KR-20260062861-A - METHOD FOR THE FABRICATION OF CHITOSAN-BASED MEMBRANES FOR WATER TREATMENT

KR20260062861AKR 20260062861 AKR20260062861 AKR 20260062861AKR-20260062861-A

Abstract

The present invention relates to a method for manufacturing a separation membrane for water treatment, comprising the steps of: (a) applying a chitosan solution onto a support to form a chitosan solution layer; and (b) immersing the chitosan solution layer in a basic solution to form a porous separation layer through a pH-induced phase transition.

Inventors

이정현
정찬희
박성준
이명석

Assignees

고려대학교 산학협력단

Dates

Publication Date: 20260507
Application Date: 20251024
Priority Date: 20241029

Claims (12)

(a) a step of forming a chitosan solution layer by applying a chitosan solution onto a support; and (b) A method for manufacturing a separation membrane for water treatment comprising the step of supporting the chitosan solution layer in a basic non-solvent to form a porous separation layer through pH-induced phase transition.
In paragraph 1, A method for manufacturing a separation membrane for water treatment, characterized in that, in step (a) above, the support is one or more natural fiber-based supports selected from the group consisting of Hanji, linen, hemp, palm, ramie, jute, sisal, kenaf, cotton, coconut coir, bamboo, bagasse, papyrus, and silk.
In paragraph 1, A method for manufacturing a separation membrane for water treatment, wherein in step (a) above, the concentration of the chitosan in the chitosan solution is 1 (w/v)% to 20 (w/v)%, and the chitosan solution is based on an aqueous solution in which one or more selected from the group consisting of acetic acid, L-ascorbic acid, glutamic acid, malic acid, maleic acid, succinic acid, phosphorous acid, formic acid, lactic acid, citric acid, carbonic acid, nitric acid, hydrochloric acid, and hyaluronic acid are dissolved.
In paragraph 1, A method for manufacturing a separation membrane for water treatment, characterized in that, in step (b) above, the basic nonsolvent is an aqueous solution in which one or more selected from the group consisting of potassium hydroxide, calcium hydroxide, potassium carbonate, sodium carbonate, ammonium hydroxide, sodium hydroxide, lithium hydroxide, and ammonia water are dissolved.
In paragraph 1, (c) A method for manufacturing a separation membrane for water treatment, characterized by further including a step of chemically crosslinking or chemically modifying the porous separation layer.
In paragraph 5, The above chemical crosslinking is the porous separation layer pyrogallol, gallic acid, ferulic acid, propyl gallate, syringic acid, catechin, catechol, methoxycatechol, benserazide, quercetin, tannin, tannic acid, phytic acid, ellagic acid, myricetin, fisetin, morin, kaempferol, rhamnetin, isorhamnetin, chrysin, luteolin, apigenin, baicalein, taxifolin, epicatechin, A method for manufacturing a separation membrane for water treatment, characterized by being performed by impregnating a solution in which one or more natural crosslinking agents selected from the group consisting of epigallocatechin, epicatechin gallate, epigallocatechin gallate, caffeic acid, and genipin are dissolved.
In paragraph 6, A method for manufacturing a separation membrane for water treatment, characterized by further including one or more oxidation additives selected from the group consisting of sodium periodate ( NaIO₄ ), lead tetraacetate (Pb(OAc) ₄ ), and potassium perlutenate ( KRuO₄ ) in a solution in which the above-mentioned natural crosslinking agent is dissolved.
In paragraph 5, A method for manufacturing a separation membrane for water treatment, characterized in that the chemical modification is performed by impregnating the porous separation layer with a solution in which one or more acetyl compounds selected from the group consisting of acetic anhydride, acetyl chloride, acetyl bromide, acetyl iodide, acetyl fluoride, and N-acetylimidazole are dissolved.
In paragraph 1, A method for manufacturing a water treatment separation membrane, characterized in that the surface porosity of the water treatment separation membrane is 1% to 100% and the porosity is 10% to 90%.
(a) a step of forming a chitosan solution layer by applying a chitosan solution onto a support; (b) a step of forming a porous separation layer through pH-induced phase transition by impregnating the chitosan solution layer in a basic non-solvent; (c) a step of chemically crosslinking the porous separation layer; and (d) A method for manufacturing a reverse osmosis separation membrane for water treatment comprising the step of sequentially impregnating the cross-linked porous separation layer with a first solution in which an amine-based or hydroxyl-based monomer is dissolved and a second solution in which an acyl chloride-based monomer is dissolved to form a second separation layer of high density through interfacial polymerization.
In Paragraph 10, In step (d) above, the amine-based or hydroxyl-based monomer is one or more selected from the group consisting of m - phenylenediamine, o -phenylenediamine, p -phenylenediamine, piperazine, diethylenetriamine, triethylenetetramine , diethylaminopropylamine, methanediamine, polyethyleneimine, o -dihydroxybenzene, m - dihydroxybenzene, p - dihydroxybenzene , and polyvinyl alcohol, and the acyl chloride-based monomer is trimesoyl chloride, terephthaloyl chloride, cyclohexane-1,3,5-tricarbonyl chloride A method for manufacturing a reverse osmosis membrane for water treatment, characterized by having one or more selected from the group consisting of chloride), 1-isocyanato-3,5-benzenedicarbonyl chloride, and isophthaloyl chloride.
In Paragraph 10, In the first solution in which an amine-based or hydroxyl-based monomer is dissolved in step (d) above, sodium dodecyl sulfate, ammonium dodecyl sulfate, lithium dodecyl sulfate, sodium ethyl sulfate, sodium octyl sulfate, sodium decyl sulfate, sodium tetradecyl sulfate, sodium lauroyl sarcosinate, sodium benzene sulfate, steartrimonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, A method for manufacturing a reverse osmosis membrane for water treatment, characterized by further comprising one or more surfactants selected from the group consisting of didocyldimethylammonium chloride, steartrimonium bromide, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, didocyldimethylammonium bromide, ethyl lauroyl arginate hydrochloride, benzalkonium chloride, Triton X, Tergitol TMN, Tween, and Span series.

