by
depolarization of the solute layer on the
membrane
62. Dean vortices
• Dean vortices are secondary
tangential flows that create a
self-cleaning flow mechanism
when induced within a cross-
flow filtering system
• The general principle of this
technology
– to design, develop and use these
tangential flows to sweep
around a curve to “clean” the
membrane, leading to enhanced
filter performance and longer
membrane life
63. Taylor Vortex
• Specialised type of Couette flow
• When the angular velocity of the
inner cylinder is increased above a
certain threshold
• Couette flow becomes unstable
and a secondary steady state
characterized by axisymmetric
toroidal vortices
Plasma collection from donors in
transfusion centers by microfiltration
64. Plasma cell filter for
plasma collection
from donors with a
rotating cylindrical
membrane
DYNAMIC FILTRATION
Biodruckfilter (sulzer AG, Winterthur,
Switzerland) http://www.sulzer.com.
Rotary biofiltration device (Membrex
Inc.) and merged into GE Osmonic
(www.gewater.com)
65. Rotating Disk Modules MSD system (Westfalia
Separator, Aalen, Germany)
Multishaft systems with overlapping
rotating membranes
The MSD system features 31-cm-
diameter ceramic membranes on eight
parallel shafts located on a cylinder for
a membrane area of 80 m2
All disks rotate at the same speed and
are enclosed in a cylindrical housing
The membrane shear rate is unsteady
and reaches a maximum in the
overlapping regions
66. Rotating disk dynamic filtration system (Pall Corp., Massachusetts, USA)
www.pall.com
Dyno (Bokela GmbH, Karlsruhe, Germany) www.bokela.com
Optifilter CR (Metso Paper, Raisio, Finland) www.metso.com/
Multi-disk system (SpinTek, Huntington, CA, USA) www.spintek.com
MSD system (Westfalia Separator, Aalen, Germany) www.westfalia-
separator.com
Rotostream (Canzler, Dueren, Germany) http://www.sms-vt.com/index.php
Multishaft disk (MSD) system (Hitachi Ltd.) www.hitachi.com
Self Cleaning Filtration, (novoflow, Oberndorf, Germany)
http://www.novoflow.com/en/home
Rotating Disk Modules
67. Flux Enhancement by Pulsatile Flows
• Another method for enhancing permeate flux
and mass transfer without using very high
fluid velocity
• Consists of superposing flow and pressure
pulsations at the membrane inlet with a
piston-in-cylinder system or special pumps
such as modified roller pumps
Pulsatile blood flow to enhance gas transfer in
membrane blood oxygenators
68. Retrofiltration
• Technique for reducing membrane fouling by
pressurizing the permeate above retentate
pressure in order to inject permeate into
retentate and clean the pores
– Backwashing
– Backpulsing
69. Vibratory shear-enhanced processing
Schematic of the vibratory
shear-enhanced processor
(VSEP) pilot series L with a
single membrane oscillating
around its vertical axis
Vibratory shear-enhance processing
(VSEP) (New Logic Research, Inc.)
www.vsep.com
PallSep Vibrating Membrane Filter
(Pall Corporation)
http://www.pall.com
70. Solute transmission through UF
membranes
Amount of solute going through an UF membrane can be
quantified in terms of the membrane intrinsic rejection coefficient
(Ri) or intrinsic sieving coefficient (Si):
i
w
p
i S
C
C
R -
-
1
1
Cw is difficult to determine and hence it is more practical to use the
apparent rejection coefficient (Ra) or the apparent sieving
coefficient (Sa):
a
b
p
a S
C
C
R -
-
1
1
71. Factors influencing the retention of a
solute by membrane
• Primary variable
– Solute diameter to pore diameter ratio
• Also depends on
– Solute shape
– Solute charge
– Solute compressibility
– Solute-membrane interactions
– Operating conditions
The amount of solute going through the membrane can be quantified in terms of
intrinsic rejection coefficient (Ri) and intrinsic sieving coefficient (Si)
72. Rejection coefficient:
Older theory new theory
2
2
-
a
R
1
a
R
for < 1
for 1
= (di / dp)=solute-pore diameter ratio
In other words, Ra is
constant for a solute-
membrane system.
