CA1157712A - Dynamic membrane process on moving porous support - Google Patents
Dynamic membrane process on moving porous supportInfo
- Publication number
- CA1157712A CA1157712A CA000309856A CA309856A CA1157712A CA 1157712 A CA1157712 A CA 1157712A CA 000309856 A CA000309856 A CA 000309856A CA 309856 A CA309856 A CA 309856A CA 1157712 A CA1157712 A CA 1157712A
- Authority
- CA
- Canada
- Prior art keywords
- membrane
- substrate
- rotating
- water
- macromolecules
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000012528 membrane Substances 0.000 title claims abstract description 87
- 238000000034 method Methods 0.000 title claims abstract description 46
- 239000000243 solution Substances 0.000 claims abstract description 29
- 239000000126 substance Substances 0.000 claims abstract description 26
- 239000012527 feed solution Substances 0.000 claims abstract description 16
- 239000000758 substrate Substances 0.000 claims description 40
- 229920002521 macromolecule Polymers 0.000 claims description 17
- 239000002195 soluble material Substances 0.000 claims description 12
- 239000000975 dye Substances 0.000 claims description 11
- 229910052751 metal Inorganic materials 0.000 claims description 10
- 239000002184 metal Substances 0.000 claims description 10
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 229920000867 polyelectrolyte Polymers 0.000 claims description 9
- 230000007935 neutral effect Effects 0.000 claims description 8
- 229920000620 organic polymer Polymers 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 7
- 239000011148 porous material Substances 0.000 claims description 7
- 239000001022 rhodamine dye Substances 0.000 claims description 7
- 150000003839 salts Chemical class 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- 239000008346 aqueous phase Substances 0.000 claims description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 4
- 229920002125 Sokalan® Polymers 0.000 claims description 4
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 4
- 238000002386 leaching Methods 0.000 claims description 4
- 239000004584 polyacrylic acid Substances 0.000 claims description 4
- 229910052726 zirconium Inorganic materials 0.000 claims description 4
- ZSLUVFAKFWKJRC-IGMARMGPSA-N 232Th Chemical compound [232Th] ZSLUVFAKFWKJRC-IGMARMGPSA-N 0.000 claims description 3
- 229910052776 Thorium Inorganic materials 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 229910044991 metal oxide Inorganic materials 0.000 claims description 3
- 150000004706 metal oxides Chemical class 0.000 claims description 3
- 239000004952 Polyamide Substances 0.000 claims description 2
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 claims description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- 239000000919 ceramic Substances 0.000 claims description 2
- 238000010411 cooking Methods 0.000 claims description 2
- 238000000855 fermentation Methods 0.000 claims description 2
- 230000004151 fermentation Effects 0.000 claims description 2
- 235000013305 food Nutrition 0.000 claims description 2
- 239000002655 kraft paper Substances 0.000 claims description 2
- 239000000463 material Substances 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 239000000123 paper Substances 0.000 claims description 2
- 229920003023 plastic Polymers 0.000 claims description 2
- 239000004033 plastic Substances 0.000 claims description 2
- 229920002647 polyamide Polymers 0.000 claims description 2
- 229920005646 polycarboxylate Polymers 0.000 claims description 2
- 229920002717 polyvinylpyridine Polymers 0.000 claims description 2
- 235000013606 potato chips Nutrition 0.000 claims description 2
- 238000002360 preparation method Methods 0.000 claims description 2
- 229910001220 stainless steel Inorganic materials 0.000 claims description 2
- 239000010935 stainless steel Substances 0.000 claims description 2
- 239000004753 textile Substances 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 239000002351 wastewater Substances 0.000 claims description 2
- 210000004379 membrane Anatomy 0.000 claims 19
- 239000010919 dye waste Substances 0.000 claims 1
- 238000005342 ion exchange Methods 0.000 claims 1
- 239000005486 organic electrolyte Substances 0.000 claims 1
- 238000000926 separation method Methods 0.000 abstract description 16
- 230000015572 biosynthetic process Effects 0.000 abstract description 15
- 230000004907 flux Effects 0.000 abstract description 12
- 239000012466 permeate Substances 0.000 abstract description 12
- 238000005265 energy consumption Methods 0.000 abstract description 5
- 239000010419 fine particle Substances 0.000 abstract 2
- 230000002730 additional effect Effects 0.000 abstract 1
- 239000002245 particle Substances 0.000 abstract 1
- 239000000725 suspension Substances 0.000 description 6
- 238000002834 transmittance Methods 0.000 description 6
- 239000007788 liquid Substances 0.000 description 5
- 230000003287 optical effect Effects 0.000 description 5
- 230000004888 barrier function Effects 0.000 description 4
- 239000003792 electrolyte Substances 0.000 description 4
- 239000012071 phase Substances 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- PYWVYCXTNDRMGF-UHFFFAOYSA-N rhodamine B Chemical compound [Cl-].C=12C=CC(=[N+](CC)CC)C=C2OC2=CC(N(CC)CC)=CC=C2C=1C1=CC=CC=C1C(O)=O PYWVYCXTNDRMGF-UHFFFAOYSA-N 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 239000000084 colloidal system Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 238000011001 backwashing Methods 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 230000002844 continuous effect Effects 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000000424 optical density measurement Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 229940043267 rhodamine b Drugs 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/14—Ultrafiltration; Microfiltration
- B01D61/145—Ultrafiltration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
- B01D63/16—Rotary, reciprocated or vibrated modules
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/14—Dynamic membranes
- B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
