DYE-SALT SEPARATION MEMBRANE AND PREPARATION METHOD THEREOF

Abstract

The present invention relates to a dye-salt separation membrane and a preparation method thereof. The method includes the following steps: firstly pouring an aqueous phase solution containing tannic acid and anhydrous piperazine on a surface of a polysulfone-based ultrafiltration base membrane at a mass ratio of the tannic acid to the anhydrous piperazine of 1:2 to 2:1, followed by complete infiltration, and draining the aqueous phase solution; and then pouring an organic phase solution of trimesoyl chloride on the surface of the base membrane, and draining the organic phase solution to obtain the dye-salt separation membrane. The method of the present invention is simple and easy to implement, and the dye-salt separation membrane prepared by the method has a relatively high solution permeability, an efficient dye retention and permeability of inorganic salts, thereby achieving an excellent dye-salt separation effect.

Claims

1. A method for preparing a dye-salt separation membrane, comprising the following steps: step 1: pouring an aqueous phase solution containing tannic acid and anhydrous piperazine on a surface of a polysulfone-based ultrafiltration base membrane at a mass ratio of the tannic acid to the anhydrous piperazine of 1:2 to 2:1, followed by complete infiltration for 3 to 6 minutes, and then draining the aqueous phase solution; and step 2: pouring an organic phase solution of trimesoyl chloride on the surface of the polysulfone-based ultrafiltration base membrane obtained in step 1, followed by complete infiltration for 0.5 to 2 minutes, then draining the organic phase solution, and after the organic phase solution being completely evaporated, storing the resulting dye-salt separation membrane in water.

2. The method according to claim 1, wherein in step 1, the polysulfone-based ultrafiltration base membrane is selected from polyethersulfone, polysulfone, or sulfonated polyethersulfone.

3. The method according to claim 1, wherein in step 1, the aqueous phase solution contains the tannic acid and the anhydrous piperazine at a combined mass fraction of 0.2 wt %.

4. The method according to claim 1, wherein in step 1, the infiltration is performed for a time period of 5 minutes.

5. The method according to claim 1, wherein in step 1, the mass ratio of the tannic acid to the anhydrous piperazine is 1:1.

6. The method according to claim 1, wherein in step 2, the organic phase solution of the trimesoyl chloride contains the trimesoyl chloride at a mass fraction of 0.1 wt %.

7. The method according to claim 1, wherein in step 2, the infiltration is performed for a time period of 1 minute.

8. The method according to claim 1, wherein in step 2, the organic phase solution contains a solvent selected from n-hexane or cyclohexane.

9. A dye-salt separation membrane prepared by the method according to claim 1.

10. A dye-salt separation membrane prepared by the method according to claim 2.

11. A dye-salt separation membrane prepared by the method according to claim 3.

12. A dye-salt separation membrane prepared by the method according to claim 4.

13. A dye-salt separation membrane prepared by the method according to claim 5.

14. A dye-salt separation membrane prepared by the method according to claim 6.

15. A dye-salt separation membrane prepared by the method according to claim 7.

16. A dye-salt separation membrane prepared by the method according to claim 8.

Description

DESCRIPTION OF THE EMBODIMENTS

[0023] The present invention will be further described below with reference to Examples.

Example 1

[0024] Step 1: An aqueous phase solution containing a mixture of tannic acid and anhydrous piperazine as a solute at a combined mass fraction of 0.2 wt % was formulated. The mass ratio of tannic acid to anhydrous piperazine in the mixture was 1:2. After the formulation of the aqueous phase solution was completed, the aqueous phase solution was poured on a surface of a polyethersulfone ultrafiltration membrane and allowed to completely infiltrate it for 5 minutes, and then, the aqueous phase solution was drained.

[0025] Step 2: A solution containing trimesoyl chloride as a solute in n-hexane at a mass fraction of 0.1 wt % was formulated. After the formulation was completed, the solution was poured on the surface of the polyethersulfone ultrafiltration membrane treated in step 1 and allowed to completely infiltrate it for 1 minute, and then the organic phase solution was drained. After the organic phase solution was completely evaporated, the resulting dye-salt separation membrane was placed in deionized water for storage.

[0026] Separation performance test 1: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium chloride, the retention rate of Congo red was 99.48%, the permeability of sodium chloride was 93.98%, and the permeate flux was 249.4 Lm.sup.2h.sup.1MPa.sup.1.

