Biaxially Stretched PFA Porous Membrane for Acidic Wastewater
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Solution Overview
Problem
Existing water treatment membranes are inadequate for high-temperature and strong acid conditions, particularly in semiconductor wastewater treatment, and there is a need for domestically producible alternatives to imported membranes.
Innovation Solution
A fluoropolymer-based membrane, specifically a PFA copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, is manufactured through melt-extrusion and biaxial stretching to control pore size and thickness, enabling resistance to high temperatures and strong acids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional membranes are used for water treatment, then general water filtration is achieved, but they fail under high temperature and strong acid conditions
Solution Approach 1:
The patent changes the chemical composition parameters by using PFA copolymer with specific fluorine content (20-70:1 ratio of tetrafluoroethylene to perfluoroalkyl vinyl ether) and controlled molecular weight to achieve both chemical resistance and mechanical properties suitable for harsh semiconductor wastewater treatment conditions
Solution Approach 2:
The patent creates a composite structure by combining PFA copolymer with specific pore-forming agents and using a multi-layer membrane structure with different functional layers to achieve both chemical stability and effective filtration performance under high temperature and strong acid conditions
2Reliability
If imported membranes are used, then adequate performance is achieved, but domestic production capability is lacking
Solution Approach 1:
The patent enables domestic self-sufficiency by developing a complete manufacturing process from raw material selection (PFA copolymer) through extrusion, biaxial stretching, and pore formation, allowing South Korea to produce high-performance membranes independently without relying on imports
Solution Approach 2:
The patent optimizes manufacturing parameters including extrusion temperature, biaxial stretching ratios, and cooling rates to enable domestic production of membranes with controlled pore sizes (10-100 nm) and thickness (50-200 μm) that match or exceed imported product performance
3Manufacturing precision
If pore size is reduced for better filtration, then separation efficiency improves, but membrane strength decreases
Solution Approach 1:
The patent controls pore size (10-100 nm) by adjusting the biaxial stretching ratio and temperature parameters during manufacturing, while maintaining membrane strength through optimized PFA copolymer composition and molecular weight selection
Solution Approach 2:
The patent creates a multi-layer composite structure where a support layer provides mechanical strength while a selective filtration layer with controlled pores (10-100 nm) provides separation efficiency, with interfacial bonding between layers maintaining overall structural integrity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The membrane effectively treats semiconductor wastewater with high fluorine concentrations under harsh conditions, allowing for domestic production of membranes previously reliant on imports.
Implementation Method 1
a fluoropolymer represented by the following Formula 1: wherein the ratio of x:y may be 20 to 70:1, and Rf may be a perfluorinated group selected from among —CF3, —CF2CF3, —CF2CF2CF3, and —CF(CF3)2
Implementation Method 2
biaxially stretching the melt-extruded fluoropolymer under dry or wet conditions to control the average pore diameter of the membrane to 10 to 100 nm
Implementation Method 3
The membrane may be for semiconductor wastewater treatment
Data Source
AI summary
There are provided a porous membrane including a perfluoroalkoxy alkane (PFA)-based melt-extruded film and having pores controlled by biaxial stretching, and a manufacturing method therefore. The porous membrane is for water treatment and includes a fluoropolymer. The method includes forming a film by melt-extruding a fluoropolymer; and controlling the pore size of the formed film by biaxial stretching. The membrane for water treatment is based on a fluoropolymer and has physical properties that are resistant to high temperatures and strong acids, and it is able to be used for treatment of wastewater such as semiconductor wastewater.