Title of Invention	A NOVEL PROCESS FOR PREPARATION OF ENHANCED TRANSMEMBRANE FLUX IN MEMBRANE BASED SEPARATION.
Abstract	The present invention provides a novel process for the preparation of enhanced transmembrane flux in membrane based separations where in higher rate of permeate collection obtained is achieved by enhancement of transmembrane flux achieved by enhancing transmembrane flux by 20-60 percent by continuously applying acoustic field having frequency in the range of 1 kHz to 2 MHz across the membrane, during the entire separation process, in plane perpendicular/lateral to the direction of flux across the said membrane. The said process is applied for both batch and continuous mode of separation.

Title of Invention

A NOVEL PROCESS FOR PREPARATION OF ENHANCED TRANSMEMBRANE FLUX IN MEMBRANE BASED SEPARATION.

Abstract

The present invention provides a novel process for the preparation of enhanced transmembrane flux in membrane based separations where in higher rate of permeate collection obtained is achieved by enhancement of transmembrane flux achieved by enhancing transmembrane flux by 20-60 percent by continuously applying acoustic field having frequency in the range of 1 kHz to 2 MHz across the membrane, during the entire separation process, in plane perpendicular/lateral to the direction of flux across the said membrane. The said process is applied for both batch and continuous mode of separation.

