CN104147937A - Method for detecting completeness of filter membrane - Google Patents
Method for detecting completeness of filter membrane Download PDFInfo
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- CN104147937A CN104147937A CN201410359048.1A CN201410359048A CN104147937A CN 104147937 A CN104147937 A CN 104147937A CN 201410359048 A CN201410359048 A CN 201410359048A CN 104147937 A CN104147937 A CN 104147937A
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- filter
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- ferric oxide
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Abstract
The invention relates to a method for detecting the completeness of a filter membrane. The method comprises the following steps: feeding nano ferric oxide particles in a filter chamber; sampling filtered water, and detecting the concentration of ferrum in the filtered water; and judging the completeness of the filter membrane in the filter chamber according to the concentration of ferrum in the filtered water. The method is simple and convenient to operate, is low in cost, can hardly affect the filtering process, can detect the completeness online, has high detection flexibility, and is an innovation.
Description
Technical field
The present invention relates to a kind of detection method of integrity of filtration membranes, relate in particular to a kind of online integrality detection method of milipore filter.
Background technology
Filtration is the core cell of drinking water treatment technique, is the basic guarantee of removing suspended particulate substance and reducing turbidity.Compare with traditional media filtration mode (as sand filtration), ultrafiltration membrance filter (abbreviation ultrafiltration) due to have stable effluent quality, occupation area of equipment little, to advantages such as the pathogenic microorganisms cutoff performances such as Cryptosporidium, merchant ground flagellate and bacterium are good, its application in drinking water treatment industry is more and more general.Be different from traditional sucrose filter type taking deep-bed filtration as mechanism, the filtration mechanism of ultrafiltration is that hold back on surface.The cutoff performance of milipore filter depends on that its thickness is only at the filtration cortex of micron dimension.If milipore filter is damaged in installation, maintenance or running, will certainly cause problems such as pathogenic microorganisms leakage, cause filtered water quality to worsen, drinking water safety is formed to very large threat.So the integrity detection of milipore filter is essential for the normal operation of hyperfiltration treatment system.The basic goal that integrity of ultrafiltration membrane detects is to find in time the damaging problem of milipore filter.
At present, in drinking water treatment technique, the integrity detection of milipore filter adopts the method that direct integrity detection and indirect integrity detection combine substantially.Directly integrity detection (as pressure decay test etc.) directly detects hyperfiltration membrane assembly, and its detection sensitivity is high, but its shortcoming is must interrupt filter process while detecting, affects explained hereafter.Integrity detection is a kind of online test method indirectly, and its some water quality index (as turbidity and granule number) of filtering rear water by detection is to reflect the integrality of film.But the sensitivity of existing indirect integrity detection is low, can not serve as the direct basis of the integrality of judging film.Integrity detection can only be served as the supplementary means of direct complete detection indirectly.In the time that indirect integrity detection finds that milipore filter may occur damaging problem, can trigger the direct integrity detection of film.
Summary of the invention
In view of this, necessaryly provide the filter membrane that a kind of detection sensitivity is high online integrality detection method.
A detection method for integrity of filtration membranes, the method comprises the following steps: in filter tank, add ferric oxide nanometer particle; Sample and detect after this filter the concentration of iron in water filtering rear water; And according to after filter in water the concentration of iron judge the integrality of filter membrane in this filter tank.
Compared with prior art, the detection method of integrity of filtration membranes provided by the invention, easy and simple to handle, cost is lower, very little on the impact of filter process, can realize online detection, and has higher detection sensitivity, is the innovation in integrity of filtration membranes detection method.
Brief description of the drawings
Fig. 1 is the electron scanning micrograph of the ferric oxide nanometer particle prepared in method of the present invention.
Fig. 2 is the particle diameter distribution map of the ferric oxide nanometer particle prepared in method of the present invention.
Fig. 3 is the principle schematic that method of the present invention detects hollow fiber ultrafiltration membrane.
Fig. 4 is equipment and the schematic flow sheet of method of the present invention practical application in drinking water plant.
Main element symbol description
| Water inlet | 100 |
| Filter tank | 110 |
| Filter membrane component | 120 |
| Milipore filter | 122 |
| Damaged | 124 |
| Delivery port | 130 |
| Sample tap | 140 |
| Beaker | 150 |
| Spectrophotometer | 160 |
| Computer | 170 |
| Ferric oxide nanometer particle | 180 |
Following detailed description of the invention further illustrates the present invention in connection with above-mentioned accompanying drawing.
Detailed description of the invention
Below in conjunction with the accompanying drawings and the specific embodiments, the detection method of integrity of filtration membranes provided by the invention is described in further detail.
Be appreciated that the detection method of integrity of filtration membranes provided by the invention is mainly for the integrity detection of milipore filter, but be also applicable to other low-pressure membrane, as the integrity detection of micro-filtration membrane.Described milipore filter mainly comprises hollow-fibre membrane and the flat sheet membrane in drinking water treatment industry.
