JP2023173814A - Surface-modified porous membrane production method - Google Patents
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- 239000012528 membrane Substances 0.000 title claims abstract description 185
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 30
- 239000000463 material Substances 0.000 claims abstract description 59
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 48
- 239000007788 liquid Substances 0.000 claims abstract description 38
- -1 poly(2-methoxyethyl acrylate) Polymers 0.000 claims abstract description 30
- 239000003446 ligand Substances 0.000 claims abstract description 13
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims abstract description 11
- 239000003054 catalyst Substances 0.000 claims abstract description 11
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 10
- 239000007870 radical polymerization initiator Substances 0.000 claims abstract description 9
- HFCUBKYHMMPGBY-UHFFFAOYSA-N 2-methoxyethyl prop-2-enoate Chemical compound COCCOC(=O)C=C HFCUBKYHMMPGBY-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229920000642 polymer Polymers 0.000 claims description 28
- 238000010560 atom transfer radical polymerization reaction Methods 0.000 claims description 17
- ZMANZCXQSJIPKH-UHFFFAOYSA-N Triethylamine Chemical compound CCN(CC)CC ZMANZCXQSJIPKH-UHFFFAOYSA-N 0.000 claims description 15
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 claims description 12
- 239000004698 Polyethylene Substances 0.000 claims description 12
- QTMDXZNDVAMKGV-UHFFFAOYSA-L copper(ii) bromide Chemical compound [Cu+2].[Br-].[Br-] QTMDXZNDVAMKGV-UHFFFAOYSA-L 0.000 claims description 12
- 229920000573 polyethylene Polymers 0.000 claims description 12
- YOCIJWAHRAJQFT-UHFFFAOYSA-N 2-bromo-2-methylpropanoyl bromide Chemical compound CC(C)(Br)C(Br)=O YOCIJWAHRAJQFT-UHFFFAOYSA-N 0.000 claims description 10
- UKODFQOELJFMII-UHFFFAOYSA-N pentamethyldiethylenetriamine Chemical compound CN(C)CCN(C)CCN(C)C UKODFQOELJFMII-UHFFFAOYSA-N 0.000 claims description 8
- 229910021590 Copper(II) bromide Inorganic materials 0.000 claims description 6
- 229960005070 ascorbic acid Drugs 0.000 claims description 6
- 235000010323 ascorbic acid Nutrition 0.000 claims description 6
- 239000011668 ascorbic acid Substances 0.000 claims description 6
- 239000004952 Polyamide Substances 0.000 claims description 4
- 229920002647 polyamide Polymers 0.000 claims description 4
- 239000004801 Chlorinated PVC Substances 0.000 claims description 3
- 239000002033 PVDF binder Substances 0.000 claims description 3
- 239000004695 Polyether sulfone Substances 0.000 claims description 3
- 239000004743 Polypropylene Substances 0.000 claims description 3
- 229920002301 cellulose acetate Polymers 0.000 claims description 3
- 229920000457 chlorinated polyvinyl chloride Polymers 0.000 claims description 3
- 229920002492 poly(sulfone) Polymers 0.000 claims description 3
- 229920002239 polyacrylonitrile Polymers 0.000 claims description 3
- 229920000515 polycarbonate Polymers 0.000 claims description 3
- 239000004417 polycarbonate Substances 0.000 claims description 3
- 229920006393 polyether sulfone Polymers 0.000 claims description 3
- 229920001470 polyketone Polymers 0.000 claims description 3
- 229920001155 polypropylene Polymers 0.000 claims description 3
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 3
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 3
- 239000004800 polyvinyl chloride Substances 0.000 claims description 3
- 229920000915 polyvinyl chloride Polymers 0.000 claims description 3
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 3
- 238000013508 migration Methods 0.000 abstract 1
- 230000005012 migration Effects 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 29
- 238000000034 method Methods 0.000 description 26
- 108091003079 Bovine Serum Albumin Proteins 0.000 description 18
- 229940098773 bovine serum albumin Drugs 0.000 description 18
- 239000011148 porous material Substances 0.000 description 16
- 238000012360 testing method Methods 0.000 description 16
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 14
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 14
- 239000000203 mixture Substances 0.000 description 11
- 229910052757 nitrogen Inorganic materials 0.000 description 8
- 230000035699 permeability Effects 0.000 description 8
- 238000003756 stirring Methods 0.000 description 8
- 235000002597 Solanum melongena Nutrition 0.000 description 7
- 230000005587 bubbling Effects 0.000 description 7
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical class ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 6
- WOZSCQDILHKSGG-UHFFFAOYSA-N adefovir depivoxil Chemical compound N1=CN=C2N(CCOCP(=O)(OCOC(=O)C(C)(C)C)OCOC(=O)C(C)(C)C)C=NC2=C1N WOZSCQDILHKSGG-UHFFFAOYSA-N 0.000 description 6
- 238000007872 degassing Methods 0.000 description 6
- 238000010559 graft polymerization reaction Methods 0.000 description 6
- 230000003647 oxidation Effects 0.000 description 6
- 238000007254 oxidation reaction Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 5
- 239000000178 monomer Substances 0.000 description 5
- 101710141544 Allatotropin-related peptide Proteins 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 4
- 238000006116 polymerization reaction Methods 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 230000031709 bromination Effects 0.000 description 3
- 238000005893 bromination reaction Methods 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 230000004907 flux Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000001471 micro-filtration Methods 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- 239000012466 permeate Substances 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- RZVAJINKPMORJF-UHFFFAOYSA-N Acetaminophen Chemical compound CC(=O)NC1=CC=C(O)C=C1 RZVAJINKPMORJF-UHFFFAOYSA-N 0.000 description 2
- 229910021589 Copper(I) bromide Inorganic materials 0.000 description 2
- 230000003373 anti-fouling effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 2
- NKNDPYCGAZPOFS-UHFFFAOYSA-M copper(i) bromide Chemical compound Br[Cu] NKNDPYCGAZPOFS-UHFFFAOYSA-M 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 150000002148 esters Chemical class 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 239000003999 initiator Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- VMGSQCIDWAUGLQ-UHFFFAOYSA-N n',n'-bis[2-(dimethylamino)ethyl]-n,n-dimethylethane-1,2-diamine Chemical compound CN(C)CCN(CCN(C)C)CCN(C)C VMGSQCIDWAUGLQ-UHFFFAOYSA-N 0.000 description 2
- DWFKOMDBEKIATP-UHFFFAOYSA-N n'-[2-[2-(dimethylamino)ethyl-methylamino]ethyl]-n,n,n'-trimethylethane-1,2-diamine Chemical compound CN(C)CCN(C)CCN(C)CCN(C)C DWFKOMDBEKIATP-UHFFFAOYSA-N 0.000 description 2
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 2
- 238000005191 phase separation Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000001629 suppression Effects 0.000 description 2
