WO2018062705A1 - Membrane distillation filtration membrane, and manufacturing method therefor - Google Patents

Membrane distillation filtration membrane, and manufacturing method therefor Download PDF

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Publication number
WO2018062705A1
WO2018062705A1 PCT/KR2017/009630 KR2017009630W WO2018062705A1 WO 2018062705 A1 WO2018062705 A1 WO 2018062705A1 KR 2017009630 W KR2017009630 W KR 2017009630W WO 2018062705 A1 WO2018062705 A1 WO 2018062705A1
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membrane
filtration
porous body
pore diameter
nominal pore
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PCT/KR2017/009630
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French (fr)
Korean (ko)
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이광진
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코오롱인더스트리 주식회사
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Publication of WO2018062705A1 publication Critical patent/WO2018062705A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/36—Pervaporation; Membrane distillation; Liquid permeation
    • B01D61/364—Membrane distillation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/36—Pervaporation; Membrane distillation; Liquid permeation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/447—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by membrane distillation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/24—Quality control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/02—Details relating to pores or porosity of the membranes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/08—Seawater, e.g. for desalination
    • 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

Definitions

  • the present invention relates to a membrane distillation filtration membrane and a method for producing the same, and more particularly, to a membrane distillation filtration membrane having excellent non-wetting property and a method for producing the same.
  • Seawater desalination is largely divided into evaporation and reverse osmosis.
  • Seawater desalination technology using the evaporation method has been actively spread around the Middle East where water shortages are serious, but as the concern about rising energy costs increases, the attractiveness of future seawater desalination technology is decreasing. For this reason, the adoption of reverse osmosis seawater desalination technology is increasing.
  • reverse osmosis has many problems. For example, since high pressure raw water is supplied to the reverse osmosis membrane, it is vulnerable to membrane contamination, and it requires difficulty in operation and management because several steps of pretreatment are required to prevent contamination of the reverse osmosis membrane. And a lot of energy is consumed because it must be operated at a higher pressure than the osmotic pressure.
  • Membrane distillation is a method of separating pure water from the raw water using a temperature difference between feed water and clean water located on opposite sides of the filter membrane.
  • Phase change (liquid-> gas) of raw water which is relatively hot, occurs at the surface of the filtration membrane, and steam generated by the phase change penetrates the micropores of the filtration membrane and loses heat to the fresh water to condense.
  • the pores get wet with water from the largest pore to the smallest pore, and water as well as water passes through the wet pores of the filtration membrane. That is, the wet pores become a leak point, and as the number of wet pores increases, the rejection rate decreases, thereby losing the filtration membrane performance.
  • the existing filtration membranes contain many relatively small pore pores, so that sufficient permeate flux (e.g., the temperature difference between the raw water and the filtrate is 20 ° C in standard conditions) is suitable for commercialization of the membrane distillation method. Filtration flow rates above LMH) were very difficult to achieve.
  • the present invention relates to a membrane distillation filtration membrane and a method of manufacturing the same that can prevent problems caused by the above limitations and disadvantages of the related art.
  • One aspect of the present invention is to provide a membrane distillation filtration membrane having excellent wet resistance.
  • Another aspect of the present invention is to provide a method for producing a membrane distillation filter membrane having excellent wet resistance.
  • a membrane distillation filter membrane including a porous member (porous member) having a nominal pore diameter of 0.1 ⁇ m or more, 99% or more of the pores of the porous body is less than 120% of the nominal pore diameter
  • a membrane distillation filtration membrane having a pore size, a contact angle with respect to pure water of the filtration membrane is 60 ° or more, and a thermal conductivity of the filtration membrane is 0.6 W / mK or less.
  • the nominal pore diameter may be 0.1 ⁇ m to 0.2 ⁇ m.
  • the contact angle may be 100 ° or more.
  • the thermal conductivity may be 0.2 W / mK or less.
  • the porous body may have a porosity of 60% to 80%.
  • the nominal pore diameter may be 0.13 ⁇ m to 0.2 ⁇ m, and at least 99% of the pores of the porous body may have a pore diameter of 115% or less of the nominal pore diameter.
  • the nominal pore diameter may be 0.13 ⁇ m to 0.16 ⁇ m.
  • the porous body may include at least one of polytetrafluoroethylene, polyethylene, polypropylene, and polyvinylidene fluoride.
  • the porous body may include polytetrafluoroethylene or polypropylene.
  • the porous body may include polypropylene.
  • a method for producing a membrane for filtration membranes is provided.
  • the porous body may be manufactured by a 3D printer, and the nominal pore size of the porous body may be 0.1 ⁇ m to 0.2 ⁇ m.
  • the polymer resin may include at least one of polytetrafluoroethylene, polyethylene, polypropylene, and polyvinylidene fluoride.
  • the polymer resin may include polytetrafluoroethylene or polypropylene.
  • the polymer resin may include polypropylene.
  • the porous body may have a porosity of 60% to 80%.
  • the nominal pore size of the porous body may be 0.13 ⁇ m to 0.2 ⁇ m.
  • the nominal pore size of the porous body may be 0.13 ⁇ m 0.16 ⁇ m.
  • the filtration performance of the membrane distillation filtration membrane can be maintained for a long time by significantly delaying the wet phenomenon during operation of the membrane distillation filtration membrane.
  • the present invention enables the commercialization of the seawater desalination system using the membrane distillation method, thereby significantly reducing the energy consumption required for seawater desalination.
  • FIG. 1 schematically shows a membrane distillation system according to an embodiment of the present invention.
  • FIG. 1 illustrates a direct contact membrane distillation system.
  • Membrane distillation system 100 of the present invention the filtration module 110 for performing a water treatment, the raw water storage tank 120, the feed water (for example seawater) to be treated, and the filtration module And a filtrate storage tank 130 for storing filtrate produced by 110.
  • the filtration module 110 includes a housing 111 and a filtration membrane 112.
  • the filtration membrane 112 is installed in the housing 111 and divides the internal space of the housing 111 into a first flow path FP1 and a second flow path FP2.
  • the first flow path FP1 constitutes a part of the circulation path of raw water
  • the second flow path FP2 constitutes a part of the circulation path of the filtered water.
  • the filtration module 110 illustrated in FIG. 1 includes a flat sheet membrane as the filtration membrane 112, but the filtration membrane 112 of the present invention is not limited to the flat membrane, and various types of filtration membranes, for example, hollow It may be a hollow fiber membrane.
  • the filtration membrane is a hollow fiber membrane
  • the space in the housing ie, the space between the housing and the hollow fiber membrane
  • the lumen of the hollow fiber membrane provides a second flow path for filtered water. .
  • Raw water stored in the raw water storage tank 120 is provided to the filtration module 110 by the first pump (P1).
  • the first pump P1
  • seawater may be directly provided to the filtration module 110 from the sea by the first pump P1 without passing through the raw water storage tank 120.
  • the raw water may be heated by the heating unit 140 immediately before being provided to the filtration membrane module 110 for the phase change on the surface of the filtration membrane 112.
  • the temperature of the raw water to be treated is sufficiently high, such as seawater in the Middle East, raw water heating by the heating unit 140 may be omitted.
  • the heating unit 140 is a heat exchanger for transmitting waste heat of a power plant to the raw water (that is, heat exchange is performed between the hot steam and hot water discharged after rotating the turbine of the power plant). Heat exchanger).
  • the raw water passing through the first flow path FP1 may be discharged directly into the sea instead of returning to the raw water storage tank 120.
  • Clean water is stored in the filtrate storage tank 130 before the filtration operation starts, but as the filtration operation proceeds, the fresh water is gradually replaced by the filtered water.
  • fresh water is referred to as filtered water.
  • Filtrate stored in the filtrate storage tank 130 is provided to the filtration module 110 by a second pump (P2).
  • the filtered water may be cooled by the cooling unit 150 immediately before being provided to the filtration membrane module 110 for the phase change of raw water on the surface of the filtration membrane 112.
  • the relatively low temperature filtered water provided to the filtration module 110 passes through the second flow path FP2 of the filtration module 100, a part of the relatively high temperature raw water passing through the first flow path FP1, that is, the The raw water in contact with the filtration membrane 112 is converted into steam by causing a phase change due to a temperature difference.
  • the vapor penetrates through the filtration membrane 112 and moves to the low temperature filtered water, and then condenses, and moves to the filtered water storage tank 130 together with the original filtered water.
  • the membrane distillation process described above is an example of a direct contact membrane distillation process, and instead of inducing a low temperature fresh water flow to the filtration side, the vapor is passed through the membrane pores to form a vacuum space, and then the condensation unit after the vacuum space.
  • Other membrane distillation processes known to date such as the vacuum membrane distillation process, which is phase-separated into separate water by air, and the air-gap membrane distillation process, which places an air layer between the membrane and the filtration fresh water stream
  • the filter membrane of the present invention can be applied to obtain the effects of the present invention.
  • the filtration membrane 112 of the present invention includes a porous member having a plurality of pores.
  • the form of the pores is not particularly limited in the present invention, but may be, for example, a pore P having a prismatic form such as a cylinder or a square pillar or a rectangular pillar.
  • the porous body has a nominal pore diameter of 0.1 ⁇ m or more, preferably 0.1 to 100 ⁇ m, more preferably 0.1 to 0.2 ⁇ m, even more preferably 0.13 to 0.2 ⁇ m, even more preferably 0.13 to 0.16 ⁇ m.
  • the nominal pore means a diameter corresponding to pore cumulative number of 90% in a cumulative distribution of pore diameter in ascending order, and gas-liquid displacement porosimetry Or Liquid-Liquid Displacement Porosimetry (LLDP).
  • the nominal pore size of the porous body is less than 0.1 mu m, a filtration flow rate suitable for commercialization of the membrane distillation method is difficult to be achieved.
  • a liquid containing impurities eg, a salt such as NaCl
  • the rejection rate is lowered to 95% or less.
  • the filtration membrane 112 In order to achieve a sufficient filtration flow rate (for example, a filtration flow rate of 20 LMH or more under standard conditions where the temperature difference between the raw water and the filtered water is 40 ° C.) suitable for commercialization of the membrane distillation method, the filtration membrane 112 according to one embodiment of the present invention
  • the porous body of may have a relatively high porosity of 50% or more, preferably 60% to 80%, in addition to a nominal pore diameter of 0.1 ⁇ m or more.