The detection method of integrity of filtration membranes provided by the invention comprises the following steps:
Step S10 adds ferric oxide nanometer particle in filter tank;
Step S20, samples and detects after this filter the concentration of iron in water filtering rear water;
Step S30, according to after filter in water the concentration of iron judge the integrality of filter membrane in this filter tank.
In described step S10, in filter tank, add ferric oxide nanometer particle, by the filter membrane in this filter tank, the former water in filter tank is filtered and obtains filtering rear water.The optimal morphology of described ferric oxide nanometer particle is the spheric granules of uniform particle diameter, can be also the comparatively form of rule such as cube shaped or elliposoidal.The optimum grain-diameter scope of described ferric oxide nanometer particle is 100 nanometer ~ 1 micron.Be appreciated that the particle that also can adopt smaller or greater particle diameter according to actual conditions, but generally need to ensure that the particle diameter of the particle that uses is greater than the average pore size of milipore filter to be measured, is less than the damaged diameter of the minimum that need to detect.The main chemical compositions of described ferric oxide nanometer particle is α-di-iron trioxide.In described ferric oxide nanometer particle, the content of α-di-iron trioxide is greater than 70%, preferably, is greater than 80%, more preferably, is greater than 90%.。The main character requirement of described ferric oxide nanometer particle and reason are in table 1.
Table 1 is for requirement and the reason of ferric oxide nanometer particle character
| Character | Requirement | Reason |
| Particle size | Be less than 1 micron | Be less than merchant ground flagellate and Cryptosporidium size, to reach enough resolution capabilities, be enough to detect the film breakage that can leak " two worms " |
| Particle diameter distributes | Concentrated as far as possible | Ensure the accuracy of detection method |
| Grain shape | Spherical | Ensure the accuracy of detection method |
| Particle chemical composition | The oxide of iron | Ensure little to health effect |
| Particle deployment conditions | Disperse as far as possible | Prevent particle aggregation, alleviate film and pollute, ensure the resolution capability that this detection method is desirable |
In the specific embodiment of the invention, the concrete preparation process of described ferric oxide nanometer particle is as follows: first use ultra-pure water as solvent, preparation is containing the iron chloride (FeCl of 0.032 mol/L
3) and the mixed solution of the hydrochloric acid (HCl) of 0.005 mol/L, and evenly mix.Secondly, this mixed solution is placed in to 100 DEG C of insulating box heated at constant temperature 12 days ~ 14 days, complete heating process after solution to be mixed cooling.Then, mixed solution is carried out to centrifugal treating twice, its medium speed is 5000 revs/min, and each centrifugal treating time is 5 minutes.After each centrifugal treating, all fall except upper strata light yellow liquid, the red precipitate of centrifuge tube bottom is dissolved with ultra-pure water and shaken up.Finally, then to the fulvic acid that adds 0.12 grams per liter in solution, after shaking up, be kept under normal temperature state.From Fig. 1-2, prepare by the method the regular spherical that the ferric oxide nanometer particle of gained is uniform particle diameter, and particle diameter is mainly distributed between 300 nanometer ~ 500 nanometers.
After described ferric oxide nanometer particle is added in former water, described ferric oxide nanometer particle is dispersed in former water, and the concentration of described ferro element in former water is 1 mg/litre ~ 20 mg/litre.Be appreciated that the concentration of described ferro element in former water can adjust according to ferro element background concn values different in former water, with the accuracy that ensures to detect.In the embodiment of the present invention, the concentration of described ferro element in described former water is 10 mg/litre.
In described step S20, after described detection filter, in water, the method for the concentration of iron can be that Ferrozine spectrophotometry or ICP-OES/ICP-MS instrument detect.
Preferably, the embodiment of the present invention adopts the concentration of iron in the rear water of Ferrozine spectrophotometry filter, and the method specifically comprises the following steps:
Step S201 gets a part as liquid to be measured from filtering in water;
Step S202 adds developer and reducing agent in this liquid to be measured, and makes this liquid to be measured, developer and reducing agent fully mix reaction a period of time to obtain a mixed solution;
Step S203, regulates pH value to 5.5 ~ 7.4 of this mixed solution, then by the absorbance of this mixed solution of spectrophotometer measurement, and the ferro element concentration that obtains this mixed solution in conjunction with graticule as this filter after the ferro element concentration of water.
In described step S202, described developer is that concentration is the Ferrozine solution of 30 mM/ls ~ 50 mM/ls.Described reducing agent is the hydroxylamine hydrochloride solution of concentration 1 mol/L ~ 2 mol/L.Be appreciated that described developer and reducing agent are not limited to Ferrozine solution and hydroxylamine hydrochloride solution, all passable as long as reaching the chemical agent of coherent detection requirement.
