WO2007117087A1

WO2007117087A1 - Facilitated olefin transporting polymer membrane containing metal nanoparticle

Info

Publication number: WO2007117087A1
Application number: PCT/KR2007/001513
Authority: WO
Inventors: Yong-Soo Kang; Kook-Heon Char; Sang-Wook Kang; Sung-Hyun Moon
Original assignee: Industry University Cooperation Foundation IUCF HYU; Industry University Cooperation Foundation of Sogang University
Current assignee: Industry University Cooperation Foundation IUCF HYU; Industry University Cooperation Foundation of Sogang University
Priority date: 2006-04-12
Filing date: 2007-03-28
Publication date: 2007-10-18
Anticipated expiration: 2008-10-12

Abstract

This invention provides a polymer membrane which is able to separate olefin and paraffin having similar molecular weights using a facilitated transport mechanism. In the polymer membrane of the invention, any one type of metal nanoparticles, selected from among silver nanoparticles, gold nanoparticles, and copper nanoparticles, function as an olefin carrier for facilitated transport, and an electron acceptor functions to cationize the metal nanoparticles to be suitable for use as the olefin carrier for facilitated transport.

Description

FACILITATED OLEFIN TRANSPORTING POLYMER MEMBRANE CONTAINING METAL NANOPARTICLE

Technical Field

[1] The present invention relates to a polymer membrane, and more particularly, to a facilitated olefin transporting polymer membrane, which enables the separation of olefin and paraffin having similar molecular weights. Background Art

[2] Conventionally, methods of separating various mixture materials using a polymer membrane have been mainly applied to only the separation of carbon dioxide and methane, oxygen and air, and organic droplets and air. However, in the case of the separation of olefin and paraffin mixtures, for example, propylene and propane, and butylene and butane, olefin and paraffin have very similar molecular sizes and physical properties, and it is thus impossible to attain sufficient separation performance using a typical polymer membrane.

[3] In order to solve difficulties in separating olefin and paraffin having similar molecular weights using a typical polymer membrane, while facilitated transport concept is introduced, thorough attempts to apply a polymer membrane to the separation of olefin and paraffin have been made.

[4] In the case where a carrier that is able to reversibly react with the specific component of a mixture to be separated is present in the membrane, the carrier reversibly reacts with the specific component (e.g., olefin) of the mixture, and thus general material transfer by the concentration gradient according to Fick' law and facilitated transport by the carrier occur simultaneously, ultimately increasing both selectivity and permeance.

[5] Methods of using a supported or immobilized liquid membrane formed by supporting a carrier, for example, silver salt, such as AgBF or AgCF SO , as the conventional polymer membrane using such facilitated transport are disclosed. In such techniques, when the separation time is increased, the activity of silver salt is undesirably reduced. To mitigate this problem, techniques using a phthalate compound or a surfactant have been proposed.

[6] The present inventors have been interested in and studied facilitated transport using metal nanoparticles as a carrier, instead of the conventional carrier in the form of such a metal salt, and consequently have completed the present invention.

[7] The nanoparticles exhibit intrinsic physicochemical properties in the fields of surface-enhanced Raman-scattering, catalysis, photonics, and sensors, and therefore are receiving increasing attention. The reason why metal nanoparticles have intrinsic physicochemical properties different from those of simple metals or metal salts is that small particles having large surface area have greater reactivity.

[8] For example, as the experimental results for reaction between silver nanoparticles and oxygen molecules at low temperatures, it has been confirmed that smaller-sized silver nanoparticles have superior ability to decompose oxygen molecules into atoms, and furthermore, oxygen molecules reacted with not nano-sized but bulky silver particles at a temperature of 80K are mainly decomposed into O . The silver nanocluster in an aqueous solution state is known to have the ability to transfer electrons to an appropriate acceptor and to show a partial positive charge under predetermined conditions to thus have high chemical activity.

[9] The present inventors have conducted research into a polymer membrane, in particular, a facilitated transporting polymer membrane for separation of olefin and paraffin, based on strong physicochemical activities of metal nanoparticles, thus completing the present invention. Disclosure of Invention Technical Problem

[10] An object of the present invention is to provide a facilitated olefin transporting polymer membrane, which is capable of separating olefin and paraffin from each other using metal nanoparticles, in particular, silver nanoparticles, gold nanoparticles, or copper nanoparticles, as a carrier for facilitated transport.