Full Text	The present invention relates to a process for the preparation of enhanced transmembrane flux in membrane based separations. The present invention particularly relates to a process of enhancement of transmembrane flux by the application of acoustic field during membrane based separation processes such as Reverse Osmosis (RO), Ultrafiltration (UF) and Microfiltration (MF). Membrane based process, namely Micro-filtration, Ultra-filtration and Reverse Osmosis, for the filtration and concentration of aqueous solutions are popular in biotechnology and food industries. These membrane based processes suffer from the common drawback of low flux across the membranes making these processes too slow, especially when the process streams are non-Newtonian in nature and, to be concentrated by removing the solvent (water) from it. Hence there is a need for an economically viable technique for the enhancement of solvent flux across membranes by the application of additional force fields. Reference may be made to the application of acoustic field in combination with electric field for solid-liquid separation process for fine coal particle suspensions (Muralidhara et al, 1988, US Patent # 4, 747, 920). However, this work refers to the separation of solid particles from liquid, that to, for coal particles. Another reference may be made the work reported for biological membranes (Julian and Zenter, 1990; Edwards and Lnager, 1994). This reference mainly deals with transfer of drugs, (in other words, solutes) across the skin (membrane). Another reference may be made to the application of high intensity electric field pulses on plant membrane permealization (Knorr and Angersbach, 1998). However, it may be noted that permanent damage to the membrane was caused during the process and test was conducted on a natural membrane. Another reference may be made to the report on solute diffusion through polymeric membranes (Lenart and Auslande, 1980). hi all the above references, the application is either in the non-food sector or for solute diffusion. It may be noted that all these refers to solid migration or flux and no report on the enhancement of solvent flux across the polymeric membrane by an acoustic or any other field is available in the literature. The main object of the present invention is to provide a process for the preparation of enhanced transmembrane flux in membrane based separation processes. Another object of the present invention is to exploit acoustic field for the enhancement of transmembrane flux across membrane during membrane based separation processes, which is a novel approach. Still another object of the present invention is to facilitate downstream processing of industrially important polysaccharides. Yet another object of the present invention is to facilitate the concentration of fruit juices to higher degree of concentration using membrane based processes. In the drawing accompanying this specification figure 1 represents the schematic diagram of the experimental set up. In figure 1, the laboratory scale, batch stir cell assembly (1) having a magnetic spin bar (2) as an attachment, consists of a polymeric membrane (3) kept on a porous support (4), placed over an acoustic transducer (5), which in turn is kept on a magnetic stir plate (6), and stir cell (1) is flushed with Nitrogen (N2) or Carbon dioxide (COj) supplied from a gas cylinder (7) having a pressure regulator (8), to collect the permeate in a reservoir (9) weight of which is measured using a balance (10) that is interfaced with the personal computer (11). Accordingly the present invention provides a process for preparation of enhanced transmembrane flux in membrane based separation processes, which comprises, carrying out a separation process for materials selected from polysaccharide solution, slurries of cells, particles or macromolecules using the method selected from the group consisting of Ultrafiltration, Microfiltration, Reverse Osmosis, Membrane distillation, Osmotic distillation, Direct Osmosis and characterizing the continuous application of acoustic field perpendicularly or laterally to the direction of flux across the membrane in entire duration of separation process employed to obtain the permeate at a faster rate and to enhance the transmembrane flux by 20-60 %. In an another embodiment of the present invention, the higher rate of permeate collection is achieved by the enhancement of transmembrane flux in the separation process used. In an another embodiment of the present invention, the gas used for compressing the stir cell is Nitrogen, Carbon dioxide or any other inert gas. In an another embodiment of the present invention, the operation selected is batch mode and continual mode. In an another embodiment of the present invention, the acoustic field application is in the frequency of 1 kHz to 2 MHz. In the present invention, polysaccharide solution (Dextran) is taken in a laboratory scale, batch stir cell fitted with a known Molecular Weight Cut off (MWCO) polymeric membrane. The stir cell is placed on an acoustic transducer, which in turn placed over a magnetic stirrer. The stir cell is then pasteurized with CO2 or N2 gas. The gas pressure and the speed of the magnetic stirrer are kept constant throughout the experiment. The acoustic field is applied to the stir cell and, the acoustic frequency is maintained constant throughout the experiment. The permeate from the stir cell is collected in the reservoir kept on the digital weighing balance. The weighing balance is interfaced with the personal computer to record the weight of permeate collected during the experimentation. The amount of permeate collected for a known period is measured and permeate flux is calculated using the software, which was developed in-house. The concentration of feed was continued till the volume reduced to half of its original volume. Conventional wisdom enabled to enhance the solute diffusion, (diffusivity 'D') by varying the convective flow and/or the effective temperature gradient by the application of acoustic field. The novelty of the present invention is that the enhancement of transmembrane flux is based on different principle, namely, disturbing the hydrodynamic boundary layer (viscous effects) and associated concentration polarization layer, which offer resistance to the flux. The following examples are given by way of illustration of the present invention and should not be construed to limit the scope of the present invention. Example-1 100 ml of polysaccharide solution (Dextran) was taken in the laboratory scale, batch stir cell assembly (1) fitted with a composite RO membrane (3) (4.0 cm diameter and 10 cm2 area) on a porous support (4). Nitrogen gas was flushed in to the stir cell from the gas cylinder (7) and the pressure in the cell was maintained at 0.34 MPa using the pressure regulator (8). The speed of the magnetic spin bar (2) and the acoustic field frequency were maintained throughout the experiment at 100 rpm and 1.2 MHz, using magnetic stir plate (6) and acoustic transducer (5) respectively. Permeate from the cell was collected in the reservoir (9) kept on a weighing balance (10). The personal computer (11), which was interfaced with the weighing balance, measured the amount of permeate collected for every 5 minutes and flux was calculated using the software developed in-house. The experiment was continued till the volume of the feed reduced to half of its original value (50 ml). Water flux, during concentration, was enhanced about 1.2 folds by the application of acoustic energy to stir cell. Example-2 100 ml of polysaccharide solution (Dextran) was taken in the laboratory scale, batch stir cell assembly (1) fitted with a composite RO membrane (3) (4.0 cm diameter and 10 cm2 area) on a porous support (4). Carbon di-oxide gas was flushed in to the stir cell from the gas cylinder (7) and the pressure in the cell was maintained at 0.34 MPa using the pressure regulator (8). The speed of the magnetic spin bar (2) and the acoustic field frequency were maintained throughout the experiment at 100 rpm and 1.2 MHz, using magnetic stir plate (6) and acoustic transducer (5) respectively. Permeate from the cell was collected in the reservoir (9) kept on a weighing balance (10). The personal computer (11), which was interfaced with the weighing balance, measured the amount of permeate collected for every 5 minutes and flux was calculated using the software developed in-house. The experiment was continued till the volume of the feed reduced to half of its original value (50 ml). Water flux, during concentration, was enhanced about 1.6 folds by the application of acoustic energy to stir cell. Though the concentration process of the present invention illustrated to use of polysaccharide solution, it can be implemented for concentrating other solutions such as here in described. The main advantages of the present invention are 1. Enables to over come the main draw back of membrane based separation processes namely low transmembrane flux. 2. Higher energy efficiency and lower cost over conventional process used for downstream processing and recovery of cells, particles or macromolecules, and for clarification and concentration of solutions such as fruit juices. This is mainly due to the energy efficiency of the membrane processes especially when supplemented by another energy efficient process in the form of acoustic field application (acoustic transducers are high voltage low current devices). 3. Enables the overcoming of the main bottleneck in the industrial recovery and purification method for these polysaccharides, which is the high cost of precipitating agent (ethyl alcohol or isopropyl alcohol). Due to the present invention, these could be accomplished with greatly reduced volumes of the solutions as well as precipitating agents, which in turn reduce the cost drastically. We claim: 1. A novel process for the preparation of enhanced transmembrane flux in membrane based separations, which comprises the steps of: (a) separating materials selected from the group consisting of polysaccharide, slurries of cells, particles and macromolecules by method selected from group consisting of ultrafilteration, microfilteration, reverse osmosis, membrane distillation, osmotic distillation and direct osmosis; and (b) enhancing transmembrane flux by 20-60 percent in order to obtain permeate at faster rate; characterized in that the said enhancement is achieved by continuously applying acoustic field having frequency in the range of 1 kHz to 2 MHz across the membrane during the entire separation process of step (a) said above. 2. A novel process as claimed in claim 1, where in higher rate of permeate collection obtained is achieved by enhancement of transmembrane flux in the separation process used. 3. A process as claimed in claims 1 and 2, wherein the gas used for pressuring stirred cell is selected from Nitrogen and Carbon dioxide. 4. A process as claimed in claims 1-3, wherein acoustic field used is applied in plane perpendicular/lateral to the direction of flux across the said membrane. 5. A process as claimed in claims 1-4, wherein separating materials used in step (a) of claim 1 is in batch mode. 6. A process as claimed in claims 1-4, wherein separating materials used in step (a) of claim 1 is in continuous mode. 7. A novel process for the preparation of enhanced transmembrane flux in membrane based separations substantially as herein described in description ; exemplified in accompanying examples and illustrated in the accompanying drawings.