[0027] Separation performance test 2: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium sulfate, the retention rate of Congo red was 99.64%, the permeability of sodium sulfate was 87.02%, and the permeate flux was 225.5 Lm.sup.2h.sup.1MPa.sup.1.

Example 2

[0028] Step 1: An aqueous phase solution containing a mixture of tannic acid and anhydrous piperazine as a solute at a combined mass fraction of 0.2 wt % was formulated. The mass ratio of tannic acid to anhydrous piperazine in the mixture was 2:1. After the formulation of the aqueous phase solution was completed, the aqueous phase solution was poured on a surface of a polyethersulfone ultrafiltration membrane and allowed to completely infiltrate it for 5 minutes, and then, the aqueous phase solution was drained.

[0029] Step 2: A solution containing trimesoyl chloride as a solute in n-hexane at a mass fraction of 0.1 wt % was formulated. After the formulation was completed, the solution was poured on the surface of the polyethersulfone ultrafiltration membrane treated in step 1 and allowed to completely infiltrate it for 1 minute, and then the organic phase solution was drained. After the organic phase solution was completely evaporated, the resulting dye-salt separation membrane was placed in deionized water for storage.

[0030] Separation performance test 1: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium chloride, the retention rate of Congo red was 99.28%, the permeability of sodium chloride was 94.55%, and the permeate flux was 235.4 Lm.sup.2h.sup.1MPa.sup.1.

[0031] Separation performance test 2: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium sulfate, the retention rate of Congo red was 99.32%, the permeability of sodium sulfate was 89.90%, and the permeate flux was 235.5 Lm.sup.2h.sup.1MPa.sup.1.

Example 3

[0032] Step 1: An aqueous phase solution containing a mixture of tannic acid and anhydrous piperazine as a solute at a combined mass fraction of 0.2 wt % was formulated. The mass ratio of tannic acid to anhydrous piperazine in the mixture was 1:1. After the formulation of the aqueous phase solution was completed, the aqueous phase solution was poured on a surface of a polyethersulfone ultrafiltration membrane and allowed to completely infiltrate it for 5 minutes, and then, the aqueous phase solution was drained.

[0033] Step 2: A solution containing trimesoyl chloride as a solute in n-hexane at a mass fraction of 0.1 wt % was formulated. After the formulation was completed, the solution was poured on the surface of the polyethersulfone ultrafiltration membrane treated in step 1 and allowed to completely infiltrate it for 1 minute, and then the organic phase solution was drained. After the organic phase solution was completely evaporated, the resulting dye-salt separation membrane was placed in deionized water for storage.

[0034] Separation performance test 1: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium chloride, the retention rate of Congo red was 99.42%, the permeability of sodium chloride was 94.59%, and the permeate flux was 315.2 Lm.sup.2h.sup.1MPa.sup.1.

[0035] Separation performance test 2: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium sulfate, the retention rate of Congo red was 99.19%, the permeability of sodium sulfate was 94.59%, and the permeate flux was 273.9 Lm.sup.2h.sup.1MPa.sup.1.

Comparative Example 1

[0036] Step 1: An aqueous phase solution containing a mixture of tannic acid and anhydrous piperazine as a solute at a combined mass fraction of 0.2 wt % was formulated. The mass ratio of tannic acid to anhydrous piperazine in the mixture was 1:4. After the formulation of the aqueous phase solution was completed, the aqueous phase solution was poured on a surface of a polyethersulfone ultrafiltration membrane and allowed to completely infiltrate it for 5 minutes, and then, the aqueous phase solution was drained.

[0037] Step 2: A solution containing trimesoyl chloride as a solute in n-hexane at a mass fraction of 0.1 wt % was formulated. After the formulation was completed, the solution was poured on the surface of the polyethersulfone ultrafiltration membrane treated in step 1 and allowed to completely infiltrate it for 1 minute, and then the organic phase solution was drained. After the organic phase solution was completely evaporated, the resulting dye-salt separation membrane was placed in deionized water for storage.

[0038] Separation performance test 1: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium chloride, the retention rate of Congo red was 99.71%, the permeability of sodium chloride was 72.91%, and the permeate flux was 216.4 Lm.sup.2h.sup.1MPa.sup.1.

[0039] Separation performance test 2: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium sulfate, the retention rate of Congo red was 99.69%, the permeability of sodium sulfate was 51.12%, and the permeate flux was 203.9 Lm.sup.2h.sup.1MPa.sup.1.