Technical Solution

[11] In order to achieve the above object, the present invention provides a facilitated olefin transporting polymer membrane containing metal nanoparticles, comprising a polymer, an electron acceptor, and any one type of metal nanoparticles, selected from among silver nanoparticles, gold nanoparticles, and copper nanoparticles.

[12] Further, if the weight ratio of the polymer and the metal nanoparticles is 1:1, the electron acceptor preferably has a weight ratio ranging from 0.3 to 0.9.

[13] Further, the metal nanoparticles preferably have a size not larger than 200 nm.

[14] Further, the facilitated olefin transporting polymer membrane may be a flat membrane further comprising a porous support.

[15] Furthermore, the facilitated olefin transporting polymer membrane may be a hollow fiber membrane.

[16] Further, SiO nanoparticles are preferably added, in addition to the metal nanoparticles.

[17] The SiO is preferably used in an amount of 0.01 to 0.2 parts by weight based on 1 part by weight of the polymer. [18] Further, the silver nanoparticles are preferably silica-silver nanocomposite particles comprising silica nanoparticles and silver nanoparticles bound thereto.

[19] Further, examples of the electron acceptor include /?-benzoquinone, anthracene, azobenzene, benzophenone, ferrocene, nitrobenzene, tetracyanoquinodimethane (TCNQ), N,N,N\N'-tetramethyl-/?-phenylenediamine (TMPD), tetrathiafulvalence (TTF), thianthrene (TH), and tri-N-p-tolylamine (TPTA).

Advantageous Effects

[20] According to the present invention, a novel facilitated olefin transporting polymer membrane, which has not been known to date, is provided, thus enabling the facilitated transport of only olefin using silver nanoparticles, gold nanoparticles, or copper nanoparticles. Compared to conventional polymer membranes using metal salts, the polymer membrane of the invention does not have a need for an additional treatment, such as humidification, to cationize the metal salts, and stably achieves the selective separation of olefin/paraffin for a long period of time. Brief Description of the Drawings

[21] FIG. 1 is a graph showing the ideal selectivity of propylene/propane of the polymer membranes of Comparative Example and Examples 1 to 3;

[22] FIG. 2 is a graph showing the pure gas permeance of propylene/propane of the polymer membrane of Example 3 depending on the permeation time;

[23] FIG. 3 is a graph showing the propylene selectivity of propylene/propane gas mixture of the polymer membrane of Example 3 depending on the separation time;

[24] FIG. 4 is a graph showing the total permeance of propylene/propane gas mixture of the polymer membrane of Example 3 depending on the separation time;

[25] FIG. 5 is a graph showing the results of XPS of binding energy of pure silver (Ag), and of binding energy of silver in the polymer membranes of Comparative Example and Examples 1 and 3;

[26] FIG. 6 is a graph showing the results of XPS of oxygen binding energy of p - benzoquinone in the polymer membranes of Examples 1 to 3;

[27] FIG. 7 is a graph showing the propylene/propane selectivity of the polymer membranes of Examples 14 to 20 ; and

[28] FIG. 8 is a graph showing the total permeance of propylene/propane gas mixtures of the polymer membranes of Examples 14 to 20; Best Mode for Carrying Out the Invention

[29] In the case of conventional facilitated olefin transporting polymer membranes using metal salts, the metal salt is dissociated into a metal cation and a salt anion on the polymer in the membrane. As such, the metal cation reversibly reacts with the double bond of an olefin-based hydrocarbon to form a complex, thereby directly taking part in the facilitated transport. Therefore, the conventional facilitated olefin transporting polymer membrane using the metal salt requires additional treatment, including supply of a solvent, for example, water, for dissociating the metal salt into the metal cation and the salt anion.

[30] Functioning as a carrier in the polymer membrane of the present invention, silver nanoparticles, gold nanoparticles, or copper nanoparticles must be essentially cationized for facilitated transport of olefin. For such cationization, an electron acceptor is used in the present invention. Such an electron acceptor is not particularly limited.

