Porous Membrane Anti-Fouling via Polymer Composition

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Solution Overview

Problem

Current porous membranes for water treatment require complex manufacturing processes, suffer from deteriorating anti-fouling properties due to water-soluble components, and have high production costs, especially when used in membrane bioreactor methods.

Innovation Solution

A porous membrane comprising polymers (A) and (B), where polymer (B) includes specific monomer units that enhance hydrophilicity and anti-fouling properties, with a higher concentration in the outermost layer, reducing the need for extensive amphiphilic block copolymers and simplifying the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polyvinylpyrrolidone is used to provide anti-fouling properties, then anti-fouling performance is improved, but the membrane performance deteriorates over time due to dissolution in water

Engineering Contradiction:

Improveanti-fouling propertiesVSAvoidmembrane performance duration

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the chemical composition parameters by replacing water-soluble polyvinylpyrrolidone with water-insoluble polyacrylic acid. This parameter change maintains the anti-fouling function while eliminating the dissolution problem, thereby preserving membrane performance over extended periods.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of using expensive and unstable polyvinylpyrrolidone, the patent employs a more stable and cost-effective polymer (polyacrylic acid) that does not dissolve in water, creating a long-lasting anti-fouling solution that does not require frequent replacement.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If controlled radical polymerization is used to synthesize block copolymers, then hydrophilicity and fractionation performance are improved, but the manufacturing process becomes complicated

Engineering Contradiction:

Improvehydrophilicity and fractionation performanceVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates the complex controlled radical polymerization step from the manufacturing process. Instead, it uses conventional free radical polymerization with simple copolymer composition, thereby simplifying the manufacturing process while maintaining the desired membrane properties through different compositional design.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than using complex polymerization methods to achieve the desired properties, the patent inverts the approach by using simple polymerization methods with carefully selected copolymer compositions (polyacrylic acid and polyvinylidene fluoride) to achieve the same hydrophilicity and fractionation performance.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If polyvinylpyrrolidone is used for anti-fouling, then initial anti-fouling properties are improved, but the membrane is easily degraded by oxidants

Engineering Contradiction:

Improveanti-fouling propertiesVSAvoidresistance to oxidant degradation

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent replaces the oxidant-sensitive polyvinylpyrrolidone with chemically stable polyacrylic acid, creating a durable anti-fouling layer that resists degradation by oxidants commonly used in water treatment, thereby extending membrane service life.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates a chemically inert anti-fouling environment by using polyacrylic acid, which is resistant to oxidation and chemical degradation, thereby protecting the membrane from harmful effects of oxidants in the water treatment process.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 exhibits high hydrophilicity, water permeability, and sustained anti-fouling properties, maintaining performance over time while being cost-effective and easier to manufacture, suitable for membrane bioreactor applications.

Implementation Method 1

the porous membrane has high hydrophilicity and water permeability

Methodology Applied

Scientific EffectHydrophilicity: Hydrophile

Data Source

PatentUS11071954B2Porous membrane, membrane module, water treatment device, and method for manufacturing porous membrane

Publication Date: 2021.07.27 MITSUBISHI CHEM CORP

AI summary

Provided is a porous membrane that can be manufactured in uncomplicated steps, has high hydrophilicity and water permeability, and exhibits excellent anti-fouling properties when used in a membrane bioreactor method (MBR method). The porous membrane of the present invention is a porous membrane containing polymer (A) and polymer (B), wherein the polymer (A) is a membrane-forming polymer, the polymer (B) is a polymer having a unit (b1) represented by formula (1) and a unit (b2) based on hydroxyl group-containing (meth)acrylate, and the concentration (mass %) of the unit (b1) is equal to or higher than the concentration (mass %) of the unit (b2) in the porous membrane.