Comparative Example 2

[0040] Step 1: An aqueous phase solution containing a mixture of tannic acid and anhydrous piperazine as a solute at a combined mass fraction of 0.2 wt % was formulated. The mass ratio of tannic acid to anhydrous piperazine in the mixture was 4:1. After the formulation of the aqueous phase solution was completed, the aqueous phase solution was poured on a surface of a polyethersulfone ultrafiltration membrane and allowed to completely infiltrate it for 5 minutes, and then, the aqueous phase solution was drained.

[0041] Step 2: A solution containing trimesoyl chloride as a solute in n-hexane at a mass fraction of 0.1 wt % was formulated. After the formulation was completed, the solution was poured on the surface of the polyethersulfone ultrafiltration membrane treated in step 1 and allowed to completely infiltrate it for 1 minute, and then the organic phase solution was drained. After the organic phase solution was completely evaporated, the resulting dye-salt separation membrane was placed in deionized water for storage.

[0042] Separation performance test 1: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium chloride, the retention rate of Congo red was 99.70%, the permeability of sodium chloride was 84.41%, and the permeate flux was 98.4 Lm.sup.2h.sup.1MPa.sup.1.

[0043] Separation performance test 2: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium sulfate, the retention rate of Congo red was 99.59%, the permeability of sodium sulfate was 66.48%, and the permeate flux was 102.1 Lm.sup.2h.sup.1MPa.sup.1.

Example 4

[0044] Step 1: An aqueous phase solution containing a mixture of tannic acid and anhydrous piperazine as a solute at a combined mass fraction of 0.2 wt % was formulated. The mass ratio of tannic acid to anhydrous piperazine in the mixture was 1:1. After the formulation of the aqueous phase solution was completed, the aqueous phase solution was poured on a surface of a polysulfone ultrafiltration membrane and allowed to completely infiltrate it for 5 minutes, and then, the aqueous phase solution was drained.

[0045] Step 2: A solution containing trimesoyl chloride as a solute in n-hexane at a mass fraction of 0.1 wt % was formulated. After the formulation was completed, the solution was poured on the surface of the polysulfone ultrafiltration membrane treated in step 1 and allowed to completely infiltrate it for 1 minute, and then the organic phase solution was drained. After the organic phase solution was completely evaporated, the resulting dye-salt separation membrane was placed in deionized water for storage.

[0046] Separation performance test 1: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium chloride, the retention rate of Congo red was 99.58%, the permeability of sodium chloride was 95.05%, and the permeate flux was 286.3 Lm.sup.2h.sup.1MPa.sup.1.

[0047] Separation performance test 2: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium sulfate, the retention rate of Congo red was 99.33%, the permeability of sodium sulfate was 90.96%, and the permeate flux was 272.1 Lm.sup.2h.sup.1MPa.sup.1.

Example 5

[0048] Step 1: An aqueous phase solution containing a mixture of tannic acid and anhydrous piperazine as a solute at a combined mass fraction of 0.2 wt % was formulated. The mass ratio of tannic acid to anhydrous piperazine in the mixture was 1:1. After the formulation of the aqueous phase solution was completed, the aqueous phase solution was poured on a surface of a polyethersulfone ultrafiltration membrane and allowed to completely infiltrate it for 5 minutes, and then, the aqueous phase solution was drained.

[0049] Step 2: A solution containing trimesoyl chloride as a solute in cyclohexane at a mass fraction of 0.1 wt % was formulated. After the formulation was completed, the solution was poured on the surface of the polyethersulfone ultrafiltration membrane treated in step 1 and allowed to completely infiltrate it for 1 minute, and then the organic phase solution was drained. After the organic phase solution was completely evaporated, the resulting dye-salt separation membrane was placed in deionized water for storage.

[0050] Separation performance test 1: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium chloride, the retention rate of Congo red was 99.34%, the permeability of sodium chloride was 94.48%, and the permeate flux was 313.0 Lm.sup.2h.sup.1MPa.sup.1.

[0051] Separation performance test 2: The resulting dye-salt separation membrane was installed in a membrane separation device in which the differential pressure across the membrane was controlled to 0.4 MPa, and it was determined that at room temperature, for a dye-salt aqueous solution containing 0.2 g/L of Congo red and 2 g/L of sodium sulfate, the retention rate of Congo red was 99.16%, the permeability of sodium sulfate was 91.68%, and the permeate flux was 294.7 Lm.sup.2h.sup.1MPa.sup.1.