[31] Examples of the electron acceptor includes /?-benzoquinone, anthracene, azobenzene, benzophenone, ferrocene, nitrobenzene, tetracyanoquinodimethane (TCNQ), N,N,N\N'-tetramethyl-/?-phenylenediamine (TMPD), tetrathiafulvalence (TTF), thianthrene (TH), and tri-N-/?-tolylamine (TPTA). In the present invention, as the electron acceptor, any electron acceptor may be used as long as it is responsible for cationizing the silver nanoparticles, gold nanoparticles, or copper nanoparticles.

[32] The technical characteristic of the present invention is that the polymer membrane includes the electron acceptor for cationizing the silver nanoparticles, gold nanoparticles, or copper nanoparticles. Hence, as a typical polymer for use in a polymer membrane, any polymer may be used as long as it has viscosity suitable for being applied on a support in the case of preparing a flat membrane.

[33] For silver nanoparticles, when pure silver nanoparticles are used, high expenses are incurred. Therefore, according to the method disclosed in "Facile route for preparation of silica-silver heterogeneous nanocomposite particles using alcohol reduction method" [Material Letters 61(2007) 1558-1562] published by Seong-Geun Oh et. al., silica-silver nanocomposite particles in which silver nanoparticles having a size of ones of nm are bound to the surfaces of spherical silica nanoparticles having a size of about 100 nm may be applied to the polymer membrane of the present invention. In the case where the silica-silver nanocomposite particles obtained through the above disclosed method are used in the present invention, expensive silver nanopaticles may be used in decreased amounts. According to the above method, spherical silica nanoparticles having a thiol group are prepared through a sol-gel process based on a Stober method, after which silver nanoparticles are bound to the thiol group of silica through an alcohol reduction method.

[34] Also, according to the results of research by the present inventors, it has been confirmed that excellent permeance and olefin selectivity are exhibited even when silica (SiO ) nanoparticles are additionally added to the metal nanoparticles, instead of binding the silver nanoparticles to silica as mentioned above.

[35] The facilitated olefin transporting polymer membrane of the present invention may be prepared in the form of a flat membrane or a hollow fiber membrane. For instance, a flat membrane may be prepared, using a typical flat membrane preparation method comprising a step I of dissolving a polymer in a solvent, a step II of dispersing nanoparticles and /?-benzoquinone in the polymer solution of the step I, a step III of applying the polymer solution of the step II on a support, a step IV of evaporating the solvent from the applied polymer solution of the step III at room temperature in a nitrogen atmosphere, and a step V of completely drying the polymer membrane of the step IV in a reduced-pressure oven at room temperature.

[36] As described above, the technical characteristic of the present invention is that silver nanoparticles, gold nanoparticles or copper nanoparticles, and an electron acceptor able to cationize the metal nanoparticles are added, regardless of the type of polymer serving as the main component of the polymer membrane, thus preparing a polymer membrane which enables the facilitated transport of olefin. The scope of the present invention is not limited only to the polymers and electron acceptors of the following examples.

[37] Below, the present invention is described in detail through the specific examples.

[38]

[39] Example 1

[40] Silver nanoparticles (70 nm, purity 99.5%), /?-benzoquinone and poly(ethylene-co-propylene) (EPR, Mw= 1.7x10 g/mol) were purchased from Aldrich Chemical, and thus were used without additional treatment (hereinafter, Ag means silver nanoparticles).

[41] To prepare a polymer membrane comprising EPR/Ag /p-benzoquinone, a 10 wt%

EPR solution in toluene was prepared, after which silver nanopowder andp - benzoquinone were dispersed therein. As such, the weight ratio of EPR:Ag :p - benzoquinone was set to be 1:1:0.5.

[42] As a support for applying the polymer mixture solution, a microporous polysulfone support (available from Saehan Industries) was used. Thereafter, the porous polysulfone support was coated with the polymer mixture solution using an RK control coater (model 101, control coater RK print-coat instruments LTD).

[43] Toluene in the coated polymer membrane was evaporated in a convection oven at room temperature in a nitrogen atmosphere, after which the polymer membrane was completely dried in a vacuum oven at room temperature.

[44] As the results of SEM measurement, the thickness of a pure polymer membrane, other than the support, was determined to be about 1 D.