  • the porosity means the percentage of the total volume of pores relative to the apparent volume of the filtration membrane 112 (ie (total volume of pores / apparent volume of the filtration membrane) ⁇ 100 (%)), and the mercury method is used. Can be obtained through
  • the membrane distillation filtration membrane 112 should have high wetting resistance.
  • the higher hydrophobicity of the filtration membrane 112 generally improves its wettability, but it has been found by the present invention that the most important factor for determining the wettability of the filtration membrane 112 is the pore size distribution of the porous body.
  • the more uniform the pore diameters of the porous body i.e., the fewer pores having pores much larger than the nominal pore size
  • satisfactory medium and long term filtration performance can be ensured. have. This is because the wetting phenomenon is mainly caused by pores of relatively large pore size (eg, a pore exceeding 120% of the nominal pore size).
  • wettability of the filtration membrane 112 may be significantly improved by having 99% or more of the pores of the porous body having a pore size of 120% or less, preferably 115% or less of the pore size of the porous body. .
  • the filtration membrane 112 of the present invention has a contact angle to pure water of 60 ° or more, preferably 100 ° or more.
  • the contact angle refers to a static contact angle that can be obtained by dropping a drop of pure water on the surface of the membrane 112 and measuring the angle between the surface of the membrane and the droplet.
  • the static contact angle should be measured after melting the filtration membrane 112 with heat and resolidifying the nonporous solid. In the case of materials that cannot be melted by heat such as PTFE, the static contact angle can be measured in the solid form of the same material.
  • plasma sputtering increases or increases the surface roughness of the porous body and changes the surface of the porous body to a fluorine-based functional group such as -CF 3 , -CF. 2 H, -CF 2 -, and modified by at least one of the -CH 2 -CF 3, may further enhance the hydrophobicity of the membrane (112).
  • the membrane distillation method utilizes the temperature difference between the raw water and the filtrate which are located opposite to each other with the filtration membrane 112 interposed therebetween, it is necessary to ensure a certain amount of filtration flow rate while performing the filtration through the membrane distillation (that is, the filtration performance In order to maintain the long term, the temperature difference between the raw water and the filtrate must be maintained at a predetermined size or more. For this reason, the filtration membrane 112 applied to membrane distillation should be able to inhibit or prevent heat transfer from relatively hot raw water to relatively cold filtration water. Therefore, according to the present invention, the thermal conductivity of the membrane distillation filtration membrane 112 is 0.6 W / mK or less, preferably 0.2 W / mK or less. The thermal conductivity may be measured after melting the filtration membrane 112 with heat and re-solidifying the non-porous solid.
  • the porous body is made of polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene (PP), and polyvinylidene fluoride (PVDF).
  • PTFE polytetrafluoroethylene
  • PE polyethylene
  • PP polypropylene
  • PVDF polyvinylidene fluoride
  • the porous body in order to produce a filtration membrane 112 having a contact angle of 100 ° or more and a thermal conductivity of 0.6 W / mK or less, may be polytetrafluoroethylene (PTFE) or polypropylene (PP). It may include.
  • PTFE polytetrafluoroethylene
  • PP polypropylene
  • the porous body may include polypropylene (PP).
  • a polymer resin having a contact angle to pure water of 60 ° or more and a thermal conductivity of 0.6 W / mK or less is prepared.
  • the polymer resin may include at least one of polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene (PP), and polyvinylidene fluoride (PVDF).
  • a polymer resin having a contact angle of 100 ° or more and a thermal conductivity of 0.6 W / mK or less for example, polytetrafluoroethylene (PTFE) or polypropylene (PP)
  • Polymer resin containing may be used.
  • a polymer resin containing polypropylene (PP) having a contact angle with respect to pure water of 100 ° or more and a thermal conductivity of 0.2 W / mK or less may be used.
  • a nominal of 0.1 ⁇ m or more preferably 0.1 to 100 ⁇ m, more preferably 0.1 to 0.2 ⁇ m, still more preferably 0.13 to 0.2 ⁇ m, even more preferably 0.13 to 0.16 ⁇ m
  • a porous body having a pore diameter is produced.
  • the porous body of the present invention can be formed using a 3D printer.
  • porous body of the filtration membrane 112 may have a relatively high porosity of 50% or more, preferably 60% to 80%.
  • a plasma sputtering process for increasing the surface roughness of the porous body, and / or ii) the surface of the porous body is fluorine-based, for example -CF 3 ,-
  • the process of modifying to at least one of CF 2 H, —CF 2 —, and —CH 2 —CF 3 may be further performed.
  • the plasma sputtering process may be performed using an RF power source in a vacuum.
  • the surface modification process may be performed by etching the porous surface with plasma to form a rough surface, and then generating a plasma in a fluorine-based gas environment.
  • the filtration membrane 112 of the present invention may have a high hydrophobicity such that the contact angle with pure water is 130 ° or more.
  • the nominal pore diameter, 99% pore range, porosity, contact angle, thermal conductivity, filtration flow rate, rejection rate, and wetting time of the filtration membrane were measured by the following methods, respectively.
  • the nominal pore means a pore corresponding to a total of 90% pore in the ascending cumulative distribution of pore size, and was obtained from a pore distribution graph obtained through Liquid-Liquid Displacement Porosimetry (LLDP) after taking a sample from the center portion of the entire filtration membrane.
  • LLDP Liquid-Liquid Displacement Porosimetry
  • the 99% nominal pore is similar to the nominal pore but refers to the pore diameter corresponding to the 99% pore accumulation in the ascending cumulative distribution of the pore sizes.
  • Samples were taken from the central portion of the entire filtration membrane and then obtained from a pore distribution graph obtained through LLDP.
  • Porosity means the percentage of the total volume of pores relative to the apparent volume of the filtration membrane (ie, (total volume of pores / apparent volume of the filtration membrane) ⁇ 100 (%)), which was obtained by mercury method.
  • the contact angle means a static contact angle
  • a drop of pure water was dropped on the surface of the filtration membrane to measure the angle between the membrane surface and the droplets.
  • the filter membrane is melted with heat and re-solidified to make a nonporous solid, and then the static contact angle is measured.
  • the static contact angle is measured in the form of a solid of the same material. do.
  • the exclusion rate was measured 10 minutes after the start of the operation, and the wetting time was the time taken until the exclusion rate was reduced by 10% after the time was measured 10 minutes after the operation in which the initial exclusion rate was measured.
  • Porous filtration membranes were made of the same materials as that of Comparative Examples 1 to 4, that is, PTFE, PE, PP and PVDF, respectively, using a 3D printer. At this time, the nominal pore size of the porous filtration membranes were unified to 0.1 ⁇ m, and had the same porosity as the filtration membranes of Comparative Examples 1 to 4, respectively. The 99% nominal pore size, filtration flow rate, rejection rate, and wetting time of the porous filtration membranes were measured, respectively, and are shown in Table 1 below.
  • PP porous filtration membranes were prepared in the same manner as in Example 3 except that the porosities were 60%, 70%, and 80%, respectively. 99% nominal pore size, filtration flow rate, rejection rate, and wetting time of the PP porous filtration membranes were measured, respectively, and are shown in Table 1 below.
  • PP porous filter membranes were prepared in the same manner as in Example 7, except that the nominal pore sizes were 0.13 ⁇ m, 0.16 ⁇ m, and 0.2 ⁇ m, respectively. 99% nominal pore size, filtration flow rate, rejection rate, and wetting time of the PP porous filtration membranes were measured, respectively, and are shown in Table 1 below.
  • the filtration membranes of Examples 5 to 10 are filtration membranes manufactured using polypropylene (PP), which is the most advantageous material in consideration of hydrophobicity and thermal conductivity.
  • PP polypropylene
  • the filtration membranes of Examples 3 and 5-7 were made to have the same nominal pore diameter (0.1 ⁇ m) of the same material (PP), with porosities of 50% to 60%, 70% and 80% When increased to each, it was confirmed that the filtration flow rate is increased while the wettability and rejection rate of the filtration membrane is maintained.
  • the filtration membranes of Examples 7 to 10 are manufactured to have the same porosity (80%) with the same material (PP), but have a nominal pore diameter of 0.13 ⁇ m, 0.16 ⁇ m, and 0.2 ⁇ m. When increased to each, while the wettability and rejection rate of the filtration membrane was maintained well it was confirmed that the filtration flow rate is rapidly increased.

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  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
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  • Life Sciences & Earth Sciences (AREA)
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  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

Disclosed are a membrane distillation filtration membrane having an excellent non-wetting property, and a manufacturing method therefor. The membrane distillation filtration membrane of the present invention comprises a porous member having a nominal pore size of 0.1 μm or more, wherein 99% or more of all of the pores of the porous member have a pore size of 120% or less of the nominal pore size of the porous member.

Description

막증류용 여과막 및 그 제조방법Membrane distillation membrane and its manufacturing method
본 발명은 막증류용 여과막 및 그 제조방법에 관한 것으로서, 더욱 구체적으로는, 우수한 내젖음성(non-wetting property)을 갖는 막증류용 여과막 및 그 제조방법에 관한 것이다.The present invention relates to a membrane distillation filtration membrane and a method for producing the same, and more particularly, to a membrane distillation filtration membrane having excellent non-wetting property and a method for producing the same.
지구 온난화에 따른 기후 변화, 산업화에 따른 공업용수 증가, 인구증가에 따른 물 수요의 증가 등으로 인해 물 부족 문제가 심각해지고 있다. 물 부족을 해결할 수 있는 방법은 지구 상에 존재하는 물의 약 97%를 차지하고 있는 바닷물로부터 염을 제거하는 기술, 즉 해수 담수화 기술을 이용하는 것이다.Due to climate change due to global warming, industrial water increase due to industrialization, and water demand due to population increase, water shortage problem is getting serious. The solution to water shortages is to use salt removal, or seawater desalination, to remove salt from seawater, which accounts for about 97% of the world's water.
해수 담수화 기술은 크게 증발법과 역삼투법으로 구분된다. 증발법을 이용한 해수 담수화 기술은 물 부족 현상이 심각한 중동 지역을 중심으로 활발하게 보급되었지만, 에너지 비용의 상승에 대한 우려가 증가함에 따라 미래의 해수 담수화 기술로서의 매력은 점점 떨어지고 있다. 이러한 이유로, 역삼투 방식의 해수 담수화 기술의 채택이 증가하고 있다.Seawater desalination is largely divided into evaporation and reverse osmosis. Seawater desalination technology using the evaporation method has been actively spread around the Middle East where water shortages are serious, but as the concern about rising energy costs increases, the attractiveness of future seawater desalination technology is decreasing. For this reason, the adoption of reverse osmosis seawater desalination technology is increasing.
그러나, 역삼투법은 많은 문제점을 내포하고 있는데, 예를 들어, 고압의 원수가 역삼투막에 공급되므로 막 오염에 취약하고, 역삼투막의 오염을 방지하기 위한 여러 단계의 전처리 과정들이 요구되므로 운전 및 관리 상의 어려움이 있고, 삼투압 이상의 높은 압력에서 운전되어야 하므로 많은 에너지가 소모된다.However, reverse osmosis has many problems. For example, since high pressure raw water is supplied to the reverse osmosis membrane, it is vulnerable to membrane contamination, and it requires difficulty in operation and management because several steps of pretreatment are required to prevent contamination of the reverse osmosis membrane. And a lot of energy is consumed because it must be operated at a higher pressure than the osmotic pressure.
따라서, 상대적으로 적은 에너지만을 요구하는 막증류법(Membrane Distillation)으로 역삼투법을 대체하기 위한 연구가 수행되고 있다. Therefore, research has been conducted to replace reverse osmosis by membrane distillation which requires relatively little energy.
막증류법은 여과막을 기준으로 서로 반대 측에 위치한 원수(feed water)와 청수(clean water) 사이의 온도 차이를 이용하여 상기 원수로부터 순수(pure water)를 분리하는 방법이다. 여과막 표면에서 상대적으로 고온인 원수의 상변화(액->기)가 일어나고, 이러한 상변화로 인해 발생된 증기가 여과막의 미세기공들을 투과한 후 청수에 열을 빼앗겨 응축된다.Membrane distillation is a method of separating pure water from the raw water using a temperature difference between feed water and clean water located on opposite sides of the filter membrane. Phase change (liquid-> gas) of raw water, which is relatively hot, occurs at the surface of the filtration membrane, and steam generated by the phase change penetrates the micropores of the filtration membrane and loses heat to the fresh water to condense.
막증류법에 의한 여과 작업이 수행될 때 공경이 큰 기공으로부터 공경이 작은 기공 순으로 기공이 물에 젖게 되고, 수증기뿐만 아니라 물도 여과막의 젖은 기공을 통과하게 된다. 즉, 젖은 기공은 리크 지점(leak point)이 되며, 젖은 기공의 개수가 증가하면 배제율이 감소하여 여과막 성능을 잃게 된다. When the filtration operation is performed by the membrane distillation method, the pores get wet with water from the largest pore to the smallest pore, and water as well as water passes through the wet pores of the filtration membrane. That is, the wet pores become a leak point, and as the number of wet pores increases, the rejection rate decreases, thereby losing the filtration membrane performance.
기존의 여과막은 그 대부분이 용융방사-냉연신(Melt Spinning Cold Stretching: MSCS) 공법으로 제조되는데, 상기 공법의 특성상 여과막이 균일한 공경 분포를 갖는 것이 매우 어렵다. 그 결과, 기존의 여과막은 비교적 넓은 공경 분포를 갖게 되고(즉, 쉽게 젖게 되는 큰 공경의 기공들을 다수 포함하고) 그 열악한 내젖음성으로 인해 분리 성능[즉, 배제율(rejection rate)]을 쉽게 상실하게 된다.Most of the existing filtration membranes are manufactured by a melt spinning cold stretching (MSCS) method, and it is very difficult for the filtration membrane to have a uniform pore distribution due to the characteristics of the method. As a result, existing filtration membranes have a relatively wide pore distribution (i.e. contain a large number of large pore pores that are easily wetted) and their poor wettability easily loses separation performance (i.e. rejection rate). Done.
한편, 기존의 여과막은 상대적으로 작은 공경의 기공들도 다수 포함하고 있어 막증류법의 상용화에 적합한 충분한 여과 유속(permeate flux)(예를 들어, 원수와 여과수의 온도 차이가 40℃인 표준조건에서 20 LMH 이상의 여과 유속)을 달성하기 매우 어려웠다.On the other hand, the existing filtration membranes contain many relatively small pore pores, so that sufficient permeate flux (e.g., the temperature difference between the raw water and the filtrate is 20 ° C in standard conditions) is suitable for commercialization of the membrane distillation method. Filtration flow rates above LMH) were very difficult to achieve.
따라서, 본 발명은 위와 같은 관련 기술의 제한 및 단점들에 기인한 문제점들을 방지할 수 있는 막증류용 여과막 및 그 제조방법에 관한 것이다.Accordingly, the present invention relates to a membrane distillation filtration membrane and a method of manufacturing the same that can prevent problems caused by the above limitations and disadvantages of the related art.
본 발명의 일 관점은, 우수한 내젖음성을 갖는 막증류용 여과막을 제공하는 것이다.One aspect of the present invention is to provide a membrane distillation filtration membrane having excellent wet resistance.
본 발명의 다른 관점은, 우수한 내젖음성을 갖는 막증류용 여과막을 제조하는 방법을 제공하는 것이다.Another aspect of the present invention is to provide a method for producing a membrane distillation filter membrane having excellent wet resistance.
위에서 언급된 본 발명의 관점 외에도, 본 발명의 다른 특징 및 이점들이 이하에서 설명되거나, 그러한 설명으로부터 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자에게 명확하게 이해될 수 있을 것이다.In addition to the aspects of the present invention mentioned above, other features and advantages of the present invention will be described below, or from such description will be apparent to those skilled in the art to which the present invention pertains.
위와 같은 본 발명의 일 관점에 따라, 막증류용 여과막으로서, 0.1㎛ 이상의 공칭공경을 갖는 다공체(porous member)를 포함하되, 상기 다공체의 기공들 중 99% 이상이 상기 공칭공경의 120% 이하의 공경을 갖고, 상기 여과막의 순수(pure water)에 대한 접촉각이 60° 이상이며, 상기 여과막의 열전도도가 0.6 W/mK 이하인, 막증류용 여과막이 제공된다.According to one aspect of the present invention as described above, as a membrane distillation filter membrane, including a porous member (porous member) having a nominal pore diameter of 0.1㎛ or more, 99% or more of the pores of the porous body is less than 120% of the nominal pore diameter A membrane distillation filtration membrane having a pore size, a contact angle with respect to pure water of the filtration membrane is 60 ° or more, and a thermal conductivity of the filtration membrane is 0.6 W / mK or less.
상기 공칭공경은 0.1㎛ 내지 0.2㎛일 수 있다.The nominal pore diameter may be 0.1 μm to 0.2 μm.
상기 접촉각은 100° 이상일 수 있다.The contact angle may be 100 ° or more.
상기 열전도도는 0.2 W/mK 이하일 수 있다.The thermal conductivity may be 0.2 W / mK or less.
상기 다공체는 60% 내지 80%의 기공도를 가질 수 있다.The porous body may have a porosity of 60% to 80%.
상기 공칭공경은 0.13㎛ 내지 0.2㎛일 수 있고, 상기 다공체의 기공들 중 99% 이상이 상기 공칭공경의 115% 이하의 공경을 가질 수 있다.The nominal pore diameter may be 0.13 μm to 0.2 μm, and at least 99% of the pores of the porous body may have a pore diameter of 115% or less of the nominal pore diameter.
상기 공칭공경은 0.13㎛ 내지 0.16㎛일 수 있다.The nominal pore diameter may be 0.13 μm to 0.16 μm.
상기 다공체는 폴리테트라플루오로에틸렌(polytetrafluoroethylene), 폴리에틸렌(polyethylene), 폴리프로필렌(polypropylene), 및 폴리비닐리덴플루오라이드(polyvinylidene fluoride) 중 적어도 하나를 포함할 수 있다.The porous body may include at least one of polytetrafluoroethylene, polyethylene, polypropylene, and polyvinylidene fluoride.
상기 다공체는 폴리테트라플루오로에틸렌 또는 폴리프로필렌을 포함할 수 있다.The porous body may include polytetrafluoroethylene or polypropylene.
상기 다공체는 폴리프로필렌을 포함할 수 있다.The porous body may include polypropylene.
본 발명의 다른 관점에 따라, 순수(pure water)에 대한 접촉각이 60° 이상이며 열전도도가 0.6 W/mK 이하인 고분자 수지를 준비하는 단계; 및 상기 고분자 수지를 이용하여 0.1㎛ 이상의 공칭공경을 갖는 다공체(porous member)를 제조하는 단계를 포함하되, 상기 다공체의 기공들 중 99% 이상이 상기 공칭공경의 120% 이하의 공경을 갖는 것을 특징으로 하는, 막증류용 여과막 제조방법이 제공된다.According to another aspect of the invention, the step of preparing a polymer resin having a contact angle to pure water (60) or more and a thermal conductivity of 0.6 W / mK or less; And producing a porous member having a nominal pore diameter of 0.1 μm or more using the polymer resin, wherein at least 99% of the pores of the porous body have a pore diameter of 120% or less of the nominal pore diameter. Provided is a method for producing a membrane for filtration membranes.
상기 다공체는 3D 프린터로 제조될 수 있고, 상기 다공체의 공칭공경은 0.1㎛ 내지 0.2㎛일 수 있다.The porous body may be manufactured by a 3D printer, and the nominal pore size of the porous body may be 0.1 μm to 0.2 μm.
상기 고분자 수지는 폴리테트라플루오로에틸렌, 폴리에틸렌, 폴리프로필렌, 및 폴리비닐리덴플루오라이드 중 적어도 하나를 포함할 수 있다.The polymer resin may include at least one of polytetrafluoroethylene, polyethylene, polypropylene, and polyvinylidene fluoride.
상기 고분자 수지는 폴리테트라플루오로에틸렌 또는 폴리프로필렌을 포함할 수 있다.상기 고분자 수지는 폴리프로필렌을 포함할 수 있다.The polymer resin may include polytetrafluoroethylene or polypropylene. The polymer resin may include polypropylene.
상기 다공체는 60% 내지 80%의 기공도를 가질 수 있다.The porous body may have a porosity of 60% to 80%.
상기 다공체의 공칭공경은 0.13㎛ 내지 0.2㎛일 수 있다.The nominal pore size of the porous body may be 0.13㎛ to 0.2㎛.
상기 다공체의 공칭공경은 0.13㎛ 내지 0.16㎛일 수 있다.The nominal pore size of the porous body may be 0.13㎛ 0.16㎛.
위와 같은 일반적 서술 및 이하의 상세한 설명 모두는 본 발명을 예시하거나 설명하기 위한 것일 뿐으로서, 특허청구범위의 발명에 대한 더욱 자세한 설명을 제공하기 위한 것으로 이해되어야 한다.It is to be understood that both the foregoing general description and the following detailed description are intended to illustrate or explain the invention, and to provide a more detailed description of the invention in the claims.
본 발명에 의하면, 막증류용 여과막의 운전 중 젖음 현상을 상당히 지연시킴으로써 막증류용 여과막의 여과 성능을 장기적으로 유지시킬 수 있다.According to the present invention, the filtration performance of the membrane distillation filtration membrane can be maintained for a long time by significantly delaying the wet phenomenon during operation of the membrane distillation filtration membrane.
또한, 본 발명에 의하면, 막증류법에 기초한 수처리를 수행함에 있어서 분리 성능의 저하 없이도 증가된 여과 유속을 담보할 수 있다. In addition, according to the present invention, it is possible to ensure an increased filtration flow rate without lowering the separation performance in performing water treatment based on the membrane distillation method.
따라서, 본 발명은 막증류법을 이용한 해수담수화 시스템의 상용화를 가능하게 함으로써 해수담수화에 필요한 에너지 소모를 획기적으로 감소시킬 수 있다.Accordingly, the present invention enables the commercialization of the seawater desalination system using the membrane distillation method, thereby significantly reducing the energy consumption required for seawater desalination.
첨부된 도면은 본 발명의 이해를 돕고 본 명세서의 일부를 구성하기 위한 것으로서, 본 발명의 실시예를 예시하며, 발명의 상세한 설명과 함께 본 발명의 원리들을 설명한다.The accompanying drawings are included to assist in understanding the present invention and to form a part of the specification, to illustrate embodiments of the present invention, and to explain the principles of the present invention together with the detailed description of the invention.
도 1은 본 발명의 일 실시예에 따른 막증류 시스템을 개략적으로 보여준다.1 schematically shows a membrane distillation system according to an embodiment of the present invention.
이하에서는 첨부된 도면을 참조하여 본 발명의 실시예들을 상세하게 설명한다. 다만, 아래에서 설명되는 실시예들은 본 발명의 명확한 이해를 돕기 위한 예시적 목적으로 제시되는 것일 뿐, 본 발명의 범위를 제한하지 않는다.Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention; However, the embodiments described below are provided for illustrative purposes only to help a clear understanding of the present invention, and do not limit the scope of the present invention.
본 발명의 기술적 사상 및 범위를 벗어나지 않는 범위 내에서 본 발명의 다양한 변경 및 변형이 가능하다는 점은 당업자에게 자명할 것이다. 따라서, 본 발명은 특허청구범위에 기재된 발명 및 그 균등물의 범위 내에 드는 변경 및 변형을 모두 포함한다.It will be apparent to those skilled in the art that various changes and modifications of the present invention are possible without departing from the spirit and scope of the present invention. Accordingly, the invention includes all modifications and variations that fall within the scope of the invention as set forth in the claims and their equivalents.
이하에서는, 도 1을 참조하여 본 발명의 막증류 시스템을 구체적으로 설명한다. 도 1은 직접 접촉 막증류 시스템을 예시한다.Hereinafter, the membrane distillation system of the present invention will be described in detail with reference to FIG. 1. 1 illustrates a direct contact membrane distillation system.
본 발명의 막증류 시스템(100)은, 수처리를 수행하는 여과 모듈(110), 처리되어야 할 원수(feed water)(예를 들어, 해수)가 저장되는 원수 저장 탱크(120), 및 상기 여과 모듈(110)에 의해 생산된 여과수를 저장하는 여과수 저장 탱크(130)를 포함한다. Membrane distillation system 100 of the present invention, the filtration module 110 for performing a water treatment, the raw water storage tank 120, the feed water (for example seawater) to be treated, and the filtration module And a filtrate storage tank 130 for storing filtrate produced by 110.
도 1에 예시된 바와 같이, 본 발명의 일 실시예에 의한 여과 모듈(110)은 하우징(111) 및 여과막(112)을 포함한다. 상기 여과막(112)은 상기 하우징(111) 내에 설치되어 있으며 상기 하우징(111)의 내부 공간을 제1 유로(flow path)(FP1) 및 제2 유로(FP2)로 나눈다. 상기 제1 유로(FP1)는 원수의 순환 경로 중 일부를 구성하고, 상기 제2 유로(FP2)는 여과수의 순환 경로 중 일부를 구성한다.As illustrated in FIG. 1, the filtration module 110 according to an embodiment of the present invention includes a housing 111 and a filtration membrane 112. The filtration membrane 112 is installed in the housing 111 and divides the internal space of the housing 111 into a first flow path FP1 and a second flow path FP2. The first flow path FP1 constitutes a part of the circulation path of raw water, and the second flow path FP2 constitutes a part of the circulation path of the filtered water.
도 1에 예시된 여과 모듈(110)은 여과막(112)으로서 평막(flat sheet membrane)을 포함하고 있으나, 본 발명의 여과막(112)이 평막으로 한정되는 것은 아니며 다양한 형태의 여과막, 예를 들어 중공사막(hollow fiber membrane)일 수도 있다. 여과막이 중공사막일 경우, 하우징 내 공간(즉, 하우징과 중공사막 사이의 공간)이 원수를 위한 제1 유로를 제공하고, 중공사막의 중공(lumen)이 여과수를 위한 제2 유로를 제공하게 된다.The filtration module 110 illustrated in FIG. 1 includes a flat sheet membrane as the filtration membrane 112, but the filtration membrane 112 of the present invention is not limited to the flat membrane, and various types of filtration membranes, for example, hollow It may be a hollow fiber membrane. When the filtration membrane is a hollow fiber membrane, the space in the housing (ie, the space between the housing and the hollow fiber membrane) provides a first flow path for raw water, and the lumen of the hollow fiber membrane provides a second flow path for filtered water. .
원수 저장 탱크(120)에 저장된 원수는 제1 펌프(P1)에 의해 여과 모듈(110)로 제공된다. 상기 원수가 해수일 경우, 원수 저장 탱크(120)를 거치지 않고 제1 펌프(P1)에 의해 바다로부터 여과 모듈(110)로 해수가 직접 제공될 수도 있다.Raw water stored in the raw water storage tank 120 is provided to the filtration module 110 by the first pump (P1). When the raw water is seawater, seawater may be directly provided to the filtration module 110 from the sea by the first pump P1 without passing through the raw water storage tank 120.
도 1에 도시된 바와 같이, 여과막(112) 표면에서의 상변화를 위하여 상기 원수는 여과막 모듈(110)로 제공되기 직전에 가열부(140)에 의해 가열될 수 있다. 그러나, 처리되어야 할 원수의 온도가 중동지역의 해수와 같이 충분히 높은 경우에는, 상기 가열부(140)에 의한 원수 가열은 생략될 수 있다. As shown in FIG. 1, the raw water may be heated by the heating unit 140 immediately before being provided to the filtration membrane module 110 for the phase change on the surface of the filtration membrane 112. However, when the temperature of the raw water to be treated is sufficiently high, such as seawater in the Middle East, raw water heating by the heating unit 140 may be omitted.
에너지 소모를 최소화하기 위하여, 상기 가열부(140)는 발전소의 폐열을 상기 원수에 전달하기 위한 열교환기(즉, 발전소의 터빈을 회전시킨 후 배출되는 고온의 증기와 상기 원수 사이에 열 교환이 이루어지는 열교환기)일 수 있다.In order to minimize energy consumption, the heating unit 140 is a heat exchanger for transmitting waste heat of a power plant to the raw water (that is, heat exchange is performed between the hot steam and hot water discharged after rotating the turbine of the power plant). Heat exchanger).
여과 모듈(110)로 제공된 원수가 여과 모듈(100)의 제1 유로(FP1)를 통과할 때, 증기로 변환된 그 중 일부가 여과막(112)을 투과하여 제2 유로(FP2)로 이동하고 그 나머지는 원수 저장 탱크(120)로 복귀한다. When the raw water provided to the filtration module 110 passes through the first flow path FP1 of the filtration module 100, some of the water converted into steam passes through the filtration membrane 112 and moves to the second flow path FP2. The rest is returned to the raw water storage tank 120.
상기 원수가 해수일 경우, 상기 제1 유로(FP1)를 통과한 원수가 원수 저장 탱크(120)로 복귀하는 대신에 바다로 직접 배출될 수도 있다.When the raw water is sea water, the raw water passing through the first flow path FP1 may be discharged directly into the sea instead of returning to the raw water storage tank 120.
여과 작업이 시작되기 전에 상기 여과수 저장 탱크(130)에 청수(clean water)가 저장되나, 여과 작업이 진행됨에 따라 상기 청수가 점진적으로 여과수로 대체된다. 이하에서는 설명의 편의상 청수도 여과수로 지칭한다.Clean water is stored in the filtrate storage tank 130 before the filtration operation starts, but as the filtration operation proceeds, the fresh water is gradually replaced by the filtered water. Hereinafter, for convenience of description, fresh water is referred to as filtered water.
여과수 저장 탱크(130)에 저장된 여과수는 제2 펌프(P2)에 의해 여과 모듈(110)로 제공된다. Filtrate stored in the filtrate storage tank 130 is provided to the filtration module 110 by a second pump (P2).
도 1에 도시된 바와 같이, 여과막(112) 표면에서의 원수의 상변화를 위하여 상기 여과수는 여과막 모듈(110)로 제공되기 직전에 냉각부(150)에 의해 냉각될 수 있다.As shown in FIG. 1, the filtered water may be cooled by the cooling unit 150 immediately before being provided to the filtration membrane module 110 for the phase change of raw water on the surface of the filtration membrane 112.
여과 모듈(110)로 제공된 상대적으로 저온인 여과수가 여과 모듈(100)의 제2 유로(FP2)를 통과할 때, 상기 제1 유로(FP1)를 통과하는 상대적으로 고온의 원수의 일부, 즉 상기 여과막(112)에 접촉하는 원수가 온도차로 인한 상변화를 일으켜 증기로 변환된다. 상기 증기는 여과막(112)을 투과하여 상기 저온의 여과수로 이동한 후 곧 응축되고, 본래 여과수와 함께 상기 여과수 저장 탱크(130)로 이동한다.When the relatively low temperature filtered water provided to the filtration module 110 passes through the second flow path FP2 of the filtration module 100, a part of the relatively high temperature raw water passing through the first flow path FP1, that is, the The raw water in contact with the filtration membrane 112 is converted into steam by causing a phase change due to a temperature difference. The vapor penetrates through the filtration membrane 112 and moves to the low temperature filtered water, and then condenses, and moves to the filtered water storage tank 130 together with the original filtered water.