Full Text

The present invention relates to a process for the preparation of enhanced transmembrane flux in membrane based separations. The present invention particularly relates to a process of enhancement of transmembrane flux by the application of acoustic field during membrane based separation processes such as Reverse Osmosis (RO), Ultrafiltration (UF) and Microfiltration (MF).
Membrane based process, namely Micro-filtration, Ultra-filtration and Reverse Osmosis, for the filtration and concentration of aqueous solutions are popular in biotechnology and food industries. These membrane based processes suffer from the common drawback of low flux across the membranes making these processes too slow, especially when the process streams are non-Newtonian in nature and, to be concentrated by removing the solvent (water) from it. Hence there is a need for an economically viable technique for the enhancement of solvent flux across membranes by the application of additional force fields.
Reference may be made to the application of acoustic field in combination with electric field for solid-liquid separation process for fine coal particle suspensions (Muralidhara et al, 1988, US Patent # 4, 747, 920). However, this work refers to the separation of solid particles from liquid, that to, for coal particles.
Another reference may be made the work reported for biological membranes (Julian and Zenter, 1990; Edwards and Lnager, 1994). This reference mainly deals with transfer of drugs, (in other words, solutes) across the skin (membrane).
Another reference may be made to the application of high intensity electric field pulses on plant membrane permealization (Knorr and Angersbach, 1998). However, it

may be noted that permanent damage to the membrane was caused during the process and test was conducted on a natural membrane.
Another reference may be made to the report on solute diffusion through polymeric membranes (Lenart and Auslande, 1980). hi all the above references, the application is either in the non-food sector or for solute diffusion. It may be noted that all these refers to solid migration or flux and no report on the enhancement of solvent flux across the polymeric membrane by an acoustic or any other field is available in the literature.
The main object of the present invention is to provide a process for the preparation of enhanced transmembrane flux in membrane based separation processes.
Another object of the present invention is to exploit acoustic field for the enhancement of transmembrane flux across membrane during membrane based separation processes, which is a novel approach.
Still another object of the present invention is to facilitate downstream processing of industrially important polysaccharides.
Yet another object of the present invention is to facilitate the concentration of fruit juices to higher degree of concentration using membrane based processes.
In the drawing accompanying this specification figure 1 represents the schematic diagram of the experimental set up. In figure 1, the laboratory scale, batch stir cell assembly (1) having a magnetic spin bar (2) as an attachment, consists of a polymeric membrane (3) kept on a porous support (4), placed over an acoustic transducer (5), which in turn is kept on a magnetic stir plate (6), and stir cell (1) is flushed with Nitrogen (N2) or Carbon dioxide (COj) supplied from a gas cylinder (7) having a pressure regulator (8),