[45]

[46] Example 2

[47] A polymer membrane was prepared in the same manner as in Example 1, with the exception that the weight ratio of EPR: Ag :/?-benzoquinone was set to be 1:1:0.75. The polymer membrane was about 1 D thick. [48]

[49] Example 3

[50] A polymer membrane was prepared in the same manner as in Example 1, with the exception that the weight ratio of EPR:Ag :/?-benzoquinone was set to be 1:1:0.85. The polymer membrane was about 1 D thick. [51]

[52] Example 4

[53] Copper nanoparticles (100 nm, 99.8%), /?-benzoquinone and

5 poly(ethylene-co-propylene) (EPR, Mw= 1.7x10 g/mol) were purchased from Aldrich

Chemical, and thus were used without additional treatment (hereinafter, Cu means copper nanoparticles). [54] To prepare a polymer membrane comprising EPR/Cu /p-benzoquinone, a 10 wt%

EPR solution in toluene was prepared, and then copper nanopowder andp - benzoquinone were dispersed therein. As such, the weight ratio of EPR:Cu :p - benzoquinone was set to be 1:1:0.85. [55] As a support for applying the polymer mixture solution, a microporous polysulfone support (available from Saehan Industries) was used. Thereafter, the porous polysulfone support was coated with the polymer mixture solution using an RK control coater (model 101, control coater RK print-coat instruments LTD). [56] Toluene in the coated polymer membrane was evaporated in a convection oven at room temperature in a nitrogen atmosphere, after which the polymer membrane was completely dried in a vacuum oven at room temperature. [57] As the results of SEM measurement, the thickness of a pure polymer membrane other than the support was determined to be about 1 D. [58]

[59] Example 5

[60] A polymer membrane was prepared in the same manner as in Example 4, with the exception that anthracene was used instead of /?-benzoquinone, and the weight ratio of

EPR:Cu :anthracene was set to be 1:1:0.85. [61]

[62] Example 6

[63] Gold nanoparticles (50-130 nm, 99.9%), /?-benzoquinone and poly(ethylene-co-propylene) (EPR, Mw= 1.7x10 g/mol) were purchased from Aldrich

Chemical and thus were used without additional treatment (hereinafter, Au means gold nanoparticles). [64] To prepare a polymer membrane comprising EPR/Au /p-benzoquinone, a 10 wt% EPR solution in toluene was prepared, and then gold nanopowder and/?-benzoquinone were dispersed therein. As such, the weight ratio of EPR:Au :/?-benzoquinone was set to be 1:1:0.85. [65] As a support for applying the polymer mixture solution, a microporous polysulfone support (available from Saehan Industries) was used. Thereafter, the porous polysulfone support was coated with the polymer mixture solution using an RK control coater (model 101, control coater RK print-coat instruments LTD). [66] Toluene in the coated polymer membrane was evaporated in a convection oven at room temperature in a nitrogen atmosphere, after which the polymer membrane was completely dried in a vacuum oven at room temperature. [67] As the results of SEM measurement, the thickness of a pure polymer membrane other than the support was determined to be about 1 D. [68]

[69] Example 7

[70] A polymer membrane was prepared in the same manner as in Example 6, with the exception that anthracene was used instead of /?-benzoquinone, and the weight ratio of

EPR: Au :anthracene was set to be 1:1:0.85. [71]

[72] Example 8

[73] Although EPR was used as the polymer in Examples 1 to 7, PDMS

(poly(dimethylsiloxane)) was used in Examples 8 to 10 and PVP was used in

Examples 11 to 13. [74] Silver nanoparticles (70 nm, purity 99.5%), /?-benzoquinone and poly- dimethylsiloxane were purchased from Aldrich Chemical and thus were used without additional treatment. [75] To prepare a polymer membrane comprising PDMS/Ag /p-benzoquinone, a 10 wt%

PDMS solution in toluene was prepared, and then silver nanopowder and p - benzoquinone were dispersed therein. As such, the weight ratio of PDMS: Au :p - benzoquinone was set to be 1:1:0.85. [76] As a support for applying the polymer mixture solution, a microporous polysulfone support (available from Saehan Industries) was used. Thereafter, the porous polysulfone support was coated with the polymer mixture solution using an RK control coater (model 101, control coater RK print-coat instruments LTD). [77] Toluene in the coated polymer membrane was evaporated in a convection oven at room temperature in a nitrogen atmosphere, after which the polymer membrane was completely dried in a vacuum oven at room temperature. [78] As the results of SEM measurement, the thickness of a pure polymer membrane other than the support was determined to be about 1 D. [79]

[80] Example 9

[81] A polymer membrane was prepared in the same manner as in Example 8, with the exception that gold nanoparticles were used instead of silver nanoparticles, and the weight ratio of PDMS:Au :/?-benzoquinone was set to be 1:1:0.85.

