Superhydrophobic filter structure for selectively separating water and oil

Patent metadata

Field	Value
Publication number	US-9862622-B2
Application number	US-201314408331-A
Country	US
Kind code	B2
Filing date	Jun 27, 2013
Priority date	Jun 28, 2012
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

A filter structure capable of efficiently separating water and oil using wettability is provided. The filter structure according to an exemplary embodiment of the present invention includes a first filter layer including a plurality of openings, a second filter layer including a plurality of openings and positioned so as to be overlapped with the first filter layer at a distance from each other, and a hydrophobic polymer layer formed on surfaces of the first filter layer and the second filter layer. The first filter layer and the second filter layer include surfaces each having a dual-scale protrusion and depression structure as a combination of a micro-scale structure and a nano-scale structure, and the hydrophobic polymer layer is formed along curves of the protrusion and depression structure.

First claim

The invention claimed is:

1. A filter structure comprising:
a first filter layer including a plurality of openings;
a second filter layer including a plurality of openings and positioned so as to be overlapped with the first filter layer at a distance from each other;
a hydrophobic polymer layer formed on surfaces of the first filter layer and the second filter layer,
an oil layer positioned between the first filter layer and the second filter layer, and
an oil absorption layer positioned outside any one of the first filter layer and the second filter layer,
wherein each of the first filter layer and the second filter layer is formed of a metal mesh made from a metal wire in the form of a mesh,
the first filter layer and the second filter layer include surfaces each having a dual-scale protrusion and depression structure as a combination of a micro-scale structure and a nano-scale structure,
the hydrophobic polymer layer is formed along curves of the dual-scale protrusion and depression structure,
the oil layer includes a space charged with a predetermined amount of oil, so that water cannot pass through the filter structure due to a repulsive force caused by the oil layer,
the oil absorption layer absorbs oil passing through the filter structure, and
the oil absorption layer includes at least one material selected from a group consisting of hydrogel, silica gel, activated alumina, zeolite, activated carbon, and sponge, and keeps the oil passing through the filter structure.

2. The filter structure of claim 1 , wherein the dual-scale protrusion and depression structure includes a first protrusion and depression structure formed in a micro-scale and a second protrusion and depression structure formed in a nano-scale along curves of the first protrusion and depression structure on a surface of the first protrusion and depression structure.

3. The filter structure of claim 2 , wherein the first protrusion and depression structure is formed by any one method of sandblasting, shot blasting, plasma etching, a discharge treatment, and a laser treatment.

4. The filter structure of claim 2 , wherein the second protrusion and depression structure is formed by an anodic oxidation process.

5. The filter structure of claim 1 , wherein the hydrophobic polymer layer includes at least one hydrophobic material selected from a group consisting of a fluorine resin, a fluorine-based silane coupling agent, a fluorine-based isocyanate compound, an alkanethiol, an organic silane compound, a fatty acid, an aromatic azide compound, mixtures thereof, and polymers thereof.

6. The filter structure of claim 5 , wherein the hydrophobic polymer layer is formed by a method of coating the dual-scale protrusion and depression structure with the hydrophobic material.

7. The filter structure of claim 5 , wherein the hydrophobic polymer layer is present in the form of a monomolecular layer or a multimolecular layer by a covalent bond between the hydrophobic material and the surfaces of the first filter layer and the second filter layer.

8. The filter structure of claim 1 , wherein the oil layer is formed by allowing only oil to pass through the filter structure or by dipping the filter structure in oil.

9. The filter structure of claim 1 , wherein a reinforcing member is present between the first filter layer and the second filter layer, and the reinforcing member is formed into an object selected from a group consisting of a metal rod, a metal mesh, a polymer rod, and a polymer mesh.

Assignees

• Postech Academy-Industry Found

Inventors

• Hwang Woon Bong
• Jo Handong
• Kim Dong Seob
• Kim Yeong Ae

Classifications

• B01D2239/0421

  Rendering the filter material hydrophilic · CPC title

• E02B15/045

  Separating means for recovering oil floating on a surface of open water (E02B15/048 takes precedence; separation in general B01D) · CPC title

• B01D17/0202

  by ab- or adsorption · CPC title

• B01D29/05

  supported · CPC title

• C02F2101/32

  Hydrocarbons, e.g. oil · CPC title