SPIRAL-TYPE SEPARATION MEMBRANE ELEMENT

Abstract

The objective of the present invention is to provide a spiral-type separation membrane element having superior oxidant resistance relative to the prior art, and a salt-blocking rate that tends not to decrease. The spiral-type separation membrane element is characterized in including: a supply-side flow-path material; a composite semipermeable membrane in which a skin layer is formed on the surface of a porous support, the skin layer containing a polyamide resin obtained by interfacial polymerization of a polyfunctional amine component and a polyfunctional acid halogen component; and a permeation-side flow-path material, wherein the polyfunctional amine component contains N,N-dimethyl-meta-phenylenediamine and the permeation-side flow-path material has a porosity of 40 to 75%.

Claims

1. A spiral-type separation membrane element including: a supply-side flow-path material; a composite semipermeable membrane in which a skin layer is formed on the surface of a porous support, the skin layer containing a polyamide resin obtained by interfacial polymerization of a polyfunctional amine component and a polyfunctional acid halogen component; and a permeation-side flow-path material, wherein the polyfunctional amine component contains N,N-dimethyl-meta-phenylenediamine and the permeation-side flow-path material has a porosity of 40 to 75%.

2. The spiral-type separation membrane element according to claim 1, wherein the permeation-side flow-path material is a tricot knit fabric.

Description

EXAMPLE

[0053] The present invention will, hereinafter, be described with reference to Examples, but the present invention is not limited at all by these Examples.

Example 1

[0054] N,N-Dimethyl-meta-phenylenediamine (3% by weight), sodium lauryl sulfate (0.15% by weight), triethylamine (2.5% by weight), and camphorsulfonic acid (5% by weight) were dissolved in ethylene glycol to prepare an amine solution. In addition, trimesic acid chloride (0.2% by weight) and isophthalic acid chloride (0.4% by weight) were dissolved in Exxsol D30 (manufactured by Exxon Mobil Corporation, distillation range 130 to 160 C., boiling point 148 C.) to prepare an acid chloride solution. Then, the amine solution was applied onto a porous support and the excess amine solution was subsequently removed to form an amine solution coating layer. After that, the acid chloride solution was applied onto the surface of the amine solution coating layer. Then, after removal of the excess solution, the coating layer was held in a hot air dryer of 100 C. for 5 minutes to form a skin layer containing a polyamide-based resin on the porous support, thereby to prepare a composite semipermeable membrane.

[0055] Using the Test Unit C40-B (manufactured by Nitto Denko Corporation), a tricot knit fabric with a porosity of 57% as a permeation-side flow-path material is laid and the prepared composite semipermeable membrane is set thereon. Then, an aqueous solution containing 0.15% NaCl and being adjusted to pH 7 with NaOH is brought into contact with the composite semipermeable membrane at 25 C. by giving a pressure difference of 1.5 MPa. A permeation velocity and electric conductivity of the permeated water obtained by this operation were measured, and a permeation flux (m.sup.3/m.sup.2.Math.d) and a salt-blocking rate (%) were calculated. The correlation (calibration curve) of the NaCl concentration and electric conductivity of the aqueous solution was made beforehand, and the salt-blocking rate was calculated by the following equation.

Salt-blocking rate (%)={1(NaCl concentration in permeated liquid [mg/L])/(NaCl concentration in supply solution) [mg/L]}100

Examples 2 to 7 and Comparative Examples 1 and 2

[0056] Using the composite semipermeable membrane prepared in Example 1, a permeation flux and a salt-blocking rate were measured in the same manner as in Example 1, except for using the permeation-side flow-path material that was a tricot knit fabric having a porosity shown in Table 1.

Reference Examples 1 to 3

[0057] A composite semipermeable membrane was prepared in the same manner as in Example 1, except for using meta-phenylenediamine (3% by weight) instead of N,N-dimethyl-meta-phenylenediamine (3% by weight) in Example 1. Then, using the composite semipermeable membrane thus prepared, a permeation flux and a salt-blocking rate were measured in the same manner as in Example 1, except for using the permeation-side flow-path material that was a tricot knit fabric having a porosity shown in Table 1.

TABLE-US-00001 TABLE 1 Porosity of permea- Salt- Permea- tion-side block- tion flow-path ing flux (m.sup.3/ Diamine material (%) rate (%) m.sup.2 .Math. d) Example 1 N,N-Dimethyl-meta- 57 95.44 0.99 phenylenediamine Example 2 N,N-Dimethyl-meta- 58 95.25 1.01 phenylenediamine Example 3 N,N-Dimethyl-meta- 60 94.91 1.04 phenylenediamine Example 4 N,N-Dimethyl- 61 94.97 1.01 meta-phenylenediamine Example 5 N,N-Dimethyl- 62 94.97 1.04 meta-phenylenediamine Example 6 N,N-Dimethyl- 65 92.42 1.05 meta-phenylenediamine Example 7 N,N-Dimethyl- 73 90.99 1.08 meta-phenylenediamine Compara- N,N-Dimethyl- 76 62.32 1.98 tive meta-phenylenediamine Example 1 Compara- N,N-Dimethyl- 79 59.12 2.19 tive meta-phenylenediamine Example 2 Reference Meta-phenylenediamine 73 99.59 0.94 Example 1 Reference Meta-phenylenediamine 76 99.69 0.83 Example 2 Reference Meta-phenylenediamine 79 99.66 0.83 Example 3

[0058] From Table 1, the composite semipermeable membranes prepared in Examples 1 to 7 using N,N-dimethyl-meta-phenylenediamine as a polyfunctional amine component are found to have superior oxidant resistance. Further, it can be seen that the salt-blocking rate hardly decreases by combination use of the composite semipermeable membrane with the permeation-side flow-path material having a specific porosity. On the other hand, in Comparative Examples 1 and 2, since the permeation-side flow-path materials each having a porosity that was outside the range of the porosity of 40 to 75% were used, the salt-blocking rate was significantly reduced. In the case of the composite semipermeable membranes prepared with use of meta-phenylenediamine as the polyfunctional amine component in Reference Examples 1 to 3, a large difference in the salt-blocking rate was not observed by a difference in the porosity of the permeation-side flow-path materials.

INDUSTRIAL APPLICABILITY

[0059] The spiral-type separation membrane element of the present invention is suitably used for production of ultrapure water, desalination of brackish water or sea water, etc., and usable for removing or collecting pollution sources or effective substances from pollution, which causes environment pollution occurrence, such as dyeing drainage and electrodeposition paint drainage, leading to contribute to closed system for drainage. Furthermore, the element can be used for concentration of active ingredients in foodstuffs usage, for an advanced water treatment, such as removal of harmful component in water purification and sewage usage etc. Moreover, the element can be used for waste water treatment in oil fields or shale gas fields.