EP-4736994-A1 - CERAMIC HOLLOW FIBER MEMBRANE COATED WITH NANO-GRAPHITE AND METHOD FOR PREPARING SAME

Abstract

The present disclosure relates to a ceramic hollow fiber membrane coated with nano graphite and a method for preparing the same and more particularly, to a coated ceramic hollow fiber membrane including a hollow tubular ceramic support with pores; and a coating layer disposed on an outer peripheral surface of the ceramic support and the coating layer is a nano graphite coating layer coated with a nano graphite and a method for preparing the same. According to the present disclosure, a ceramic hollow fiber membrane for water treatment coated with a nano graphite forms a nano graphite coating layer to have a lower decline rate of a filtration amount to continuously maintain the filtration performance. Further, as compared with an uncoated ceramic hollow fiber membrane, an ion removal performance, for example, fluoride removal performance is more excellent and the coating cost is low to have an economical coating layer. Therefore, a ceramic hollow fiber membrane for water treatment which is coated with a nano graphite having further improved filtration performance may be provided.

Inventors

• PARK, CHANHYUK
• KIM, Soyoun
• KIM, Hyeyool
• JEONG, Yebin

Assignees

• Ewha University-Industry Collaboration Foundation

Dates

Publication Date

20260506

Application Date

20251022

Claims (9)

1. A coated ceramic hollow fiber membrane, comprising: a hollow tubular ceramic support with pores formed therein; and a coating layer disposed on an outer peripheral surface of the ceramic support, wherein the coating layer is a nano graphite coating layer coated with a nano graphite which is a surface modified nano material.
2. The coated ceramic hollow fiber membrane according to claim 1, wherein the ceramic support includes at least one of alumina (Al 2 O 3 ), titania (TiO 2 ), zirconia (ZrO 2 ), and silicon carbide (SiC).
3. The coated ceramic hollow fiber membrane according to claim 1, wherein a pore size of the ceramic support is 0.01 µm to 2 µm.
4. The coated ceramic hollow fiber membrane according to claim 1, wherein a size of the nano graphite is 20 nm to 200 nm and a thickness of the coating layer is 50 µm to 200 µm.
5. A water treatment module, comprising: a hollow fiber membrane module including at least one ceramic hollow fiber membrane of claim 1; a housing in which the hollow fiber membrane module is disposed; and an inlet and an outlet which are formed to be spaced apart from each other in the housing.
6. A method for preparing a ceramic hollow fiber membrane for water treatment, comprising: a step (a first step) of providing a hollow tubular ceramic support with pores formed therein; and a step (a second step) of forming a coating layer on an outer peripheral surface of the ceramic support, wherein the second step includes: preparing a nano graphite solution by dispersing a nano graphite which is a surface-modified nano material in a solvent; coating the nano graphite solution on an outer peripheral surface of the ceramic support; and drying the nano graphite solution.
7. The method according to claim 6, wherein in the second step, a concentration of the nano graphite solution is 25 mg/L to 1000 mg/L.
8. The method according to claim 6, wherein in the second step, the coating is performed by at least one of deep coating, spray coating, and a pressure filtration coating.
9. The method according to claim 6, wherein a thickness of the coating layer dried in the second step is 50 µm to 200 µm.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the priority of Korean Patent Application No. 10-2024-0154933 filed on November 05, 2024, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. BACKGROUND Field The present disclosure relates to a ceramic hollow fiber membrane and a method for preparing the same, and more particularly, to a coated ceramic hollow fiber membrane for water treatment and a method for preparing the same. Description of the Related Art In accordance with the development of the industry, the harmful effects of hazardous materials, such as dust, soot, waste gases, smoke, and volatile organic chemicals generated from each industrial process are increasing. Accordingly, some uses polymer filters to suppress emission of pollutants, but the polymer filters have weak points in heat resistance, chemical resistance, wear resistance, and flame retardancy. Accordingly, in order to solve this problem, the ceramic filter has been developed. The ceramic filter has heat resistance, chemical resistance, and wear resistance more excellent than the polymer filter and specifically, the heat resistance of the ceramic filter is excellent so that there is no need to separately install a cooling device in an exhaust device, thereby saving installation cost and maintenance cost. The membrane filtration process using a nanofiltration membrane (NF) is getting attention as an advanced water purification process because it may maintain a relatively high membrane permeable flux compared to the reverse osmosis (RO) membrane filtration process and has an advantage of removing even low-molecular-weight organic material. A filtration membrane material which is mainly used for the nanofiltration membrane (NF) process is formed of polymer which is relatively cheap and is easily fabricated, but is vulnerable to high temperature and organic solvent. In order to overcome this problem, recently, research and technology development are actively being conducted in Japan, mainly, on ceramic nanofiltration membrane formed of an inorganic material which has excellent heat resistance, chemical resistance, and pressure resistance and is used semi-permanently, with various materials, such as Al2O3, TiO2, or ZrO2. However, currently, the ceramic membrane remains at a level of microfiltration/ultrafiltration and ceramic nanofiltration technique has not been developed much. Specifically, the domestic ceramic nanofiltration technique does not exist. In the meantime, the ceramic hollow fiber membrane offers superior and cost-effective performance in fluid filtration applications. Inherently chemically inert ceramics are excellent materials for process applications where the existing polymer membranes are unsuitable due to high pressure, high temperature, or extreme pH. The ceramic hollow fiber membrane prevents bacteria and other impurities from sticking to the membrane surface, extending the life of the filtration system and lowering the total cost of ownership. Ceramic hollow fiber membranes are widely used in industries, such as biotechnology, chemical treatment, water treatment, and wastewater treatment, pharmaceuticals, and food and beverage treatment. However, in order to provide a ceramic hollow fiber membrane which further improves filtration performance and removal performance and is used for an advanced water purification process, studies are required for not only a material, a size, and a structure of the ceramic hollow fiber membrane, but also a coating layer appropriately coated on the ceramic hollow fiber membrane. The related arts of the technical field as described above are as follows: Korean Registered Patent No. 10-2641726 (registered on February 23, 2024) discloses a hollow ceramic fiber membrane for water treatment, a water treatment module, and a manufacturing method of a ceramic hollow fiber membrane for water treatment and specifically, discloses a hollow ceramic fiber membrane for water treatment which includes a hollow tubular ceramic support with pores, and a coating layer which includes activated carbon particles and is disposed on an outer peripheral surface of the ceramic support. However, the above-mentioned related art uses the activated carbon particles as the coating layer, but does not teach or imply a nano graphite coating layer with the excellent filtration performance and removal performance with a low coating cost, like the present disclosure. Further, Korean Registered Patent No. 10-2427811 (registered on July 27, 2022) discloses a surface modified ceramic hollow fiber membrane, a membrane contactor including the same, and a preparing method thereof and specifically, discloses a surface modified ceramic hollow membrane including a hydrophilic ceramic hollow fiber membrane including a hydrophilic inorganic material and a hydrophobic surface modified layer which is formed on a surface of the hydrophilic ceramic hollow fiber membra