CORE-SHELL STRUCTURE MEMBRANE SCALE INHIBITOR AND PREPARATION METHOD THEREFOR

Abstract

Disclosed are a core-shell structure membrane scale inhibitor and a preparation method therefor, wherein the core-shell structure membrane scale inhibitor has a core emulsion obtained via emulsion polymerization, and a shell structure obtained via ultraviolet-light grafting functional monomers. The preparation method has first preparing a core by using an emulsion polymerization process, adding a reactive photo-initiator in the later stage of polymerization, so that the reactive photo-initiator is grafted on the surface of the core, and finally initiating the polymerization of functional monomers by means of ultraviolet light to obtain a core-shell structure membrane scale inhibitor. The surface structure of the core is modified, such that a large number of ionizable groups are grafted on the surface thereof, and thus, a large number of scaling ions such as Ca2+, Mg2+ and Al3+ can be adsorbed.

Claims

1. A preparation method for a core-shell structure membrane scale inhibitor, comprising the steps of: Step 1, adding a core monomer, emulsifier and an initiator to deionized water to obtain a solution, introducing nitrogen into and removing oxygen from the solution, and performing a polymerization process on the solution to obtain a pre-emulsion; Step 2, adding a reactive photo-initiator to the pre-emulsion obtained in step A, and mixing them well to obtain a core emulsion; and Step 3, dissolving the core emulsion and functional monomers in deionized water to obtain a solution, adding the solution to an ultraviolet-light reactor, and introducing nitrogen into and removing oxygen from the solution, and performing a polymerization process on the solution to obtain a membrane scale inhibitor.

2. The preparation method for a core-shell structure membrane scale inhibitor of claim 1, wherein the core monomer is selected from the group consisting of styrene, methyl styrene, methyl methacrylate, methyl acrylate, butyl acrylate, or combinations thereof.

3. The preparation method for a core-shell structure membrane scale inhibitor of claim 1, wherein the emulsifier is selected from the group consisting of sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, or combinations thereof.

4. The preparation method for a core-shell structure membrane scale inhibitor of claim 1, wherein the initiator is selected from the group consisting of azobisisobutyronitrile, potassium persulfate, ammonium persulfate, tert-butyl hydroperoxide, or combinations thereof.

5. The preparation method for a core-shell structure membrane scale inhibitor of claim 1, wherein a method for preparing the reactive photo-initiator comprises: dissolving a photo-initiator and reactive monomers in acetone to obtain a mixture, allowing the mixture to be subjected to a polymerization process at an ice bath for 12 hours to obtain the reactive photo-initiator.

6. The preparation method for a core-shell structure membrane scale inhibitor of claim 5, wherein the photo-initiator is selected from the group consisting of 2-hydroxy-2-methyl-1-phenylacetone, hydroxycyclohexylphenyl ketone, 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio) phenyl]-1-acetone, 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl) phenyl]-1-butanone, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy) phenyl]-1-acetone, or combinations thereof.

7. The preparation method for a core-shell structure membrane scale inhibitor of claim 5, wherein the reactive monomer is selected from the group consisting of vinyl phosphonoyl chloride, 2-butenoyl chloride, acryloyl chloride and methacryloyl chloride, or combinations thereof.

8. The preparation method for a core-shell structure membrane scale inhibitor of claim 1, wherein the functional monomer is selected from the group consisting of acrylic acid, methacrylic acid, sodium styrenesulfonate, maleic acid, and 2-acrylamide-2-methylpropanesulfonic acid, or combinations thereof.

9. The preparation method for a core-shell structure membrane scale inhibitor of claim 1, wherein the ultraviolet-light reactor uses an ultraviolet light having a wavelength of 205-395 nm.

10. A core-shell structure membrane scale inhibitor obtained by the preparation method for a core-shell structure membrane scale inhibitor of claim 1 comprises a core emulsion obtained via emulsion polymerization, and a shell structure obtained via ultraviolet-light grafting functional monomers.