[82]

[83] Example 10

[84] A polymer membrane was prepared in the same manner as in Example 8, with the exception that copper nanoparticles were used instead of silver nanoparticles, and the weight ratio of PDMS:Cu :/?-benzoquinone was set to be 1:1:0.85.

[85]

[86] Example 11

[87] Silver nanoparticles (70 nm, purity 99.5%), /?-benzoquinone and polyvinylpyrrolidone (PVP) were purchased from Aldrich Chemical and thus were used without additional processing treatment.

[88] To prepare a polymer membrane comprising PVP/Ag /p-benzoquinone, a 10 wt%

PVP solution in ethanol was prepared, and then silver nanopowder andp - benzoquinone were dispersed therein. As such, the weight ratio of PVP:Ag :p - benzoquinone was set to be 1:1:0.85.

[89] As a support for applying the polymer mixture solution, a microporous polysulfone support (available from Saehan Industries) was used. Thereafter, the porous polysulfone support was coated with the polymer mixture solution using an RK control coater (model 101, control coater RK print-coat instruments LTD).

[90] Ethanol in the coated polymer membrane was evaporated in a convection oven at room temperature in a nitrogen atmosphere, after which the polymer membrane was completely dried in a vacuum oven at room temperature.

[91] As the results of SEM measurement, the thickness of a pure polymer membrane other than the support was determined to be about 1 D.

[92]

[93] Example 12

[94] A polymer membrane was prepared in the same manner as in Example 11, with the exception that gold nanoparticles were used instead of silver nanoparticles, and the weight ratio of PVP: Au :/?-benzoquinone was set to be 1:1:0.85.

[95]

[96] Example 13

[97] A polymer membrane was prepared in the same manner as in Example 11, with the exception that copper nanoparticles were used instead of silver nanoparticles, and the weight ratio of PVP:Cu :/?-benzoquinone was set to be 1:1:0.85. [99] Example 14

[100] Examples 14 to 21 are examples for preparing a polymer membrane by adding silica nanoparticles to the polymer, the metal nanoparticles and the electron acceptor. [101] The same preparation method as in Example 3 was used, with the exception that silica (SiO ) nanoparticles (10 nm) were additionally added to prepare a polymer membrane. The weight ratio of EPR:Ag°:pBQ:SiO was set to be 1:1:0.85:0.01. [102]

[103] Example 15

[104] A polymer membrane was prepared in the same manner as in Example 14, with the exception that the weight ratio of EPR:Ag°:pBQ:SiO was set to be 1 : 1 :0.85:0.025. [105]

[106] Example 16

[107] A polymer membrane was prepared in the same manner as in Example 14, with the exception that the weight ratio of EPR:Ag°:pBQ:SiO was set to be 1 : 1 :0.85:0.05. [108]

[109] Example 17

[110] A polymer membrane was prepared in the same manner as in Example 14, with the exception that the weight ratio of EPR:Ag°:pBQ:SiO was set to be 1 : 1 :0.85:0.075. [I l l]

[112] Example 18

[113] A polymer membrane was prepared in the same manner as in Example 14, with the exception that the weight ratio of EPR:Ag :pBQ:SiO was set to be 1:1:0.85:0.1. [114]

[115] Example 19

[116] A polymer membrane was prepared in the same manner as in Example 14, with the exception that the weight ratio of EPR:Ag°:pBQ:SiO was set to be 1 : 1 :0.85:0.15. [117]

[118] Example 20

[119] A polymer membrane was prepared in the same manner as in Example 14, with the exception that the weight ratio of EPR:Ag°:pBQ:SiO was set to be 1 : 1 :0.85:0.2. [120]

[121] Example 21

[122] To use silica-silver nanocomposite particles comprising spherical silica nanoparticles and silver nanoparticles bound thereto, the silica-silver nanocomposite particles were prepared according to the above disclosed method by Seong-Keun Oh et. al. Thus, a polymer membrane was prepared in the same manner as in Example 3, with the exception that the silica-silver nanocomposite particles were used instead of silver nanoparticles, and the weight ratio of EPR:silica-Ag nanocomposite particles:/? - benzoquinone was set to be 1:1:0.85.

[123] Tetraethyl orthosilicate (TEOS 98%, Aldrich), ethanol (HPLC grade 99.9%), and ammonia solution (NH OH 25%) were used, thus preparing silica particles. 3-Mercaptopropyltrimethoxysilane (MPTMS, 97%) was used as a medium for binding silica and silver. Silver nitrate (AgNO , 99.995%, Aldrich) was used as material for silver ion. To reduce the silver ion through an alcohol reduction method, poly(vinylpyrrolidone) (PVP, Mw 10,000) was used.

[124] First, a sol-gel process based on a Stober method was applied to prepare silica nanoparticles having a thiol group. 10.6 g of 25% ammonia solution was mixed with 125 g of pure ethanol while being stirred. After about 20 min, 5 g of a TEOS solution was added to thus induce a sol-gel reaction for formation of silica particles. After about 1 hour, 1 g of MPTMS was added to the above solution, and the mixture was stirred for about 6 hours. To separate only the silica particles having a thiol group, cen- trifugation was conducted at 3000 rpm for 30 min. The separated silica particles were washed with ethanol, and were then dried in an incubator at 4O⁰C for 1 day.

[125] To prepare the silica-silver nanocomposite particles comprising the silica particles having a thiol group and the silver nanoparticles bound thereto, an alcohol reduction method was applied. 0.1 g of the prepared silica particles having a thiol group were added to ethanol and were then mixed well, after which 4 g of PVP was added to the above solution to prevent the distortion of the polymer chain. After the complete dissolution of PVP, 0.1575 g of AgNO was added to the above solution, and then the solution was heated under reflux conditions for 2 hours. The total amount of the mixture solution was 100 g.

[126] [127] Comparative Example [128] A polymer membrane was prepared in the same manner as in Example 1, with the exception that the silver nanoparticles were not added. The polymer membrane was about 1 D thick.

[129] The weight ratios of respective components of Examples 1 to 21 and Comparative Example were summarized in Table 1 below (the numerical values of Table 1 indicate weight ratios).

[130] Table 1

[131] [132] Experimental Example 1: Permeance of Propylene and Propane of EPR/Ag/pBO Membrane

[133] Using the results of Comparative Example and Examples 1 to 3, the performance of the polymer membrane of the present invention composed of EPR/ Ag /pBQ was evaluated.

[134] As examples of olefin and paraffin having similar molecular weights, propylene and propane were used in the experiment, and pure gas permeance and mixed gas permeance thereof were measured. FIGS. 1 and 2 show the results of measurement of permeation performance of each of propylene and propane, and FIGS. 3 and 4 show the results of measurement of selectivity and total permeance of propylene and propane mixed gas.

[135] Permeance was measured using a mass flow meter (MFM). The gas permeance unit was represented by GPU, 1 GPU = 1 x lO^'6 D (STP)/(D sec DHg). In the propylene and propane mixed gas system, respective permeances were unable to be measured using only the MFM. Thus, the permeance of propylene and propane was measured using not only MFM but also gas chromatography. As the gas chromatography apparatus, a gas chromatograph (G 1530A, available from Hewlett-Packard) equipped with a TCD detector and a unibead 2S 60/80 packing column was used.

[136] The gas permeance of each of propylene and propane was determined and then calculated into the ideal selectivity (=propylene permeance/propane permeance). The results of ideal selectivity and gas permeance are shown in FIGS. 1 and 2. FIG. 1 shows the ideal selectivity of propylene to propane depending on the amount of p - benzoquinone. In the membrane of EPR/silver nanoparticles having no p - benzoquinone as Comparative Example, the gas permeance was determined to be 0.01 GPU, and the ideal selectivity was approximated to 1, making it impossible to separate propylene and propane.

[137] However, in the case of the polymer membranes of Examples 1 to 3, the ideal selectivity of propylene to propane was increased in proportion to an increase in the weight ratio of /?-benzoquinone. When the weight ratio of /?-benzoquinone was 0.85 (Example 3), the ideal selectivity was determined to be 165. In particular, the ideal selectivity began to be drastically increased at the weight ratio of /?-benzoquinone of 0.5. This was believed to be because the silver nanoparticles in the polymer membrane were sufficiently cationized to be suitable for function as the propylene carrier, consequently realizing facilitated transport.

[138] FIG. 2 shows the permeance of the polymer membrane of Example 3 (weight ratio of p-benzoquinone of 0.85). The permeance of propylene began to be increased after 30 min and then reached the steady state after 1 hour. However, in the case of propane, initial low permeance was continuously maintained. From the results of FIGS. 1 and 2, /?-benzoquinone could be seen to convert the surface of the silver nanoparticles into positive charges (partial positive charges), making it possible to realize facilitated transport of olefin.

[139] FIGS. 3 and 4 show the results of selectivity and permeance of propylene and propane mixed gas. To evaluate the separation stability of the propylene/propane mixed gas of the polymer membrane of the present invention, the permeance of the propylene/propane mixed gas was measured for 105 hours, resulting in almost constant selectivity and mixed gas permeance for 105 hours as shown in FIGS. 3 and 4. From the above results, the silver nanoparticles cationized by /?-benzoquinone in the polymer membrane of the present invention could be seen to stably function as the olefin carrier.

[140] After taking the results of FIGS. 1 to 4 into consideration, there reached a conclusion that, in the polymer membrane of the present invention, the silver nanoparticles were activated, that is, cationized by /?-benzoquinone to thus reversibly react with the p bond of olefin, preferably realizing facilitated transport.

[141]

[142] Experimental Example 2: XPS Measurement

[143] To evaluate the carrier activity of the silver nanoparticles depending on changes in surface polarity of the silver nanoparticles, binding energy of four samples, including pure silver, Comparative Example, and Examples 1 and 3, was measured using X-ray photoelectron spectroscopy (XPS). The results are graphed in FIG. 5. As the X-ray photoelectron spectroscopy (XPS) of Experimental Example 2, physical electronics PHI 5400 X-ray photoelectron spectrometer available from Perkin-Elmer was used.

[144] As shown in FIG. 5, in the EPR/ Ag system, binding energy of a d orbital of silver was increased from 368.26 to 368.89 in proportion to an increase in the amount ofp - benzoquinone. This was believed to be because the binding energy of outermost electrons of silver was increased through interaction between silver andp - benzoquinone.

[145] Although not shown in FIG. 5, in the case where the weight ratio ofp - benzoquinone was greater than 0.85, binding energy was supposed to be rather decreased. This was believed to be because /?-benzoquinone was not uniformly dispersed in silver nanoparticles but had formed homo- aggregates at the weight ratio of /?-benzoquinone greater than 0.85. Further, since the critical weight ratio ofp - benzoquinone varied surely depending on the type of polymer membrane, in at least the polymer membrane having EPR/ Ag of 1:1, the weight ratio of /?-benzoquinone was preferably set to be 0.85 or less.

[146] To evaluate changes in oxygen binding energy of /?-benzoquinone in the EPR/Ag system, the membranes of Examples 1, 2 and 3 were measured for XPS. As shown in FIG. 6, the oxygen binding energy of /?-benzoquinone was gradually decreased from 532.30 eV (Example 1) to 531.89 eV (Example 3) in proportion to an increase in the weight ratio of /?-benzoquinone.

[147] As shown in FIGS. 5 and 6, when the amount of /?-benzoquinone was increased in the EPR/Ag system, the polarity of silver nanoparticles was increased, and furthermore, the polarity of oxygen of p-benzoquinone was decreased, thus interaction between olefin and silver nanoparticles was favorably induced, making it possible to realize facilitated transport.

[148] [149] Experimental Example 3: Permeance with use of Au. Cu Nanoparticles [150] Permeance was measured in cases of using Au or Cu nanoparticles in Examples 4 to 7, instead of Ag. The same permeance measurement method as in Experimental Example 1 was used. The results of permeance and selectivity are given in Table 2 below.

[151] Table 2

[152] As is apparent from Table 2, when the gold nanoparticles and copper nanoparticles were used, total permeance and propylene/propane selectivity were evaluated to be excellent, as when using the silver nanoaprticles of Examples 1 to 3.

[153] [154] Experimental Example 4: Permeance with use of PDMS/PVP Polymer [155] To evaluate changes in permeance depending on the type of polymer, the permeance was determined using the polymer membranes of Examples 8 to 13. The same permeance measurement method as in Experimental Example 1 was used. The results of permeance and selectivity are given in Table 3 below.

[156] Table 3

[157] As is apparent from Table 3, when the PDMS and PVP were used as the polymer, total permeance and propylene/propane selectivity were evaluated to be excellent, as when using the EPR of Examples 1 to 3.

[158] [159] Experimental Example 5: Permeance depending on Amount of SiO

2 [160] To evaluate permeance depending on the addition of silica (SiO ), the permeance was determined using the membranes of Examples 14 to 20. The same permeance measurement method as in Experimental Example 1 was used. The results are given in Table 4 below. [161] Table 4

[162] As is apparent from Table 4, total permeance was much higher in the presence of SiO than in the absence of SiO of Examples 1 to 13. In particular, the propylene/ propane selectivity of the above examples, other than Example 20, was approximately doubled, compared to Comparative Example and Examples 1 to 13. Example 20, which is a typical example in which permeance was increased but selectivity was decreased, presented the appropriate guideline for the amount of SiO . The theoretical background of total permeance and selectivity with regard to the addition of SiO has not yet been specified, and further theoretical research thereto is required. The results of selectivity and permeance of Table 4 are graphed in FIGS. 7 and 8.

[163] [164] Ex *perimental Exam *ple 6: Permeance de ^Apending on SiO 2 -Ag Nanoparticles [165] To evaluate permeance using silica-silver nanocomposite particles in place of the silver nanoparticles, the permeance was determined using the membrane of Example 21. The same permeance measurement method as in Experimental Example 1 was used. As the experimental results, even in the case where the silica-silver nanocomposite particles were used, total permeance (GPU) was determined to be 0.7, and propylene/propane selectivity was determined to be 14, resulting in facilitated olefin transport similar to the results of Example 3. Industrial Applicability

[166] The technique of the present invention may be applied to the separation of olefin and paraffin having similar molecular weights, which have been conventionally difficult to separate. For example, as in the separation of propylene and propane, the separation of olefin and paraffin having very similar molecular weights may be realized using a facilitated transport mechanism. Therefore, the technique of the invention may be used for various separation processes henceforth.

Claims

[1] A facilitated olefin transporting polymer membrane containing metal nanoparticles, comprising a polymer, an electron acceptor, and any one type of metal nanoparticles selected from among silver nanoparticles, gold nanoparticles, and copper nanoparticles.

[2] The facilitated olefin transporting polymer membrane containing metal nanoparticles according to claim 1, wherein the electron acceptor has a weight ratio ranging from 0.3 to 0.9 when a weight ratio of the polymer and the metal nanoparticles is 1:1.

[3] The facilitated olefin transporting polymer membrane containing metal nanoparticles according to claim 1, wherein the metal nanoparticles have a size not larger than 200 nm.

[4] The facilitated olefin transporting polymer membrane containing metal nanoparticles according to claim 1, which is a flat membrane further comprising a porous support.

[5] The facilitated olefin transporting polymer membrane containing metal nanoparticles according to claim 1, which is a hollow fiber membrane.

[6] The facilitated olefin transporting polymer membrane containing metal nanoparticles according to claim 1, further comprising silica (SiO ) nanoparticles.

[7] The facilitated olefin transporting polymer membrane containing metal nanoparticles according to claim 6, wherein the silica nanoparticles are used in an amount of 0.01 to 0.2 parts by weight, based on 1 part by weight of the polymer.

[8] The facilitated olefin transporting polymer membrane containing metal nanoparticles according to claim 1, wherein the silver nanoparticles are silica- silver nanocomposite particles comprising silica nanoparticles and silver nanoparticles bound thereto.

[9] The facilitated olefin transporting polymer membrane containing metal nanoparticles according to claim 1, wherein the electron acceptor is any one selected from among /?-benzoquinone, anthracene, azobenzene, benzophenone, ferrocene, nitrobenzene, tetracyanoquinodimethane (TCNQ), N,N,N',N'-tetramethyl-/?-phenylenediamine (TMPD), tetrathiafulvalence (TTF), thianthrene (TH), and tri-N-p-tolylamine (TPTA).