CN107589049A - A kind of method and device for being used to determine cleaning agent diffusion coefficient in fouling membrane layer - Google Patents
A kind of method and device for being used to determine cleaning agent diffusion coefficient in fouling membrane layer Download PDFInfo
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- CN107589049A CN107589049A CN201710650386.4A CN201710650386A CN107589049A CN 107589049 A CN107589049 A CN 107589049A CN 201710650386 A CN201710650386 A CN 201710650386A CN 107589049 A CN107589049 A CN 107589049A
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Abstract
The present invention is directed to the membrane separation technique related process used in sewage disposal, is related to a kind of method and device of cleaning agent diffusion coefficients in fouling membrane layer, belongs to water-treatment technology field.Comprise the following steps：Film surface pollution thickness degree is determined using micrometer；Film surface pollution layer is downwardly fixed in test device；Use the upper surface of the colour developing test paper cover layer of mark cleaning agent diffusion terminal（The back side）；Cleaning agent is injected into device to default scale and timing；Test paper stops timing when all changing colour, and calculates diffusion coefficient according to diffusion model of the cleaning agent in fouling membrane layer.Such a method of testing establishes the diffusion model of cleaning agent in pollution layer, realize the cleaning agent diffusion process Quantitative Monitoring under the conditions of having pressure of experimental size, not only time of measuring is short, repeatable height, it is and easy to operate, use cost is low, and providing effective method for the cleaning agent diffusion mechanism research in Process of Chemical Cleaning supports.
Description
Technical Field
The invention relates to the technical field of water treatment, in particular to a method and a device for measuring diffusion coefficient of a cleaning agent in a membrane pollution layer, aiming at a membrane separation technology related process used in sewage treatment.
Background
Membrane separation techniques (such as microfiltration, ultrafiltration, nanofiltration, reverse osmosis, etc.) and membrane bioreactor techniques are now widely used in the field of water treatment technology. However, the problems of the decrease in membrane flux, the reduction in service life, and the like due to membrane fouling become important factors that restrict the application of membrane technology. Therefore, in order to recover the membrane flux and prolong the service life of the membrane, the membrane cleaning process becomes an essential important measure in the application process of the membrane technology. Membrane cleaning includes physical cleaning, chemical cleaning and biological cleaning. The chemical cleaning can effectively remove stubborn membrane surface pollutants which are difficult to remove by physical cleaning by means of reaction, dissolution, emulsification, dispersion and adsorption of chemical reagents, so that the membrane performance is recovered efficiently. Therefore, as the most common cleaning process in the application of membrane technology, the research on the mechanism of chemical cleaning is of great significance for optimizing the chemical cleaning process, effectively controlling membrane pollution and popularizing and applying the membrane separation technology.
The chemical cleaning process is mainly divided into two steps: 1. the cleaning agent is diffused from the membrane surface to the inside of the pollution layer; 2. the cleaning agent and the pollutants generate a series of chemical reactions, so that the pollutants fall off and are removed from the membrane surface. Currently, many scholars have studied on the reaction mechanism between the cleaning agent and the contaminant, such as the influence of the type, dosage, pH, temperature, ionic strength, etc. of the cleaning agent on the cleaning efficiency. However, there has been little research on the effect of the diffusion process of the cleaning agent in the membrane fouling layer on the cleaning mechanism. The reason for this is that the diffusion process of the cleaning agent is difficult to quantitatively monitor, and the change of the diffusion condition of the cleaning agent in the pollution layer under different conditions cannot be accurately described. And at present, an effective determination method for the diffusion coefficient of the cleaning agent in the pollution layer is not available.
Based on the problem, the invention establishes a related testing device aiming at the diffusion process of the cleaning agent in the film surface pollution layer in the chemical cleaning process, marks the diffusion end point of the cleaning agent by using the color development reaction of the test paper, and calculates the diffusion coefficient of the cleaning agent in the pollution layer by recording the color development time of the cleaning agent diffusing through the pollution layer under the pressure condition, thereby realizing the quantitative monitoring of the diffusion process of the cleaning agent.