11. A core-shell structure membrane scale inhibitor obtained by the preparation method for a core-shell structure membrane scale inhibitor of claim 2 comprises a core emulsion obtained via emulsion polymerization, and a shell structure obtained via ultraviolet-light grafting functional monomers.

12. A core-shell structure membrane scale inhibitor obtained by the preparation method for a core-shell structure membrane scale inhibitor of claim 3 comprises a core emulsion obtained via emulsion polymerization, and a shell structure obtained via ultraviolet-light grafting functional monomers.

13. A core-shell structure membrane scale inhibitor obtained by the preparation method for a core-shell structure membrane scale inhibitor of claim 4 comprises a core emulsion obtained via emulsion polymerization, and a shell structure obtained via ultraviolet-light grafting functional monomers.

14. A core-shell structure membrane scale inhibitor obtained by the preparation method for a core-shell structure membrane scale inhibitor of claim 5 comprises a core emulsion obtained via emulsion polymerization, and a shell structure obtained via ultraviolet-light grafting functional monomers.

15. A core-shell structure membrane scale inhibitor obtained by the preparation method for a core-shell structure membrane scale inhibitor of claim 6 comprises a core emulsion obtained via emulsion polymerization, and a shell structure obtained via ultraviolet-light grafting functional monomers.

16. A core-shell structure membrane scale inhibitor obtained by the preparation method for a core-shell structure membrane scale inhibitor of claim 7 comprises a core emulsion obtained via emulsion polymerization, and a shell structure obtained via ultraviolet-light grafting functional monomers.

17. A core-shell structure membrane scale inhibitor obtained by the preparation method for a core-shell structure membrane scale inhibitor of claim 8 comprises a core emulsion obtained via emulsion polymerization, and a shell structure obtained via ultraviolet-light grafting functional monomers.

18. A core-shell structure membrane scale inhibitor obtained by the preparation method for a core-shell structure membrane scale inhibitor of claim 9 comprises a core emulsion obtained via emulsion polymerization, and a shell structure obtained via ultraviolet-light grafting functional monomers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, together with the specification, illustrate exemplary embodiments of the present disclosure, and, together with the description, serve to explain the principles of the present invention.

[0035] FIG. 1 is a graph showing influent water flow rate of CaCO.sub.3 scale inhibition by each scale inhibitor in an embodiment of the present invention.

[0036] FIG. 2 is a graph showing outfluent water flow rate of CaCO.sub.3 scale inhibition by each scale inhibitor in an embodiment of the present invention.

DETAILED DESCRIPTION

[0037] The technical solution of the present invention will now be described clearly and fully hereinafter with reference to the embodiments of the present invention for helping those skilled in the art to better understand the technical solution of the invention.

[0038] A core-shell structure membrane scale inhibitor in this example comprises a core emulsion obtained via emulsion polymerization, and a shell structure obtained via ultraviolet-light grafting functional monomers. The preparation method comprises: first adding a core monomer, emulsifier and an initiator to deionized water to obtain a solution, introducing nitrogen into and removing oxygen from the solution, and performing a polymerization process on the solution at a certain temperature for 2-3 hours to obtain a pre-emulsion; then adding a reactive photo-initiator to the pre-emulsion obtained in Step 1, and mixing them well to obtain a core emulsion; and finally dissolving the core emulsion and functional monomers in deionized water to obtain a solution, adding the solution to an ultraviolet-light reactor, and introducing nitrogen into and removing oxygen from the solution, and performing a polymerization process on the solution for 2-3 hours to obtain a membrane scale inhibitor.