It is now recognised that rejection coefficients depend on
operating and environmental parameters such as
•pH
•Ionic strength
•System hydrodynamics
•Permeate flux
1 p
i
w
C
R
C
-
1 p
a
b
C
R
C
-
73. Sieving coefficients
w
p
i
C
C
S
Intrinsic sieving coefficient
•Depends on solute-membrane system
•Depends on physicochemical parameters
such as pH and ionic strength
•Depends on permeate flux
Apparent sieving coefficient
•Depends on solute-membrane system
•Depends on physicochemical parameters
such as pH and ionic strength
•Depends on permeate flux
•Depends on system hydrodynamics
b
p
a
C
C
S
74. Effect of permeate flux on intrinsic
sieving coefficient
1
exp
exp
-
+
eff
m
v
eff
m
v
i
D
J
S
S
D
J
S
S
S
d
d
Intrinsic
sieving
coefficient
Permeate flux (log scale)
Asymptotic
intrinsic sieving
coefficient
S͚
75. Effect of permeate flux and mass transfer
coefficient on apparent sieving coefficient
+
+
-
-
+
k
J
D
J
S
S
D
J
S
S
k
J
D
J
S
S
S
v
eff
m
v
eff
m
v
v
eff
m
v
a
d
d
d
exp
exp
1
1
exp
Permeate flux (log scale)
Apparent
sieving
coefficient
Mass transfer coefficient
Apparent
sieving
coefficient
76. Determination of intrinsic sieving
coefficient and mass transfer coefficient
+
-
- k
J
S
S
S
S v
i
i
a
a
1
ln
1
ln
- a
a
S
S
1
ln
k
Jv
- i
i
S
S
1
ln
77. Problem
The intrinsic and apparent rejection coefficients for a
solute in an ultrafiltration process were found to be
0.95 and 0.63 respectively at a permeate flux value of
6 x 10-3 cm/s.
What is the solute mass transfer coefficient?
79. Solute fractionation
For fractionation of a binary mixture of solutes, it is desirable to
achieve maximum transmission of the solute desirable in the
permeate and minimum transmission of the solute desirable in the
retentate.
2
1
2
1
1
1
a
a
a
a
R
R
S
S
-
-
Enhancement of fractionation
• pH optimization
• Feed concentration optimization
• Salt concentration optimization
• Membrane surface pre-treatment
• Optimization of permeate flux and system hydrodynamics
Selectivity parameter
80. Problem
A feed solution (10 g/l) of dextran (MW=505 kDa) is ultrafiltered through a 25 kDa
MWCO Membrane. The pure water flux values and the dextran UF permeate flux
values at different TMP are given below
The osmotic pressure is given by the following correlation
where Δπ is in dynes/cm2 and Cw is in %w/v.
Calculate the membrane resistance and the mass transfer coefficient for dextran
assuming that Rg and Rcp are negligible
ΔP (kPa) Pure water flux
(m/s)
Jv (m/s)
30 9.71x10-6 6.24x10-6
40 1.23 x 10-5 7.08x10-6
50 1.57x10-5 7.63x10-6
60 1.87x10-5 8.02x10-6
0.35
log 2.48 1.22( )
w
C
+
81. y = 3E-07x + 4E-07
0.00E+00
2.00E-06
4.00E-06
6.00E-06
8.00E-06
1.00E-05
1.20E-05
1.40E-05
1.60E-05
1.80E-05
2.00E-05
0 20 40 60 80
Plot of Pure water flux vs transmembrane pressure
Pure water flux (m/s)
Linear (Pure water flux (m/s) )
Solution
The MWCO of the membrane is 25 kDa while the MW of dextran is
505 kDa. Hence we can safely assume that dextran is totally
retained. Pure water ultrafiltration is governed by
m
v
R
P
J
Rm = 3.33 x 109 Pa.s/m
82. v
m cp g
P
J
R R R
-
+ +
We also know that
v
m
P
J
R
-
Since Rcp and Rg are negligible the equation becomes
Using the above equation we can calculate the osmotic pressure for
every value of transmembrane pressure
ΔP
(kPa)
Pure
water flux
(m/s)
Jv
(m/s)
Δπ
(kPa)
Δπ
(dynes/c
m2)
Cw
(%w/v)
Cw
(g/l)
K
(m/s)
30 9.71x10-6 6.24x10-6 9.22 92208 7.63 76.31 3.07x10-6
40 1.23 x 10-5 7.08x10-6 16.42 164236 10.04 100.43 3.7x10-6
50 1.57x10-5 7.63x10-6 24.59 245921 11.99 119.94 3.07x10-6
60 1.87x10-5 8.02x10-6 33.29 332934 13.61 136.08 3.07x10-6
83. The correlation for osmotic pressure given in the problem can be
rearranged to
2.857
log10 2.48
1.22
w
C
-
Using the above equation the wall concentration at different TMP
can be calculated
The mass transfer coefficient in an UF process with total solute
retention is given by
ln w
v
b
C
J k
C
Rearranging the equation we get