Disclosure of Invention
The invention aims to provide a method and a device for measuring the diffusion coefficient of a cleaning agent in a membrane pollution layer. The invention mainly solves the technical problem that the diffusion coefficient test method and the device for the cleaning agent in the chemical cleaning process of the membrane separation technology are difficult to quantitatively analyze, and provides a laboratory scale diffusion coefficient test method and a laboratory scale diffusion coefficient test device for the cleaning agent.
The invention provides a method for testing the diffusion coefficient of a cleaning agent in a membrane pollution layer, which comprises the following steps:
(1) Measuring the average thickness of the uncontaminated film and the average thickness of the contaminated film by using a micrometer, and obtaining the average thickness of the contaminated layer by subtracting the average thickness of the uncontaminated film and the average thickness of the contaminated film;
(2) Placing a pollution layer of the membrane to be detected on a circular platform of the U-shaped permeation device downwards so as to enable the pollution layer to be in contact with a cleaning agent;
(3) Covering the upper surface (back surface) of the membrane to be tested with chromogenic test paper for marking the diffusion end point of the cleaning agent, ensuring that the test paper is tightly attached to the membrane to be tested, and fixing the membrane to be tested by using a fixing device;
(4) Injecting a cleaning agent from one end of the U-shaped penetration device until the water surface is just leveled with the preset scale, and starting timing;
(5) And observing the color change condition of the test paper on the back of the film to be detected, stopping timing when the test paper is completely changed in color, and calculating the diffusion coefficient according to a diffusion model of the cleaning agent in the film pollution layer.
In the invention, the derivation process of the diffusion model of the cleaning agent in the membrane pollution layer in the step (5) is as follows:
as can be seen from the law of darcy,
v＝K×J
wherein Q is the seepage flow;
k is the permeability coefficient;
a is the sectional area vertical to the water flow direction;
l is the seepage length;
delta h is the difference between the upstream and downstream water heads;
since the thickness of the contamination layer is only a few hundred micrometers, the penetration rate of the cleaning agent in the contamination layer can be approximately regarded as constant, i.e. constant
Wherein v' is the diffusion rate, cm/s;
is the average thickness of the contamination layer, cm;
t is diffusion time, s;
from darcy's law, the diffusion coefficient describing the cleaning agent in the contaminated layer can be defined as:
in the formula, K' is the diffusion coefficient of the cleaning agent in the pollution layer, and is cm/s;
is the average thickness of the contamination layer, cm;
t is diffusion time, s;
Δ h is the head difference, cm, of the upper and lower surfaces of the film.
In the invention, the cleaning agent is an oxidizing cleaning agent, specifically any one of sodium hypochlorite, hydrogen peroxide, hydrochloric acid or sodium hydroxide; the test paper for marking the diffusion end point of the cleaning agent can be selected according to different types of the measured cleaning agent, and specifically comprises a starch potassium iodide test paper (for marking an oxidative cleaning agent) and a pH test paper (for marking an acid-base cleaning agent).
The device used by the method for testing the diffusion coefficient of the cleaning agent in the membrane pollution layer comprises a U-shaped pressure permeation device, a membrane component fixing device and color development test paper for marking the diffusion end point of the cleaning agent, wherein the membrane component fixing device is connected with the U-shaped pressure permeation device through a bolt; placing a pollution layer of the membrane to be detected on a circular platform of the U-shaped permeation device downwards so as to enable the pollution layer to be in contact with a cleaning agent; covering the upper surface (back surface) of the membrane to be tested with chromogenic test paper for marking the diffusion end point of the cleaning agent, ensuring that the test paper is tightly attached to the membrane to be tested, and fixing the membrane to be tested by using a fixing device; in addition, a stopwatch is required for recording diffusion time, and a micrometer is used for measuring and calculating the thickness of the contaminated layer.
