Interface control prepares the aromatic polyamides of anti-chlorine reverse osmosis composite membrane method
The invention belongs to and adopt interface control to prepare the method for the aromatic polyamides of anti-chlorine reverse osmosis composite membrane.
Composite membrane is that one deck ultrathin functional layer is deposited to suitable micropore counterdie surface, aperture.Depositional mode mainly contains surface-coated, interfacial polycondensation and polymerization in situ etc.Composite membrane has many advantages than asymmetric membrane: it can make every layer to reach optimum performance by cutting out.Ultrathin functional layer can be optimized to ideal and select perviousness, and counterdie can reach best intensity and pressure tightness, and the two reaches best chemical-resistant stability together.In addition, composite membrane can make the material that is difficult to form asymmetric membrane form ultrathin membrane, as because solvent limitation and crosslinking polymer can form composite membrane by polymerization in situ or interfacial polycondensation.On the polysulfones counterdie, become the composite membrane kind of present over-all properties optimum by the reverse osmosis composite membrane of the compound one deck aromatic polyamides of interfacial polycondensation ultrathin functional layer gained.Because the leading role of ultrathin functional layer on the composite membrane performance, the physical chemistry structure of therefore controlling ultrathin functional layer becomes the focus of people's research.Though obtained many achievements, but some problems are still unresolved: be subjected to great restriction as the raising of the chemical-resistant stability of reverse osmosis composite membrane owing to the structure of superthin layer itself, just thereby limiting the use range of reverse osmosis composite membrane using the short period of time film properties seriously to descend under certain well-oxygenated environment as under the free chlorine condition.Scientists makes the superthin layer molecule produce the crosslinked resistance to chlorine that improves by the chemical structure that changes superthin layer as adopting polyfunctional monomer.Cadotte US Patent4 in 1981,277,344 adopt interface polycondensation compound aromatic polyamides film on the polysulfones counterdie, this film is linking agent with the pyromellitic trimethylsilyl chloride, film after compound is handled through oxychlorination earlier increases resistance to chlorine, this film is through 2, and salt-stopping rate does not have considerable change after the chlorination of 400ppm.h; Uemura etc. were at US Patent 4 in 1988,761, adopting interface polycondensation in 234 is linking agent with equal benzene triamine, the gained composite membrane is 1, the NaCl aqueous solution of 500ppm, 1.5MPa under the pressure, during pH=7.5 behind the 10ppm free chlorine effect 100h its salt-stopping rate reduce to 99.05% from 99.65%, salt-stopping rate descends 0.6% in 1000ppm.h.Though the over-all properties of Umeura film is better, its used equal this important source material of benzene triamine is difficult to obtain.
The purpose of this invention is to provide and a kind ofly polysulfones is supported the treated reactive group of introducing on the surface of counterdie make the interface of composite membrane produce crosslinked and improve the preparation method of the chlorine-resistant property of aromatic polyamides reverse osmosis composite membrane.
The polysulfones that the present invention adopts phase inversion process to make mean pore size 30nm supports counterdie, then counterdie is handled 30-300 second with the solution of acetic anhydride of the chlorsulfonic acid of 1-5% or with the Cement Composite Treated by Plasma 2-10h of 10-50W power, the counterdie of handling is immersed in contains in 2.0% the mphenylenediamine aqueous solution 7 minutes, with reaction in the hexane solution that is immersed in 0.15% pyromellitic trimethylsilyl chloride behind the rubber roll roll extrusion counterdie surface 20 seconds, in 110 ℃ baking oven, handled 10 minutes.Because thereby the reactive behavior of sulfo group and free radical makes at the interface polymeric amide molecule and the crosslinked chlorine-resistant property that increases film of the intermolecular generation of polysulfones.The gained composite membrane is 5, and the NaCl aqueous solution of 000ppm and the NaClO aqueous solution of 100ppm, the pressure of 1.5MPa are surveyed its chlorine-resistant property down.Reach 3 with the crosslinked resistance to chlorine of film that makes of chlorsulfonic acid, 000ppm.h reaches 25,000ppm.h with the crosslinked chlorine-resistant property of film that makes of plasma body.
Embodiment provided by the invention is as follows:
Embodiment 1. adopts the solution of acetic anhydride of 3% chlorsulfonic acid to carry out surperficial heterogeneous sulfonation 40 seconds the polysulfones counterdie of mean pore size 30nm, then its immersion is contained in the aqueous solution of 2.0% mphenylenediamine 7 minutes, be immersed in the hexane solution 20 seconds that contains 0.15% pyromellitic trimethylsilyl chloride after half-dried with rubber roll roll extrusion counterdie surface, take out the baking oven of putting into 110 ℃ and handled 10 minutes.Gained composite membrane salt-stopping rate is 98.4%, and film is immersed in pH=8, and its salt-stopping rate is 98.1% behind the NaClO aqueous solution 30h of 100ppm, and 3, salt-stopping rate descends 0.3% in the 000ppm.h.
Embodiment 2. counterdies are with example 1, and the solution of acetic anhydride of the chlorsulfonic acid with 1% was handled 150 seconds, and other condition is with example 1, and the salt-stopping rate of gained composite membrane is 97.7%, and through 3, after the chlorination of 000ppm.h, salt-stopping rate is 97.5%.
Embodiment 3. counterdies are with example 1, and the solution of acetic anhydride of the chlorsulfonic acid with 1% was handled 300 seconds, and other condition is with example 1, and the salt-stopping rate of gained composite membrane is 96.2, and through 3, salt-stopping rate is 96.1% after the chlorination of 000ppm.h.
Embodiment 4. counterdies are with example 1, and with the Cement Composite Treated by Plasma 5h of 30W power, complex liquid is with example 1, and heat-treat condition is with example 1.Gained composite membrane salt-stopping rate 98.2% is immersed in pH=8 with film, in the aqueous solution of 100ppm NaClO behind the 200h its salt-stopping rate be 97.9%, 20, salt-stopping rate descends 0.3% in the 000ppm.h.
Embodiment 5. becomes 50w with the Cement Composite Treated by Plasma power of example 4, and other condition is identical, and the gained composite membrane is through 2, and salt-stopping rate reduces to 98.2% from 98.6% after the 5000ppm.h chlorination.
Embodiment 6. becomes 10h with the plasma treatment time of example 4, and other condition is identical, and the gained composite membrane is through 2, and its salt-stopping rate drops to 97.1% from 97.2% after the chlorination of 5000ppm.h.