In described step S203, described pH value is 5.5 ~ 7.4 to show that this mixed solution approaches the neutral state of natural water.The method of the pH value of described this mixed solution of adjusting is to add ammonium acetate solution or other can reach the chemical agent that coherent detection requires to this mixed solution.
In the specific embodiment of the invention, get 7.0 milliliters of liquid to be measured, adding 0.4 ml concn to liquid to be measured is the Ferrozine solution of 40 mM/ls, then to add 1.5 ml concns to liquid to be measured be that the hydroxylamine hydrochloride solution of 1.4 mol/L obtains mixed solution; Stirring fully mixes this mixed solution and reacts 20 minutes; Then, then to this mixed solution add 4.0 milliliters of pH values be 9.5 and the w/v ammonium acetate solution that is 10% regulate the pH of this mixed solution; Finally, by the absorbance of this mixed solution of spectrophotometer measurement, obtain the ferro element concentration of this solution in conjunction with graticule.
In described step S30, the described concentration according to iron in water after filter judges that the method for the integrality of this filter membrane is: the concentration of iron in water after this filter and a threshold value are compared, if be greater than this threshold value, be judged as this integrity of filtration membranes breakage has occurred, if be less than this threshold value, be judged as this integrity of filtration membranes good.Be appreciated that described threshold value can determine according to the diameter of the average pore size of milipore filter to be measured and the minimum that need to detect breakage.
Experimental results show that complete milipore filter, as PVDF material, all can have very high rejection for the amorphous iron in water and the ferric oxide nanometer particle that manually adds, conventionally exceed 99.5%, what have even reaches 100%.As shown in Figure 3, in the time that milipore filter 122 occurs damaged 124, ferric oxide nanometer particle 180 can leak at damaged 124 places.Ferric oxide nanometer particle 180 is in the concentration that goes out the ferric oxide nanometer particle 180 that water concentration adds in equaling filter tank at damaged 124 places, and therefore, its ferro element concentration in water after filter is directly related with the ratio of complete film area with breakage 124 areas of milipore filter 122.If so detect after filter in water that ferro element concentration exceedes a certain setting limit value, as 10 micrograms per litre, and extremely raise, can judge that these milipore filter 180 integralities have suffered destruction.
Described according to after filter in water the concentration of iron judge that the method for the integrality of this filter membrane can further include: when this integrity of filtration membranes has occurred when damaged, infer the damaged area of this filter membrane according to the concentration of iron in water after this filter.Be appreciated that, because the concentration of iron in water after this filter is relevant with the damaged area of this filter membrane, determine after this filter the relation between the concentration of iron and the damaged area of this filter membrane in water as long as repeatedly measure, can realize after this filter the concentration of iron in water and infer the damaged area of this filter membrane.
The sensitivity analysis of the ferric oxide nanometer particle spike detection method adopting in the present invention is as follows, wherein, and the maximum interception capacity of this filter element that this sensitivity reflection can be determined by integrality detection method of the present invention to certain pollutant.The ferro element concentration adding in former water is 10 mg/litre, i.e. C
f=10 mg/litre, wherein, C
frefer to the concentration of selected index substance in former water; Ferro element concentration in water purification after filtration is by Ferrozine spectrophotometry, if adopt 1 meter of long colorimetric cylinder, the detectability that the ferro element concentration of supposing absorbance A=0.05 correspondence is AAS, C
p=1.62 × 10
-3mg/litre, wherein, C
prefer to the concentration of selected index substance in the rear water of filter.Therefore, logarithm clearance LRV=log (C
f/ C
p)=3.79, that is, the LRV of this detection method is about 3.8.If further extend the length of colorimetric cylinder, the sensitivity of the method can reach higher in theory.
Refer to Fig. 4, method of the present invention can directly apply to the integrity detection of the milipore filter of drinking water plant.Particularly, this ferric oxide nanometer particle is directly joined former water from the water inlet 100 of drinking water plant.Then, this former water enters filter tank 110, and is filtered and obtained water purification by filter membrane component 120.Water purification after this filtration flows out by delivery port 130, and water flows into beaker 150 after sample tap 140 places sampling filter.By the concentration of iron in water after spectrophotometer 160 these filters of detection, and this result is transferred to computer 170.The concentration of this iron and a threshold value are compared analysis by this computer 170, judges the integrality of this filter membrane, and show judged result to user.
The present invention adopts ferric oxide nanometer particle to realize as tracer the method that the integrality of milipore filter is detected to have following beneficial effect.The first, iron is harmful to human health, and therefore, uses ferric oxide nanometer particle security good.The second, the concentration of iron in natural water body is conventionally lower, and therefore, the background value of detection is very low.The 3rd, adopt ferrozine AAS can detect the iron of micrograms per litre magnitude, therefore, in filtering ponds, add the ferric oxide nanometer particle of 10 mg/litre left and right, can realize the high-sensitivity detection of 4 orders of magnitude.The 4th, iron is the high metallic element of abundance second in the earth's crust, and the preparation method of ferric oxide nanometer particle is simple, and therefore, this detection method is with low cost.The 5th, the method can directly apply in drinking water plant, realizes the continuous on-line detection of integrity of ultrafiltration membrane.