ln
v
w
b
J
k
C
C
84. Microfiltration
• Microfiltration separates
micron-sized particles from
fluids
• The modules used for
microfiltration are similar to
those used in ultrafiltration
• Microfiltration membranes are
microporous and retain
particles by a purely sieving
mechanism
Microfiltration can be operated either in
dead-ended (normal flow) mode or cross-
flow mode
Typical permeate flux values are higher than ultrafiltration
processes even though the processes are operated at much lower
TMP
85. Applications of microfiltration
• Cell harvesting from bioreactors
• Virus removal for solutions
• Clarification of fruit juice and beverages
• Removal of cells from fermentation media
• Water purification
• Air filtration
• Sterilization
86. The permeate flux in microfiltration
)
( C
M
v
R
R
P
J
+
Jv = Permeate flux
P = Pressure difference across the
membrane
RM = Membrane resistance
RC = Cake resistance
= Liquid medium viscosity
The cake resistance
M
S
C
A
V
r
R
r = Specific cake resistance
VS = Volume of cake
AM = Area of membrane
For micron sized particles, r is given by
-
2
3
1
1
180
s
d
r
= Porosity of cake
ds = Mean particle diameter
87. Problem: Microfiltration of bacteria
Bacterial cells having 0.8 micron average diameter are
being microfiltered in the cross-flow mode using a
membrane having an area of 100 cm2.
The steady state cake layer formed on the membrane has
a thickness of 10 microns and a porosity value of 0.35. If
the viscosity of the filtrate obtained is 1.4 cP, predict the
volumetric premeate flux at a transmembrane pressure
of 50 kPa.
When pure water of viscosity 1 cP was filtered through
the same transmembrane pressure, the permeate flux
obtained was 10-4 m/s
88. v
M
P
J
R
For pure water filtration the flux is written as
11
3 4
50000
5 10 /
(1 10 ) (1 10 )
M
v
P
R m
J
-
- -
The specific cake resistance of the bacterial cell cake can be calculated
from
The cake resistance Rc can be calculated from
15 2
3 2 3 7 2
1 1 1 0.35 1
180 180 4.264 10 /
0.35 (8 10 )
s
r m
d
-
- -
15 5 10
4.264 10 1 10 4.264 10 /
S
C c
M
V
R r r m
A
d -
Solution
89. The permeate flux can be calculated from
3 10 11
50000
( ) 1.4 10 (4.264 10 5 10 )
v
M C
P
J
R R
-
+ +
= 6.58 x 10-5 m/s
90. Dialysis
• The mode of transport in
dialysis is diffusion
• Separation occurs
because
– Small molecules diffuse
more rapidly than larger
ones
– Also due to the degree to
which the membrane
restricts transport of
molecules usually
increases with solute size
Membrane
Bulk concentration
on downstream side
(C2)
Boundary layers
Concentration profile in dialysis
Bulk concentration
on upstream side (C1)
91. The rate of mass transport or solute flux (N) is directly proportional
to the difference in concentration (C) at the membrane surfaces
d
C
SD
N eff
S is a dimensionless solute partition coefficient
Deff is the effective diffusivity of the solute within the
membrane
d is the membrane thickness
Deff and d can be combined and termed the membrane mass
transfer coefficient (KM) for a given membrane-solute system
M
M
R
C
C
K
N
Dialysis
92. 2
1
1
1
1
1
K
K
K
K M
O
+
+
KO = the overall mass transfer coefficient
K1 and K2 are the mass transfer
coefficients on the upstream and
downstream sides
2
1 C
C
K
N O -
In terms of mass transfer coefficient
C1 and C2 are the upstream (feed) and
downstream (dialysate) concentrations
2
1 R
R
R
R M
O +
+
The membrane resistance alone seldom governs the overall mass
transport. The liquid boundary layers on either side of the
membrane also contribute to resistance to transport
RO = the overall resistance
R1 = the resistance on the upstream surface
R2 = the resistance on the downstream
surface
94. Co-current and counter-current dialysis
-
-
-
-
-
4
2
3
1
4
2
3
1
ln
)
(
)
(
C
C
C
C
C
C
C
C
Clm
Log-mean concentration difference (∆Clm)
Co-current Counter-current
-
-
-
-
-
3
2
4
1
3
2
4
1
ln
)
(
)
(
C
C
C
C
C
C
C
C
Clm
Length of membrane
Conc.
