AQUAPORIN Z INTEGRATED MEMBRANE PRODUCTION METHOD

Abstract

Integrating an aquaporin Z protein addition to an outer surface of hollow fiber membranes and a production method of aquaporin Z integrated hollow fiber membranes using different hollow fiber support membranes are provided. The production method includes polymeric, nanocomposite materials. When an aquaporin protein integrated onto reinforced hollow fiber membranes, increase in a mechanical strength and a flux of the reinforced hollow fiber membranes was observed.

Claims

1. A production method of aquaporin Z integrated membranes using different hollow fiber reinforced membranes, comprising the following steps: dissolving dioleoylphosphocholine lipid in chloroform, using the dioleoylphosphocholine lipid and evaporating the chloroform present in a solution having 0.1% dioleoylphosphocholine concentration by weight in a nitrogen medium, adding 10 mM phosphate buffer solution into the dioleoylphosphocholine lipid, adding 1% aquaporin by weight into liposomes, adding 1% dodecylmaltoside detergent into the liposomes, for increasing a reconstitution process of aquaporins into the liposomes to obtain aquaporin reconstituted liposomes, using biobeads consisting of neutral, porous styrene divinylbenzene beads to remove the 1% dodecylmaltoside detergent from the nitrogen medium, passing the solution through 200 nm polytetrafluoroethylene membranes by using a mini extruder to ensure the aquaporin reconstituted liposomes have similar sizes, using an interfacial surface polymerization technique to provide a polyamide layer between two phases to settle an aquaporin protein into three different support layers, wherein the three different support layers are an only polymeric layer, a nanocomposite layer and a reinforced layer, dissolving 2% piperazine in water and 0.2% trimesoyl chloride in cyclohexane to carry the interfacial surface polymerization, adding the aquaporin reconstituted liposomes, wherein the aquaporin reconstituted liposomes were prepared as 0.1% into the solution with the 2% piperazine to obtain a mixed solution of the 2% piperazine and the aquaporin reconstituted liposomes, immersing hollow fiber membranes initially into the mixed solution for 2 minutes, passing the hollow fiber membranes through 1 atmosphere pressure nitrogen gas for 1 minute to remove non-reacted piperazine monomers available on a surface from a membrane, leaving the hollow fiber membranes obtained in cyclohexane solution for 1 minute and immersing the hollow fiber membranes into a trimesoyl chloride solution and leaving the hollow fiber membranes here for 1 minute, and keeping the hollow fiber membranes in a drying oven for 5 minutes at 50° C., and obtaining an aquaporin Z integrated membrane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The production method of aquaporin Z integrated membrane using different hollow fiber support membranes carried out in order to reach the aims of this invention has been illustrated in the attached figures.

[0019] According to these figures;

[0020] FIG. 1A: View of the surface SEM images of p-UF membranes.

[0021] FIG. 1B: View of the surface SEM images of p-AqpZ membranes.

[0022] FIG. 1C: View of the surface SEM images of p-TFC membranes.

[0023] FIG. 1D: View of the surface SEM images of p-com.AqpZ membranes.

[0024] FIG. 2A: View of the surface SEM images of CNT-UF membranes.

[0025] FIG. 2B: View of the surface SEM images of CNT-AqpZ membranes.

[0026] FIG. 2C: View of the surface SEM images of r-UF membranes.

[0027] FIG. 2D: View of the surface SEM images of r-AqpZ membranes.

[0028] FIG. 2E: View of the surface SEM images of CNT-TFC membranes.

[0029] FIG. 2F: View of the surface SEM images of CNT-com.AqpZ membranes.

[0030] FIG. 2G: View of the surface SEM images of r-TFC membranes

[0031] FIG. 2H: View of the surface SEM images of r-com.AqpZ membranes.

[0032] FIG. 3: Graphical view of the water permeabilities belonging to the produced membranes.

[0033] FIG. 4A: View of the flux changes depending on membrane contamination and organic agent retention belonging to TFC, TFC-AqpZ and TFC-com.AqpZ membranes.

[0034] FIG. 4B: View of the flux changes depending on membrane contamination and organic agent retention belonging to CNT-TFC, CNT-AqpZ and CNT-com.AqpZ membranes.

[0035] FIG. 4C: View of the flux changes depending on membrane contamination and organic agent retention belonging to r-TFC, r-AqpZ and r-com.AqpZ membranes.

[0036] FIG. 5A: Graphical view of the synthetic lake water flux

[0037] FIG. 5B: Graphical view of the synthetic lake water removal efficiency.

[0038] FIG. 6A: Graphical view of the lake water flux.

[0039] FIG. 6B: Graphical view of the removal efficiency.

[0040] FIG. 6C: Graphical view of the removal efficiency.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] Hollow fiber membrane is produced in order to be used as 3 different support layers in the membrane production method subject to the invention. The contents of the membrane dope solution for production is 16% polysulfone, 10% polyvinyl pyrrolidone (Molecular weight: 360 kDa (kilo Daltons)), 74% n-methyl pyrrolidone. 0.01% carbon nanotube (external diameter <8 nm) is used for the nanocomposite doped support layer. The contents of the membrane dope solution for the production of reinforced support layer is 16% polysulfone, 10% polyvinyl pyrrolidone (Molecular weight: 40 kDa (kilo Daltons)), 74% n-methyl pyrrolidone and polyester (PET) textile yarn.

[0042] Dioleoylphosphocholine (DOPC) lipid that was dissolved in chloroform for aquaporin protein doping was used and the chloroform that was present inside the solution having 0.1% DOPC concentration by weight has been evaporated in nitrogen medium. Following this 10 mM phosphate buffer solution (PBS) has been added into DOPC lipid. The liposomes have been produced by being vortexed with the rehydration method and 1% aquaporin by weight has been added into the liposomes. 1% dodecylmaltoside (DDM) detergent was added for the aquaporin protein to reconstitute into liposomes more effectively. Detergent added during the reconstitution process was removed by adding biobeads which are consisting of neutral, porous styrene divinylbenzene beads.

[0043] The solution has been extruded by a mini extruder by using polytetrafluoroethylene (PTFE) membranes having 200 nm pore size in order to reduce the liposomes that contain aquaporin Z to a similar size. In order to compare the performance of the purified protein, aquaporin protein that was purchased commercially was used.

TABLE-US-00002 TABLE II Production Parameters Only Production polymeric Nanocomposite Reinforced parameters membrane membrane membrane Coagulation bath 45 45 45 temperature, ° C. Air gap distance, cm 0 0 0 Take-up speed m/s 0.105 0.105 0.033 Membrane dope 6 6 1 solution speed, mL/min Inner solution speed, 3 3 — mL/min

[0044] Parameters that are used in the production of hollow fiber membranes have been given in Table II. An interfacial surface polymerization has been used in order to reconstitute the aquaporin protein into the 3 different support layer. 2% piperazine (PIP) was dissolved in water and 0.2% trimesoyl chloride (TMC) was dissolved in cyclohexane in order to carry our interfacial polymerization. The Aquaporin Z reconstituted DOPC liposomes were prepared at 0.1% concentration was added into the solution with piperazine. The hollow fiber membranes were first immersed into the PIP+Aquaporin including solution for 2 minutes. Following this the membranes were passed through 1 atm nitrogen gas in order to remove the non-reacted PIP monomers available on the surface from the membrane. After this, the membranes were left in 100% cyclohexane solution for 1 minute and they were then immersed into TMC solution and after they were kept here for 1 minute, they were kept in a drying oven for 5 minutes at 50° C.

TABLE-US-00003 TABLE III The abbreviations of the produced HF NF Membranes The NF membranes that were produced Membranes in Membranes in Only which purified which commercial Type of support TFC aquaporin in the aquaporins were support layer layer membrane study was used used Only p-UF p-TFC p-AqpZ p-com. AqpZ polymeric Nanocomposite CNT-UF CNT-TFC CNT-AqpZ CNT-com. AqpZ Reinforced r-UF r-TFC r-AqpZ r-com.AqpZ

[0045] The membrane area was increased from 26 cm.sup.2 to 280 cm.sup.2 and the water purification performance was evaluated from this membrane area by comparing both synthetic water and the water sample obtained from the lake water of Ömerli barrage. The results of this comparison were given in FIG. 5A and FIG. 5B.

[0046] When aquaporin protein integration is carried out using reinforced hollow fiber membranes in the invention, increase in the strength and flux of membranes was observed. As a result several benefits were gained. First of all by means of the Aquaporin addition, increase was observed in membrane flux and as a result lower pressure is applied to obtain flux similar to other hollow fiber nanofiltration membranes. Aquaporin protein integrated reinforced membranes increased resilience of membranes to higher pressures. This shows that the usage of membranes in processes that are subject to high pressure such as reverse osmosis and nanofiltration could be advantageous.

REFERENCES

[0047] 1. Cadotte, J. E.; Reverse Osmosis Membrane. U.S. Pat. No. 4,039,440, 1977, Cadotte, J. E.; Peterson, R. J. (1981) Thin film composite reverse osmosis membranes: origin, development, and recent advances. In: Turbak, A. F. (Ed.) Synthetic Membranes. Vol: I; ACS: Washington, DC, U.S.A. [0048] 2. M. Kumar, M. Grzelakowski, J. Zilles, M. Clark and W. Meier, Proc. Natl. Acad. Sci. U.S.A., 2007, 104, 20719-20724.