In addition, those skilled in the art can also do other and change in spirit of the present invention, and the variation that these do according to spirit of the present invention, all should be included in the present invention's scope required for protection.
Claims (10)
1. a detection method for integrity of filtration membranes, the method comprises the following steps:
In filter tank, add ferric oxide nanometer particle;
Sample and detect after this filter the concentration of iron in water filtering rear water; And
Judge the integrality of filter membrane in this filter tank according to the concentration of iron in water after filter.
2. the method for claim 1, is characterized in that, the particle diameter of described ferric oxide nanometer particle is distributed between 300 nanometer ~ 500 nanometers.
3. the method for claim 1, is characterized in that, the chemical composition of described ferric oxide nanometer particle is α-di-iron trioxide.
4. the method for claim 1, is characterized in that, one or more in regular spherical that described ferric oxide nanometer particle is uniform particle diameter, cube shaped or elliposoidal.
5. the method for claim 1, is characterized in that, describedly in filter tank, adds after ferric oxide nanometer particle, and the ferro element concentration in the former water in described filter tank is 1 mg/litre ~ 20 mg/litre.
6. the method for claim 1, is characterized in that, the method that the concentration of iron in rear water is filtered in described detection is to adopt Ferrozine AAS or ICP-OES/ICP-MS instrument to detect the concentration of iron in the rear water of filter.
7. method as claimed in claim 6, is characterized in that, after the filter of described employing Ferrozine spectrophotometry, in water, the method for the concentration of iron comprises the following steps:
From filtering, in water, get part as liquid to be measured;
In this liquid to be measured, add developer and reducing agent, and make this liquid to be measured, developer and reducing agent fully mix reaction a period of time to obtain a mixed solution;
Regulate the pH to 5.5-7.4 of this mixed solution, then by the absorbance of this mixed solution of spectrophotometer measurement, and the ferro element concentration that obtains this mixed solution in conjunction with graticule as this filter after the ferro element concentration of water.
8. method as claimed in claim 7, is characterized in that, described developer is that concentration is the Ferrozine solution of 30 mM/ls ~ 50 mM/ls; Described reducing agent is that concentration is the hydroxylamine hydrochloride solution of 1 mol/L ~ 2 mol/L; The method of the pH of described this mixed solution of adjusting is for to add ammonium acetate solution to this mixed solution.
9. the method for claim 1, it is characterized in that, the described concentration according to iron in water after filter judges that the method for the integrality of filter membrane in this filter tank is that the concentration of iron in water after this filter and a threshold value are compared, if be greater than this threshold value, be judged as this integrity of filtration membranes breakage has occurred, if be less than this threshold value, be judged as this integrity of filtration membranes good.
10. method as claimed in claim 9, it is characterized in that, described according to after filter in water the concentration of iron judge that the method for the integrality of filter membrane in this filter tank further comprises: when this integrity of filtration membranes has occurred when damaged, infer the damaged area of this filter membrane according to the concentration of iron in water after this filter.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107308823A (en) * | 2017-07-07 | 2017-11-03 | 中国神华能源股份有限公司 | For judging the method and apparatus that membrane component is damaged |
| CN109724958A (en) * | 2019-01-17 | 2019-05-07 | 天津工业大学 | A kind of membrane bioreactor film integrality detection method |
| CN110621998A (en) * | 2017-05-19 | 2019-12-27 | 哈希公司 | Membrane integrity monitoring in water treatment |
| CN114526024A (en) * | 2022-02-21 | 2022-05-24 | 濮阳市中原锐实达石油设备有限公司 | Screen cloth leaks sand monitoring devices |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110621998A (en) * | 2017-05-19 | 2019-12-27 | 哈希公司 | Membrane integrity monitoring in water treatment |
| CN107308823A (en) * | 2017-07-07 | 2017-11-03 | 中国神华能源股份有限公司 | For judging the method and apparatus that membrane component is damaged |
| CN109724958A (en) * | 2019-01-17 | 2019-05-07 | 天津工业大学 | A kind of membrane bioreactor film integrality detection method |
| CN109724958B (en) * | 2019-01-17 | 2021-07-06 | 天津工业大学 | Membrane integrity detection method for membrane bioreactor |
| CN114526024A (en) * | 2022-02-21 | 2022-05-24 | 濮阳市中原锐实达石油设备有限公司 | Screen cloth leaks sand monitoring devices |
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| CN104147937B (en) | 2016-04-27 |
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