- B01D69/148—Organic/inorganic mixed matrix membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2315/00—Details relating to the membrane module operation
- B01D2315/02—Rotation or turning
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2323/00—Details relating to membrane preparation
- B01D2323/40—Details relating to membrane preparation in-situ membrane formation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/14—Paint wastes
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/26—Nature of the water, waste water, sewage or sludge to be treated from the processing of plants or parts thereof
- C02F2103/28—Nature of the water, waste water, sewage or sludge to be treated from the processing of plants or parts thereof from the paper or cellulose industry
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/30—Nature of the water, waste water, sewage or sludge to be treated from the textile industry
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/32—Nature of the water, waste water, sewage or sludge to be treated from the food or foodstuff industry, e.g. brewery waste waters
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Water Supply & Treatment (AREA)
- Inorganic Chemistry (AREA)
- Dispersion Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
ABSTRACT
It is known the dynamic membrane process in which dynamic membrane formation and further rejection of the dissolved substances and/or fine particle separation from a solution are made on a motionless porous support at the transmembrane pressure in the range of 400-I000 psig.Frequently,in addition to this high transmembrane pressure, a high velocity circulating cross-flow feed stream is used in order to achieve high permeate flux.To carry out this feed circulation an additio-nal energy consumption is required.
In this invention the dynamic membrane formation and further rejection and/or particle separation by previously formed dynamic membrane are carried out on a rotating porous support that allows to achieve both dynamic membrane formation and further rejection of dissolved substances and/or fine particle separation from solution by previously formed membrane at forty- to hundredfold lower transmembrane pressure(7-20psig.
and without or under very low cross-flow stream of the feed solution.
By this,the permeate flux,i.e. specific productivity of the dynamic membrane,is in the same range as for high transmembrane pressure and high velocity cross-flow feed stream dynamic membrane process carried out on a motionless porous support.
It is known the dynamic membrane process in which dynamic membrane formation and further rejection of the dissolved substances and/or fine particle separation from a solution are made on a motionless porous support at the transmembrane pressure in the range of 400-I000 psig.Frequently,in addition to this high transmembrane pressure, a high velocity circulating cross-flow feed stream is used in order to achieve high permeate flux.To carry out this feed circulation an additio-nal energy consumption is required.
In this invention the dynamic membrane formation and further rejection and/or particle separation by previously formed dynamic membrane are carried out on a rotating porous support that allows to achieve both dynamic membrane formation and further rejection of dissolved substances and/or fine particle separation from solution by previously formed membrane at forty- to hundredfold lower transmembrane pressure(7-20psig.
and without or under very low cross-flow stream of the feed solution.
By this,the permeate flux,i.e. specific productivity of the dynamic membrane,is in the same range as for high transmembrane pressure and high velocity cross-flow feed stream dynamic membrane process carried out on a motionless porous support.
Description
~ ?;1i Z
SPECIFICATION
This invention relates to a new dynamic membrane process with applica-tion of the forces developed in the vicinity of the moving porous support,in particular apllication of the centrifugal forces developed in the vicinity of the rotating porous support.
More particularly,the invention relates to a new process of dynamic membrane formation and then rejection and/or separation of suspended particulates from continuous phase by the help of previously formed dynamic membrane,using in the both stages(i.e. membrane formation and further rejection and/or separation of suspended particulates)the forces developed in the vicinity of the moving porous support,in par-ticular the centrifugal forces developed in the vicinity of the rotating porous support.
It i~ known the process of dynamic membrane formation by filtration of dilute suspensions or ~lectrol~tes through the motionless support at high pressure drop across the support of about 400-I000 psig,thus forming on the surface of the support a thin colloid layer,naimly dynamic membrane,used then in a motionless state as a semi-conductive membrane for rejection of dissolved substances and/or separation of fine particulates from a continuous fluid contaminated by these substan-ces and/or suspended particulates.
In some other known dynamic membrane processes and appllcatloDs of these processes, the additional flow of suspenslon along the surface of the motionless p~rous barrier, so-called Cross-Flow, is used in both membrane formation and further separation and/or re~ection processes in order to form more stable and uniform dynamic membrane, increase the permeate flux (i.e., the specific production rate~, degree of separation and the useful life of the membrane. In all these applications of dynamic membrane processes, the usual range of the pressure drop across porous barrier is of about 400 to 1000 psig and the circulation velocity of Cross-Flow is of about 15-25 ft/sec. All this results in high energy consumption per unit of permeate flux and disadvantages of operation at high pressure.
Another known method for separation of fine particulates from a continuous phase is centrifugation, application of which is often limited by high energy consumptions required for high speed rotation of the body ant for the motion of the whole liquid mass within the rotating centrifugal device.