Feed side
Dialysate
Conc.
Length of membrane
Feed side
Dialysate
97. Co-current flow Counter-current flow
C1
C3
C3
C4
C1
-
-
-
-
-
4
2
3
1
4
2
3
1
ln
)
(
)
(
C
C
C
C
C
C
C
C
Clm
-
-
-
-
-
3
2
4
1
3
2
4
1
ln
)
(
)
(
C
C
C
C
C
C
C
C
Clm
Dialysis modes
C4
98. Applications of dialysis
• Removal of acid or alkali from products
• Removal of alcohol from beer (to make alcohol free
beer)
• Removal of salts and low molecular weight
compounds from solutions of macromolecules
• Concentration of macromolecules
• Dialysis provides a tool for controlling the chemical
species within a reactor
• Purification of biotechnological products
• Haemodialysis
99. The figure below shows a completely mixed dialyser unit. Plasma
having a glutamine concentration of 2 kg/m3 is pumped into the
dialyser at a rate of 5x10-6 m3/s and water at a flow rate of 9 x 10-6
m3/s is used as the dialysing fluid. If the membrane mass transfer
coefficient is 2 x 10-4 m/s and the membrane area is 0.05 m2,
calculate the steady state concentrations of glutamine in the product
and dialysate streams.
Problem
100. Solution
The overall material balance for glutamine gives ------- (a)
The glutamine concentration flux per unit area can be obtained using equation
The amount of glutamine in of the dialysate should be equal to the product of
the concentration flux and area:
The amount of glutamine in the dialysate = Q2C4, therefore
------- (b)
Solving the two equations simultaneously, we get:
C2 = 1.027 kg/m3
C4 = 0.541 kg/m3
2 4
( )
c m m
J K C K C C
-
2 4
* * * ( )
c m m
J A K A C K A C C
-
2 4 2 4
Q C K *A(C C )
m
-
1 1 l 2 2 4
Q C Q C Q C
+
101. Packed bed adsorption has several major
limitations
• High pressure drop
• Increase in pressure drop
during operation
• Column blinding by
proteins
• Dependence on
intraparticle diffusion for
the transport of proteins
to their binding sites
• High process times (due
to iv)
• High flow rates cannot be
used
• High recovery liquid
volume
• Radial and axial dispersion
resulting from the use of
polydisperse media
• Problems associated with
scale-up
102. Advantages of membrane adsorbers
• Low process time
• Low recovery liquid volume
• Possibility of using higher flow rates
• Lower pressure drop
• Less column blinding
• Ease of scale-up
• Fewer problems associated with validation (if
a disposable membrane is used)
103. Comparison of solute transport in particulate
packed bed and membrane adsorbers
104.
105. Different types separation chemistries are
used in membrane adsorption
• Affinity binding
• Ion-exchange interaction
• Reverse phase and hydrophobic interaction
Size exclusion based separation using membrane
beds has not yet been feasible
106. Membrane adsorption
• Membrane adsorption processes are carried
out in two different modes
– Pulse
– Step
• Based on the membrane geometry, three
types of membrane adsorbers are used:
– Flat sheet
– Radial flow
– Hollow fibre
109. δm
θC θD
Diffusion and convection times in
membrane adsorption
Re
s pore
pore
u d
v
Reynolds number of the fluid flowing through
the membrane pores
us = superficial velocity (m/s)
dpore = average pore diameter (m)
v = kinematic viscosity (m2/s)
ε = porosity (-)
2
m
c
s
u
d
2
4
pore
d
d
D
Time taken for solute to diffuse
from central line to the pore wall
Residence time of solute moving
along central line through a pore
dpore
110. An adsorptive membrane has a thickness of 2 mm
and a diameter of 5 cm. The porosity of the
membrane is 0.75 and the tortuosity is 1.5. The
pore diameter was estimated to be 2 x 10-6 m.