to collect the permeate in a reservoir (9) weight of which is measured using a balance (10) that is interfaced with the personal computer (11).
Accordingly the present invention provides a process for preparation of enhanced transmembrane flux in membrane based separation processes, which comprises, carrying out a separation process for materials selected from polysaccharide solution, slurries of cells, particles or macromolecules using the method selected from the group consisting of Ultrafiltration, Microfiltration, Reverse Osmosis, Membrane distillation, Osmotic distillation, Direct Osmosis and characterizing the continuous application of acoustic field perpendicularly or laterally to the direction of flux across the membrane in entire duration of separation process employed to obtain the permeate at a faster rate and to enhance the transmembrane flux by 20-60 %.
In an another embodiment of the present invention, the higher rate of permeate collection is achieved by the enhancement of transmembrane flux in the separation process used.
In an another embodiment of the present invention, the gas used for compressing the stir cell is Nitrogen, Carbon dioxide or any other inert gas.
In an another embodiment of the present invention, the operation selected is batch mode and continual mode.
In an another embodiment of the present invention, the acoustic field application is in the frequency of 1 kHz to 2 MHz.
In the present invention, polysaccharide solution (Dextran) is taken in a laboratory scale, batch stir cell fitted with a known Molecular Weight Cut off (MWCO) polymeric membrane. The stir cell is placed on an acoustic transducer, which in turn placed over a

magnetic stirrer. The stir cell is then pasteurized with CO2 or N2 gas. The gas pressure and the speed of the magnetic stirrer are kept constant throughout the experiment. The acoustic field is applied to the stir cell and, the acoustic frequency is maintained constant throughout the experiment. The permeate from the stir cell is collected in the reservoir kept on the digital weighing balance. The weighing balance is interfaced with the personal computer to record the weight of permeate collected during the experimentation. The amount of permeate collected for a known period is measured and permeate flux is calculated using the software, which was developed in-house. The concentration of feed was continued till the volume reduced to half of its original volume.
Conventional wisdom enabled to enhance the solute diffusion, (diffusivity 'D') by varying the convective flow and/or the effective temperature gradient by the application of acoustic field.
The novelty of the present invention is that the enhancement of transmembrane flux is based on different principle, namely, disturbing the hydrodynamic boundary layer (viscous effects) and associated concentration polarization layer, which offer resistance to the flux.
The following examples are given by way of illustration of the present invention and should not be construed to limit the scope of the present invention.
Example-1
100 ml of polysaccharide solution (Dextran) was taken in the laboratory scale, batch stir cell assembly (1) fitted with a composite RO membrane (3) (4.0 cm diameter and 10 cm2 area) on a porous support (4). Nitrogen gas was flushed in to the stir cell from the gas cylinder (7) and the pressure in the cell was maintained at 0.34 MPa using the

pressure regulator (8). The speed of the magnetic spin bar (2) and the acoustic field frequency were maintained throughout the experiment at 100 rpm and 1.2 MHz, using magnetic stir plate (6) and acoustic transducer (5) respectively. Permeate from the cell was collected in the reservoir (9) kept on a weighing balance (10). The personal computer (11), which was interfaced with the weighing balance, measured the amount of permeate collected for every 5 minutes and flux was calculated using the software developed in-house.
The experiment was continued till the volume of the feed reduced to half of its original value (50 ml). Water flux, during concentration, was enhanced about 1.2 folds by the application of acoustic energy to stir cell.
Example-2
100 ml of polysaccharide solution (Dextran) was taken in the laboratory scale, batch stir cell assembly (1) fitted with a composite RO membrane (3) (4.0 cm diameter and 10 cm2 area) on a porous support (4). Carbon di-oxide gas was flushed in to the stir cell from the gas cylinder (7) and the pressure in the cell was maintained at 0.34 MPa using the pressure regulator (8). The speed of the magnetic spin bar (2) and the acoustic field frequency were maintained throughout the experiment at 100 rpm and 1.2 MHz, using magnetic stir plate (6) and acoustic transducer (5) respectively. Permeate from the cell was collected in the reservoir (9) kept on a weighing balance (10). The personal computer (11), which was interfaced with the weighing balance, measured the amount of permeate collected for every 5 minutes and flux was calculated using the software developed in-house. The experiment was continued till the volume of the feed reduced to