It is the object of this invention to overcome the forgoing disadvantages by providing a new dynamic membrane formation process and then separation of particulates and/or rejection of the dissolved substances by previously formed dynamic membrane, using for both stages the forces developed in the vicinity of the moving porous support, in particular in the vicinity of the rotating porous support.
-7~
In the case of rotatable motion of the porous support,the process of thisinvention comprises,generally saying,the rotatable element or elements with a perforated or porous surface(that is the support for the forming dynamic membrane),which rotate in the suspension or electrolyte going across the porous barrier under a definite pressure drop between the outside and inside of the elements.Due to the centrifugal forces developed in the vicinity of the rotating elements,the uniform and stable dynamic membrane formation is possible to perform under the pressure drop across the porous barrier that is tenfold to hundredfold lower than that for the known dynamic membrane processes on the motionless porous support and even without additional intensive cross-flow stream of the feed suspension.
In the stage of separation of particulates and/or rejection of dissolved substances by previously formed dynamic membrane the same conditions,i.e.
low pressure drop,rotation of the membrane and even absence of cros-flow result in high selectivity of the membranejand permeate flux,as well as in long working period or useful life of the dynam~cemembrane.
In both stages the rotation velocity of the elements should be equal or beyond the threshold velocity.
The energy consumption for the process of this invention is much less in comparison with the known dynamic membrane processes on motionless modules,bec~use of the absence of pumping system required for high pressure and high velocity cros$-flow stream.
The energy consumption for the process of this invention is much less also in comparison with the conventional centrifugal separation,since the diameter of required rotating porous surface will be,generally saying, much less in the process of this invention than that in the conventional centrifugal process.On the other hand the energy required for rotation of of the body is proportional to the rotated diameter in the FORTH POWER.
Another factor responsible for the energy saving in the process of this invention in comparison to conventional centrifugal separation is that in the last case an additional energy required for rotational motion of the whole mass of the liquid within the centrifugal device,while in the process of this invention the motion only of the continuous phase layer in the vicinity of rotating elememt or elements is induced.
The process of this invention will be more fully illustrated by the following example,particulatlly with reference to the accompanying d,agrammic drawing-(Figure I).
In no way,however,it is intended to limit thereto the scope of the invention.
E X A M P L E
In a waste liquid treatment plant designed for separation of fine particulates and/or rejection of dissolved substances from waste liquid and further reuse of the purified liquid and/orrecovery of the chemicals, the first stage of the process of this invention is dynamic membrane formation:
The suspension or electrolyte from which dynamic membrane must be formed is prepared and placed in the mixing tank I.During membrane ormation process the suspension or electrolyte is circulating in the the pump 2, close loop-mixing tank I,the space between motionless body 3 and rotaing element(or elements) with porous surface 4, mixing tank I., - being under definite controlled pressure outside the rotating element(or elements).
lZ
In time of the dynamic membrane formation stage,on the surface of the element(or elements) the thin colloid layer,i.e. dynamic membrane,is formed.The clean liquid phase of the suspension or electrolyte is comming from the inside space of the rotating element(or elements) and accumulating in the tank 6,while the concentration of particulates in the circulating stream is increasing.
The second stage of the process of this invention is separation of the particulates and/or rejection of dissolved substances from contaminated continuous phase by the previously formed dynamic membrane:
This stage can be carried out as or batch,or semibatch,or continuous process.For continuous version of the process,the same scheme as described above can be applied.
The third staqe of the process of this invention is reqeneration or _ withd~aw of the~ c-ontamina-te~ -dynamic membrane:
After decrease of the permeate flux in the course of the second stage of the process of this invention to a definite forseen value the contaminated membrane must be regenerated or withdrawn without dismantling the device~
by washing or backwashing of the rotating element by a special solutions.
Then,once again the membrane forma~ion stage s~uld be carried out and so on.
~7 Some results from the test runs are shown in the enclosed Figure 2 and Figure 3. These results should not be construed to limit the range of operation.
In these test runs the dynamic membrane was formed from the 0.2% ZrOC12 in 0.05M NaCl solutio ~on a rotating 0.2 micron support under the pressure drop across support of about I0.2 psig and 2000rpm.,corresponding to the linear velocity of rotating element of about I5.4 ft/sec.
In figure 2 are plotted the rejection of Zirconium and permeate flux in time of dynamic membrane formation,that was about 30 minutes.
The rejection was calculated on the basis of turbidity control of the reject stream and the permeate flux.
As it can be seen from the figure 2 after 3-5 minutes o~ membrane formation process the rejection of Zr had reached the stable value of about 95 ~,that determines a good performance of membrane formation process under described conditions.
The selectivity of formed dynamic membrane was tested by Rhodamine dye rejection from the solution with initial optical density corresponding to about 60 % in Transmittance and g % in Transmittance,measuured by Bausch and Lomb Spectrophotometer,model Spectronic 70,in the 550 nm wavelength.The pressure drop across the rotating dynamic membrane was about I0.2 psig.