- 238000004381 surface treatment Methods 0.000 description 2
- HRFJEOWVAGSJNW-UHFFFAOYSA-N 1,4,8,11-tetramethyl-1,4,8,11-tetrazacyclotetradecane Chemical compound CN1CCCN(C)CCN(C)CCCN(C)CC1 HRFJEOWVAGSJNW-UHFFFAOYSA-N 0.000 description 1
- MHXMVFDLNGKBSR-UHFFFAOYSA-N 2-hydroxyethyl 2-bromo-2-methylpropanoate Chemical compound CC(C)(Br)C(=O)OCCO MHXMVFDLNGKBSR-UHFFFAOYSA-N 0.000 description 1
- WMPPDTMATNBGJN-UHFFFAOYSA-N 2-phenylethylbromide Chemical compound BrCCC1=CC=CC=C1 WMPPDTMATNBGJN-UHFFFAOYSA-N 0.000 description 1
- 125000006479 2-pyridyl methyl group Chemical group [H]C1=C([H])C([H])=C([H])C(=N1)C([H])([H])* 0.000 description 1
- 229910021591 Copper(I) chloride Inorganic materials 0.000 description 1
- 229910021592 Copper(II) chloride Inorganic materials 0.000 description 1
- 238000001157 Fourier transform infrared spectrum Methods 0.000 description 1
- KWIUHFFTVRNATP-UHFFFAOYSA-O N,N,N-trimethylglycinium Chemical group C[N+](C)(C)CC(O)=O KWIUHFFTVRNATP-UHFFFAOYSA-O 0.000 description 1
- 239000007983 Tris buffer Substances 0.000 description 1
- 239000012190 activator Substances 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- SXDBWCPKPHAZSM-UHFFFAOYSA-M bromate Inorganic materials [O-]Br(=O)=O SXDBWCPKPHAZSM-UHFFFAOYSA-M 0.000 description 1
- SXDBWCPKPHAZSM-UHFFFAOYSA-N bromic acid Chemical compound OBr(=O)=O SXDBWCPKPHAZSM-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- OXBLHERUFWYNTN-UHFFFAOYSA-M copper(I) chloride Chemical compound [Cu]Cl OXBLHERUFWYNTN-UHFFFAOYSA-M 0.000 description 1
- 238000010612 desalination reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
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- 230000000694 effects Effects 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- IOLQWGVDEFWYNP-UHFFFAOYSA-N ethyl 2-bromo-2-methylpropanoate Chemical compound CCOC(=O)C(C)(C)Br IOLQWGVDEFWYNP-UHFFFAOYSA-N 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
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- 238000002347 injection Methods 0.000 description 1
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- WSSMOXHYUFMBLS-UHFFFAOYSA-L iron dichloride tetrahydrate Chemical compound O.O.O.O.[Cl-].[Cl-].[Fe+2] WSSMOXHYUFMBLS-UHFFFAOYSA-L 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- YDCHPLOFQATIDS-UHFFFAOYSA-N methyl 2-bromoacetate Chemical compound COC(=O)CBr YDCHPLOFQATIDS-UHFFFAOYSA-N 0.000 description 1
- ACEONLNNWKIPTM-UHFFFAOYSA-N methyl 2-bromopropanoate Chemical compound COC(=O)C(C)Br ACEONLNNWKIPTM-UHFFFAOYSA-N 0.000 description 1
- JLEJCNOTNLZCHQ-UHFFFAOYSA-N methyl 2-chloropropanoate Chemical compound COC(=O)C(C)Cl JLEJCNOTNLZCHQ-UHFFFAOYSA-N 0.000 description 1
- 238000001728 nano-filtration Methods 0.000 description 1
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Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
Description
本開示は、表面修飾多孔質膜の製造方法に関する。 The present disclosure relates to a method for manufacturing a surface-modified porous membrane.
液体に溶解した高分子などの溶質や、液体に含まれる汚濁物などを多孔質膜によって分離する膜処理技術が利用されている。膜処理技術を利用した水処理として、例えば、浄水処理、下排水処理、海水淡水化処理、工業用水処理など挙げられる。水処理以外に、例えば生体分子を含有するサンプル処理が挙げられる。 Membrane processing technology is used to separate solutes such as polymers dissolved in liquids and contaminants contained in liquids using porous membranes. Examples of water treatment using membrane treatment technology include water purification treatment, sewage treatment, seawater desalination treatment, and industrial water treatment. In addition to water treatment, examples include treatment of samples containing biomolecules.
現在、膜処理技術を用いた水処理施設の大型化が急速に進んでおり、今後より広い範囲における膜処理技術の活用が有望視されている。
一方で、膜を長期間用いることにより膜が汚れて膜性能の劣化（ファウリング）が生じる。ファウリングは膜処理における動力費、さらに洗浄及び交換のコストを押し上げ、膜処理技術において大きな問題となっている。
Currently, water treatment facilities using membrane treatment technology are rapidly increasing in size, and it is expected that membrane treatment technology will be used in a wider range of areas in the future.
On the other hand, when the membrane is used for a long period of time, the membrane becomes dirty and deterioration of membrane performance (fouling) occurs. Fouling increases power costs in membrane processing, as well as cleaning and replacement costs, and is a major problem in membrane processing technology.
そこで、ファウリングを抑制する膜の開発が盛んに行われている。ファウリングを抑制する手法として、主に、市販膜に対する表面改質（低ファウリング性を有するポリマーを物理的・化学的に膜面に固定）する手法と、従来の膜作製手法において膜原料に低ファウリングポリマーを含有させる手法が提案されている、
例えば、多孔質膜にファウリングを抑制する性質（低ファウリング性）を有するポリマーを物理的・化学的に膜面に固定する技術として、（ａ）物理的付着（例えば非特許文献１）、（ｂ）紫外線（ＵＶ）やプラズマを利用したグラフト（例えば非特許文献２）、（ｃ）ＡＴＲＰ：原子移動ラジカル重合（例えば非特許文献３）による方法が提案されている。
また、膜作製手法において膜原料に低ファウリングポリマーを含有させる技術として、ＮＩＰＳ、ＴＩＰＳ、ＶＩＰＳ等の相分離誘起製膜が提案されている（例えば特許文献１、非特許文献４）。
Therefore, efforts are being made to develop membranes that suppress fouling. The main methods for suppressing fouling include surface modification of commercially available membranes (physically and chemically fixing polymers with low fouling properties to the membrane surface), and methods for modifying the membrane raw materials in conventional membrane production methods. A method of incorporating a low-fouling polymer has been proposed.
For example, as a technique for physically and chemically fixing a polymer having a property of suppressing fouling (low fouling property) to a porous membrane on the membrane surface, there are techniques such as (a) physical attachment (for example, Non-Patent Document 1); (b) Grafting using ultraviolet (UV) or plasma (for example, Non-Patent Document 2), and (c) ATRP: Atom transfer radical polymerization (for example, Non-Patent Document 3) have been proposed.
In addition, phase separation-induced membrane formation such as NIPS, TIPS, and VIPS has been proposed as a technique for incorporating a low-fouling polymer into a membrane raw material in a membrane manufacturing method (for example, Patent Document 1, Non-Patent Document 4).
前記（ａ）物理的付着は簡便な手法が多いが、修飾ポリマーが剥離し易い。（ｂ）ＵＶやプラズマを利用したグラフト又は（ｃ）ＡＴＲＰによる膜は、安定性は高いが、複数の改質ステップを要し、実用的ではない脱気など、膜面積の大型化には適用が難しい操作が含まれる。
また、ＮＩＰＳ、ＴＩＰＳ、ＶＩＰＳ等の相分離誘起製膜は、さまざまなポリマーのブレンドが検討されているが、高価なポリマーが多い。
The above-mentioned (a) physical attachment is often a simple method, but the modified polymer is likely to peel off. Membranes made by (b) grafting using UV or plasma or (c) ATRP are highly stable, but require multiple modification steps and are not practical for degassing, etc., and are not suitable for larger membrane areas. Contains difficult operations.
Further, for phase separation-induced film formation such as NIPS, TIPS, VIPS, etc., blends of various polymers are being considered, but most of them are expensive polymers.
本開示は、上記課題に鑑み、ファウリングが抑制される多孔質膜を大面積でも簡便に製造することができる表面修飾多孔質膜の製造方法を提供することを目的とする。 In view of the above problems, an object of the present disclosure is to provide a method for manufacturing a surface-modified porous membrane that can easily manufacture a porous membrane in which fouling is suppressed even over a large area.
上記課題を解決するための手段には、以下の態様が含まれる。
＜１＞ 多孔質構造を有する膜素材を、水及びオゾンを含む第１処理液に浸漬する第１処理工程と、
前記膜素材を前記第１処理液から取り出し、原子移動ラジカル重合開始剤を含む第２処理液に浸漬する第２処理工程と、
前記膜素材を前記第２処理液から取り出し、水、２－メトキシエチルアクリレート、還元剤、配位子、及び触媒を含む第３処理液に浸漬して前記膜素材にポリ（２－メトキシエチルアクリレート）を固定する第３処理工程と、
を含む表面修飾多孔質膜の製造方法。
＜２＞ 前記第２処理液が、トリエチルアミン、及び前記原子移動ラジカル重合開始剤であるα－ブロモイソブチリルブロミドを含み、
前記第３処理液が、前記還元剤であるアスコルビン酸、前記配位子であるＮ，Ｎ，Ｎ’，Ｎ”，Ｎ”－ペンタメチルジエチレントリアミン、及び前記触媒である臭化銅（ＩＩ）を含む請求項１に記載の表面修飾多孔質膜の製造方法。
＜３＞ 前記膜素材が、ポリエチレン、ポリプロピレン、ポリフッ化ビニリデン、ポリスルホン、ポリエーテルスルホン、ポリ塩化ビニル、ポリアクリロニトリル、酢酸セルロース、ポリアミド、ポリテトラフルオロエチレン、塩素化ポリ塩化ビニル、ポリケトン、及びポリカーボネートからなる群より選ばれる１種又は２種以上のポリマーを含む、＜１＞又は＜２＞に記載の表面修飾多孔質膜の製造方法。
Means for solving the above problems include the following aspects.
<1> A first treatment step of immersing a membrane material having a porous structure in a first treatment liquid containing water and ozone;
a second treatment step of taking out the membrane material from the first treatment liquid and immersing it in a second treatment liquid containing an atom transfer radical polymerization initiator;
The membrane material is taken out from the second treatment liquid and immersed in a third treatment liquid containing water, 2-methoxyethyl acrylate, a reducing agent, a ligand, and a catalyst to coat the membrane material with poly(2-methoxyethyl acrylate). ), a third treatment step of fixing the
A method for producing a surface-modified porous membrane comprising:
<2> The second treatment liquid contains triethylamine and the atom transfer radical polymerization initiator α-bromoisobutyryl bromide,
The third treatment liquid contains ascorbic acid as the reducing agent, N,N,N',N",N"-pentamethyldiethylenetriamine as the ligand, and copper(II) bromide as the catalyst. The method for producing a surface-modified porous membrane according to claim 1.
<3> The membrane material is made of polyethylene, polypropylene, polyvinylidene fluoride, polysulfone, polyethersulfone, polyvinyl chloride, polyacrylonitrile, cellulose acetate, polyamide, polytetrafluoroethylene, chlorinated polyvinyl chloride, polyketone, and polycarbonate. The method for producing a surface-modified porous membrane according to <1> or <2>, comprising one or more polymers selected from the group consisting of:
本開示によれば、ファウリングが抑制される多孔質膜を大面積でも簡便に製造することができる表面修飾多孔質膜の製造方法が提供される。 According to the present disclosure, there is provided a method for producing a surface-modified porous membrane that can easily produce a porous membrane that suppresses fouling even over a large area.
以下、本開示の実施形態について図面を参照しながら説明する。
なお、本明細書において「～」を用いて表される数値範囲は、「～」の前後に記載される数値を下限値及び上限値として含む範囲を意味する。
また、本明細書中の「工程」の用語は、独立した工程だけではなく、他の工程と明確に区別できない場合であっても、その工程の所期の目的が達成されれば本用語に含まれる。
Embodiments of the present disclosure will be described below with reference to the drawings.
In addition, in this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as a lower limit value and an upper limit value.
Furthermore, the term "process" in this specification refers not only to an independent process, but also to the term "process" when the intended purpose of the process is achieved, even if the process cannot be clearly distinguished from other processes. included.
本開示の発明者らは、ファウリングが抑制される多孔質膜を大面積でも簡便に製造する手法について検討を重ねたところ、脱気操作などを行わずに、ポリエチレンなどの安価な膜素材にポリ（２－メトキシエチルアクリレート）をグラフト固定することができる、安全かつ安価な手法を開発し、製造された表面修飾多孔質膜が優れたファウリング防止性を発現することを見出した。
本開示において、２－メトキシエチルアクリレートを「ＭＥＡ」、ポリ（２－メトキシエチルアクリレート）を「ＭＥＡポリマー」又は「ＰＭＥＡ」と称する場合がある。
また、ファウリングが抑制される多孔質膜を「低ファウリング膜」と称する場合がある。
また、本開示において表面修飾多孔質膜とは、多孔質膜（膜素材）全体としての表面だけでなく、孔の内壁面もグラフト重合によって修飾されている多孔質膜を意味する。
The inventors of the present disclosure have repeatedly studied methods for easily manufacturing porous membranes that suppress fouling even over large areas, and found that they can be made from inexpensive membrane materials such as polyethylene without performing deaeration operations. We have developed a safe and inexpensive method for graft-fixing poly(2-methoxyethyl acrylate) and found that the surface-modified porous membrane produced exhibits excellent anti-fouling properties.
In this disclosure, 2-methoxyethyl acrylate may be referred to as "MEA," and poly(2-methoxyethyl acrylate) may be referred to as "MEA polymer" or "PMEA."
Further, a porous membrane that suppresses fouling is sometimes referred to as a "low-fouling membrane."
Furthermore, in the present disclosure, a surface-modified porous membrane refers to a porous membrane in which not only the entire surface of the porous membrane (membrane material) but also the inner wall surfaces of the pores are modified by graft polymerization.
本開示に係る表面修飾多孔質膜の製造方法は、多孔質構造を有する膜素材（本開示において「膜素材」又は「多孔質膜」と称する場合がある。）を、水及びオゾンを含む第１処理液に浸漬する第１処理工程と、
膜素材を第１処理液から取り出し、原子移動ラジカル重合開始剤を含む第２処理液に浸漬する第２処理工程と、
膜素材を第２処理液から取り出し、水、２－メトキシエチルアクリレート、還元剤、配位子、及び触媒を含む第３処理液に浸漬して膜素材にポリ（２－メトキシエチルアクリレート）を固定する第３処理工程と、を含む。
A method for producing a surface-modified porous membrane according to the present disclosure involves using a membrane material having a porous structure (sometimes referred to as a "membrane material" or "porous membrane" in the present disclosure) to a membrane material containing water and ozone. 1. A first treatment step of immersing in a treatment solution;
a second treatment step of removing the membrane material from the first treatment liquid and immersing it in a second treatment liquid containing an atom transfer radical polymerization initiator;
The membrane material is taken out from the second treatment solution and immersed in a third treatment solution containing water, 2-methoxyethyl acrylate, a reducing agent, a ligand, and a catalyst to fix poly(2-methoxyethyl acrylate) to the membrane material. and a third treatment step.
例えば、多孔質の膜素材にＭＥＡポリマーをグラフト固定した低ファウリング膜を作製した例はあるが（例えば特許文献３）、本開示に係る表面修飾多孔質膜の製造方法によれば、脱気操作など行わずに大面積の低ファウリング膜の製造が可能である。
膜素材を上記３種類の処理液に順次浸漬させることで、脱気操作を行わずに低ファウリング性に優れた表面修飾多孔質膜を製造することができるメカニズムは不明であるが、以下のように推測される。
まず、第１処理工程では、膜素材を水及びオゾンを含む第１処理液に浸漬させることで、酸化が促進されて膜表面のＨがＯＨ基となり、ハロゲン化、例えばブロモ化され易くなる。第２処理工程では、膜表面のＯＨ基がブロモ化される。酸素が存在すると膜表面のブロモ化された部位にＭＥＡに置換され難いが、第３処理工程では、処理液がＭＥＡと共に特にアスコルビン酸を含むことでＭＥＡが膜表面のブロモ化された部位がＭＥＡが置換され易くなり、ＡＧＥＴ（電子移動により生成した活性化剤）－ＡＴＲＰ（原子移動ラジカル重合）によりＭＥＡポリマーが膜表面に固定（グラフト重合）されると考えられる。
以下、各工程について説明する。
For example, there are examples of producing low-fouling membranes in which MEA polymers are grafted and fixed onto porous membrane materials (for example, Patent Document 3), but according to the method for producing surface-modified porous membranes according to the present disclosure, degassing It is possible to manufacture large-area, low-fouling membranes without any operations.
The mechanism by which a surface-modified porous membrane with excellent low fouling properties can be produced without degassing by sequentially immersing the membrane material in the three types of treatment solutions mentioned above is unknown, but the following method can be used: It is assumed that.
First, in the first treatment step, the membrane material is immersed in a first treatment solution containing water and ozone, thereby promoting oxidation and converting H on the membrane surface into OH groups, making it more likely to be halogenated, for example, brominated. In the second treatment step, OH groups on the membrane surface are brominated. When oxygen is present, it is difficult for the brominated sites on the membrane surface to be replaced by MEA, but in the third treatment step, the treatment solution contains ascorbic acid together with MEA, so that MEA replaces the brominated sites on the membrane surface with MEA. is likely to be substituted, and it is thought that the MEA polymer is fixed to the membrane surface (graft polymerization) by AGET (activator generated by electron transfer)-ATRP (atom transfer radical polymerization).
Each step will be explained below.
＜第１処理工程＞
まず、第１処理工程として、多孔質構造を有する膜素材を、水及びオゾンを含む第１処理液に浸漬する。
<First treatment step>
First, as a first treatment step, a membrane material having a porous structure is immersed in a first treatment liquid containing water and ozone.
（膜素材）
低ファウリング膜を製造する際の基材となる膜素材は、多孔質構造を有し、各処理工程を経て膜の表面及び孔の内壁面にＭＥＡポリマーを固定することができれば特に限定されない。安価な膜素材を用いることもでき、例えば、ポリエチレン、ポリプロピレン、ポリフッ化ビニリデン、ポリスルホン、ポリエーテルスルホン、ポリ塩化ビニル、ポリアクリロニトリル、酢酸セルロース、ポリアミド、ポリアミド、ポリテトラフルオロエチレン、塩素化ポリ塩化ビニル、ポリケトン、及びポリカーボネートからなる群より選ばれる１種又は２種以上のポリマーを含む多孔質樹脂膜が挙げられる。
(membrane material)
The membrane material that serves as the base material for manufacturing the low-fouling membrane is not particularly limited as long as it has a porous structure and can fix the MEA polymer to the surface of the membrane and the inner wall surfaces of the pores through each treatment step. Inexpensive membrane materials can also be used, such as polyethylene, polypropylene, polyvinylidene fluoride, polysulfone, polyethersulfone, polyvinyl chloride, polyacrylonitrile, cellulose acetate, polyamide, polyamide, polytetrafluoroethylene, chlorinated polyvinyl chloride. Examples include porous resin membranes containing one or more polymers selected from the group consisting of , polyketone, and polycarbonate.
膜素材における多孔構造の孔の形状、大きさ、分布、形態も特に限定されない。製造する表面改質多孔質膜の用途にもよるが、例えば、分離膜として使用する場合、膜の一方の面側から他方の面側に向けて孔径（平均）が大きくなるに伴い空隙率が大きくなっている非対称多孔構造を有する非対称多孔質膜が好ましい。非対称多孔質膜は、典型的には、一方の面側はスポンジ状の多孔構造を持ち、他方の面側は孔の小さい緻密な多孔構造を持った多孔質膜である。緻密な層を分離面として機能させることで、精密ろ過膜、限外ろ過膜、ナノろ過膜又は逆浸透膜として用いられる。
また、膜素材として用いる多孔質膜の形状も特に限定されず、例えば平膜でも中空糸膜でもよい。
The shape, size, distribution, and form of the pores in the porous structure of the membrane material are also not particularly limited. It depends on the purpose of the surface-modified porous membrane being manufactured, but for example, when used as a separation membrane, the porosity increases as the pore diameter (average) increases from one side of the membrane to the other. Asymmetric porous membranes with enlarged asymmetric pore structures are preferred. An asymmetric porous membrane typically has a sponge-like porous structure on one side and a dense porous structure with small pores on the other side. By making the dense layer function as a separation surface, it can be used as a microfiltration membrane, ultrafiltration membrane, nanofiltration membrane, or reverse osmosis membrane.
Furthermore, the shape of the porous membrane used as the membrane material is not particularly limited, and may be, for example, a flat membrane or a hollow fiber membrane.
孔径は特に限定されないが、例えば、非対称多孔質膜の一方の面側は０．０１～１０００μｍであり、他方の面側は０．０００１～５０μｍである。なお、孔径の測定は、例えば、多孔質膜の各面を電界放出型走査電子顕微鏡（ＦＥ－ＳＥＭ）で観察し、無作為に選んだ５０個の各孔の最大径を測定して数平均によって算出される。 Although the pore size is not particularly limited, for example, one side of the asymmetric porous membrane has a diameter of 0.01 to 1000 μm, and the other side has a diameter of 0.0001 to 50 μm. The pore diameter can be measured, for example, by observing each surface of the porous membrane with a field emission scanning electron microscope (FE-SEM), measuring the maximum diameter of each of 50 randomly selected pores, and calculating the number average. Calculated by
また、膜素材の空隙率は特に限定されない。なお、膜素材が非対称多孔質膜の場合、分離面として機能する緻密層と緻密層の反対側で支持部として機能する支持層とでは空隙率が大きく変化する。空隙率は一概に言えないが、膜全体の平均空隙率として、例えば、２０～９０％が挙げられる。 Further, the porosity of the membrane material is not particularly limited. Note that when the membrane material is an asymmetric porous membrane, the porosity changes greatly between the dense layer that functions as a separation surface and the support layer that functions as a support portion on the opposite side of the dense layer. Although the porosity cannot be determined unconditionally, the average porosity of the entire membrane is, for example, 20 to 90%.
膜素材の厚みは特に限定されないが、膜厚が薄過ぎると、製造中、膜設置中、又は使用中に破損し易く、厚過ぎると溶液が透過し難くなり、動力費が高くなる可能性がある。膜素材の膜厚は、膜の用途などに応じて選択すればよいが、例えば、１０μｍ～１．０ｍｍである。 The thickness of the membrane material is not particularly limited, but if the membrane is too thin, it will be easily damaged during manufacturing, membrane installation, or use, and if it is too thick, it will be difficult for the solution to pass through, potentially increasing power costs. be. The thickness of the membrane material may be selected depending on the purpose of the membrane, and is, for example, 10 μm to 1.0 mm.
第１処理液は、水及びオゾンを含み、さらに過酸化水素を含んでもよい。このような第１処理液として、オゾン濃度０．１～１０ｐｐｍ、過酸化水素濃度０～２ｐｐｍの促進酸化水が好適である。すなわち、第１処理液は、水のほかにオゾンと過酸化水素の両方を含んでもよいし、オゾンを含み、過酸化水素は含まないものでもよい。なお、第１処理液の製造方法は限定されず、例えば、市販のオゾン水をつくる装置で製造したオゾン水を用いてもよい。 The first treatment liquid contains water and ozone, and may further contain hydrogen peroxide. As such a first treatment liquid, accelerated oxidation water having an ozone concentration of 0.1 to 10 ppm and a hydrogen peroxide concentration of 0 to 2 ppm is suitable. That is, the first treatment liquid may contain both ozone and hydrogen peroxide in addition to water, or may contain ozone but not hydrogen peroxide. Note that the method for producing the first treatment liquid is not limited, and for example, ozonated water produced using a commercially available ozonated water producing device may be used.
第１処理工程では、膜素材を第１処理液中に例えば０．１～３時間浸漬させる。膜素材を第１処理液に浸漬している間、攪拌、紫外線照射、超音波振動などを行ってもよい。
第１処理液中に膜素材を浸漬させることで膜表面の酸化が促進され、Ｈ基がＯＨ基となる。
In the first treatment step, the membrane material is immersed in the first treatment liquid for, for example, 0.1 to 3 hours. While the membrane material is immersed in the first treatment liquid, stirring, ultraviolet irradiation, ultrasonic vibration, etc. may be performed.
By immersing the membrane material in the first treatment liquid, oxidation of the membrane surface is promoted, and the H groups become OH groups.
＜第２処理工程＞
第２処理工程では、膜素材を第１処理液から取り出し、原子移動ラジカル重合開始剤（ＡＴＲＰ開始剤）を含む第２処理液に浸漬する。原子移動ラジカル重合開始剤としては、公知のＡＴＲＰ開始剤を用いることができ、第１処理工程後の膜素材の表面（孔内壁面を含む）をブロモ化することができるものが好ましく、例えばα－ブロモイソブチリルブロミド（ＢＩＢＢ）を好適に用いることができる。なお、原子移動ラジカル重合開始剤としては、ＢＩＢＢのほかに、２－ブロモイソ酪酸エチル、２－ブロモプロピオン酸メチル、２－ブロモ－２－メチルプロパン酸２－ヒドロキシエチル、ブロモ酢酸メチル、（１－ブロモエチル）ベンゼン、２－クロロプロピオン酸メチルなどが挙げられる。
<Second treatment step>
In the second treatment step, the membrane material is taken out from the first treatment liquid and immersed in a second treatment liquid containing an atom transfer radical polymerization initiator (ATRP initiator). As the atom transfer radical polymerization initiator, a known ATRP initiator can be used, and one that can bromate the surface (including the inner wall surface of the pores) of the membrane material after the first treatment step is preferable, for example, α -Bromoisobutyryl bromide (BIBB) can be preferably used. In addition to BIBB, examples of atom transfer radical polymerization initiators include ethyl 2-bromoisobutyrate, methyl 2-bromopropionate, 2-hydroxyethyl 2-bromo-2-methylpropanoate, methyl bromoacetate, (1- (bromoethyl)benzene, methyl 2-chloropropionate, and the like.
例えば、容器内に、体積基準で、超脱水ジクロロメタン（溶媒）１Ｌに対し、トリエチルアミン０．０２～０．４Ｌ、α－ブロモイソブチリルブロミド（ＢＩＢＢ）０．０２～０．４Ｌを入れて攪拌し、第２処理液を調製する。そして、第１処理液から取り出した膜素材を第２処理液中に浸漬させる。膜素材を第２処理液に浸漬している間、攪拌、超音波振動などを行ってもよい。また、溶媒としては、ジクロロメタンに限定されず、トルエン、ヘキサンなどを用いることもできる。 For example, add 0.02 to 0.4 L of triethylamine and 0.02 to 0.4 L of α-bromoisobutyryl bromide (BIBB) to 1 L of ultra-dehydrated dichloromethane (solvent) in a container and stir. and prepare a second treatment solution. Then, the membrane material taken out from the first treatment liquid is immersed in the second treatment liquid. While the membrane material is immersed in the second treatment liquid, stirring, ultrasonic vibration, etc. may be performed. Further, the solvent is not limited to dichloromethane, and toluene, hexane, etc. can also be used.
膜素材を第２処理液中に入れた後、速やかに氷冷する。例えば、３０～２００ｒｐｍで０．０１～２時間撹拌し、さらに氷冷を止めて０．１～４８時間攪拌する。
このような第２処理工程により、膜素材の表面（孔の内壁面を含む）をブロモ化することができる。
After the membrane material is placed in the second treatment solution, it is immediately cooled on ice. For example, the mixture is stirred at 30 to 200 rpm for 0.01 to 2 hours, and further stirred for 0.1 to 48 hours after stopping ice cooling.
Through such a second treatment step, the surface of the membrane material (including the inner wall surface of the pores) can be brominated.
＜第３処理工程＞
第３処理工程では、膜素材を第２処理液から取り出し、水、２－メトキシエチルアクリレート、還元剤、配位子、及び触媒を含む第３処理液に浸漬する。
還元剤、配位子、及び触媒は、第２処理工程後の膜素材をＭＥＡポリマーで修飾することができれば限定されない。還元剤、配位子、及び触媒として、例えば、アスコルビン酸、Ｎ，Ｎ，Ｎ’，Ｎ”，Ｎ”－ペンタメチルジエチレントリアミン（ＰＭＤＥＴＡ）、及び臭化銅（ＩＩ）をそれぞれ好適に用いることができる。
なお、第３処理工程で用いる還元剤、配位子、及び触媒は、上記組み合わせに限定されない。
例えば、配位子として、ＰＭＤＥＴＡのほかに、トリス［２－（ジメチルアミノ）エチル］アミン（Ｍｅ６ＴＲＥＮ）、１，１，４，７，１０，１０－ヘキサメチルトリエチレンテトラミン（ＨＭＴＥＴＡ）、トリス（２－ピリジルメチル）アミン（ＴＰＭＡ）、１，４，８，１１－テトラメチル－１，４，８，１１－テトラアザシクロテトラデカンなどが挙げられる。
また、触媒として、臭化銅（ＩＩ）のほかに、臭化銅（Ｉ）、塩化銅（ＩＩ）、塩化銅（Ｉ）等が挙げられる。
<Third treatment step>
In the third treatment step, the membrane material is taken out from the second treatment solution and immersed in a third treatment solution containing water, 2-methoxyethyl acrylate, a reducing agent, a ligand, and a catalyst.
The reducing agent, the ligand, and the catalyst are not limited as long as the membrane material after the second treatment step can be modified with the MEA polymer. As the reducing agent, the ligand, and the catalyst, for example, ascorbic acid, N,N,N',N",N"-pentamethyldiethylenetriamine (PMDETA), and copper(II) bromide can be preferably used, respectively. can.
Note that the reducing agent, ligand, and catalyst used in the third treatment step are not limited to the above combination.
For example, in addition to PMDETA, the ligands include tris[2-(dimethylamino)ethyl]amine (Me6TREN), 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA), and tris( Examples include 2-pyridylmethyl)amine (TPMA), 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, and the like.
In addition to copper(II) bromide, examples of the catalyst include copper(I) bromide, copper(II) chloride, copper(I) chloride, and the like.
例えば、容器内に、水１Ｌに対し、ＭＥＡ０．２～５ｍｏｌ、臭化銅（ＩＩ）０．２～５ｇ、リガンドのＰＭＤＥＴＡ１～４０ｍＬ、アスコルビン酸０．０４～１ｍｏｌを入れて攪拌し、第３処理液を調製する、そして、第２処理液から取り出した膜素材を第３処理液中に浸漬させさせる。室温で１～２４時間浸漬させることで、ＭＥＡポリマーがグラフト重合により膜素材に固定される。 For example, put 0.2 to 5 mol of MEA, 0.2 to 5 g of copper(II) bromide, 1 to 40 mL of PMDETA as a ligand, and 0.04 to 1 mol of ascorbic acid per 1 L of water in a container, stir, and stir. A treatment solution is prepared, and the membrane material taken out from the second treatment solution is immersed in the third treatment solution. By soaking at room temperature for 1 to 24 hours, the MEA polymer is fixed to the membrane material by graft polymerization.
ＭＥＡは安価な材料であり、市場で入手することが可能である。
膜素材に固定されるＭＥＡポリマーは、ＭＥＡの単独重合体でもよいし、ＭＥＡと、１種又は２種以上の他のモノマーとの共重合体であってもよい。他のモノマーとして、ベタイン構造を有し低ファウリング性が認められているモノマーや、低ファウリング性が認められている親水性モノマーが挙げられる。２－メトキシエチルアクリレートと、他のモノマーとの共重合体である場合、２－メトキシエチルアクリレートに由来する構成単位の質量割合が最も大きいことが好ましく、５０質量％以上であることがより好ましい。
MEA is an inexpensive material and is available on the market.
The MEA polymer fixed to the membrane material may be a homopolymer of MEA, or a copolymer of MEA and one or more other monomers. Other monomers include monomers that have a betaine structure and are known to have low fouling properties, and hydrophilic monomers that are known to have low fouling properties. In the case of a copolymer of 2-methoxyethyl acrylate and another monomer, it is preferable that the mass proportion of the structural unit derived from 2-methoxyethyl acrylate is the largest, and more preferably 50% by mass or more.
膜素材に固定されるＭＥＡポリマーの分子量は特に限定されないが、例えば、重量平均分子量で１万～５００万が挙げられる。 The molecular weight of the MEA polymer fixed to the membrane material is not particularly limited, but for example, the weight average molecular weight may be 10,000 to 5,000,000.
膜面積に対してＭＥＡポリマーのグラフト量が少ないとファウリングを抑制する効果（耐ファウリング性能）が不十分となる可能性がある。耐ファウリング性能を高める観点から、ＭＥＡポリマーのグラフト量は、０．０５ｍｇ／ｃｍ２以上が好ましく、０．１０ｍｇ／ｃｍ２以上が好ましく、０．１５ｍｇ／ｃｍ２以上がさらに好ましい。
一方、ＭＥＡポリマーのグラフト量が多過ぎると、表面修飾多孔質膜の生産性の低下を招くほか、ＭＥＡポリマーによって膜素材の孔が小さくなり、透過率が低下する可能性がある。膜素材の孔径、製造する表面修飾多孔質膜の用途などにもよるが、ＭＥＡポリマーのグラフト量は、０．２５ｍｇ／ｃｍ２以下であってもよい。
膜素材に固定されるＭＥＡポリマーの量（グラフト量）は、例えば第３処理工程の処理時間（浸漬時間）によって調整することができる。
If the amount of grafted MEA polymer is small relative to the membrane area, the effect of suppressing fouling (fouling resistance performance) may be insufficient. From the viewpoint of improving fouling resistance, the amount of grafting of the MEA polymer is preferably 0.05 mg/cm 2 or more, preferably 0.10 mg/cm 2 or more, and even more preferably 0.15 mg/cm 2 or more.
On the other hand, if the amount of grafting of the MEA polymer is too large, the productivity of the surface-modified porous membrane will be reduced, and the pores of the membrane material will become smaller due to the MEA polymer, which may reduce the transmittance. The amount of grafting of the MEA polymer may be 0.25 mg/cm 2 or less, although it depends on the pore size of the membrane material and the intended use of the surface-modified porous membrane to be produced.
The amount of MEA polymer fixed to the membrane material (grafting amount) can be adjusted, for example, by the treatment time (immersion time) of the third treatment step.
以上の工程を経て、膜素材の表面及び孔内部がＭＥＡポリマーで修飾された低ファウリング性に優れた表面修飾多孔質膜（低ファウリング膜）が製造される。本開示に係る方法によれば、脱気設備が不要であり、安価にかつ簡便に、しかも大面積の低ファウリング膜を製造することが可能である。 Through the above steps, a surface-modified porous membrane (low-fouling membrane) with excellent low fouling properties in which the surface of the membrane material and the inside of the pores are modified with MEA polymer is manufactured. According to the method according to the present disclosure, there is no need for degassing equipment, and it is possible to manufacture a large-area, low-fouling membrane inexpensively and easily.
本開示に係る方法によって製造される表面修飾多孔質膜の用途は特に限定されないが、例えば、水処理に用いることでファウリングを効果的に抑制することができ、製膜コストだけでなく、ランニングコスト、膜交換コストの抑制にも大きく貢献できる。 The use of the surface-modified porous membrane produced by the method according to the present disclosure is not particularly limited, but for example, by using it for water treatment, it can effectively suppress fouling, reduce not only the film production cost but also the running time. It can also greatly contribute to reducing costs and membrane replacement costs.
以下、本開示に係る表面修飾多孔質膜の製造方法について、実施例を挙げてさらに具体的に説明する。ただし、これら各実施例は、本発明を制限するものではない。 Hereinafter, the method for manufacturing a surface-modified porous membrane according to the present disclosure will be described in more detail with reference to Examples. However, these examples do not limit the present invention.
［実施例］
＜表面修飾多孔質膜の製造＞
（１）第１処理工程（促進酸化水への浸漬）
膜素材（基材）として、ポリエチレン製精密ろ過膜（平均孔径：０．０６μｍ、厚さ：３０μｍ、空隙率：４１％）を準備した。
水電解装置を用い、促進酸化水（２ｐｐｍオゾン、０．３ｐｐｍ過酸化水素水）を１Ｌｍｉｎ－１で生成し、１Ｌビーカーに溜め撹拌した。促進酸化水はオーバーフローさせながら、このビーカーの中に上記の精密ろ過膜（以下、「ポリエチレン多孔質膜」と記す。）を入れ、３０分間浸漬した。
[Example]
<Manufacture of surface modified porous membrane>
(1) First treatment step (immersion in accelerated oxidation water)
A polyethylene microfiltration membrane (average pore diameter: 0.06 μm, thickness: 30 μm, porosity: 41%) was prepared as a membrane material (base material).
Promoted oxidation water (2 ppm ozone, 0.3 ppm hydrogen peroxide) was produced at 1 L min −1 using a water electrolysis device, and was stored in a 1 L beaker and stirred. The above microfiltration membrane (hereinafter referred to as "polyethylene porous membrane") was placed in this beaker while allowing the accelerated oxidation water to overflow, and was immersed for 30 minutes.
（２）第２処理工程（ブロモ化）
３００ｍＬナスフラスコに超脱水ジクロロメタン４０ｍＬ、トリエチルアミン３．５ｍＬを入れた。
さらにナスフラスコに、前記第１処理をしたポリエチレン多孔質膜とα－ブロモイソブチリルブロミド（ＢＩＢＢ）３．３ｍＬを入れた。ナスフラスコの開口部にはパラフィルムを貼った。その際、大気開放とするため少し隙間を開けた。
その後、速やかに氷冷し、１００ｒｐｍで１時間撹拌した。次いで、ナスフラスコの氷冷を止め、１００ｒｐｍで２４時間攪拌した。
(2) Second treatment step (bromination)
40 mL of super dehydrated dichloromethane and 3.5 mL of triethylamine were placed in a 300 mL eggplant flask.
Further, the first-treated polyethylene porous membrane and 3.3 mL of α-bromoisobutyryl bromide (BIBB) were placed in an eggplant flask. Parafilm was pasted on the opening of the eggplant flask. At that time, a small gap was left open to allow the atmosphere to open.
Thereafter, the mixture was quickly cooled on ice and stirred at 100 rpm for 1 hour. Next, the ice-cooling of the eggplant flask was stopped, and the mixture was stirred at 100 rpm for 24 hours.
（３）第３処理工程（ＡＧＥＴ－ＡＴＲＰ）
２０ｍＬビーカーに純水１７．０ｍＬ、ＭＥＡ１．０ｍｏｌＬ－１、臭化銅（ＩＩ）０．０２０ｇ、リガンドのＰＭＤＥＴＡ１４０μＬを加え、撹拌し、溶解した。
もう１つの２０ｍＬビーカーに純水３．０ｍＬ、アスコルビン酸０．２ｍｏｌＬ－１を加え、撹拌し、溶解した。
その後、１００ｍＬねじ口瓶に、前記第２処理をしたポリエチレン多孔質膜と、２つのビーカーの溶液を入れ、蓋をした。その後は室温で数時間放置し、ポリエチレン多孔質膜にＭＥＡポリマーがグラフト重合した表面修飾多孔質膜を得た。
(3) Third treatment step (AGET-ATRP)
17.0 mL of pure water, 1.0 mol L −1 of MEA, 0.020 g of copper(II) bromide, and 140 μL of PMDETA as a ligand were added to a 20 mL beaker, and the mixture was stirred and dissolved.
3.0 mL of pure water and 0.2 mol L -1 of ascorbic acid were added to another 20 mL beaker, stirred, and dissolved.
Thereafter, the second-treated polyethylene porous membrane and the solutions in the two beakers were placed in a 100 mL screw cap bottle, and the bottle was covered with a lid. Thereafter, the mixture was left at room temperature for several hours to obtain a surface-modified porous membrane in which the MEA polymer was graft-polymerized onto the polyethylene porous membrane.
第３処理工程における処理時間を変更して数種類の表面修飾多孔質膜を製造した。 Several types of surface-modified porous membranes were manufactured by changing the treatment time in the third treatment step.
＜重合量（グラフト量）の測定＞
実施例における第３処理工程の処理時間を変更し、下記式によりグラフト重合したＭＥＡポリマーの量（グラフト重合量）を算出した。
重合量（グラフト量）＝（Ｗ－Ｗ０）／Ｓ
Ｗ：表面処理後の膜重量
Ｗ０：表面処理前の膜重量
Ｓ：膜素材の面積
<Measurement of polymerization amount (grafting amount)>
The treatment time of the third treatment step in the example was changed, and the amount of graft-polymerized MEA polymer (graft polymerization amount) was calculated using the following formula.
Polymerization amount (grafting amount) = (W-W 0 )/S
W: Film weight after surface treatment W 0 : Film weight before surface treatment S: Area of membrane material
第３処理時間と単位面積当たりのグラフト重合量との関係を図１に示す。図１に見られるように、処理時間の増加に伴い、重合量が増加している。 FIG. 1 shows the relationship between the third treatment time and the amount of graft polymerization per unit area. As seen in FIG. 1, the amount of polymerization increases as the treatment time increases.
＜ＦＴ－ＩＲ分析＞
重合量を変更した表面修飾多孔質膜に対し、フーリエ変換赤外分光法（ＦＴ－ＩＲ）測定より、１７３５ｃｍ－２にＰＭＥＡ由来のエステルピークを確認した。未処理の多孔質膜も含め、各膜の膜表面のＦＴ－ＩＲスペクトルを図２に示す。図２に見られるように、未処理膜以外では、１７３５ｃｍ－１付近にＰＭＥＡ由来のエステルピークを確認できる。この結果より、膜がＰＭＥＡで修飾されていることが分かる。
<FT-IR analysis>
An ester peak derived from PMEA was confirmed at 1735 cm -2 by Fourier transform infrared spectroscopy (FT-IR) measurement of the surface-modified porous membranes with different polymerization amounts. FIG. 2 shows the FT-IR spectra of the surface of each membrane, including the untreated porous membrane. As seen in FIG. 2, an ester peak derived from PMEA can be confirmed around 1735 cm −1 in the non-treated membranes. This result shows that the membrane is modified with PMEA.
［参考例］
＜特許文献３に記載の手法による表面修飾多孔質膜の製造＞
（１）フェントン反応
試験管内にエタノール２０ｍＬ、純水２０ｍＬを加え、撹拌子を入れ、マグネットスターラー４００ｒｐｍ程度で攪拌しながら１５分間窒素バブリングした。
次に、塩化鉄四水和物０．０４０ｇ入れ、さらに１５分間窒素バブリングを行った。
この溶液にポリエチレン多孔質膜を浸漬した。さらに過酸化水素２．２０ｍＬを滴下した。過酸化水素滴下後、注射筒を刺したセプタムで試験管に蓋をし、１時間５０℃のオイルバス中で攪拌した。これによりフェントン反応を誘起し、膜表面及び孔の内壁面に水酸基を生じさせた。
[Reference example]
<Manufacture of surface-modified porous membrane by the method described in Patent Document 3>
(1) Fenton Reaction 20 mL of ethanol and 20 mL of pure water were added into a test tube, a stirrer was inserted, and nitrogen bubbling was carried out for 15 minutes while stirring at about 400 rpm using a magnetic stirrer.
Next, 0.040 g of iron chloride tetrahydrate was added, and nitrogen bubbling was further performed for 15 minutes.
A polyethylene porous membrane was immersed in this solution. Further, 2.20 mL of hydrogen peroxide was added dropwise. After dropping hydrogen peroxide, the test tube was capped with a septum inserted with a syringe, and stirred in an oil bath at 50° C. for 1 hour. This induced a Fenton reaction and produced hydroxyl groups on the membrane surface and the inner wall surfaces of the pores.
（２）ブロモ化
３００ｍＬナスフラスコに超脱水ジクロロメタン４０ｍＬ、トリエチルアミン３．５ｍＬを入れ、窒素バブリングしながら２００～３００ｒｐｍで１５分間攪拌した。
バブリング終了後、ナスフラスコに（１）の処理をしたポリエチレン多孔質膜とＢＩＢＢ３．３ｍＬを入れて真空管に接続し、窒素置換、減圧（５０～６０Ｐａ程度まで）した。
その後、速やかに氷冷し、１００ｒｐｍで１時間撹拌した。次いでナスフラスコの氷冷を止め、１００ｒｐｍで２４時間攪拌した。
(2) Bromination 40 mL of ultra-dehydrated dichloromethane and 3.5 mL of triethylamine were placed in a 300 mL eggplant flask, and the mixture was stirred at 200 to 300 rpm for 15 minutes while bubbling nitrogen.
After bubbling, the polyethylene porous membrane treated in (1) and 3.3 mL of BIBB were placed in an eggplant flask, connected to a vacuum tube, and replaced with nitrogen and reduced pressure (to about 50 to 60 Pa).
Thereafter, the mixture was quickly cooled on ice and stirred at 100 rpm for 1 hour. Next, the ice-cooling of the eggplant flask was stopped, and the mixture was stirred at 100 rpm for 24 hours.
（３）ＳＩ－ＡＴＲＰ（表面開始原子移動ラジカル重合）
上記（２）の処理（ブロモ化）をしたポリエチレン多孔質膜を三口フラスコ（両サイドの入り口はゴム栓をした）に入れ、真空管に接続し、３回窒素置換した後に５０～６０Ｐａまで減圧した。減圧したフラスコは閉鎖系とした。
試験管にＭＥＡ０．５ｍｏｌＬ－１、ＰＭＤＥＴＡ２８０μＬ、純水３２ｍＬ、エタノール８ｍＬを加え、３００ｒｐｍで攪拌しながら１５分間窒素バブリングを行った。臭化銅（Ｉ）０．０４０ｇを加え、１０分間攪拌、窒素バブリングを行った後、長針注射針をつけたシリンジで採取し、三口フラスコのゴム栓に刺し、注入した。数時間静置することでＭＥＡ重合膜（表面修飾多孔質膜）を製膜した。
(3) SI-ATRP (Surface initiated atom transfer radical polymerization)
The polyethylene porous membrane treated in (2) above (bromination) was placed in a three-necked flask (inlets on both sides were sealed with rubber stoppers), connected to a vacuum tube, and after being replaced with nitrogen three times, the pressure was reduced to 50 to 60 Pa. . The reduced pressure flask was a closed system.
0.5 mol L −1 of MEA, 280 μL of PMDETA, 32 mL of pure water, and 8 mL of ethanol were added to a test tube, and nitrogen bubbling was performed for 15 minutes while stirring at 300 rpm. After adding 0.040 g of copper (I) bromide, stirring for 10 minutes, and bubbling with nitrogen, the mixture was collected with a syringe fitted with a long injection needle, inserted into a rubber stopper of a three-necked flask, and injected. A MEA polymeric membrane (surface-modified porous membrane) was formed by allowing the mixture to stand for several hours.
［ファウリング防止性評価］
＜ウシ血清アルブミン（ＢＳＡ）溶液透過試験＞
流量２Ｌ／分、液温２５℃、クロスフロー方式でウシ血清アルブミン（ＢＳＡ）溶液透過試験を行った。
まず、純水をフラックスを４×１０－６［ｍ３ｍ－２ｓ－１］一定で透過させ、１０分間隔（透過液の採取時間は約５分）、合計３０分測定した。
純水透過後、供給液全体がＢＳＡ１０００ｐｐｍになるよう調製し、ＢＳＡ溶液透過試験を合計３００分間行った。ＢＳＡ溶液透過試験中、透過液は純水透過時同様１０分間隔で５分間採取した。
[Fouling prevention evaluation]
<Bovine serum albumin (BSA) solution permeation test>
A bovine serum albumin (BSA) solution permeation test was conducted using a cross-flow method at a flow rate of 2 L/min and a liquid temperature of 25°C.
First, pure water was passed through the flux at a constant rate of 4×10 −6 [m 3 m −2 s −1 ], and measurements were carried out at 10 minute intervals (the collection time of the permeate was approximately 5 minutes) for a total of 30 minutes.
After passing through the pure water, the entire feed solution was adjusted to contain 1000 ppm of BSA, and a BSA solution permeation test was conducted for a total of 300 minutes. During the BSA solution permeation test, the permeate was sampled for 5 minutes at 10 minute intervals, similar to when pure water was permeated.
図３は、ＢＳＡ溶液透過試験結果を示すグラフである。試験開始後、純水からＢＳＡ１０００ｐｐｍ水溶液に交換することで、未処理膜では透水性能が急激に低下し、設定フラックスが４×１０－６［ｍ３ｍ－２ｓ－１］の場合は、６７％減少した。
一方、実施例のＰＭＥＡをグラフト重合した多孔質膜（グラフト量：０．１２ｍｇ／ｃｍ２）では、純水からＢＳＡ溶液に交換することで透水性能が若干低下したものの、フラックス減少率は２３～４０％であり、ＢＳＡ溶液に対し効果的にファウリングが抑制された。
なお、参考例の表面修飾多孔質膜（グラフト量：０．１１ｍｇ／ｃｍ２）も実施例の表面修飾多孔質膜と同等のファウリング抑制性能を示したが、参考例では窒素バブリングによる脱気が必要であるのに対し、実施例ではそのような脱気が不要であり、簡便に製造することができた点で有利である。
FIG. 3 is a graph showing the results of a BSA solution permeation test. After the start of the test, by replacing pure water with a 1000 ppm BSA aqueous solution, the water permeability of the untreated membrane rapidly decreased, and when the set flux was 4 × 10 -6 [m 3 m -2 s -1 ], it was 67 %Diminished.
On the other hand, in the porous membrane in which PMEA was graft-polymerized (grafting amount: 0.12 mg/cm 2 ), although the water permeability decreased slightly by replacing pure water with BSA solution, the flux reduction rate was 23~ 40%, and fouling was effectively suppressed compared to the BSA solution.
Note that the surface-modified porous membrane of the reference example (grafting amount: 0.11 mg/cm 2 ) also showed the same fouling suppression performance as the surface-modified porous membrane of the example, but in the reference example, degassing by nitrogen bubbling In contrast, in the example, such deaeration is not necessary, and it is advantageous in that it can be easily manufactured.
＜純水透過実験＞
流量２Ｌ／分、液温２５℃とし、クロスフロー方式で純水透過試験を行い、純水透過係数（Ｌｐ）を求め、膜の透水性能を比較した。図４は、未処理膜のＢＳＡ溶液透過試験後の純水透過係数Ｌｐを１００とした場合の各膜のグラフト量とＢＳＡ溶液透過試験前後の純水透過係数Ｌｐとの関係を示すグラフである。Ｌｐが高いほど膜抵抗が小さく、低い圧力で水が透過するため、膜分離に有利である。
実施例の表面修飾多孔質膜は、未処理膜に比べ、ＢＳＡ溶液透過試験前後での純水透過係数Ｌｐの差が小さく、ファウリングが抑制されていることがわかる。特にグラフト量が０．０５ｍｇ／ｃｍ２以上、特に０．１ｍｇ／ｃｍ２以上ではＢＳＡ溶液透過試験前後での純水透過係数Ｌｐの差がほとんどなく、極めて優れた耐ファウリング性能を示した。
<Pure water permeation experiment>
A pure water permeation test was conducted using a cross-flow method at a flow rate of 2 L/min and a liquid temperature of 25° C., the pure water permeability coefficient (Lp) was determined, and the water permeability performance of the membranes was compared. FIG. 4 is a graph showing the relationship between the amount of grafting of each membrane and the pure water permeability coefficient Lp before and after the BSA solution permeation test, assuming that the pure water permeation coefficient Lp of the untreated membrane after the BSA solution permeation test is 100. . The higher Lp is, the lower the membrane resistance is, and water permeates at lower pressure, which is advantageous for membrane separation.
It can be seen that the difference in the pure water permeability coefficient Lp before and after the BSA solution permeation test is smaller in the surface-modified porous membrane of the example than in the untreated membrane, and fouling is suppressed. In particular, when the amount of grafting was 0.05 mg/cm 2 or more, particularly 0.1 mg/cm 2 or more, there was almost no difference in the pure water permeability coefficient Lp before and after the BSA solution permeation test, and extremely excellent anti-fouling performance was exhibited.
本開示に係る表面修飾多孔質膜の製造方法は、脱気操作等の必要が無く、優れた低ファウリング性を有する多孔質膜を製造することができる。そのため、本開示に係る表面修飾多孔質膜の製造方法によれば、膜モジュール内でＰＭＥＡの一括修飾も可能である。
また、本開示に係る表面修飾多孔質膜の製造方法によって製造された多孔質膜は、優れたファウリング抑制性能を有しており、水処理以外にも、タンパク分画など新しい用途を開拓できる可能性がある。特にタンパク様物質又は多糖様物質に対する低ファウリング性に優れると考えられる。
The method for producing a surface-modified porous membrane according to the present disclosure does not require a degassing operation, and can produce a porous membrane with excellent low fouling properties. Therefore, according to the method for manufacturing a surface-modified porous membrane according to the present disclosure, it is also possible to modify PMEA all at once within the membrane module.
In addition, the porous membrane produced by the method for producing a surface-modified porous membrane according to the present disclosure has excellent fouling suppression performance, and can develop new uses such as protein fractionation in addition to water treatment. there is a possibility. It is considered to be particularly excellent in low fouling properties against protein-like substances or polysaccharide-like substances.
Claims (3)
前記膜素材を前記第１処理液から取り出し、原子移動ラジカル重合開始剤を含む第２処理液に浸漬する第２処理工程と、
前記膜素材を前記第２処理液から取り出し、水、２－メトキシエチルアクリレート、還元剤、配位子、及び触媒を含む第３処理液に浸漬して前記膜素材にポリ（２－メトキシエチルアクリレート）を固定する第３処理工程と、
を含む表面修飾多孔質膜の製造方法。 a first treatment step of immersing a membrane material having a porous structure in a first treatment liquid containing water and ozone;
a second treatment step of taking out the membrane material from the first treatment liquid and immersing it in a second treatment liquid containing an atom transfer radical polymerization initiator;
The membrane material is taken out from the second treatment liquid and immersed in a third treatment liquid containing water, 2-methoxyethyl acrylate, a reducing agent, a ligand, and a catalyst to coat the membrane material with poly(2-methoxyethyl acrylate). ), a third treatment step of fixing the
A method for producing a surface-modified porous membrane comprising:
前記第３処理液が、前記還元剤であるアスコルビン酸、前記配位子であるＮ，Ｎ，Ｎ’，Ｎ”，Ｎ”－ペンタメチルジエチレントリアミン、及び前記触媒である臭化銅（ＩＩ）を含む請求項１に記載の表面修飾多孔質膜の製造方法。 The second treatment liquid contains triethylamine and the atom transfer radical polymerization initiator α-bromoisobutyryl bromide,
The third treatment liquid contains ascorbic acid as the reducing agent, N,N,N',N",N"-pentamethyldiethylenetriamine as the ligand, and copper(II) bromide as the catalyst. The method for producing a surface-modified porous membrane according to claim 1.
The membrane material is selected from the group consisting of polyethylene, polypropylene, polyvinylidene fluoride, polysulfone, polyethersulfone, polyvinyl chloride, polyacrylonitrile, cellulose acetate, polyamide, polytetrafluoroethylene, chlorinated polyvinyl chloride, polyketone, and polycarbonate. The method for producing a surface-modified porous membrane according to claim 1 or 2, comprising one or more selected polymers.
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