상술한 막증류 공정은 직접촉 막증류(Direct Contact Membrane Distillation) 공정의 한 예이며, 여과측에 저온의 청수 흐름을 유도하는 대신 진공공간으로 만들어 막 기공을 통과한 수증기가 진공공간 이후의 응축장치에 의해 별도 물로 상전이 되는 진공 막증류(Vacuum Membrane Distillation) 공정, 막과 여과측 청수 흐름 사이에 공기층을 두는 에어갭 막증류(Air-Gap Membrane Distillation) 공정 등 지금까지 알려진 다른 막증류 공정들에도 본 발명의 여과막이 적용되어 본 발명의 효과를 얻을 수 있다.The membrane distillation process described above is an example of a direct contact membrane distillation process, and instead of inducing a low temperature fresh water flow to the filtration side, the vapor is passed through the membrane pores to form a vacuum space, and then the condensation unit after the vacuum space. Other membrane distillation processes known to date, such as the vacuum membrane distillation process, which is phase-separated into separate water by air, and the air-gap membrane distillation process, which places an air layer between the membrane and the filtration fresh water stream The filter membrane of the present invention can be applied to obtain the effects of the present invention.
이하에서는 본 발명의 여과막(112)에 대하여 더욱 구체적으로 설명한다.Hereinafter, the filtration membrane 112 of the present invention will be described in more detail.
본 발명의 여과막(112)은, 다수의 기공들을 갖는 다공체(porous member)를 포함한다. The filtration membrane 112 of the present invention includes a porous member having a plurality of pores.
상기 기공들의 형태는 본 발명에서 특별히 제한되지 않지만, 예를 들어 원기둥 또는 정사각기둥, 직사각기둥 등의 각기둥 형태를 갖는 기공(P)일 수 있다.The form of the pores is not particularly limited in the present invention, but may be, for example, a pore P having a prismatic form such as a cylinder or a square pillar or a rectangular pillar.
상기 다공체는 0.1㎛ 이상, 바람직하게는 0.1 내지 100 ㎛, 더 바람직하게는 0.1 내지 0.2 ㎛, 더욱 더 바람직하게는 0.13 내지 0.2 ㎛, 더욱 더 바람직하게는 0.13 내지 0.16 ㎛의 공칭공경(nominal pore diameter)을 갖는다. 상기 공칭공경은 공경의 오름차순 누적 분포(cumulative distribution of pore diameter in ascending order)에서 90% 기공 누계에 해당하는 공경(diameter corresponding to pore cumulative number of 90%)을 의미하며, GLDP(Gas-Liquid Displacement Porosimetry) 또는 LLDP(Liquid-Liquid Displacement Porosimetry)를 이용하여 구해질 수 있다.The porous body has a nominal pore diameter of 0.1 μm or more, preferably 0.1 to 100 μm, more preferably 0.1 to 0.2 μm, even more preferably 0.13 to 0.2 μm, even more preferably 0.13 to 0.16 μm. Has The nominal pore means a diameter corresponding to pore cumulative number of 90% in a cumulative distribution of pore diameter in ascending order, and gas-liquid displacement porosimetry Or Liquid-Liquid Displacement Porosimetry (LLDP).
상기 다공체의 공칭공경이 0.1㎛ 미만이면, 막증류법의 상용화에 적합한 여과 유속이 달성되기 어렵다. 반면, 상기 다공체가 100㎛를 초과하는 공칭공경을 가질 경우에는 불순물(예를 들어, NaCl과 같은 염)이 섞여 있는 액체도 막을 투과하게 되어 배제율이 95% 이하로 저하될 위험이 있다.If the nominal pore size of the porous body is less than 0.1 mu m, a filtration flow rate suitable for commercialization of the membrane distillation method is difficult to be achieved. On the other hand, when the porous body has a nominal pore diameter of more than 100 μm, a liquid containing impurities (eg, a salt such as NaCl) also penetrates the membrane, and there is a risk that the rejection rate is lowered to 95% or less.
막증류법의 상용화에 적합한 충분한 여과 유속(예를 들어, 원수와 여과수의 온도 차이가 40℃인 표준조건에서 20 LMH 이상의 여과 유속)을 달성하기 위하여, 본 발명의 일 실시예에 따른 여과막(112)의 다공체는, 0.1㎛ 이상의 공칭공경 외에도, 50% 이상, 바람직하게는 60% 내지 80%의 상대적으로 높은 기공도를 가질 수 있다. 상기 기공도는 여과막(112)의 겉보기 부피(apparent volume)에 대한 기공들의 총 부피의 퍼센티지[즉, (기공들의 총 부피/여과막의 겉보기 부피)×100 (%)]를 의미하며, 수은법을 통해 구해질 수 있다.In order to achieve a sufficient filtration flow rate (for example, a filtration flow rate of 20 LMH or more under standard conditions where the temperature difference between the raw water and the filtered water is 40 ° C.) suitable for commercialization of the membrane distillation method, the filtration membrane 112 according to one embodiment of the present invention The porous body of may have a relatively high porosity of 50% or more, preferably 60% to 80%, in addition to a nominal pore diameter of 0.1 μm or more. The porosity means the percentage of the total volume of pores relative to the apparent volume of the filtration membrane 112 (ie (total volume of pores / apparent volume of the filtration membrane) × 100 (%)), and the mercury method is used. Can be obtained through
전술한 바와 같이, 막증류법에 의한 여과 작업이 수행될 때, 물에 젖은 기공은 수증기가 아닌 물의 이동 통로를 제공하는 리크 포인트(leak point)가 되며, 물에 젖은 기공의 개수가 일정 개수를 초과하면 여과 성능을 상실하게 된다. 따라서, 막증류용 여과막(112)은 높은 내젖음성을 가져야 한다.As described above, when the filtration operation by the membrane distillation method is performed, the water-soaked pores become a leak point that provides a passage of water rather than water vapor, and the number of the water-soaked pores exceeds a certain number. This will result in loss of filtration performance. Therefore, the membrane distillation filtration membrane 112 should have high wetting resistance.
여과막(112)이 높은 소수성을 가질수록 그 내젖음성도 일반적으로 향상되지만, 여과막(112)의 내젖음성을 결정하는 가장 중요한 인자는 다공체의 공경 분포임이 본 발명에 의해 밝혀졌다. 상기 다공체의 공경들이 균일할수록(즉, 공칭공경보다 훨씬 큰 공경을 갖는 기공들의 개수가 적을수록) 여과막(112)이 더 높은 내젖음성을 갖게 되고, 그 결과, 만족할만한 중장기 여과성능이 확보될 수 있다. 이것은 젖음 현상이 상대적으로 큰 공경(예를 들어, 공칭공경의 120%를 초과하는 공경)의 기공들에서 주로 유발되기 때문이다. The higher hydrophobicity of the filtration membrane 112 generally improves its wettability, but it has been found by the present invention that the most important factor for determining the wettability of the filtration membrane 112 is the pore size distribution of the porous body. The more uniform the pore diameters of the porous body (i.e., the fewer pores having pores much larger than the nominal pore size), the higher the wettability of the filtration membrane 112 becomes. As a result, satisfactory medium and long term filtration performance can be ensured. have. This is because the wetting phenomenon is mainly caused by pores of relatively large pore size (eg, a pore exceeding 120% of the nominal pore size).
본 발명에 의하면, 상기 다공체의 기공들 중 99% 이상이 상기 다공체의 공칭공경의 120% 이하, 바람직하게는 115% 이하의 공경을 가짐으로써 상기 여과막(112)의 내젖음성이 현격히 향상될 수 있다.According to the present invention, wettability of the filtration membrane 112 may be significantly improved by having 99% or more of the pores of the porous body having a pore size of 120% or less, preferably 115% or less of the pore size of the porous body. .
본 발명의 여과막(112)은 순수(pure water)에 대한 접촉각이 60° 이상, 바람직하게는 100° 이상이다. 상기 접촉각이 60° 미만이면, 낮은 소수성으로 인해 공경 분포의 균일성과 관계 없이 여과막(112)이 빨리 젖게 되어 그 여과 성능이 장시간 유지될 수 없다. 상기 접촉각은 여과막(112) 표면에 순수 한 방울을 떨어뜨려 막 표면과 물방울 간의 각도를 측정함으로써 얻어질 수 있는 정적접촉각(static contact angle)을 의미한다. 정적접촉각 측정시 여과막의 다공성으로 인하여 물방울 형태가 유지되기 어려울 경우, 여과막(112)을 열로 녹인 후 재응고시켜 비다공질 고체로 만든 뒤 정적접촉각을 측정해야 한다. PTFE 등 열로 녹일 수 없는 재질의 경우는 동일한 재질의 고체형태로 정적접촉각을 측정할 수 있다.The filtration membrane 112 of the present invention has a contact angle to pure water of 60 ° or more, preferably 100 ° or more. When the contact angle is less than 60 °, the low hydrophobicity causes the filtration membrane 112 to wet rapidly regardless of uniformity of pore distribution, so that the filtration performance cannot be maintained for a long time. The contact angle refers to a static contact angle that can be obtained by dropping a drop of pure water on the surface of the membrane 112 and measuring the angle between the surface of the membrane and the droplet. When it is difficult to maintain the droplet shape due to the porosity of the filtration membrane in the static contact angle measurement, the static contact angle should be measured after melting the filtration membrane 112 with heat and resolidifying the nonporous solid. In the case of materials that cannot be melted by heat such as PTFE, the static contact angle can be measured in the solid form of the same material.
선택적으로, 상기 다공체가 1㎛ 이상의 상대적으로 큰 공칭공경을 가질 경우, 플라즈마 스퍼터링을 통해 상기 다공체 표면 조도를 증가시키거나/증가시키고 상기 다공체의 표면을 불소계 작용기, 예를 들어 -CF3, -CF2H, -CF2-, 및 -CH2-CF3 중 적어도 하나로 개질함으로써, 상기 여과막(112)의 소수성을 더욱 향상시킬 수도 있다.Optionally, when the porous body has a relatively large nominal pore diameter of 1 μm or more, plasma sputtering increases or increases the surface roughness of the porous body and changes the surface of the porous body to a fluorine-based functional group such as -CF 3 , -CF. 2 H, -CF 2 -, and modified by at least one of the -CH 2 -CF 3, may further enhance the hydrophobicity of the membrane (112).