In figure 3 are plotted the permeate flux and rejection of Rhodamine dye from solution by previously formed dynamic membrane under rotations of the membrane equal to 2000rpm and initial optical density of feed Rhoda-mine solution of about 60% in transmittance during the first 60 minutes of the rejection process,and further at the initial optical density of feed solution raised up to 9% in transmittance.Another curves in the Figure 3 show the rejection of the dye and permeate flux when initial optical density of the feed dye solution was about 60~ in Transmittance, the pressure drop across rotating dynamic membrane was once again about I0.2 psig,but rotations were decreased to I500 rpm.
As it can be seen from the Figure 3 the rejection of the dye,calculated on the basis of feed and product optical density measurements,was rather high and stable under the rotations of 2000 rpm,that was found for described conditions as equal to threshold velocity.Increase in initial optical density of the Rhodamine dye solution from 60% to 9% in Transmittance resulted in small changes in terms of dye rejection and permeate flux.
On the other hand,separation of Rhodamine dye solution by dynamic membrane under the same co~ditions in terms of initial feed concentration and pressure drop,~ut rotation velocity below the threshold value resulted in some decrease of dye rejection after 45-55 minutes of the process,and understandable increase in permeate flux.
The Rhodamine dye rejection test runs were carried out in the version of continuou~circulation of the dye feed solution .However,the circulation velocity along the rotating element was negligible low(about 0.2 ft/sec).
For some types of Rhodamine dye such as Rhodamine B dye it was found the interaction between Zr hydrous oxide dynamic membrane and dye solution.
In t~is case the stable rejection performance was achieved by the dual Zr-PAA membrane previously formed dynamically under described above conditions(i.e.low pressure drop about 7.5-I0.2 psig and rotation about 2000 rpm).
.Y12 SUPPLEMENTARY DISCLOSURE
The material contained in the aqueous phase to be used for formation of a dynamic permeable substance-re~ecting membrane on a rotating permeable substrate is a polyvalent metal selected from the group consisting of iron, zirconium, ant thorium, and capable of forming a hydrous metal oxide, or polyvinylpyridine, neutral organic polymer, or polyelectrolyte selected from the group consisting of polysulfonates, polyamides, and polycarboxylates;
or polyacrylic acid at concentration of 50 to 150 ppm; or a mixture of a polyvalent metal capable of forming a hydrous metal oxide such as iron, zirconium, or thorium and polyacrylic acid; or a mixture of at least one component selected from a first group of classes consisting of polyelectrolytes and uater-soluble polyvalent metal salts, and at least one component from a different class selected from a second group consistin& of polyelectrolytes and neutral organic polymers, or a mixture of a polyelectrolyte and a neutral organic polymer; or a mixture of water-soluble polyva~ent metal salts and a member selected from the group consisting of polyelectrolytes and neutral organic polymers.
A dynamic permeable substance-rejecting membrane formed by forcing an aqueous phase containing a water soluble material selected from the groups mentioned above through a rotating permeable substrate containing pores (30 A to 20 microns diame~er) and selected from the group consisting of acropor membrane, X
nuclepore membrane, porous stainless steel, porous titanium, porous nickel, porous ceramics and porous plastics at rotational velocity of said substrate equivalent to linear velocity of said substrate of 3.2 meters per second to 6.4 meters per second and pressure of 0.7 atmosphere to 45.0 a~mospheres.
A dynamic permeable substance-rejecting membrane formed by forcing an aqueous phase containing a water soluble material selected from the groups mentioned above through a rotating permeable substrate containing pores has capability to re~ect macromolecules and dissolved substances from a feed solution containing said macromolecules and subtances when a dose of feed solution is passing over said rotating face of the resulting substrate at a pressure and a flow velocity sufficient to force the first portion of feed solution through the pores of said rotating resulting substrate and a second portion of feed solution parallel to the face of said rotating resulting substrate.
A dynamic membrane contaminated with said macromolecules and dissolved substances is reconstituted by passing a membrane reconstituting solution through said rotating substrate with said dynamic membrane contaminated with said macromolecules and dissolved substances at rotational speed of said resulting substrate and temperature and pressure sufficient for leaching out said macromolecules and dissolvet substances from said membrane and preparation of said permeable substrate for forming next dynamic permeable substance-rejecting membrane.
- 10 ~
Macromolecules and dissolvet substances:are reiected by a dynamic permeable substance-re~ecting membrane formed by forcing said aqueous phase containing a water-soluble material selected from the said groups through a said rotating permeable substrate containing sald pores from feed solutions selected from tne group consisting of organic or inorganic dye solution, in particular, Rhodamine tye solution, dye water from textile production, waste waters from food productions, in particular, potato chips production, cooking sulfite and black kraft liquors from pulp and paper productions, fermentation and other solutions containing said macromolecules and dissolved substance by passing said feed solutions over said rotating face of the resulting substrate at rotational velocity of said resulting substrate equivalent to linear velocity of said resulting substrate of 4.3 to 6.4 meters per second at pressure of 0.7 atmosphere to 45.0 atmospheres.
Membrane reconstituting solution is selected from the group of solutions capable of leaching out contaminates from dynamic membranes formed from the said water soluble materials on substrate selected from the said group, in particular, I.O M sodium hydroxide solution. The said membrane reconstituting solution is passing through rotating resulting substrate with contaminated membrane at rotational velocity of said resulting substrate with contaminated membrane equivalent to linear velocity of said substrate with contaminated membrane of 4.3 to 6.4 meters per second at temperature of said membrane reconstitution solution of 25C to 60C and pressure of 0.1 atmosphere to ~5.0 atmospheres.
SPECIFICATION
This invention relates to a new dynamic membrane process with applica-tion of the forces developed in the vicinity of the moving porous support,in particular apllication of the centrifugal forces developed in the vicinity of the rotating porous support.
More particularly,the invention relates to a new process of dynamic membrane formation and then rejection and/or separation of suspended particulates from continuous phase by the help of previously formed dynamic membrane,using in the both stages(i.e. membrane formation and further rejection and/or separation of suspended particulates)the forces developed in the vicinity of the moving porous support,in par-ticular the centrifugal forces developed in the vicinity of the rotating porous support.
It i~ known the process of dynamic membrane formation by filtration of dilute suspensions or ~lectrol~tes through the motionless support at high pressure drop across the support of about 400-I000 psig,thus forming on the surface of the support a thin colloid layer,naimly dynamic membrane,used then in a motionless state as a semi-conductive membrane for rejection of dissolved substances and/or separation of fine particulates from a continuous fluid contaminated by these substan-ces and/or suspended particulates.
In some other known dynamic membrane processes and appllcatloDs of these processes, the additional flow of suspenslon along the surface of the motionless p~rous barrier, so-called Cross-Flow, is used in both membrane formation and further separation and/or re~ection processes in order to form more stable and uniform dynamic membrane, increase the permeate flux (i.e., the specific production rate~, degree of separation and the useful life of the membrane. In all these applications of dynamic membrane processes, the usual range of the pressure drop across porous barrier is of about 400 to 1000 psig and the circulation velocity of Cross-Flow is of about 15-25 ft/sec. All this results in high energy consumption per unit of permeate flux and disadvantages of operation at high pressure.
Another known method for separation of fine particulates from a continuous phase is centrifugation, application of which is often limited by high energy consumptions required for high speed rotation of the body ant for the motion of the whole liquid mass within the rotating centrifugal device.
It is the object of this invention to overcome the forgoing disadvantages by providing a new dynamic membrane formation process and then separation of particulates and/or rejection of the dissolved substances by previously formed dynamic membrane, using for both stages the forces developed in the vicinity of the moving porous support, in particular in the vicinity of the rotating porous support.
-7~
In the case of rotatable motion of the porous support,the process of thisinvention comprises,generally saying,the rotatable element or elements with a perforated or porous surface(that is the support for the forming dynamic membrane),which rotate in the suspension or electrolyte going across the porous barrier under a definite pressure drop between the outside and inside of the elements.Due to the centrifugal forces developed in the vicinity of the rotating elements,the uniform and stable dynamic membrane formation is possible to perform under the pressure drop across the porous barrier that is tenfold to hundredfold lower than that for the known dynamic membrane processes on the motionless porous support and even without additional intensive cross-flow stream of the feed suspension.
In the stage of separation of particulates and/or rejection of dissolved substances by previously formed dynamic membrane the same conditions,i.e.
low pressure drop,rotation of the membrane and even absence of cros-flow result in high selectivity of the membranejand permeate flux,as well as in long working period or useful life of the dynam~cemembrane.
In both stages the rotation velocity of the elements should be equal or beyond the threshold velocity.
The energy consumption for the process of this invention is much less in comparison with the known dynamic membrane processes on motionless modules,bec~use of the absence of pumping system required for high pressure and high velocity cros$-flow stream.
The energy consumption for the process of this invention is much less also in comparison with the conventional centrifugal separation,since the diameter of required rotating porous surface will be,generally saying, much less in the process of this invention than that in the conventional centrifugal process.On the other hand the energy required for rotation of of the body is proportional to the rotated diameter in the FORTH POWER.
Another factor responsible for the energy saving in the process of this invention in comparison to conventional centrifugal separation is that in the last case an additional energy required for rotational motion of the whole mass of the liquid within the centrifugal device,while in the process of this invention the motion only of the continuous phase layer in the vicinity of rotating elememt or elements is induced.
The process of this invention will be more fully illustrated by the following example,particulatlly with reference to the accompanying d,agrammic drawing-(Figure I).
In no way,however,it is intended to limit thereto the scope of the invention.
E X A M P L E
In a waste liquid treatment plant designed for separation of fine particulates and/or rejection of dissolved substances from waste liquid and further reuse of the purified liquid and/orrecovery of the chemicals, the first stage of the process of this invention is dynamic membrane formation:
The suspension or electrolyte from which dynamic membrane must be formed is prepared and placed in the mixing tank I.During membrane ormation process the suspension or electrolyte is circulating in the the pump 2, close loop-mixing tank I,the space between motionless body 3 and rotaing element(or elements) with porous surface 4, mixing tank I., - being under definite controlled pressure outside the rotating element(or elements).
lZ
In time of the dynamic membrane formation stage,on the surface of the element(or elements) the thin colloid layer,i.e. dynamic membrane,is formed.The clean liquid phase of the suspension or electrolyte is comming from the inside space of the rotating element(or elements) and accumulating in the tank 6,while the concentration of particulates in the circulating stream is increasing.
The second stage of the process of this invention is separation of the particulates and/or rejection of dissolved substances from contaminated continuous phase by the previously formed dynamic membrane:
This stage can be carried out as or batch,or semibatch,or continuous process.For continuous version of the process,the same scheme as described above can be applied.
The third staqe of the process of this invention is reqeneration or _ withd~aw of the~ c-ontamina-te~ -dynamic membrane:
After decrease of the permeate flux in the course of the second stage of the process of this invention to a definite forseen value the contaminated membrane must be regenerated or withdrawn without dismantling the device~
by washing or backwashing of the rotating element by a special solutions.
Then,once again the membrane forma~ion stage s~uld be carried out and so on.
~7 Some results from the test runs are shown in the enclosed Figure 2 and Figure 3. These results should not be construed to limit the range of operation.
In these test runs the dynamic membrane was formed from the 0.2% ZrOC12 in 0.05M NaCl solutio ~on a rotating 0.2 micron support under the pressure drop across support of about I0.2 psig and 2000rpm.,corresponding to the linear velocity of rotating element of about I5.4 ft/sec.
In figure 2 are plotted the rejection of Zirconium and permeate flux in time of dynamic membrane formation,that was about 30 minutes.
The rejection was calculated on the basis of turbidity control of the reject stream and the permeate flux.
As it can be seen from the figure 2 after 3-5 minutes o~ membrane formation process the rejection of Zr had reached the stable value of about 95 ~,that determines a good performance of membrane formation process under described conditions.
The selectivity of formed dynamic membrane was tested by Rhodamine dye rejection from the solution with initial optical density corresponding to about 60 % in Transmittance and g % in Transmittance,measuured by Bausch and Lomb Spectrophotometer,model Spectronic 70,in the 550 nm wavelength.The pressure drop across the rotating dynamic membrane was about I0.2 psig.
In figure 3 are plotted the permeate flux and rejection of Rhodamine dye from solution by previously formed dynamic membrane under rotations of the membrane equal to 2000rpm and initial optical density of feed Rhoda-mine solution of about 60% in transmittance during the first 60 minutes of the rejection process,and further at the initial optical density of feed solution raised up to 9% in transmittance.Another curves in the Figure 3 show the rejection of the dye and permeate flux when initial optical density of the feed dye solution was about 60~ in Transmittance, the pressure drop across rotating dynamic membrane was once again about I0.2 psig,but rotations were decreased to I500 rpm.
As it can be seen from the Figure 3 the rejection of the dye,calculated on the basis of feed and product optical density measurements,was rather high and stable under the rotations of 2000 rpm,that was found for described conditions as equal to threshold velocity.Increase in initial optical density of the Rhodamine dye solution from 60% to 9% in Transmittance resulted in small changes in terms of dye rejection and permeate flux.
On the other hand,separation of Rhodamine dye solution by dynamic membrane under the same co~ditions in terms of initial feed concentration and pressure drop,~ut rotation velocity below the threshold value resulted in some decrease of dye rejection after 45-55 minutes of the process,and understandable increase in permeate flux.
The Rhodamine dye rejection test runs were carried out in the version of continuou~circulation of the dye feed solution .However,the circulation velocity along the rotating element was negligible low(about 0.2 ft/sec).
For some types of Rhodamine dye such as Rhodamine B dye it was found the interaction between Zr hydrous oxide dynamic membrane and dye solution.
In t~is case the stable rejection performance was achieved by the dual Zr-PAA membrane previously formed dynamically under described above conditions(i.e.low pressure drop about 7.5-I0.2 psig and rotation about 2000 rpm).
.Y12 SUPPLEMENTARY DISCLOSURE
The material contained in the aqueous phase to be used for formation of a dynamic permeable substance-re~ecting membrane on a rotating permeable substrate is a polyvalent metal selected from the group consisting of iron, zirconium, ant thorium, and capable of forming a hydrous metal oxide, or polyvinylpyridine, neutral organic polymer, or polyelectrolyte selected from the group consisting of polysulfonates, polyamides, and polycarboxylates;
or polyacrylic acid at concentration of 50 to 150 ppm; or a mixture of a polyvalent metal capable of forming a hydrous metal oxide such as iron, zirconium, or thorium and polyacrylic acid; or a mixture of at least one component selected from a first group of classes consisting of polyelectrolytes and uater-soluble polyvalent metal salts, and at least one component from a different class selected from a second group consistin& of polyelectrolytes and neutral organic polymers, or a mixture of a polyelectrolyte and a neutral organic polymer; or a mixture of water-soluble polyva~ent metal salts and a member selected from the group consisting of polyelectrolytes and neutral organic polymers.
A dynamic permeable substance-rejecting membrane formed by forcing an aqueous phase containing a water soluble material selected from the groups mentioned above through a rotating permeable substrate containing pores (30 A to 20 microns diame~er) and selected from the group consisting of acropor membrane, X
nuclepore membrane, porous stainless steel, porous titanium, porous nickel, porous ceramics and porous plastics at rotational velocity of said substrate equivalent to linear velocity of said substrate of 3.2 meters per second to 6.4 meters per second and pressure of 0.7 atmosphere to 45.0 a~mospheres.
A dynamic permeable substance-rejecting membrane formed by forcing an aqueous phase containing a water soluble material selected from the groups mentioned above through a rotating permeable substrate containing pores has capability to re~ect macromolecules and dissolved substances from a feed solution containing said macromolecules and subtances when a dose of feed solution is passing over said rotating face of the resulting substrate at a pressure and a flow velocity sufficient to force the first portion of feed solution through the pores of said rotating resulting substrate and a second portion of feed solution parallel to the face of said rotating resulting substrate.
A dynamic membrane contaminated with said macromolecules and dissolved substances is reconstituted by passing a membrane reconstituting solution through said rotating substrate with said dynamic membrane contaminated with said macromolecules and dissolved substances at rotational speed of said resulting substrate and temperature and pressure sufficient for leaching out said macromolecules and dissolvet substances from said membrane and preparation of said permeable substrate for forming next dynamic permeable substance-rejecting membrane.
- 10 ~
Macromolecules and dissolvet substances:are reiected by a dynamic permeable substance-re~ecting membrane formed by forcing said aqueous phase containing a water-soluble material selected from the said groups through a said rotating permeable substrate containing sald pores from feed solutions selected from tne group consisting of organic or inorganic dye solution, in particular, Rhodamine tye solution, dye water from textile production, waste waters from food productions, in particular, potato chips production, cooking sulfite and black kraft liquors from pulp and paper productions, fermentation and other solutions containing said macromolecules and dissolved substance by passing said feed solutions over said rotating face of the resulting substrate at rotational velocity of said resulting substrate equivalent to linear velocity of said resulting substrate of 4.3 to 6.4 meters per second at pressure of 0.7 atmosphere to 45.0 atmospheres.
Membrane reconstituting solution is selected from the group of solutions capable of leaching out contaminates from dynamic membranes formed from the said water soluble materials on substrate selected from the said group, in particular, I.O M sodium hydroxide solution. The said membrane reconstituting solution is passing through rotating resulting substrate with contaminated membrane at rotational velocity of said resulting substrate with contaminated membrane equivalent to linear velocity of said substrate with contaminated membrane of 4.3 to 6.4 meters per second at temperature of said membrane reconstitution solution of 25C to 60C and pressure of 0.1 atmosphere to ~5.0 atmospheres.
Claims (14)
Claim Supported by the Major Disclosure I. A method of separating macromolecules and dissolved substances from solutions and concentrating said macromolecules and dissolved sub-stances comprising the steps of:
1) forming a dynamic permeable substance-rejecting membrane on a rotating permeable substrate containing pores, said permeable sub-strate in an untreated state being incapable of rejecting said macromolecules and dissolved substances, by forcing an aqueous phase containing a water-soluble material selected from the group consisting of polyvalent metal salts, neutral organic polymers, ion exchange materials and high-molecular-weight organic electrolytes through said rotating substrate to form a finely pored permeable substance-rejecting membrane on said substance; and 2) passing a dose of feed solution containing said macromolecules and dissolved substances over said rotating face of the resulting sub-strate at a pressure and a flow velocity sufficient to force the first portion of feed solution through the pores of said rotating resulting substrate and a second portion of feed solution parallel to the face of said rotating resulting substrate, said first portion thereby becoming depleted in said macromolecules and dissolved substances and said second portion becoming enriched in said macromolecules and dissolved substances;
and 3) reconstitution of said dynamic membrane contaminated with said macromolecules and dissolved substances, forming next said dynamic membrane as in I (1) on the same said rotating permeable substrate and passing next dose of feed solution containing said macromolecules and dissolved substances over said face of rotating resulting sub-strate as in I (2) and passing a membrane reconstituting solution through said rotating substrate with said dynamic membrane contaminated with said macromolecules and dissolved substances at rotational speed of said resulting substrate and temperature and pressure of said membrane reconstituting solution sufficient for leaching out said macromolecules and dissolved substances from said membrane and pre-paration of said permeable substrate for forming next dynamic permeable substance-rejecting membrane as in I (1).
Claims Supported by the Supplementary Disclosure
and 3) reconstitution of said dynamic membrane contaminated with said macromolecules and dissolved substances, forming next said dynamic membrane as in I (1) on the same said rotating permeable substrate and passing next dose of feed solution containing said macromolecules and dissolved substances over said face of rotating resulting sub-strate as in I (2) and passing a membrane reconstituting solution through said rotating substrate with said dynamic membrane contaminated with said macromolecules and dissolved substances at rotational speed of said resulting substrate and temperature and pressure of said membrane reconstituting solution sufficient for leaching out said macromolecules and dissolved substances from said membrane and pre-paration of said permeable substrate for forming next dynamic permeable substance-rejecting membrane as in I (1).
Claims Supported by the Supplementary Disclosure
2. The method of claim I wherein a dynamic permeable substance-rejecting membrane is formed by forcing an aqueous phase containing a water soluble material selected from the group said in claim I through a rotating permeable substrate containing pores of 30.ANG. to 20 micrones diameter and selected from the group consisting of acropor membrane, nuclepore mem-brane, porous stainless steel, porous titanium, porous nickel, porous ceramics and porous plastics at rotational velocity of said substrate equivalent to linear velocity of said substrate of 3.2 meters per second to 6.4 meters per second and pressure of 0.7 atmosphere to 45.0 atmospheres.
3. The method of claim I wherein feed solution is selected from the group consisting of an organic or inorganic dye solution, in particular, Rhodamine dye solution, dye waste water from textile production, waste waters from food productions, in particular, potato chips production, cooking sulfite and black kraft liquors from pulp and paper productions, fermentation solutions.
4. The method of claim I wherein said feed solution is passing over said rotating face of the resulting substrate at rotational velocity of said resulting substrate equivalent to linear velocity of said resulting substrate of 4.3 to 6.4 meters per second at pressure of 0.7 atmosphere to 45.0 atmospheres.
5. The method of claim I wherein membrane reconstituting solution is selected from the group of solutions capable of leaching out contaminates from dynamic membranes formed from the said in claim I water soluble materials on substrate selected from the groups said in claim 2.
6. The method of claim I wherein membrane reconstituting solution said in claim 5 is passing through rotating resulting substrate with con-taminated membrane in direction concurrent or opposite to that of feed solution at rotational velocity of said resulting substrate with con-taminated membrane equivalent to linear velocity of said substrate with contaminated membrane of 4.3 to 6.4 meters per second at temperature of said membrane reconstituting solution of 25°C to 60°C and pressure of 0.1 atmosphere to 45.0 atmospheres.
7. The method of claim I wherein said water soluble material is a water-soluble salt of a polyvalent metal capable of forming a hydrous metal oxide.
8. The method of claim 7 wherein said polyvalent metal is selected from the group consisting of iron, zirconium, and thorium.
9. The method of claim I wherein the neutral organic polymer is polyvinyl pyridine.
10. The method of claim I wherein said polyelectrolyte is selected from the group consisting of polysulfonates, polyamides, and polycarboxylates.
11. The method of claim I wherein said water-soluble material is a polyacrylic acid at concentration of 50 to 150 ppm.
12. The method of claim I wherein said water-soluble material is a mixture of water-soluble salt of a polyvalent metal said in claim 7 and poly-acrylic acid said in claim 11.
13. The method of claim I wherein said water-soluble material is a mixture of at least one component selected from a first group of classes con-sisting of polyelectrolytes and water-soluble polyvalent metal salts, and at least one component from a different class selected from a second group consisting of polyelectrolytes and neutral organic polymers.
14. The method of claim I wherein said water-soluble material is a mixture of water-soluble polyvalent metal salts and a member selected from the group consisting of polyelectrolytes and neutral organic polymers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000309856A CA1157712A (en) | 1978-08-23 | 1978-08-23 | Dynamic membrane process on moving porous support |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000309856A CA1157712A (en) | 1978-08-23 | 1978-08-23 | Dynamic membrane process on moving porous support |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1157712A true CA1157712A (en) | 1983-11-29 |
Family
ID=4112189
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000309856A Expired CA1157712A (en) | 1978-08-23 | 1978-08-23 | Dynamic membrane process on moving porous support |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1157712A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0230928A2 (en) * | 1986-01-20 | 1987-08-05 | Ab Asea-Atom | A method of regenerating a dynamic membrane in a separation means for a liquid medium and device for carrying out the method |
| EP0248599A2 (en) * | 1986-05-30 | 1987-12-09 | Water Research Commission | Dynamic membranes |
| CN108854547A (en) * | 2018-06-12 | 2018-11-23 | 合肥丰洁生物科技有限公司 | A kind of high-pressure membrane concentrator |
| CN113234434A (en) * | 2021-05-12 | 2021-08-10 | 河北工业大学 | Preparation method of water-resistant rhodamine B/zirconia composite fluorescent film |
-
1978
- 1978-08-23 CA CA000309856A patent/CA1157712A/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0230928A2 (en) * | 1986-01-20 | 1987-08-05 | Ab Asea-Atom | A method of regenerating a dynamic membrane in a separation means for a liquid medium and device for carrying out the method |
| EP0230928A3 (en) * | 1986-01-20 | 1988-04-13 | Ab Asea-Atom | A method of regenerating a dynamic membrane in a separation means for a liquid medium and device for carrying out the method |
| EP0248599A2 (en) * | 1986-05-30 | 1987-12-09 | Water Research Commission | Dynamic membranes |
| EP0248599A3 (en) * | 1986-05-30 | 1989-12-27 | Water Research Commission | Dynamic membranes |
| CN108854547A (en) * | 2018-06-12 | 2018-11-23 | 合肥丰洁生物科技有限公司 | A kind of high-pressure membrane concentrator |
| CN113234434A (en) * | 2021-05-12 | 2021-08-10 | 河北工业大学 | Preparation method of water-resistant rhodamine B/zirconia composite fluorescent film |
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