Description

Method for the fabrication of chitosan-based membranes for water treatment The present invention relates to a method for manufacturing a chitosan-based separation membrane for water treatment. As water pollution becomes more severe due to population growth and industrial advancement, interest in water treatment membrane technology, which can secure clean water resources through purification, is increasing. Filtration technology using water treatment membranes has the advantages of high separation efficiency, simple processes, and high integration density. Water treatment membranes are classified into reverse osmosis, microfiltration, nanofiltration, and ultrafiltration membranes, which have different pore sizes depending on the size of the contaminants to be removed. These membranes are primarily manufactured into a porous form by inducing a non-solvent phase transition of petrochemical-based polymer materials. Additionally, when manufacturing water treatment membranes, a petrochemical-based polymer nonwoven fabric is used as a support to enhance the mechanical properties of the membrane under submerged pressurization conditions. As such, when manufacturing water treatment membranes, large amounts of petrochemical-based polymer materials and harmful organic solvents are used, releasing large amounts of environmental pollutants. In addition, water treatment membranes are made of non-biodegradable polymers, which can generate secondary pollutants such as microplastics when disposed of. Recently, attempts have been made to manufacture eco-friendly water treatment membranes using natural and eco-friendly materials and solvents. However, there have been problems in applying these membranes to water treatment processes, such as the partial or limited use of natural and eco-friendly materials and solvents, or the low performance and mechanical and chemical durability of the manufactured membranes. FIG. 1 schematically illustrates a method for manufacturing a chitosan-based water treatment separation membrane according to one embodiment of the present invention. FIG. 2 schematically illustrates a method for manufacturing a reverse osmosis separation membrane for water treatment by forming a second separation layer of high density on a chitosan-based separation membrane for water treatment according to one embodiment of the present invention. Figure 3 shows the results of analyzing the chemical structures of Examples A, B, and C using Fourier transform-infrared spectroscopy. Figure 4 shows the results of observing the structures of Example A and Comparative Example A. Figure 5 shows the results of analyzing the surface structures of Examples A, B, and C using a scanning electron microscope. Figure 6 shows the results of analyzing the surface and cross-sectional structures of Examples B, C and Comparative Example B using a scanning electron microscope. Figure 7 shows the results of comparing the structural stability with respect to pressure of Examples A, B, C and Comparative Example B, including the reduced water permeability after 2 hours with the process pressure fixed at 5 bar and the water permeability after 2 hours at various process pressures (1-15 bar). Figure 8 shows the results of measuring water permeability after immersing Examples A and C in aqueous solutions of various pH (pH 3-11) for 1 hour. Figure 9 shows the results of observing the shape change during the biodegradability evaluation process of Example B and Comparative Example B. Figure 10 shows the results of analyzing the chemical structural changes of Example B and Comparative Example B before and after the biodegradability evaluation using Fourier transform infrared spectroscopy. While continuing research to manufacture biodegradable water treatment membranes using natural/eco-friendly materials and solvents, the inventors manufactured a chitosan-based water treatment membrane by supporting a chitosan solution layer in a basic non-solvent to induce a pH-induced phase transition, and confirmed that the membrane exhibits excellent mechanical properties and enables stable operation of the water treatment process, thereby completing the present invention. The present invention will be described in detail below. Method for manufacturing a chitosan-based separation membrane for water treatment The present invention provides a method for manufacturing a separation membrane for water treatment, comprising the steps of: (a) applying a chitosan solution onto a support to form a chitosan solution layer; and (b) supporting the chitosan solution layer in a basic non-solvent to form a porous separation layer through a pH-induced phase transition. FIG. 1 schematically illustrates a method for manufacturing a chitosan-based separation membrane for water treatment according to one embodiment of the present invention. Specifically, a chitosan solution may be applied onto a support (e.g., Hanji) and then immersed in a basic non-solvent to form a porous separation