[0039] The core monomer is selected from the group consisting of styrene, methyl styrene, methyl methacrylate, methyl acrylate, butyl acrylate, or combinations thereof, and a mass of the core monomer accounts for 1-10% of the total mass of the core emulsion. The emulsifier is selected from the group consisting of sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, or combinations thereof, and a mass of the emulsifier accounts for 0.01-0.2% of the total mass of the core emulsion. The initiator is selected from the group consisting of azobisisobutyronitrile, potassium persulfate, ammonium persulfate, tert-butyl hydroperoxide, or combinations thereof, and a mass of the initiator accounts for 0.1-1% of the total mass of the core emulsion. The polymerization process is carried out at a temperature between 60° C. to 100° C., preferably between 75° C. to 85° C. A mass of the core emulsion accounts for 10-70%, preferably 20-50% of the total mass of the membrane scale inhibitor. The functional monomer is selected from the group consisting of acrylic acid, methacrylic acid, sodium styrenesulfonate, maleic acid, and 2-acrylamide-2-methylpropanesulfonic acid, or combinations thereof, and a mass of the functional monomer accounts for 0.1-1% of the total mass of the membrane scale inhibitor. The ultraviolet light has a wavelength of 205-395 nm, preferably 365 nm.

[0040] A preparation method for the reactive photo-initiator comprises the steps of dissolving a photo-initiator and reactive monomers in acetone to obtain a mixture, allowing the mixture to be subjected to a polymerization process at an ice bath for 12 hours to obtain the reactive photo-initiator, wherein a mass of the reactive photo-initiator accounts for 0.05-0.5% of the total mass of the core emulsion.

[0041] The photo-initiator is selected from the group consisting of 2-hydroxy-2-methyl-1-phenylacetone, hydroxycyclohexylphenyl ketone, 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio) phenyl]-1-acetone, 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl) phenyl]-1-butanone, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy) phenyl]-1-acetone, or combinations thereof, and a mass of the photo-initiator accounts for 60-70% of the total mass of the reactive photo-initiator. The reactive monomer is selected from the group consisting of vinyl phosphonoyl chloride, 2-butenoyl chloride, acryloyl chloride and methacryloyl chloride, or combinations thereof, and a mass of the reactive monomer accounts for 30-40% of the total mass of the reactive photo-initiator.

[0042] Four samples were prepared by using the above-mentioned methods:

[0043] Sample 1: 12 g of styrene, 0.25 g of sodium dodecyl sulfonate, 0.75 g of potassium persulfate and 287 g of deionized water were added to a four-necked flask with 500 ml volume, nitrogen was introduced into and the oxygen was removed from the flask, it was heated at 80° C. for two hours, and then 1.5 g of a reactive photo-initiator was added therein, and a polymerization process was carried out for 2 hours to obtain a core emulsion. 150 g of the core emulsion, 5 g of acrylic acid and 345 g of deionized water were transferred into a photo-reactor, nitrogen was introduced into and oxygen was removed from the photo-reactor, and finally the polymerization process was carried out for 3 hours to obtain the sample 1.

[0044] Sample 2: 15 g of methyl methacrylate, 0.3 g of sodium dodecyl benzene sulfonate, 0.75 g of azodiisobutyronitrile and 284 g of deionized water were added to a four-necked flask with 500 ml volume, nitrogen was introduced into and the oxygen was removed from the flask, it was heated at 80° C. for two hours, and then 2 g of a reactive photo-initiator was added therein, and a polymerization process was carried out for 2 hours to obtain a core emulsion. 150 g of the core emulsion, 5 g of 2-acrylamide-2-methylpropanesulfonic acid and 345 g of deionized water were transferred into a photo-reactor, nitrogen was introduced into and oxygen was removed from the photo-reactor, and finally the polymerization process was carried out for 3 hours to obtain the sample 2.

[0045] Sample 3: 12 g of styrene, 0.25 g of sodium dodecyl benzene sulfonate, 0.75 g of ammonium persulfate and 287 g of deionized water were added to a four-necked flask with 500 ml volume, nitrogen was introduced into and the oxygen was removed from the flask, it was heated at 80° C. for two hours, and then 1.5 g of a reactive photo-initiator was added therein, and a polymerization process was carried out for 2 hours to obtain a core emulsion. 150 g of the core emulsion, 5 g of methacrylic acid and 345 g of deionized water were transferred into a photo-reactor, nitrogen was introduced into and oxygen was removed from the photo-reactor, and finally the polymerization process was carried out for 3 hours to obtain the sample 3.

[0046] Sample 4: 60 g of styrene, 1.5 g of sodium dodecyl sulfate, 4 g of ammonium persulfate and 1434.5 g of deionized water were added to a four-necked flask with 2000 ml volume, nitrogen was introduced into and the oxygen was removed from the flask, it was heated at 80° C. for two hours, and then 15 g of a reactive photo-initiator was added therein, and a polymerization process was carried out for 2 hours to obtain a core emulsion. 150 g of the core emulsion, 5 g of maleic acid and 345 g of deionized water were transferred into a photo-reactor, nitrogen was introduced into and oxygen was removed from the photo-reactor, and finally the polymerization process was carried out for 3 hours to obtain the sample 4.

[0047] The above-mentioned four samples, commonly used reagents in the market (ASD 200, MDC754) and blank samples were evaluated for scale inhibition.

[0048] Experimental water was prepared first, and water parameters required for inhibition of calcium carbonate are shown in Table 1.

TABLE-US-00001 TABLE 1 Water quality performance for inhibition of calcium carbonate Electrical Calcium Total Langelier pH conductivity (us/cm) hardness ppm Alkalinity ppm Index 8.6 2974 571 588 2.23

[0049] Then the above four samples, the reagent 1 (ASD 200), the reagent 2 (MDC 754) and the blank samples were diluted 11000 times. Then the above four samples, the reagent 1, the reagent 2 and the blank samples, which are diluted by 5 ppm, were added to the prepared experimental water, respectively, lasting for 1 week for observation of the experiment. The experimental results are as follows:

[0050] FIG. 1 shows influent water flow rate of CaCO.sub.3 scale inhibition by each scale inhibitor. FIG. 2 shows outfluent water flow rate of CaCO.sub.3 scale inhibition by each scale inhibitor. The weight gain data of each scale inhibitor membrane are shown in Table 2.

TABLE-US-00002 TABLE 2 Weight gain data of each scale inhibitor membrane Before After Weight Name experiment (g) experiment (g) gain (g) Blank sample 204.32 268.74 64.42 Sample 1 207.98 232.77 24.79 Sample 2 204.66 228.50 23.84 Sample 3 207.33 234.91 27.58 Sample 4 206.33 230.13 23.80 Reagent 1 204.19 238.72 34.53 Reagent 2 203.77 241.34 37.57

[0051] Through the above experimental results, it proves that the influent water flow rate and the outfluent water flow rate of the core-shell structure membrane scale inhibitor in this example are higher than those of commonly used reagents in the market, indicating that the core-shell structure membrane scale inhibitor can maintain the permeation of influent water flow and outfluent water flow, so as to ensure a normal operation of the membrane permeation system, thus, the scale inhibition efficiency is higher; it can be known from the analysis of the membrane weight gain data that the membrane weight gain of the core-shell structure membrane scale inhibitor in this example is much lower than that of the commonly used reagents in the market, since the core structure is modified, so that a large number of ionizable groups are grafted on the surface thereof, and thus, a large number of scaling ions can be adsorbed. The present invention has excellent scale inhibition performance, and can be widely used in the field of scale inhibition of membrane systems in water treatments such as municipal, electric power, papermaking, environmental protection and domestic water, for example, it is used in the field of scale inhibition of reverse osmosis membranes, nanofiltration membranes, ultrafilteration membranes and microfiltration membranes etc.

[0052] The above descriptions are only the preferred embodiments of the invention, not thus limiting the embodiments and scope of the invention. Those skilled in the art should be able to realize that the schemes obtained from the content of specification and drawings of the invention are within the scope of the invention.