막증류법은 여과막(112)을 사이에 두고 서로 반대편에 위치한 원수와 여과수의 온도 차이를 이용하는 것이기 때문에, 막증류를 통한 여과 작업을 지속적으로 수행하면서 일정량 이상의 여과 유속을 담보하기 위해서는(즉, 여과 성능을 장기적으로 유지시키기 위해서는) 원수와 여과수 사이의 온도 차이를 소정 크기 이상으로 유지시켜야 한다. 이러한 이유로, 막증류에 적용되는 여과막(112)은 상대적으로 고온인 원수로부터 상대적으로 저온인 여과수로의 열 전달을 억제 또는 방지할 수 있어야 한다. 따라서, 본 발명에 의하면, 막증류용 여과막(112)의 열전도도는 0.6 W/mK 이하, 바람직하게는 0.2 W/mK 이하이다. 상기 열전도도는 여과막(112)을 열로 녹인 후 재응고시켜 비다공질 고체로 만든 후 측정될 수 있다. Since the membrane distillation method utilizes the temperature difference between the raw water and the filtrate which are located opposite to each other with the filtration membrane 112 interposed therebetween, it is necessary to ensure a certain amount of filtration flow rate while performing the filtration through the membrane distillation (that is, the filtration performance In order to maintain the long term, the temperature difference between the raw water and the filtrate must be maintained at a predetermined size or more. For this reason, the filtration membrane 112 applied to membrane distillation should be able to inhibit or prevent heat transfer from relatively hot raw water to relatively cold filtration water. Therefore, according to the present invention, the thermal conductivity of the membrane distillation filtration membrane 112 is 0.6 W / mK or less, preferably 0.2 W / mK or less. The thermal conductivity may be measured after melting the filtration membrane 112 with heat and re-solidifying the non-porous solid.
높은 소수성(60° 이상의 접촉각) 및 낮은 열전도도(0.6 W/mK 이하)를 갖는 여과막(112)을 제조하기 위하여, 상기 다공체는 폴리테트라플루오로에틸렌(PTFE), 폴리에틸렌(PE), 폴리프로필렌(PP), 및 폴리비닐리덴플루오라이드(PVDF) 중 적어도 하나를 포함할 수 있다.In order to produce a filtration membrane 112 having high hydrophobicity (contact angle of 60 ° or more) and low thermal conductivity (0.6 W / mK or less), the porous body is made of polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene ( PP), and polyvinylidene fluoride (PVDF).
본 발명의 일 실시예에 의하면, 100° 이상의 접촉각 및 0.6 W/mK 이하의 열전도도를 갖는 여과막(112)을 제조하기 위하여, 상기 다공체는 폴리테트라플루오로에틸렌(PTFE) 또는 폴리프로필렌(PP)을 포함할 수 있다.According to one embodiment of the present invention, in order to produce a filtration membrane 112 having a contact angle of 100 ° or more and a thermal conductivity of 0.6 W / mK or less, the porous body may be polytetrafluoroethylene (PTFE) or polypropylene (PP). It may include.
특히, 100° 이상의 접촉각 및 0.2 W/mK 이하의 열전도도를 갖는 여과막(112)을 제조하기 위하여, 상기 다공체는 폴리프로필렌(PP)을 포함할 수 있다.In particular, in order to manufacture the filtration membrane 112 having a contact angle of 100 ° or more and a thermal conductivity of 0.2 W / mK or less, the porous body may include polypropylene (PP).
이하에서는, 본 발명의 여과막(112)을 제조하는 방법을 구체적으로 설명한다.Hereinafter, a method of manufacturing the filtration membrane 112 of the present invention will be described in detail.
먼저, 순수에 대한 접촉각이 60° 이상이며 열전도도가 0.6 W/mK 이하인 고분자 수지를 준비한다. 전술한 바와 같이, 상기 고분자 수지는 폴리테트라플루오로에틸렌(PTFE), 폴리에틸렌(PE), 폴리프로필렌(PP), 및 폴리비닐리덴플루오라이드(PVDF) 중 적어도 하나를 포함할 수 있다. 본 발명의 일 실시예에 의하면, 순수에 대한 접촉각이 100° 이상이고 0.6 W/mK 이하의 열전도도를 갖는 고분자 수지, 예를 들어, 폴리테트라플루오로에틸렌(PTFE) 또는 폴리프로필렌(PP)을 포함하는 고분자 수지가 이용될 수 있다. 특히, 순수에 대한 접촉각이 100° 이상이고, 열전도도가 0.2 W/mK 이하인 폴리프로필렌(PP)을 포함하는 고분자 수지가 이용될 수 있다.First, a polymer resin having a contact angle to pure water of 60 ° or more and a thermal conductivity of 0.6 W / mK or less is prepared. As described above, the polymer resin may include at least one of polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene (PP), and polyvinylidene fluoride (PVDF). According to one embodiment of the present invention, a polymer resin having a contact angle of 100 ° or more and a thermal conductivity of 0.6 W / mK or less, for example, polytetrafluoroethylene (PTFE) or polypropylene (PP) Polymer resin containing may be used. In particular, a polymer resin containing polypropylene (PP) having a contact angle with respect to pure water of 100 ° or more and a thermal conductivity of 0.2 W / mK or less may be used.
이어서, 상기 고분자 수지를 이용하여 0.1㎛ 이상, 바람직하게는 0.1 내지 100 ㎛, 더 바람직하게는 0.1 내지 0.2 ㎛, 더욱 더 바람직하게는 0.13 내지 0.2 ㎛, 더욱 더 바람직하게는 0.13 내지 0.16 ㎛의 공칭공경을 갖는 다공체를 제조한다.Subsequently, using the polymer resin, a nominal of 0.1 μm or more, preferably 0.1 to 100 μm, more preferably 0.1 to 0.2 μm, still more preferably 0.13 to 0.2 μm, even more preferably 0.13 to 0.16 μm A porous body having a pore diameter is produced.
전술한 바와 같이, 통상의 막 제조 공정을 통해 다공체가 형성될 경우 공경 편차로 인해 공칭공경보다 훨씬 큰 직경의 기공이 발생될 위험이 있는데, 이와 같이 큰 기공은 막의 젖음을 유발하여 분리 성능(즉, 염 배제율)을 저하시킬 수 있다. As described above, when the porous body is formed through a conventional membrane manufacturing process, there is a risk that pores having a diameter larger than the nominal pore are generated due to the pore deviation, and such large pores cause the membrane to wet and cause separation performance (i.e., , Salt rejection rate) can be reduced.
따라서, 본 발명에 의하면, 다공체의 전체 기공들 중 99% 이상이 상기 다공체의 공칭공경의 120% 이하, 바람직하게는 115% 이하의 공경을 갖는다. 다공체의 기공들이 이와 같이 균일한 공경을 갖도록 하기 위하여(즉, 공경 편차를 최소화하기 위하여), 본 발명의 다공체는 3D 프린터를 이용하여 형성될 수 있다.Therefore, according to the present invention, at least 99% of the pores of the porous body have a pore diameter of 120% or less, preferably 115% or less of the nominal pore size of the porous body. In order to make the pores of the porous body have such a uniform pore diameter (that is, to minimize the pore variation), the porous body of the present invention can be formed using a 3D printer.
또한, 전술한 바와 같이, 막증류법의 상용화에 적합한 충분한 여과 유속(예를 들어, 원수와 여과수의 온도 차이가 40℃인 표준조건에서 20 LMH 이상의 여과 유속)을 달성하기 위하여, 본 발명의 일 실시예에 따른 여과막(112)의 다공체는 50% 이상, 바람직하게는 60% 내지 80%의 상대적으로 높은 기공도를 가질 수 있다.In addition, as described above, in order to achieve a sufficient filtration flow rate (for example, a filtration flow rate of 20 LMH or more under standard conditions where the temperature difference between the raw water and the filtered water is 40 ° C.) suitable for commercialization of the membrane distillation method, one embodiment of the present invention The porous body of the filtration membrane 112 according to the example may have a relatively high porosity of 50% or more, preferably 60% to 80%.
선택적으로, 여과막(112)의 소수성을 더욱 향상시키기 위하여, i) 상기 다공체 표면 조도를 증가시키기 위한 플라즈마 스퍼터링 공정, 및/또는 ii) 상기 다공체의 표면을 불소계 작용기, 예를 들어 -CF3, -CF2H, -CF2-, 및 -CH2-CF3 중 적어도 하나로 개질시키는 공정이 더 수행될 수 있다. Optionally, in order to further enhance the hydrophobicity of the filtration membrane 112, i) a plasma sputtering process for increasing the surface roughness of the porous body, and / or ii) the surface of the porous body is fluorine-based, for example -CF 3 ,- The process of modifying to at least one of CF 2 H, —CF 2 —, and —CH 2 —CF 3 may be further performed.
상기 플라즈마 스퍼터링 공정은 진공 중에서 RF 전원을 사용하여 수행될 수 있는데, 예를 들어 산소와 아르곤의 혼합가스(몰비 = 2:1) 내에서 700V의 바이어스 전압으로 2 시간 동안 수행될 수 있다.The plasma sputtering process may be performed using an RF power source in a vacuum. For example, the plasma sputtering process may be performed at a bias voltage of 700 V in a mixed gas of oxygen and argon (molar ratio = 2: 1) for 2 hours.
상기 표면 개질 공정은 다공체 표면을 플라즈마로 에칭하여 거친 표면을 만든 후 불소계 가스 환경에서 플라즈마를 발생시킴으로써 수행될 수 있다.The surface modification process may be performed by etching the porous surface with plasma to form a rough surface, and then generating a plasma in a fluorine-based gas environment.
이와 같은 추가적 표면처리 공정(들)을 더 수행함으로써 본 발명의 여과막(112)은 순수에 대한 접촉각이 130° 이상이 될 정도로 높은 소수성을 가질 수 있다.By further performing such additional surface treatment process (s), the filtration membrane 112 of the present invention may have a high hydrophobicity such that the contact angle with pure water is 130 ° or more.
이하, 실시예들 및 비교예를 통해 본 발명을 구체적으로 설명한다. 다만, 하기의 실시예는 본 발명의 이해를 돕기 위한 것일 뿐으로 이것에 의해 본 발명의 권리범위가 제한되지 않는다.Hereinafter, the present invention will be described in detail through examples and comparative examples. However, the following examples are only intended to help the understanding of the present invention, and the scope of the present invention is not limited thereto.
실험예Experimental Example
여과막의 공칭공경, 99% 공경 범위, 기공도, 접촉각, 열전도도, 여과유속, 배제율, 및 젖음시간은 아래의 방법들에 의해 각각 측정되었다.The nominal pore diameter, 99% pore range, porosity, contact angle, thermal conductivity, filtration flow rate, rejection rate, and wetting time of the filtration membrane were measured by the following methods, respectively.
* 공칭공경(㎛)* Nominal pore size (㎛)
공칭공경은 공경의 오름차순 누적 분포에서 90% 기공 누계에 해당하는 공경을 의미하며, 전체 여과막 중 중앙부로부터 샘플을 취한 후 LLDP(Liquid-Liquid Displacement Porosimetry)를 통해 얻어진 공경 분포 그래프로부터 구하였다. The nominal pore means a pore corresponding to a total of 90% pore in the ascending cumulative distribution of pore size, and was obtained from a pore distribution graph obtained through Liquid-Liquid Displacement Porosimetry (LLDP) after taking a sample from the center portion of the entire filtration membrane.
* 99% 공칭공경(㎛)* 99% nominal pore diameter (㎛)
99% 공칭공경은 공칭공경과 유사하나 공경의 오름차순 누적 분포에서 99% 기공 누계에 해당하는 공경을 의미한다. 전체 여과막 중 중앙부로부터 샘플을 취한 후 LLDP를 통해 얻어진 공경 분포 그래프로부터 구하였다.The 99% nominal pore is similar to the nominal pore but refers to the pore diameter corresponding to the 99% pore accumulation in the ascending cumulative distribution of the pore sizes. Samples were taken from the central portion of the entire filtration membrane and then obtained from a pore distribution graph obtained through LLDP.
* 기공도(%)* Porosity (%)
기공도는 여과막의 겉보기 부피(apparent volume)에 대한 기공들의 총 부피의 퍼센티지[즉, (기공들의 총 부피/여과막의 겉보기 부피)×100 (%)]를 의미하며, 수은법을 통해 구하였다.Porosity means the percentage of the total volume of pores relative to the apparent volume of the filtration membrane (ie, (total volume of pores / apparent volume of the filtration membrane) × 100 (%)), which was obtained by mercury method.
* 접촉각(°)* Contact angle (°)
접촉각은 정적접촉각(static contact angle)을 의미하며, 여과막 표면에 순수 한 방울을 떨어뜨려 막 표면과 물방울 간의 각도를 측정하였다. 물방울이 막의 기공 내부로 스며들어갈 경우, 여과막을 열로 녹인 후 재응고시켜 비다공질 고체로 만든 뒤 정적접촉각을 측정하며, PTFE 증 열로 녹일 수 없는 재질의 경우는 동일한 재질의 고체형태로 정적접촉각을 측정한다.The contact angle means a static contact angle, and a drop of pure water was dropped on the surface of the filtration membrane to measure the angle between the membrane surface and the droplets. When water droplets penetrate into the pores of the membrane, the filter membrane is melted with heat and re-solidified to make a nonporous solid, and then the static contact angle is measured.In the case of a material that cannot be dissolved by PTFE steam, the static contact angle is measured in the form of a solid of the same material. do.
* 열전도도(W/mK)* Thermal conductivity (W / mK)
여과막을 열로 녹인 후 재응고시켜 비다공질 고체로 만든 후 열전도도를 측정하였다.After dissolving the filter membrane with heat and resolidifying to form a non-porous solid, the thermal conductivity was measured.
* 여과유속(LMH), 배제율(%) 및 젖음 시간(hour)* Filtration flow rate (LMH), rejection rate (%) and wetting time (hour)
60℃의 원수 및 20℃의 여과수를 이용한 직접 접촉 막증류 공정을 수행함으로써 여과유속, 아래의 식 1에 의해 정의되는 배제율, 및 젖음 시간을 각각 측정하였다. 50 μS/cm의 NaCl을 함유한 원수가 사용되었고, 순환 유속은 80 mL/min이었으며, 순환수 압력은 0.01 bar이었다. By performing a direct contact membrane distillation process using raw water at 60 ° C. and filtered water at 20 ° C., the filtration flow rate, exclusion rate defined by Equation 1 below, and wetting time were measured, respectively. Raw water containing 50 μS / cm NaCl was used, the circulation flow rate was 80 mL / min and the circulation water pressure was 0.01 bar.
식 1: 배제율 = [(원수 농도 - 여과수 농도)/원수 농도] × 100 (%)Equation 1: Exclusion rate = [(raw water concentration-filtered water concentration) / raw water concentration] × 100 (%)
상기 배제율은 운전 시작 10분 후에 측정하였으며, 상기 젖음 시간은 초기 배제율을 측정한 운전 10분 후부터 시간을 측정하기 시작하여 상기 배제율이 10%만큼 감소할 때까지 소요된 시간이다.The exclusion rate was measured 10 minutes after the start of the operation, and the wetting time was the time taken until the exclusion rate was reduced by 10% after the time was measured 10 minutes after the operation in which the initial exclusion rate was measured.
비교예 1 내지 4Comparative Examples 1 to 4
PTFE, PE, PP 및 PVDF로 각각 제조된 상용 여과막들을 준비하였다. 상기 여과막들의 공칭공경, 99% 공칭공경, 기공도, 접촉각, 열전도도, 여과유속, 배제율, 및 젖음 시간을 각각 측정한 후 아래의 표 1에 나타내었다.Commercial filtration membranes made of PTFE, PE, PP and PVDF, respectively, were prepared. The nominal pore size, 99% nominal pore size, porosity, contact angle, thermal conductivity, filtration flow rate, rejection rate, and wetting time of the filtration membranes were measured, respectively, and are shown in Table 1 below.
실시예 1 내지 4Examples 1-4
3D 프린터를 이용하여 비교예 1 내지 4와 동일한 재질들, 즉 PTFE, PE, PP 및 PVDF로 다공성 여과막들을 각각 제조하였다. 이때, 상기 다공성 여과막들의 공칭공경은 0.1㎛로 통일하였고, 상기 비교예 1 내지 4의 여과막들과 동일한 기공도를 각각 갖도록 하였다. 상기 다공성 여과막들의 99% 공칭공경, 여과유속, 배제율, 및 젖음 시간을 각각 측정한 후 아래의 표 1에 나타내었다.Porous filtration membranes were made of the same materials as that of Comparative Examples 1 to 4, that is, PTFE, PE, PP and PVDF, respectively, using a 3D printer. At this time, the nominal pore size of the porous filtration membranes were unified to 0.1 ㎛, and had the same porosity as the filtration membranes of Comparative Examples 1 to 4, respectively. The 99% nominal pore size, filtration flow rate, rejection rate, and wetting time of the porous filtration membranes were measured, respectively, and are shown in Table 1 below.
실시예 5 내지 7Examples 5-7
기공도가 각각 60%, 70% 및 80%이었다는 것을 제외하고는 실시예 3과 동일한 방법으로 PP 다공성 여과막들을 제조하였다. 상기 PP 다공성 여과막들의 99% 공칭공경, 여과유속, 배제율, 및 젖음 시간을 각각 측정한 후 아래의 표 1에 나타내었다.PP porous filtration membranes were prepared in the same manner as in Example 3 except that the porosities were 60%, 70%, and 80%, respectively. 99% nominal pore size, filtration flow rate, rejection rate, and wetting time of the PP porous filtration membranes were measured, respectively, and are shown in Table 1 below.
실시예 8 내지 10Examples 8-10
공칭공경이 각각 0.13㎛, 0.16㎛ 및 0.2㎛이었다는 것을 제외하고는 실시예 7과 동일한 방법으로 PP 다공성 여과막들을 제조하였다. 상기 PP 다공성 여과막들의 99% 공칭공경, 여과유속, 배제율, 및 젖음 시간을 각각 측정한 후 아래의 표 1에 나타내었다.PP porous filter membranes were prepared in the same manner as in Example 7, except that the nominal pore sizes were 0.13 μm, 0.16 μm, and 0.2 μm, respectively. 99% nominal pore size, filtration flow rate, rejection rate, and wetting time of the PP porous filtration membranes were measured, respectively, and are shown in Table 1 below.
재질material 공칭공경(㎛)Nominal pore diameter (㎛) 99% 공칭공경(㎛)99% nominal pore diameter (㎛) 기공도(%)Porosity (%) 접촉각(°)Contact angle (°) 열전도도(W/mK)Thermal Conductivity (W / mK) 여과유속(LMH)Filtration Flow Rate (LMH) 배제율Exclusion rate 젖음시간(h)Wetting time (h)
비교예1Comparative Example 1 PTFEPTFE 0.10.1 2.02.0 5555 110110 0.380.38 1515 >99%> 99% 1212
비교예2Comparative Example 2 PEPE 0.40.4 4.04.0 6060 9090 0.520.52 1616 >91%> 91% 0.20.2
비교예3Comparative Example 3 PPPP 0.40.4 3.93.9 5050 108108 0.120.12 1818 >92%> 92% 0.40.4
비교예4Comparative Example 4 PVDFPVDF 0.10.1 0.40.4 6565 6060 0.230.23 1010 >99%> 99% 0.10.1
실시예1Example 1 PTFEPTFE 0.10.1 0.120.12 5555 110110 0.380.38 1515 >99%> 99% 168168
실시예2Example 2 PEPE 0.10.1 0.120.12 6060 9090 0.520.52 1616 >99%> 99% 2424
실시예3Example 3 PPPP 0.10.1 0.120.12 5050 108108 0.120.12 1515 >99%> 99% 720720
실시예4Example 4 PVDFPVDF 0.10.1 0.120.12 6565 6060 0.230.23 1313 >99%> 99% 2828
실시예5Example 5 PPPP 0.10.1 0.120.12 6060 108108 0.120.12 2020 >99%> 99% 720720
실시예6Example 6 PPPP 0.10.1 0.120.12 7070 108108 0.120.12 2323 >99%> 99% 720720
실시예7Example 7 PPPP 0.10.1 0.120.12 8080 108108 0.120.12 2626 >99%> 99% 720720
실시예8Example 8 PPPP 0.130.13 0.150.15 8080 108108 0.120.12 3535 >99%> 99% 720720
실시예9Example 9 PPPP 0.160.16 0.180.18 8080 108108 0.120.12 4444 >99%> 99% 720720
실시예10Example 10 PPPP 0.20.2 0.220.22 8080 108108 0.120.12 6060 >95%> 95% 480480
위 표 1로부터 알 수 있는 바와 같이, 비교예 1 내지 4의 상용 여과막들은 그 젖음 시간이 12 시간 이하로 지나치게 짧았다. 특히, PTFE 여과막을 제외한 나머지 여과막들(비교예 2 내지 4)은 0.5 시간도 채 되지 않아 젖어버렸다.As can be seen from Table 1 above, the commercial filtration membranes of Comparative Examples 1 to 4 were too short as the wet time was 12 hours or less. In particular, the remaining filtration membranes (Comparative Examples 2 to 4) except the PTFE filtration membrane were wetted in less than 0.5 hours.
이에 반해, 공칭공경에 대한 99% 공칭공경의 비율을 획기적으로 감소시킨(즉, 공경 분포를 현저히 좁힌) 본 발명의 실시예 1 내지 4의 여과막들의 경우, 비교예 1 내지 4의 상용 여과막들 대비 여과유속과 배제율에 있어서는 별 차이가 없었음에도 불구하고, 젖음 시간은 각 재질마다 100배 이상 개선된 것을 확인할 수 있었다.In contrast, in the case of the filtration membranes of Examples 1 to 4 of the present invention, which significantly reduced the ratio of the 99% nominal pore to the nominal pore diameter (ie, significantly narrowing the pore distribution), compared to the commercial filtration membranes of Comparative Examples 1 to 4. Although there was no difference in the filtration flow rate and the rejection rate, the wetting time was confirmed to be improved more than 100 times for each material.
실시예 5 내지 10의 여과막들은 소수성 및 열전도도를 고려할 때 가장 유리한 재질인 폴리프로필렌(PP)을 이용하여 제조된 여과막들이다.The filtration membranes of Examples 5 to 10 are filtration membranes manufactured using polypropylene (PP), which is the most advantageous material in consideration of hydrophobicity and thermal conductivity.
실시예 3 및 5 내지 7의 여과막들로부터 알 수 있는 바와 같이, 여과막들이 동일한 재질(PP)로 동일한 공칭공경(0.1㎛)을 갖도록 제조되되 기공도가 50%에서 60%, 70% 및 80%로 각각 증가될 경우, 여과막의 내젖음성 및 배제율은 유지되면서도 여과유속이 증가하는 것을 확인할 수 있었다.As can be seen from the filtration membranes of Examples 3 and 5-7, the filtration membranes were made to have the same nominal pore diameter (0.1 μm) of the same material (PP), with porosities of 50% to 60%, 70% and 80% When increased to each, it was confirmed that the filtration flow rate is increased while the wettability and rejection rate of the filtration membrane is maintained.
또한, 실시예 7 내지 10의 여과막들로부터 알 수 있는 바와 같이, 여과막들이 동일한 재질(PP)로 동일한 기공도(80%)를 갖도록 제조되되 공칭공경이 0.1㎛에서 0.13㎛, 0.16㎛ 및 0.2㎛로 각각 증가될 경우, 여과막의 내젖음성 및 배제율은 양호하게 유지되면서도 여과유속이 급격히 증가하는 것을 확인할 수 있었다.In addition, as can be seen from the filtration membranes of Examples 7 to 10, the filtration membranes are manufactured to have the same porosity (80%) with the same material (PP), but have a nominal pore diameter of 0.13 μm, 0.16 μm, and 0.2 μm. When increased to each, while the wettability and rejection rate of the filtration membrane was maintained well it was confirmed that the filtration flow rate is rapidly increased.

Claims (18)

  1. 막증류용 여과막에 있어서,In the membrane for membrane distillation,
    0.1㎛ 이상의 공칭공경을 갖는 다공체(porous member)를 포함하되,It includes a porous member having a nominal pore diameter of 0.1㎛ or more,
    상기 다공체의 기공들 중 99% 이상이 상기 공칭공경의 120% 이하의 공경을 갖고,At least 99% of the pores of the porous body have a pore diameter of 120% or less of the nominal pore diameter,
    상기 여과막의 순수(pure water)에 대한 접촉각이 60° 이상이며,The contact angle of the filtration membrane with respect to pure water is 60 ° or more,
    상기 여과막의 열전도도가 0.6 W/mK 이하인,Thermal conductivity of the filtration membrane is 0.6 W / mK or less,
    막증류용 여과막.Membrane for membrane distillation.
  2. 제1항에 있어서,The method of claim 1,
    상기 공칭공경은 0.1㎛ 내지 0.2㎛인,The nominal pore diameter is 0.1 μm to 0.2 μm,
    막증류용 여과막.Membrane for membrane distillation.
  3. 제2항에 있어서,The method of claim 2,
    상기 접촉각은 100° 이상인,The contact angle is at least 100 °,
    막증류용 여과막.Membrane for membrane distillation.
  4. 제3항에 있어서,The method of claim 3,
    상기 열전도도는 0.2 W/mK 이하인,The thermal conductivity is 0.2 W / mK or less,
    막증류용 여과막.Membrane for membrane distillation.
  5. 제4항에 있어서,The method of claim 4, wherein
    상기 다공체는 60% 내지 80%의 기공도를 갖는,The porous body has a porosity of 60% to 80%,
    막증류용 여과막.Membrane for membrane distillation.
  6. 제5항에 있어서,The method of claim 5,
    상기 공칭공경은 0.13㎛ 내지 0.2㎛이고,The nominal pore diameter is 0.13㎛ to 0.2㎛,
    상기 다공체의 기공들 중 99% 이상이 상기 공칭공경의 115% 이하의 공경을 갖는,99% or more of the pores of the porous body has a pore diameter of 115% or less of the nominal pore diameter,
    막증류용 여과막.Membrane for membrane distillation.
  7. 제6항에 있어서,The method of claim 6,
    상기 공칭공경은 0.13㎛ 내지 0.16㎛인,The nominal pore diameter is 0.13 μm to 0.16 μm,
    막증류용 여과막.Membrane for membrane distillation.
  8. 제2항에 있어서,The method of claim 2,
    상기 다공체는 폴리테트라플루오로에틸렌(polytetrafluoroethylene), 폴리에틸렌(polyethylene), 폴리프로필렌(polypropylene), 및 폴리비닐리덴플루오라이드(polyvinylidene fluoride) 중 적어도 하나를 포함하는,The porous body includes at least one of polytetrafluoroethylene, polyethylene, polypropylene, and polyvinylidene fluoride.
    막증류용 여과막.Membrane for membrane distillation.
  9. 제8항에 있어서,The method of claim 8,
    상기 다공체는 폴리테트라플루오로에틸렌 또는 폴리프로필렌을 포함하는,The porous body comprises polytetrafluoroethylene or polypropylene
    막증류용 여과막.Membrane for membrane distillation.
  10. 제9항에 있어서,The method of claim 9,
    상기 다공체는 폴리프로필렌을 포함하는 것을 특징으로 하는,The porous body is characterized in that it comprises a polypropylene,
    막증류용 여과막.Membrane for membrane distillation.
  11. 순수에 대한 접촉각이 60° 이상이며 열전도도가 0.6 W/mK 이하인 고분자 수지를 준비하는 단계; 및Preparing a polymer resin having a contact angle to pure water of 60 ° or more and a thermal conductivity of 0.6 W / mK or less; And
    상기 고분자 수지를 이용하여 0.1㎛ 이상의 공칭공경을 갖는 다공체(porous member)를 제조하는 단계를 포함하되, Including the step of producing a porous member (porous member) having a nominal pore diameter of 0.1 ㎛ or more using the polymer resin,
    상기 다공체의 기공들 중 99% 이상이 상기 공칭공경의 120% 이하의 공경을 갖는 것을 특징으로 하는,Characterized in that more than 99% of the pores of the porous body has a pore diameter of less than 120% of the nominal pore diameter,
    막증류용 여과막 제조방법.Membrane filtration membrane production method.
  12. 제11항에 있어서,The method of claim 11,
    상기 다공체는 3D 프린터로 제조되고,The porous body is made of a 3D printer,
    상기 다공체의 공칭공경은 0.1㎛ 내지 0.2㎛인,The nominal pore diameter of the porous body is 0.1㎛ to 0.2㎛,
    막증류용 여과막 제조방법.Membrane filtration membrane production method.
  13. 제12항에 있어서,The method of claim 12,
    상기 고분자 수지는 폴리테트라플루오로에틸렌, 폴리에틸렌, 폴리프로필렌, 및 폴리비닐리덴플루오라이드 중 적어도 하나를 포함하는,Wherein the polymer resin comprises at least one of polytetrafluoroethylene, polyethylene, polypropylene, and polyvinylidene fluoride,
    막증류용 여과막 제조방법.Membrane filtration membrane production method.
  14. 제13항에 있어서,The method of claim 13,
    상기 고분자 수지는 폴리테트라플루오로에틸렌 또는 폴리프로필렌을 포함하는,The polymer resin, polytetrafluoroethylene or polypropylene,
    막증류용 여과막 제조방법.Membrane filtration membrane production method.
  15. 제14항에 있어서,The method of claim 14,
    상기 고분자 수지는 폴리프로필렌을 포함하는,The polymer resin includes a polypropylene,
    막증류용 여과막 제조방법.Membrane filtration membrane production method.
  16. 제15항에 있어서,The method of claim 15,
    상기 다공체는 60% 내지 80%의 기공도를 갖는,The porous body has a porosity of 60% to 80%,
    막증류용 여과막 제조방법.Membrane filtration membrane production method.
  17. 제16항에 있어서,The method of claim 16,
    상기 다공체의 공칭공경은 0.13㎛ 내지 0.2㎛인,The nominal pore size of the porous body is 0.13㎛ to 0.2㎛,
    막증류용 여과막 제조방법.Membrane filtration membrane production method.
  18. 제16항에 있어서,The method of claim 16,
    상기 다공체의 공칭공경은 0.13㎛ 내지 0.16㎛인,The nominal pore diameter of the porous body is 0.13㎛ 0.16㎛,
    막증류용 여과막 제조방법.Membrane filtration membrane production method.
PCT/KR2017/009630 2016-09-28 2017-09-04 Membrane distillation filtration membrane, and manufacturing method therefor WO2018062705A1 (en)

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