The invention has the beneficial effects that:
(1) Aiming at the diffusion process of the cleaning agent in a membrane surface pollution layer in the chemical cleaning process, the invention marks the diffusion end point of the cleaning agent by using the color development test paper, realizes the quantitative monitoring of the diffusion process of the cleaning agent under the pressure condition, and provides effective method support for the research of the diffusion mechanism of the cleaning agent in the chemical cleaning process;
(2) According to the Darcy's law, from the perspective of permeability coefficient, the diffusion model of the cleaning agent in the polluted layer is established by combining the actual condition of the cleaning agent diffusion in the membrane polluted layer, and the diffusion coefficient capable of quantitatively representing the diffusion condition of the cleaning agent is defined;
(3) The device realizes the diffusion coefficient monitoring of the cleaning agent in the pollution layer, has short measuring time, high repeatability, convenient operation and low use cost, can be effectively used for the research of the diffusion mechanism of the cleaning agent, and has good practicability.
Drawings
FIG. 1 is a schematic view of a device for measuring the diffusion coefficient of a cleaning agent according to the present invention;
FIG. 2 is a detailed view of a membrane fixture assembly of the cleaning agent diffusion coefficient testing apparatus;
FIG. 3 is a flow chart of the operation of the present invention;
reference numbers in the figures: 1 is a U-shaped pressure permeation device, 2 is a membrane component fixing device, 3 is a color test paper for marking the diffusion end point of the cleaning agent, 4 is a fixing bolt, 5 is a pollution layer, and 6 is a membrane.
Detailed Description
The invention is further illustrated by the following examples.
Example 1: an ultrafiltration membrane was contaminated with a Bovine Serum Albumin (BSA) solution and Sodium Alginate (SA) at a concentration of 1g/L, respectively, and the diffusion coefficients of NaClO cleaning agents having a total available chlorine concentration of 100mg/L, pH of 5 and 11, respectively, in the two contaminated layers were measured. Firstly, the thickness of the contaminated membrane was measured by using a micrometer, and the average thickness of the BSA contaminated layer was 210 μm and the thickness of the SA contaminated layer was 213 μm. A potassium iodide starch test paper is used as a color development test paper, the membrane is fixed on a permeation device according to the operation method, a cleaning agent is added, the water head of one side of the U-shaped tube is 0.5cm higher than the membrane surface, and a stopwatch is used for timing. After repeating the above experiment three times, in the BSA contaminated layer, the average diffusion time of the cleaning agent at pH =5 was 177.5s, and the average diffusion time of the cleaning agent at pH =11 was 99s; in the SA contaminated layer, the average diffusion time of the cleaning agent at pH =5 was 217.5s, and the average diffusion time of the cleaning agent at pH =11 was 133.5s. According to a diffusion coefficient calculation formula deduced from the test method, the following results are obtained after calculation: in the BSA contaminated layer, the detergent diffusion coefficient of pH =5 was 4.99 × 10 -8 The diffusion coefficient of the cleaning agent with cm/s and pH =11 is 8.94X 10 -8 cm/s; in the SA-contaminated layer, the cleaning agent diffusion coefficient of pH =5 was 4.19 × 10 -8 The diffusion coefficient of the cleaning agent having a concentration of cm/s and a pH of =11 was 6.81X 10 -8 cm/s. The above results confirmed the different pH-induced cleaning agents from the quantitative analysis point of viewDifferences in diffusion processes.
Example 2: on the basis of the experiment described in example 1, 0.5mmol/L Sodium Dodecyl Sulfate (SDS) was added to the cleaning agent to further increase the diffusion rate of the cleaning agent, and the above diffusion coefficient measurement experiment was repeated. The diffusion process of NaClO cleaning agent with total effective chlorine concentration of 100mg/L, SDS and concentration of 0.5mmol/L, pH of 5 and 11 respectively in BSA and SA two pollution layers is measured, the diffusion time is recorded and the diffusion coefficient is calculated according to the diffusion coefficient calculation formula deduced from the test method. The measurement results show that: in the BSA contaminated layer, the pH =5 detergent diffusion coefficient after adding SDS was 7.68 × 10 - 8 cm/s is significantly greater than 4.99X 10 without SDS addition -8 cm/s; the diffusion coefficient of the cleaning agent with pH =11 was 14.3X 10 - 8 cm/s is significantly greater than 8.94X 10 without SDS addition -8 cm/s. Similarly, in the SA-contaminated layer, the diffusion coefficient of the detergent with pH =5 after SDS was 5.84 × 10 -8 cm/s is greater than 4.19X 10 without SDS -8 The diffusion coefficient of the cleaning agent with cm/s and pH =11 is 12.4X 10 -8 cm/s is greater than 6.81X 10 without SDS -8 cm/s. (data were all numerically analyzed using T-test, p<, 0.01, demonstrating significant differences). SDS is a surfactant, can reduce the surface tension of the cleaning agent, thus promote the diffusion of the cleaning agent in the contaminated layer. The data measured by the invention can quantitatively reflect the phenomenon, and prove the promoting effect of SDS on the diffusion of the cleaning agent.
Claims (4)
1. A method for testing the diffusion coefficient of a cleaning agent in a membrane pollution layer is characterized by comprising the following steps:
(1) Measuring the average thickness of the uncontaminated film and the average thickness of the contaminated film by using a micrometer, and obtaining the average thickness of the contaminated layer by subtracting the average thickness of the uncontaminated film and the average thickness of the contaminated film;
(2) Placing a pollution layer of the membrane to be detected on a circular platform of the U-shaped permeation device downwards so as to enable the pollution layer to be in contact with a cleaning agent;
(3) Covering the upper surface (back surface) of the membrane to be tested with chromogenic test paper for marking the diffusion end point of the cleaning agent, ensuring that the test paper is tightly attached to the membrane to be tested, and fixing the membrane to be tested by using a fixing device;
(4) Injecting a cleaning agent from one end of the U-shaped penetration device until the water surface is just leveled with the preset scale, and starting timing;
(5) And observing the color change condition of the test paper on the back of the film to be detected, stopping timing when the test paper is completely changed in color, and calculating the diffusion coefficient according to a diffusion model of the cleaning agent in the film pollution layer.
2. The method for testing the diffusion coefficient of the cleaning agent in the membrane fouling layer according to claim 1, which is characterized in that: the derivation process of the diffusion model of the cleaning agent in the membrane pollution layer in the step (5) is as follows:
according to the law of Darcy,
v＝K×J
wherein Q is the seepage flow;
k is the permeability coefficient;
a is the sectional area vertical to the water flow direction;
l is the seepage length;
delta h is the difference between the upstream and downstream water heads;
since the thickness of the contamination layer is only a few hundred micrometers, the penetration rate of the cleaning agent in the contamination layer can be approximately regarded as constant, i.e. constant
Wherein v' is the diffusion rate, cm/s;
is the average thickness of the contamination layer, cm;
t is diffusion time, s;
from darcy's law, the diffusion coefficient describing the cleaning agent in the contaminated layer can be defined as:
in the formula, K' is the diffusion coefficient of the cleaning agent in the pollution layer, and is cm/s;
is the average thickness of the contamination layer, cm;
t is diffusion time, s;
Δ h is the head difference, cm, of the upper and lower surfaces of the film.
3. The method for testing the diffusion coefficient of the cleaning agent in the membrane fouling layer according to claim 1, which is characterized in that: the cleaning agent is an oxidizing cleaning agent, and specifically is any one of sodium hypochlorite, hydrogen peroxide, hydrochloric acid or sodium hydroxide; the test paper for marking the diffusion end point of the cleaning agent can be selected according to different measured cleaning agents, and specifically comprises starch potassium iodide test paper (for marking an oxidative cleaning agent) and pH test paper (for marking an acid-base cleaning agent).
4. The device for testing the diffusion coefficient of the cleaning agent in the membrane fouling layer as claimed in claim 1, wherein: the device comprises a U-shaped pressure permeation device, a membrane assembly fixing device and color development test paper for marking the diffusion end point of a cleaning agent, wherein the membrane assembly fixing device is connected with the U-shaped pressure permeation device through a bolt; placing a pollution layer of the membrane to be detected on a circular platform of the U-shaped permeation device downwards so as to enable the pollution layer to be in contact with a cleaning agent; covering the upper surface (back surface) of the membrane to be tested with chromogenic test paper for marking the diffusion end point of the cleaning agent, ensuring that the test paper is tightly attached to the membrane to be tested, and fixing the membrane to be tested by using a fixing device; in addition, a stopwatch is required for recording diffusion time, and a micrometer is used for measuring and calculating the thickness of the contaminated layer.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109297867A (en) * | 2018-10-15 | 2019-02-01 | 成都理工大学 | A kind of contaminated area field quick detection pipe and detection method |
| CN112394012A (en) * | 2020-11-06 | 2021-02-23 | 东莞市卓越新材料科技有限公司 | Method for detecting moisture permeability of polypropylene film for lithium battery aluminum plastic film |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103926179A (en) * | 2014-02-27 | 2014-07-16 | 新疆水利水电科学研究院 | Asphalt concrete permeability detector |
| CN204177710U (en) * | 2014-09-16 | 2015-02-25 | 中国电力工程顾问集团西北电力设计院有限公司 | A kind of varying head permeability apparatus preventing infiltration cutting ring side seam from leaking |
| CN104819920A (en) * | 2015-03-24 | 2015-08-05 | 河南理工大学 | Varying-head permeability experiment apparatus for indoor freezing and thawing equipment |
| US20160076987A1 (en) * | 2014-09-11 | 2016-03-17 | Korea Institute Of Geoscience And Mineral Resources | Apparatus for measuring saturated hydraulic conductivity of unsaturated porous media |
| CN105688681A (en) * | 2016-01-31 | 2016-06-22 | 苏州博尔达生物科技有限公司 | Manifold, and system and method for detecting permeability of porous film containing manifold |
| CN206095880U (en) * | 2016-06-25 | 2017-04-12 | 河南工业大学 | Joint appearance is concretied in infiltration |
| CN106706500A (en) * | 2017-01-21 | 2017-05-24 | 三峡大学 | Device for determining permeability of concrete |
-
2017
- 2017-08-02 CN CN201710650386.4A patent/CN107589049B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103926179A (en) * | 2014-02-27 | 2014-07-16 | 新疆水利水电科学研究院 | Asphalt concrete permeability detector |
| US20160076987A1 (en) * | 2014-09-11 | 2016-03-17 | Korea Institute Of Geoscience And Mineral Resources | Apparatus for measuring saturated hydraulic conductivity of unsaturated porous media |
| CN204177710U (en) * | 2014-09-16 | 2015-02-25 | 中国电力工程顾问集团西北电力设计院有限公司 | A kind of varying head permeability apparatus preventing infiltration cutting ring side seam from leaking |
| CN104819920A (en) * | 2015-03-24 | 2015-08-05 | 河南理工大学 | Varying-head permeability experiment apparatus for indoor freezing and thawing equipment |
| CN105688681A (en) * | 2016-01-31 | 2016-06-22 | 苏州博尔达生物科技有限公司 | Manifold, and system and method for detecting permeability of porous film containing manifold |
| CN206095880U (en) * | 2016-06-25 | 2017-04-12 | 河南工业大学 | Joint appearance is concretied in infiltration |
| CN106706500A (en) * | 2017-01-21 | 2017-05-24 | 三峡大学 | Device for determining permeability of concrete |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109297867A (en) * | 2018-10-15 | 2019-02-01 | 成都理工大学 | A kind of contaminated area field quick detection pipe and detection method |
| CN109297867B (en) * | 2018-10-15 | 2023-10-13 | 成都理工大学 | On-site rapid detection tube and detection method for polluted area |
| CN112394012A (en) * | 2020-11-06 | 2021-02-23 | 东莞市卓越新材料科技有限公司 | Method for detecting moisture permeability of polypropylene film for lithium battery aluminum plastic film |
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