If we are to use this membrane for adsorption of a
DNA fragment (diffusivity = 9.5 x 10-12 m2/s) from an
aqueous solution, what is the maximum solution
flow rate that can be used? Assume that the flow
through the pores is laminar
Problem: Membrane adsorption of DNA
111. Area of the membrane = 1.964 x 10-3 m2
The superficial velocity is given by
The convection time can be obtained from
Diffusion time can be calculated using
For total capture of DNA θC > θD . Therefore
The solution flow rate should be lower than 2.098 x 10-5 m3/s.
3
3 2
( / )
/
1.964 10 ( )
s
Q Q m s
u m s
A m
-
3 3 6
2 10 ( ) 1.5 0.75 1.964 10 2.2095 10
2 2
m
c
s
m
s
u Q Q
d
- - -
2 6 2
12
(2 10 )
0.1053
4 4 9.5 10
pore
d
d
s
D
-
-
6
2.2095 x10
0.1053
Q
-
Solution
112. ChromaSorb™ Membrane Adsorber (Millipore)
Single-use, flow-through anion exchanger designed for the removal of
trace impurities including host cell protein (HCP), DNA, endotoxins and
viruses from monoclonal antibody or other protein feedstocks.
115. Liquid membrane technology
• Liquid membrane extraction
involves
– the transport of solutes
across thin layers of liquid
interposed between two
otherwise miscible liquids
• There are two types of
liquid membrane processes:
– Emulsion liquid membrane
(ELM) processes
– Supported liquid membrane
(SLM) processes
121. Introduction
• In RO, the goal is usually to remove a solute
from solution by passing the solvent through
the membrane and leaving the solute in a
concentrated retentate (reject) stream
• Note that this is a continuous process, unlike
filtration; purified water is produced
continuously
122. Advantages
• low energy consumption
• high removal of solute in one stage
• no components added (such as absorbing gas
or extracting liquid)
• no phase change
• low capital costs
• easy, modular, installation
123. Disadvantages
• Membrane life (hopefully 3-5 years)
• Fouling
• Pretreatment costs (removal of suspended solids, fouling
materials)
• Relatively low concentration of solutes
• In order to understand and to predict membrane performance
it is necessary to have transport equations that describe the
transport of solvent and solute through the membrane
• In all membrane processes, we are looking at relationships
between forces (driving forces) and fluxes;
– [Class: you name some examples of these relationships that you
already know.]
124. Osmotic Pressure
• Thermodynamic property of a solution which represents how
different a solution is compared to a pure solvent in terms of
the pressure required to bring the solution up to the same
chemical potential (ie., in equilibrium with) pure solvent
– what this means, practically, is that osmotic pressure acts against the
pressure driving force for transport across a membrane.
• This osmotic pressure can be 'looked up' in a book - a
thermodynamic property.
• A reasonable approximation of osmotic pressure is the Van't
Hoff Eqn
where n is the kmol of solute per
Vm m3 of pure solvent, which is the
same as the molar concentration, ci
125. Osmotic pressure
cRT
2 3
1 2 3
( ......)
RT AC A C A C
+ + +
For concentrated solutions of
uncharged solutes correlations
involving series of virial coefficients
are used
van’t Hoff equation
The osmotic pressure difference across a
membrane is given by
1 2
-
126.
127. Summary of the transport equations
Solvent flux )
(
-
P
A
N W
W
)
( P
A
N W
W
Pure water flux
Solute Flux )
(
)
( 2
2 c
c
A
c
c
L
K
D
N b
S
b
M
S
S
S -
-
Concentration Polarization
)
(
)
(
ln
2
1
2
c
c
c
c
k
c
N
N
c
N
J b
S
W
T
V
-
-
+
Material Balance on Solute
S
W
S
N
N
N
c
c
+
2