half of its original value (50 ml). Water flux, during concentration, was enhanced about 1.6 folds by the application of acoustic energy to stir cell.
Though the concentration process of the present invention illustrated to use of polysaccharide solution, it can be implemented for concentrating other solutions such as here in described. The main advantages of the present invention are
1. Enables to over come the main draw back of membrane based separation
processes namely low transmembrane flux.
2. Higher energy efficiency and lower cost over conventional process used for
downstream processing and recovery of cells, particles or macromolecules, and
for clarification and concentration of solutions such as fruit juices. This is mainly
due to the energy efficiency of the membrane processes especially when
supplemented by another energy efficient process in the form of acoustic field
application (acoustic transducers are high voltage low current devices).
3. Enables the overcoming of the main bottleneck in the industrial recovery and
purification method for these polysaccharides, which is the high cost of
precipitating agent (ethyl alcohol or isopropyl alcohol). Due to the present
invention, these could be accomplished with greatly reduced volumes of the
solutions as well as precipitating agents, which in turn reduce the cost drastically.

We claim:
1. A novel process for the preparation of enhanced transmembrane flux in
membrane based separations, which comprises the steps of:
(a) separating materials selected from the group consisting of polysaccharide,
slurries of cells, particles and macromolecules by method selected from group
consisting of ultrafilteration, microfilteration, reverse osmosis, membrane
distillation, osmotic distillation and direct osmosis; and
(b) enhancing transmembrane flux by 20-60 percent in order to obtain permeate at
faster rate; characterized in that the said enhancement is achieved by
continuously applying acoustic field having frequency in the range of 1 kHz to
2 MHz across the membrane during the entire separation process of step (a)
said above.

2. A novel process as claimed in claim 1, where in higher rate of permeate collection
obtained is achieved by enhancement of transmembrane flux in the separation
process used.
3. A process as claimed in claims 1 and 2, wherein the gas used for pressuring
stirred cell is selected from Nitrogen and Carbon dioxide.
4. A process as claimed in claims 1-3, wherein acoustic field used is applied in plane
perpendicular/lateral to the direction of flux across the said membrane.
5. A process as claimed in claims 1-4, wherein separating materials used in step (a)
of claim 1 is in batch mode.

6. A process as claimed in claims 1-4, wherein separating materials used in step (a)
of claim 1 is in continuous mode.
7. A novel process for the preparation of enhanced transmembrane flux in
membrane based separations substantially as herein described in description ;
exemplified in accompanying examples and illustrated in the accompanying
drawings.

Documents:

385-del-2001-abstract.pdf

385-del-2001-claims.pdf

385-del-2001-correspondence-others.pdf

385-del-2001-correspondence-po.pdf

385-del-2001-description (complete).pdf

385-del-2001-drawings.pdf

385-del-2001-form-1.pdf

385-del-2001-form-18.pdf

385-del-2001-form-2.pdf

385-del-2001-form-3.pdf

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Patent Number

231590

Indian Patent Application Number

385/DEL/2001

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

06-Mar-2009

Date of Filing

29-Mar-2001

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	NAVEEN NAGARAJ	CENTRAL FOOD TECHNOLOGICAL RESEARCH INSTITUTE, MYSORE-570013, KARNATAKA, INDIA.
2	RAGHAVARAO KSMS	CENTRAL FOOD TECHNOLOGICAL RESEARCH INSTITUTE, MYSORE-570013, KARNATAKA, INDIA.
3	RAMESH THOTADAMOOLE	CENTRAL FOOD TECHNOLOGICAL RESEARCH INSTITUTE, MYSORE-570013, KARNATAKA, INDIA.
4	HANGALORE UMESH HEBBAR	CENTRAL FOOD TECHNOLOGICAL RESEARCH INSTITUTE, MYSORE-570013, KARNATAKA, INDIA.

PCT International Classification Number

C02F 1/44

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA