GB2201967A - Electrochemical filter conditioning - Google Patents
Electrochemical filter conditioning Download PDFInfo
- Publication number
- GB2201967A GB2201967A GB08705411A GB8705411A GB2201967A GB 2201967 A GB2201967 A GB 2201967A GB 08705411 A GB08705411 A GB 08705411A GB 8705411 A GB8705411 A GB 8705411A GB 2201967 A GB2201967 A GB 2201967A
- Authority
- GB
- United Kingdom
- Prior art keywords
- filter
- membrane
- filtration
- conditioning
- electrode
- 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.)
- Withdrawn
Links
- 230000003750 conditioning effect Effects 0.000 title claims description 7
- 239000012528 membrane Substances 0.000 claims abstract description 28
- 238000000034 method Methods 0.000 claims abstract description 21
- 238000001914 filtration Methods 0.000 claims abstract description 18
- 239000003792 electrolyte Substances 0.000 claims abstract description 5
- 239000007788 liquid Substances 0.000 claims description 4
- 229910001220 stainless steel Inorganic materials 0.000 claims description 3
- 239000010935 stainless steel Substances 0.000 claims description 3
- 239000000919 ceramic Substances 0.000 claims description 2
- 230000001143 conditioned effect Effects 0.000 abstract 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 8
- 239000000463 material Substances 0.000 description 3
- 239000012466 permeate Substances 0.000 description 3
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 230000003292 diminished effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000009295 crossflow filtration Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000004931 filters and membranes Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000009285 membrane fouling Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 238000001471 micro-filtration Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000000108 ultra-filtration Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
- B01D35/06—Filters making use of electricity or magnetism
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
- B01D65/08—Prevention of membrane fouling or of concentration polarisation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
- B01D2321/22—Electrical effects
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Water Supply & Treatment (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
A porous, electrically conducting filtration membrane 2 is conditioned by setting up an electrochemical cell comprising a first electrode constituted by the filter, a second electrode 5, and an electrolyte. Application of a potential across the cell results in restructuring or realignment of the layers formed on the filter during filtration. This realignment or restructuring is such as to prevent or substantially diminish the further fouling of the filter or membrane. The overall rate of filtration is therefore greatly improved. The electrolyte is normally the process feed. <IMAGE>
Description
Electrochemical Filter Conditioning
This invention relates to a method of conditioning electrically conducting filters.
Filtration is a widely used industrial process operation. The clogging or fouling of filters and membranes used for such processes can be a severe problem. This clogging or fouling is due to the deposition of materials from the process stream in or on the filter or membrane.
As clogging or fouling takes place, the rate of filtration progressively decreases. Conventionally, the effect of filter fouling may be diminished by pre-coating the filter with a filter-aid and sometimes in addition adding such a filter-aid to the process stream. Conventionally, the rate of membrane fouling may to a certain extent be diminished by flowing the process stream tangentially across the face of the membrane.
The invention provides a means of limiting or preventing the build up of such fouling layers. It is applicable to electrically conducting membranes and filters. Thus, the invention consists of (i) the formation of an electrochemical cell comprising a first electrode
constituted by the filter, a counter electrode, and an electrolyte
normally constituted by the process liquid, and, (ii) operating the cell to restructure and realign the layers formed on
the filter during filtration.
This realignment or restructuring is such as to prevent or substantially diminish the further fouling of the filter or membrane. The overall rate of filtration is therefore greatly improved. It is the materials being processed which normally constitute the restructured layer. Thus, it is not normally necessary to use a filter aid, though the invention may improve the effect of such a pre-coat. The invention is more effective at preventing fouling than tangential flow regimes.
Examples of filters to which the invention is applicable are woven and non-woven metallic meshes such as those of stainless steel, metallic microporous membranes such as those of stainless steel, microporous graphite membranes, and conducting ceramic microfiltration and ultrafiltration membranes such as metallic oxide membranes of doped titania, titanates, or doped zirconia.
A specific application of the invention will now be described with reference to the accompanying drawings.
Figure 1 is a schematic diagram of a cross-flow flat-sheet filtration apparatus used to demonstrate the invention. The filtration module defined by its walls 1 is divided into two chambers separated by the membrane 2. The process stream which is to undergo filtration enters the feed chamber 3 at a. As it passes through this chamber, permeate passes through the membrane 2. The process stream then emerges in more a concentrated form at b and permeate is collected at c. The membrane 2 and counter electrode 5 may be connected to a potential source which is not shown. When it is desired to condition the membrane by realigning and restructuring any deposited layer, a potential difference is applied between the membrane and the counter electrode.
The invention is applicable to other types of filtration equipment, for example, filter presses and rotary vacuum filters.
As an example, 5L of an aqueous slurry of 5% TiO2 was continuously filtered in a flow recycling mode using a cross-flow filtration apparatus as shown in Figure 1 having a sintered stainless 2 steel filter membrane of nominal pore size 3 pm and an area of 100 cm The slurry was passed through the apparatus at 65 kPa with a cross-flow -l velocity of lm s . The time taken for 50 mL of liquid membrane permeate to be collected was measured continuously. This time is an inverse measure of the membrane flux.
The results of this experimental demonstration are shown in Figure 2.
The upper curve shows data for normal filtration and the lower curve shows data for filtration with membrane conditioning. In the latter case, filtration proceeded as normal from A to B, a layer of TiO2 building up on the membrane. At B a current of 10A at9V was applied for 15 seconds, causing realignment and restructuring of the TiO2 layer. Between C and D the rate of filtration then remained essentially constant as no further fouling of the membrane took place.
The magnitude and duration of the applied current and voltage required for effective operation of the invention are a function of the material to be filtered, the suspending electrolyte, the nature of the membrane and the process conditions. In the example presented in Figure 2, a single application of the electric field was sufficient for conditioning, further applications of the same magnitude and duration would give no additonal benefit in the region C to D. In some cases it may be beneficial to recondition the membrane from time to time during the time course of filtration.
Claims (9)
- Electrochemical Filter Conditioning (Application No.8705411)CLAIMS 1. A method of conditioning a porous electrically conducting filter membrane comprising the steps of (i) forming an electrochemical cell consisting of a first electrode constituted by the filter, a counter electrode, and an electrolyte normally constituted by the process liquid, and (ii) operating the cell to restructure and realign the layers formed on the filter during filtration.
- 2. A method as claimed in claim 1 where the process liquid is caused to flow continuously through the filtration module.
- 3. A method as claimed in the preceding claims where a filter aid is additionally used.
- 4. A method as claimed in any of the preceding claims where the filter is a woven metallic mesh.
- 5. A method as claimed in claims 1 to 3 where the filter is a non-woven metallic mesh.
- 6. A method as claimed in claims 1 to 2 where the filter is a sintered stainless steel membrane.
- 7. A method as claimed in claims 1 to 2 where the filter is a ceramic membrane.
- 8. A method as claimed in claims 1 to 2 where the filter is an inorganic membrane.
- 9. A method as claimed in claims 1 to 2 where the filter is a polmeric membrane.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08705411A GB2201967A (en) | 1987-03-07 | 1987-03-07 | Electrochemical filter conditioning |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08705411A GB2201967A (en) | 1987-03-07 | 1987-03-07 | Electrochemical filter conditioning |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8705411D0 GB8705411D0 (en) | 1987-04-08 |
| GB2201967A true GB2201967A (en) | 1988-09-14 |
Family
ID=10613543
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08705411A Withdrawn GB2201967A (en) | 1987-03-07 | 1987-03-07 | Electrochemical filter conditioning |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2201967A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4102156A1 (en) * | 1991-01-25 | 1992-07-30 | Univ Dresden Tech | Electric filter for liq. suspension or emulsion - esp. for particle sepn. from water |
| EP0576157A2 (en) * | 1992-06-20 | 1993-12-29 | United Kingdom Atomic Energy Authority | In situ cleanable electrically conducting filter |
| GB2315428A (en) * | 1996-07-18 | 1998-02-04 | Atkins Fulford Limited | Membrane Filter |
| CN101596406B (en) * | 2008-06-02 | 2012-02-22 | 中国科学院过程工程研究所 | Device and method for rapidly concentrating by film under intensified electric field |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0241308A1 (en) * | 1986-04-11 | 1987-10-14 | Dorr-Oliver Incorporated | Method of removing selected ions from cakes deposited on an EAVF device |
-
1987
- 1987-03-07 GB GB08705411A patent/GB2201967A/en not_active Withdrawn
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0241308A1 (en) * | 1986-04-11 | 1987-10-14 | Dorr-Oliver Incorporated | Method of removing selected ions from cakes deposited on an EAVF device |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4102156A1 (en) * | 1991-01-25 | 1992-07-30 | Univ Dresden Tech | Electric filter for liq. suspension or emulsion - esp. for particle sepn. from water |
| EP0576157A2 (en) * | 1992-06-20 | 1993-12-29 | United Kingdom Atomic Energy Authority | In situ cleanable electrically conducting filter |
| EP0576157A3 (en) * | 1992-06-20 | 1994-01-12 | United Kingdom Atomic Energy Authority | In situ cleanable electrically conducting filter |
| US5342514A (en) * | 1992-06-20 | 1994-08-30 | United Kingdom Atomic Energy Authority | Electrical filter |
| AU653477B2 (en) * | 1992-06-20 | 1994-09-29 | Aea Technology Plc | A filter |
| GB2315428A (en) * | 1996-07-18 | 1998-02-04 | Atkins Fulford Limited | Membrane Filter |
| GB2315426A (en) * | 1996-07-18 | 1998-02-04 | Atkins Fulford Limited | Membrane Filters |
| CN101596406B (en) * | 2008-06-02 | 2012-02-22 | 中国科学院过程工程研究所 | Device and method for rapidly concentrating by film under intensified electric field |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8705411D0 (en) | 1987-04-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |