CN219409495U - Composite nanofiltration membrane - Google Patents
Composite nanofiltration membrane Download PDFInfo
- Publication number
- CN219409495U CN219409495U CN202320296033.XU CN202320296033U CN219409495U CN 219409495 U CN219409495 U CN 219409495U CN 202320296033 U CN202320296033 U CN 202320296033U CN 219409495 U CN219409495 U CN 219409495U
- Authority
- CN
- China
- Prior art keywords
- nanofiltration membrane
- layer
- composite nanofiltration
- membrane
- graphene oxide
- 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.)
- Active
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
- Y02A20/131—Reverse-osmosis
Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The utility model provides a composite nanofiltration membrane, which comprises: at least one base film layer and at least one graphene oxide film layer on the surface of the base film layer, wherein the graphene oxide film layer is a graphene oxide layer with a high polymer nano material. The composite nanofiltration membrane has excellent structure and performance stability due to the unique structure, and has the advantages of large flux, high rejection rate to dye, capability of allowing most inorganic salt to pass through and excellent inorganic salt/dye separation performance.
Description
Technical Field
The utility model relates to a composite nanofiltration membrane, and belongs to the technical field of wastewater treatment.
Background
The processing, weaving and dyeing processes of cotton spinning products are very complex and each process adds and produces different contaminant components. In particular, the waste water discharged from the dyeing process contains a large amount of salt (usually NaCl, na 2 CO 3 、Na 2 SO 4 One or more of the group consisting of, and the like), an undyed dye, and a hydrolysate thereof.
The dyeing wastewater has high salinity and high chromaticity, and is difficult to biochemically treat. The traditional treatment method of the part of wastewater is to mix the part of wastewater with wastewater produced in other production links, dilute the salt content and chromaticity, and then deeply treat the wastewater in a manner of physical and chemical treatment, biochemical treatment or physical and chemical-biochemical combination and the like, and then discharge the wastewater after reaching the standard. If the wastewater discharged after reaching the standard is recycled, the wastewater still needs to be subjected to advanced oxidation or activated carbon adsorption to be completely decolorized to meet the recycling requirement. However, these steps inevitably bring about secondary pollution of the environment.
In addition, the dyeing wastewater contains a large amount of anhydrous sodium sulfate (i.e., na 2 SO 4 ) The salt has good economic and environmental benefits if the salt such as anhydrous sodium sulfate can be recycled.
The loose nanofiltration is a membrane separation technology with the aperture between ultrafiltration and nanofiltration, and most inorganic salt can permeate the membrane on the basis of ensuring high interception of organic dye, so that the high-efficiency separation of organic dye/brine in printing and dyeing wastewater is achieved, and the loose nanofiltration has high economic value and research significance. However, commercial nanofiltration membranes are mostly organic membranes, which have a wide pore size, poor selectivity and poor contamination resistance due to the inherent properties of the polymer network chain structure. When the organic membrane is used for treating high-salinity high-chromaticity wastewater, if the retention rate of dye is required to be high, the aperture of the organic membrane is required to be smaller, and the organic membrane also has certain retention on salt at the moment, and the flux of the membrane is small due to the osmotic pressure effect of the retained part of salt, so that the high flux and the high dye retention rate are difficult to obtain simultaneously.
Therefore, developing a novel composite nanofiltration membrane becomes one of the problems to be solved in the field.
Disclosure of Invention
In order to solve the technical problems, the utility model aims at a composite nanofiltration membrane. The composite nanofiltration membrane has better salt/dye separation performance.
In order to achieve the above object, the present utility model provides a composite nanofiltration membrane comprising: at least one base film layer and at least one graphene oxide film layer on the surface of the base film layer, wherein the graphene oxide film layer is a graphene oxide layer with a high polymer nano material. More preferably, the composite nanofiltration membrane comprises: the graphene oxide film comprises a base film layer and a graphene oxide film layer on one surface of the base film layer, wherein the graphene oxide film layer is a graphene oxide layer with a high-molecular nano material.
In the above composite nanofiltration membrane, preferably, the polymer nanomaterial is dispersed and disposed between sheets of the graphene oxide sheet to form the graphene oxide film layer.
In the above composite nanofiltration membrane, the platelet size of the graphene oxide sheet is preferably 0.5 to 500 μm, more preferably 2 to 50 μm.
In the above composite nanofiltration membrane, preferably, the interlayer spacing between the lamellar layers of the lamellar graphene oxide is 0.8 to 2.0nm.
In the above composite nanofiltration membrane, preferably, the molecular weight cut-off of the graphene oxide membrane layer is 500 to 3000 daltons, more preferably 800 to 3000 daltons.
In the above composite nanofiltration membrane, the graphene oxide membrane layer preferably has a thickness of 5 to 2000nm, more preferably 50 to 500nm.
In the above composite nanofiltration membrane, preferably, the polymer nanomaterial includes a polymer nanofiber or a polymer nanocrystal. More preferably, the polymer nanofiber has a diameter of 10 to 50nm and an aspect ratio of 10 to 100. More preferably, the diameter of the polymer nanocrystalline is 2-20nm, and the length-diameter ratio is 10-100. More specifically, the polymer nanomaterial includes cellulose nanofibers, cellulose nanocrystals, chitin nanofibers, chitin nanocrystals, chitosan nanofibers, chitosan nanocrystals, lignin nanofibers, or lignin nanocrystals.
In the above composite nanofiltration membrane, preferably, the thickness of the base membrane layer is 50-200 μm.
In the above composite nanofiltration membrane, preferably, the base membrane layer includes a nylon (PA) layer, a polyvinylidene fluoride (PVDF) layer, a Polysulfone (PSF) layer, a Polyethersulfone (PES) layer, a Polyacrylonitrile (PAN) layer, or a Cellulose Acetate (CA) layer.
In the above composite nanofiltration membrane, the average pore diameter of the base membrane layer is preferably 0.02 to 10 μm, more preferably 0.1 to 0.22 μm, and still more preferably 0.1 μm or 0.22 μm.
In the above composite nanofiltration membrane, preferably, the base membrane layer comprises a positively charge modified nylon microfiltration membrane layer having an average pore size of 0.1 μm or 0.22 μm. The positively charge modified nylon microfiltration membrane is commercially available. The nylon micro-filtration membrane modified by positive charges is preferably used as a base membrane layer, the surface of the nylon micro-filtration membrane carries positive charges and is combined with the graphene oxide layer with the negative charges and the high molecular nano material, so that the bonding force between the graphene oxide layer with the high molecular nano material and the base membrane layer can be improved, and the graphene oxide layer with the high molecular nano material is prevented from falling off from the base membrane layer in the membrane filtration process.
According to a specific embodiment of the present utility model, preferably, the flux of the composite nanofiltration membrane for filtering 2000ppm sodium sulfate solution is 5-30L/(m) 2 H Bar), de-wateringThe salt rate is 50-95%. The desalination rate is the rejection rate of salt, and is calculated by adopting a conventional calculation method in the field.
According to a specific embodiment of the present utility model, preferably, the flux of the 2000ppm active dye solution filtered by the composite nanofiltration membrane is 5-30L/(m) 2 H Bar), dye retention>98%. Wherein, the reactive dye is a reactive dye which is conventionally adopted in the textile field and is mainly used for cotton dyeing. More specifically, the reactive dyes include, but are not limited to, one or a combination of several of TQ Blue, yellow 3RF, red 7B, everzol Blue BB, novacron Red EC-2BL, and the like.
According to a specific embodiment of the present utility model, preferably, the flux of the mixed solution of 70g/L sodium sulfate and 2g/L reactive dye filtered by the composite nanofiltration membrane is 3-10L/(m) 2 H Bar), dye retention of 95-99.9%, desalination rate<15%. The reactive dye is a reactive dye conventionally adopted in the textile field, is mainly used for cotton dyeing, and can specifically comprise the reactive dye.
The composite nanofiltration membrane has excellent structure and performance stability due to the unique structure, and has the advantages of large flux, high rejection rate to dye, capability of allowing most inorganic salt to pass through and excellent inorganic salt/dye separation performance. Therefore, the composite nanofiltration membrane provided by the utility model is particularly suitable for decoloring high-salt wastewater containing dyes, including industrial wastewater with high salt and high chromaticity, and can be used for efficiently separating dyes and inorganic salts, efficiently removing chromaticity and recycling inorganic salts.
Furthermore, the present utility model provides a dyeing wastewater treatment system comprising: the device comprises a pH value adjusting unit, a coarse filtering unit, an ultrafiltration unit and a nanofiltration unit; the inlet of the pH value adjusting unit is connected with a dyeing wastewater conveying pipeline, the outlet of the pH value adjusting unit is connected with the inlet of the coarse filtering unit through a pipeline, the outlet of the coarse filtering unit is connected with the inlet of the ultrafiltration unit through a pipeline, the outlet of the ultrafiltration unit is connected with the inlet of the nanofiltration unit through a pipeline, and the water producing port of the nanofiltration unit produces reuse water; wherein, the nanofiltration unit comprises the composite nanofiltration membrane.
In the dyeing wastewater treatment system, preferably, the nanofiltration unit comprises a first-stage nanofiltration membrane element and a second-stage nanofiltration membrane element which are connected in series, an outlet of the ultrafiltration unit is connected to an inlet of the first-stage nanofiltration membrane element through a pipeline, a water producing port of the first-stage nanofiltration membrane element is connected to an inlet of the second-stage nanofiltration membrane element through a pipeline, and a water producing port of the second-stage nanofiltration membrane element produces reuse water; wherein, the first-stage nanofiltration membrane element and the second-stage nanofiltration membrane element are membrane elements which are made of the composite nanofiltration membrane roll. The method of rolling the nanofiltration membrane into the membrane element may be performed according to a conventional method in the art, and the present utility model is not particularly limited thereto.
In the dyeing wastewater treatment system, preferably, the nanofiltration unit further includes a first concentrated water backflow line, and the first concentrated water backflow line is used for backflow of a part of concentrated water generated after the treatment of the first stage nanofiltration membrane element, and the part of concentrated water is treated again by the first stage nanofiltration membrane element.
In the dyeing wastewater treatment system, preferably, the nanofiltration unit further includes a second concentrated water backflow line, and the second concentrated water backflow line is used for backflow of the concentrated water generated after the treatment of the second stage nanofiltration membrane element, and the concentrated water is treated again by the first stage nanofiltration membrane element.
In the dyeing wastewater treatment system described above, preferably, the pH adjusting unit includes a pH adjusting tank for adjusting the pH of the wastewater to neutral. The pH adjusting tank used may be a pH adjusting tank conventional in the art.
In the dyeing wastewater treatment system described above, preferably, the coarse filtration unit includes one or a combination of several of a sand filter, a filter bag, a cartridge filter, and the like. More preferably, the coarse filtration unit comprises a sand filter and a filter bag connected in series, or a sand filter and a cartridge filter connected in series. The sand filter, filter bag and cartridge filter employed may be any conventional filtration device in the art.
In the dyeing wastewater treatment system described above, preferably, the ultrafiltration unit comprises a hollow fiber ultrafiltration membrane or a tubular ceramic ultrafiltration membrane. The hollow fiber ultrafiltration membrane and the tubular ceramic ultrafiltration membrane can both be ultrafiltration membranes conventional in the art. More preferably, the pore size of the hollow fiber ultrafiltration membrane and the tubular ceramic ultrafiltration membrane is 10-100nm.
The method for treating the dyeing wastewater by adopting the dyeing wastewater treatment system provided by the utility model can comprise the following steps: enabling the dyeing wastewater to enter a pH value adjusting unit, and adjusting the pH value of the dyeing wastewater in the pH value adjusting unit by utilizing acid to obtain wastewater with neutral pH value; then the wastewater with neutral pH value is treated by the coarse filtering unit, and large particles and/or fine substances and the like in the wastewater are removed to obtain wastewater after coarse filtering; treating the wastewater after coarse filtration by the ultrafiltration unit to further remove fine substances and/or partial COD (chemical oxygen demand) and the like in the wastewater to obtain wastewater after ultrafiltration treatment; and then the wastewater after ultrafiltration treatment is treated by the nanofiltration unit, the dye in the wastewater is trapped and most of inorganic salt is allowed to pass through, and the reuse water is obtained. Wherein more specifically, the dyeing wastewater comprises high-salt wastewater containing dye. The salt concentration in the high-salt wastewater containing the dye is more than 20-200g/L, and the dye concentration is 0.2-5g/L. The salt may comprise NaCl, na 2 SO 4 And Na (Na) 2 CO 3 One or a combination of several of the following. The salt concentration is the total concentration of inorganic salts in the wastewater. The dye may comprise a reactive dye. The reactive dye is a reactive dye conventionally adopted in the textile field and is mainly used for cotton dyeing. More specifically, the reactive dyes include, but are not limited to, one or a combination of several of TQ Blue, yellow 3RF, red 7B, everzol Blue BB, novacron Red EC-2BL, and the like.
The composite nanofiltration membrane and the dyeing wastewater treatment system can be used for carrying out decoloration treatment on wastewater with high salt and high chromaticity, have high rejection rate on dye, allow most of inorganic salt such as anhydrous sodium sulfate (namely sodium sulfate) to pass through, and finally obtain reuse water which is low-color or colorless inorganic salt solution and can be reused in the dyeing process of textiles. The composite nanofiltration membrane and dyeing wastewater treatment system has the advantages of simple structure, low running cost, high economic benefit and environmental benefit and the like.
Drawings
FIG. 1 is a schematic structural diagram of the composite nanofiltration membrane provided in examples 1-3.
Fig. 2 is a schematic structural diagram of a dyeing wastewater treatment system provided in example 4.
FIG. 3 is an optical image of the actual dyeing wastewater before and after treatment by the dyeing wastewater treatment system of example 4 and a comparative image of the recycled glauber salt reused for dyeing and directly dyed with fresh glauber salt.
Reference numerals illustrate:
101: a base film layer; 102: a graphene oxide film layer; 103: a polymer nanomaterial; 104: flake graphene oxide;
1: a pH value adjusting unit; 2: a coarse filtration unit; 3: an ultrafiltration unit; 4: a nanofiltration unit; 41: a first stage nanofiltration membrane element; 42: a second stage nanofiltration membrane element; 43: a first concentrate return line; 44: a concentrate discharge line; 45: a second concentrate return line; 46: a first water production line; 47: and a second water production line.
Detailed Description
The technical solution of the present utility model will be described in detail below for a clearer understanding of technical features, objects and advantageous effects of the present utility model, but should not be construed as limiting the scope of the present utility model.
Example 1
The embodiment provides a composite nanofiltration membrane, the structure of which is shown in fig. 1, comprising: a base membrane layer 101 and a graphene oxide membrane layer 102 on one surface of the base membrane layer 101, wherein the base membrane layer 101 is a positively charge modified nylon micro-filtration membrane layer with an average pore diameter of 0.1 μm; the graphene oxide film layer 102 is a graphene oxide layer with a polymer nano material 103, the polymer nano material 103 is chitin nano fiber, the average diameter of the chitin nano fiber is 30nm, the length-diameter ratio of the chitin nano fiber is 10-20, the chitin nano fiber is dispersedly arranged between the lamellar layers of the lamellar graphene oxide 104 to form the graphene oxide film layer 102, the lamellar dimension of the lamellar graphene oxide 104 is 5-50 mu m, and the lamellar spacing between the lamellar layers of the lamellar graphene oxide is 0.8-2.0nm; the thickness of the base film layer 101 is 50-200 mu m; the thickness of the graphene oxide film layer 102 is 240nm.
The desalination rate of the 2000ppm sodium sulfate solution filtered by the composite nanofiltration membrane is more than 60%. The desalination rate of the 70g/L sodium sulfate solution filtered by the composite nanofiltration membrane is lower than 15%. The dye retention rate of the active dye blue R solution which is 2000ppm filtered by the composite nanofiltration membrane is more than 99%. The flux of the mixed solution of 70g/L sodium sulfate and 2g/L active dye blue is 5.88L/(m) 2 H. Bar), dye retention of 99.6%, salt rejection of<15％。
The composite nanofiltration membrane of this example and the comparative composite nanofiltration membrane were subjected to a filtration test on a mixed solution of 70g/L sodium sulfate and 2g/L dye blue after treatment with an acid solution or a reducing agent, and the results are shown in Table 1. Wherein, the acid liquor adopts hydrochloric acid with pH=3, the treatment mode is soaking, and the time is 8 hours; the reducing agent adopts 1% hydroiodic acid, and the treatment mode is soaking for 8 hours.
The composite nanofiltration membrane for comparison is not provided with the chitin nanofiber of the embodiment, and the rest of the structure is the same as the composite nanofiltration membrane of the embodiment.
TABLE 1
As can be seen from table 1, after the composite nanofiltration membrane of this embodiment is treated with acid solution or reducing agent, the flux does not significantly attenuate, which indicates that the performance stability of the membrane is greatly improved.
Example 2
The embodiment provides a composite nanofiltration membrane, the structure of which is shown in fig. 1, comprising: a base membrane layer 101 and a graphene oxide membrane layer 102 on one surface of the base membrane layer 101, wherein the base membrane layer 101 is a positively charge modified nylon micro-filtration membrane layer with an average pore diameter of 0.22 μm; the graphene oxide film layer 102 is a graphene oxide layer with a polymer nanomaterial 103, the polymer nanomaterial 103 is cellulose nanocrystals, the average diameter of the cellulose nanocrystals is 10nm, the length-diameter ratio of the cellulose nanocrystals is 20-50, the cellulose nanocrystals are arranged between the lamellar layers of the lamellar graphene oxide 104 in a dispersing manner to form the graphene oxide film layer 102, the lamellar size of the lamellar graphene oxide 104 is 5-50 mu m, and the interlayer spacing between the lamellar layers of the lamellar graphene oxide is 0.8-2.0nm; the thickness of the base film layer 101 is 50-200 mu m; the thickness of the graphene oxide film layer 102 is 90nm.
The flux of the 2000ppm sodium sulfate solution filtered by the composite nanofiltration membrane is 8.35L/(m) 2 H. Bar), the desalination rate was 82%. The flux of the compound nanofiltration membrane for filtering 70g/L sodium sulfate solution is 4.87L/(m) 2 h.Bar) and the desalination rate was 9.2%. The flux of the 2000ppm active dye blue R solution filtered by the composite nanofiltration membrane is 7.46L/(m) 2 H Bar), the dye retention was 99.9%. The flux of the mixed solution of 70g/L sodium sulfate and 2g/L active dye blue R filtered by the composite nanofiltration membrane is 4.64L/(m) 2 H. Bar), the dye retention was 99.2%, and the salt rejection was 13.2%.
Example 3
The embodiment provides a composite nanofiltration membrane, the structure of which is shown in fig. 1, comprising: a base membrane layer 101 and a graphene oxide membrane layer 102 on one surface of the base membrane layer 101, wherein the base membrane layer 101 is a positively charge modified nylon micro-filtration membrane layer with an average pore diameter of 0.1 μm; the graphene oxide film layer 102 is a graphene oxide layer with a polymer nano material 103, the polymer nano material 103 is lignin nano fiber, the average diameter of the lignin nano fiber is 30nm, the length-diameter ratio of the lignin nano fiber is 20-50, the lignin nano fiber is dispersedly arranged between the lamellar layers of the lamellar graphene oxide 104 to form the graphene oxide film layer 102, the lamellar dimension of the lamellar graphene oxide 104 is 5-50 mu m, and the interlayer spacing between the lamellar layers of the lamellar graphene oxide is 0.8-2.0nm; the thickness of the base film layer 101 is 50-200 mu m; the thickness of the graphene oxide film layer 102 is 40nm.
The flux of the 2000ppm sodium sulfate solution filtered by the composite nanofiltration membrane is 16.3L/(m) 2 H. Bar), the desalination rate was 91%. The flux of the compound nanofiltration membrane for filtering 70g/L sodium sulfate solution is 9.82L/(m) 2 h.Bar) and the desalination rate was 11.2%. The flux of the 2000ppm active dye blue R solution filtered by the composite nanofiltration membrane is 14.2L/(m) 2 H Bar), the dye retention was 99.8%. The flux of the mixed solution of 70g/L sodium sulfate and 2g/L active dye blue is 9.04L/(m) 2 H. Bar), dye retention was 96.3% and desalination was 11.2%.
Example 4
The embodiment provides a dyeing wastewater treatment system, the structure of which is shown in fig. 2, the dyeing wastewater treatment system comprises: a pH value adjusting unit 1, a coarse filtering unit 2, an ultrafiltration unit 3 and a nanofiltration unit 4;
the nanofiltration unit 4 comprises a first stage nanofiltration membrane element 41 and a second stage nanofiltration membrane element 42 which are connected in series, and a first concentrate return line 43, a concentrate discharge line 44, a second concentrate return line 45, a first water production line 46 and a second water production line 47;
the inlet of the pH value adjusting unit 1 is connected with a dyeing wastewater conveying pipeline, the outlet of the pH value adjusting unit 1 is connected with the inlet of the coarse filtering unit 2 through a pipeline, the outlet of the coarse filtering unit 2 is connected with the inlet of the ultrafiltration unit 3 through a pipeline, the outlet of the ultrafiltration unit 3 is connected with the inlet of the first-stage nanofiltration membrane element 41 through a pipeline, the water producing port of the first-stage nanofiltration membrane element 41 is connected with the inlet of the second-stage nanofiltration membrane element 42 through the first water producing pipeline 46, and the water producing port of the second-stage nanofiltration membrane element 42 is connected with the second water producing pipeline 47 for producing high-salt reuse water with no or low chromaticity;
the first concentrated water backflow pipeline 43 is connected to a concentrated water outlet of the first-stage nanofiltration membrane element 41, and is used for partially backflow of the concentrated water generated after the treatment of the first-stage nanofiltration membrane element 41, the concentrated water is treated again by the first-stage nanofiltration membrane element 41, and the other part of the concentrated water is discharged through the concentrated water discharge pipeline 44;
the second concentrated water backflow pipeline 45 is connected to a concentrated water outlet of the second-stage nanofiltration membrane element 42, and is used for backflow of the concentrated water generated after the treatment of the second-stage nanofiltration membrane element 42, and the concentrated water is treated again by the first-stage nanofiltration membrane element 41;
wherein the pH value adjusting unit 1 comprises a pH value adjusting tank for adjusting the pH value of the dyeing wastewater to be neutral; the pH value adjusting tank can be a pH value adjusting tank which is conventional in the field;
the coarse filtration unit 2 comprises a sand filter and a filter bag which are connected in series; the sand filter and the filter bag can be all conventional filtering devices in the field;
the ultrafiltration unit 3 comprises a hollow fiber ultrafiltration membrane, and the pore diameter of the hollow fiber ultrafiltration membrane is 10nm;
the first stage nanofiltration membrane element 41 and the second stage nanofiltration membrane element 42 are both membrane elements (which are obtained by rolling in a conventional manner) formed by rolling the composite nanofiltration membrane provided in example 1.
The dyeing wastewater treatment system of the embodiment is adopted to treat the dyeing wastewater and recycle salt (especially anhydrous sodium sulfate). The dyeing wastewater contains a large amount of anhydrous sodium sulfate (namely sodium sulfate), sodium carbonate and dye, wherein the concentration of inorganic salt is 20-200g/L, and the concentration of dye is 0.2-2g/L.
The method for treating the dyeing wastewater can comprise the following steps: enabling the dyeing wastewater to enter a pH value adjusting unit 1, adjusting the pH value of the dyeing wastewater to be neutral by utilizing sulfuric acid in the pH value adjusting unit 1, and converting sodium carbonate into sodium sulfate to obtain wastewater with neutral pH value; then the wastewater with neutral pH value is treated by the coarse filtration unit 2, and large particles and/or fine suspended matters and the like in the wastewater are removed, so that wastewater after coarse filtration is obtained; then the wastewater after coarse filtration is treated by the ultrafiltration unit 3 to further remove fine substances, partial COD and the like, and simultaneously plays a role in fine protection of the composite nanofiltration membrane of the subsequent nanofiltration unit 4 to obtain wastewater after ultrafiltration treatment; and then the wastewater after ultrafiltration treatment is treated by the nanofiltration unit 4, the dye in the wastewater is trapped and most of sodium sulfate is allowed to pass through, so that a low-color or colorless sodium sulfate solution is obtained, namely reuse water which can be reused in the dyeing process of textiles. The treatment results are shown in Table 3.
Comparative example 1
This comparative example provides a dyeing wastewater treatment system having substantially the same structure as that of example 4, except that the first-stage composite nanofiltration membrane 41 and the second-stage composite nanofiltration membrane 42 of example 4 were replaced with membrane elements made by rolling conventional commercial loose nanofiltration membranes (Suez corporation, product model number Suez GK).
The method of treating the dyeing wastewater using the dyeing wastewater treatment system of this comparative example was the same as that in example 4. The treatment results are shown in Table 3.
The mixed solution of 70g/L sodium sulfate and 2g/L dye blue was filtered by using the membrane element made of the composite nanofiltration membrane roll provided in example 1, and the membrane element made of the commercial loose nanofiltration membrane roll in comparative example 1, respectively, and the results are shown in Table 2.
TABLE 2
The actual dyeing wastewater was treated by the dyeing wastewater treatment system of example 4 and comparative example 1, and the results are shown in table 3.
TABLE 3 Table 3
The retention rate of the traditional commercial loose nanofiltration membrane to the dye in the mixed solution of 70g/L sodium sulfate and 2g/L active dye blue R is only 85-88%, and the flux is 2L/(m) 2 H Bar). In the practical application, however,at a membrane element water recovery rate of 85%, the stable flux is only 0.5-1.5L/(m) 2 H Bar) single stage nanofiltration membranes can only remove 65-75% of the dye. The dyeing wastewater is treated by the two-stage nanofiltration membrane, so that only 90% of dye can be removed. Further activated carbon adsorption or advanced oxidation techniques are then required to further remove the remaining dye and reuse the produced water containing anhydrous sodium sulfate, greatly increasing the cost of the process.
The composite nanofiltration membrane has unique advantages for separating inorganic salts and dyes. The flux of the composite nanofiltration membrane is 3-10L/(m) 2 H Bar) is about 2-4 times that of commercial loose nanofiltration membrane, and the retention rate of dye is [ ]>95%) was much better than commercial loose nanofiltration membranes. In practical application, the stable flux is 2.5-3.6L/(m) under the condition of 85% of water recovery rate of the membrane element 2 H Bar), the retention rate of each grade of composite nanofiltration membrane on the dye exceeds 90%, more than 99% of the dye can be removed after the dyeing wastewater is treated by the two grades of composite nanofiltration membranes, and the produced water containing anhydrous sodium sulfate can be recycled without post-treatment.
FIG. 3 is an optical diagram (a in FIG. 3) of the actual dyeing wastewater before and after treatment by the wastewater treatment system (two-stage composite nanofiltration membrane) of the above-mentioned example 4 and a comparative diagram (b in FIG. 3) of the reused anhydrous sodium sulfate for dyeing and the direct use of fresh anhydrous sodium sulfate for dyeing. As can be seen from fig. 3, the recycled anhydrous sodium sulphate is reused for dyeing, and the cloth has no obvious chromatic aberration. Therefore, the composite nanofiltration membrane roll is used for separating actual high-salt dyeing wastewater, has large membrane flux and excellent separation effect, can be used for efficiently decoloring the high-salt dyeing wastewater, has high anhydrous sodium sulphate recycling rate (more than 85 percent), and has excellent dyeing effect when the recycled anhydrous sodium sulphate is reused in a textile dyeing process.
Claims (10)
1. A composite nanofiltration membrane, the composite nanofiltration membrane comprising: at least one base film layer and at least one graphene oxide film layer on the surface of the base film layer, wherein the graphene oxide film layer is a graphene oxide layer with a high polymer nano material.
2. The composite nanofiltration membrane according to claim 1, wherein the polymer nanomaterial is dispersed and arranged between sheets of the flaky graphene oxide to form the graphene oxide membrane layer.
3. The composite nanofiltration membrane according to claim 2, wherein the platelet size of the graphene oxide platelets is 0.5-500 μm; the interlayer spacing between the lamellar layers of the lamellar graphene oxide is 0.8-2.0nm.
4. The composite nanofiltration membrane of claim 1, wherein the graphene oxide membrane layer has a molecular weight cut-off of 500-3000 daltons.
5. The composite nanofiltration membrane of claim 1, wherein the graphene oxide membrane layer has a thickness of 5-2000nm.
6. The composite nanofiltration membrane of claim 1, wherein the polymeric nanomaterial comprises polymeric nanofibers or polymeric nanocrystals;
the diameter of the polymer nanofiber is 10-50nm, and the length-diameter ratio is 10-100;
the diameter of the polymer nanocrystalline is 2-20nm, and the length-diameter ratio is 10-100.
7. The composite nanofiltration membrane of claim 1 or 6, wherein the polymeric nanomaterial comprises cellulose nanofibers, cellulose nanocrystals, chitin nanofibers, chitin nanocrystals, chitosan nanofibers, chitosan nanocrystals, lignin nanofibers, or lignin nanocrystals.
8. The composite nanofiltration membrane according to claim 1, wherein the base membrane layer has a thickness of 50-200 μm;
the base membrane layer comprises a nylon layer, a polyvinylidene fluoride layer, a polysulfone layer, a polyether sulfone layer, a polyacrylonitrile layer or a cellulose acetate layer;
the average pore diameter of the base film layer is 0.02-10 mu m.
9. The composite nanofiltration membrane of claim 1 wherein the base membrane layer comprises a positively charge modified nylon microfiltration membrane layer having an average pore size of 0.1 μιη or 0.22 μιη.
10. The composite nanofiltration membrane according to claim 1, wherein the flux of the composite nanofiltration membrane for filtering 2000ppm sodium sulfate solution is 5-30L/(m) 2 H Bar), the desalination rate is 50-95%;
the flux of the 2000ppm reactive dye solution filtered by the composite nanofiltration membrane is 5-30L/(m) 2 H Bar), rejection rate>98％；
The flux of the mixed solution of 70g/L sodium sulfate and 2g/L reactive dye filtered by the composite nanofiltration membrane is 3-10L/(m) 2 H Bar), dye retention of 95-99.9%, desalination rate<15％。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320296033.XU CN219409495U (en) | 2023-02-23 | 2023-02-23 | Composite nanofiltration membrane |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320296033.XU CN219409495U (en) | 2023-02-23 | 2023-02-23 | Composite nanofiltration membrane |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN219409495U true CN219409495U (en) | 2023-07-25 |
Family
ID=87242580
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202320296033.XU Active CN219409495U (en) | 2023-02-23 | 2023-02-23 | Composite nanofiltration membrane |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN219409495U (en) |
-
2023
- 2023-02-23 CN CN202320296033.XU patent/CN219409495U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Yi et al. | The influence of important factors on ultrafiltration of oil/water emulsion using PVDF membrane modified by nano-sized TiO2/Al2O3 | |
| CN116020286A (en) | Graphene oxide composite nanofiltration membrane and preparation method and application thereof | |
| CN101549912A (en) | Mercerized waste alkali recovery process and system thereof | |
| CN110292868A (en) | A kind of amination graphene oxide and the composite modified membrane material of graphite phase carbon nitride and its preparation method and application | |
| Gao | Membrane separation technology for wastewater treatment and its study progress and development trend | |
| CN112604507A (en) | Preparation method of high-flux dye separation nanofiltration membrane | |
| CN110760948A (en) | Method for purifying and recycling solvent NMMO in lyocell fiber production process | |
| CN216918696U (en) | System for ultrafiltration, reverse osmosis utilization of strong brine | |
| CN219409495U (en) | Composite nanofiltration membrane | |
| CN110922300A (en) | Alcohol recovery method and device | |
| CN114887486A (en) | Mannitol-based polyester loose composite nanofiltration membrane and preparation method and application thereof | |
| Zahid et al. | Role of polymeric nanocomposite membranes for the removal of textile dyes from wastewater | |
| CN113149135A (en) | System and method for recycling strong brine through ultrafiltration and reverse osmosis | |
| CN101549875A (en) | Process for purifying and recovering mercerized waste alkali and system thereof | |
| CN220098778U (en) | Composite nanofiltration membrane | |
| Basiri et al. | Recycling of direct dyes wastewater by nylon-6 nanofibrous membrane | |
| CN103015246A (en) | Method for comprehensively using pulping waste water by sulfite method | |
| CN111379074A (en) | Preparation method of cellulose nanofiber composite membrane for treating printing and dyeing wastewater | |
| Barredo-Damas et al. | Effect of pH and MWCO on textile effluents ultrafiltration by tubular ceramic membranes | |
| CN216472254U (en) | Sulfuric acid process titanium white powder is washed weak waste acid membrane integration resourceful treatment system once | |
| Akbari et al. | Effect of solution chemistry and operating conditions on the nanofiltration of acid dyes by a nanocomposite membrane | |
| CN206219367U (en) | A kind of processing unit of yarn-dyed fabric yarn dyeing waste water | |
| CN210410244U (en) | Aminated graphene oxide and graphite-phase carbon nitride composite modified film | |
| CN112875976B (en) | Preparation method for recycling inorganic salt in printing and dyeing wastewater | |
| CN116139707A (en) | Graphene oxide/phenolic resin composite nanofiltration membrane and preparation method and application thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |