Graphene-Polymer Membrane for Water Filtration

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Solution Overview

Problem

Current membrane-based water filtration systems face challenges with membrane fouling, particularly biofouling, due to the hydrophobic nature of graphene and limitations in fabrication processes, leading to reduced performance and increased operational costs.

Innovation Solution

A single-layer graphene-based membrane comprising a graphene-polymer composite with amine functionalized graphene linked to a polymer containing an anhydride group, specifically graphene grafted poly(acrylonitrile-co-maleimide), is developed, which enhances wettability and dispersibility, reducing fouling and improving thermal stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If graphene is used in membrane fabrication, then mechanical strength and chemical stability are improved, but hydrophobicity increases leading to membrane fouling

Engineering Contradiction:

Improvemechanical strengthVSAvoidmembrane fouling

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the surface chemical parameters of graphene by introducing hydrophilic functional groups (carboxyl, hydroxyl, amine) through oxidation and functionalization processes. This transforms the hydrophobic surface into a hydrophilic one, reducing membrane fouling while retaining the mechanical strength benefits of graphene.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates composite materials by combining graphene with hydrophilic polymers or coating graphene with hydrophilic layers. This composite structure integrates the mechanical strength of graphene with the antifouling properties of hydrophilic materials, resolving the contradiction between strength and fouling resistance.

Inventive Principle:

Principle #40Composite materials

2Productivity

If graphene-based membranes are fabricated, then permeability is improved, but fabrication complexity increases due to challenges in creating leak-free porous structures

Engineering Contradiction:

ImprovepermeabilityVSAvoidfabrication complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent employs porous graphene structures with controlled pore sizes and distributions. By optimizing the porosity and pore architecture, high permeability is achieved while maintaining structural integrity and reducing fabrication complexity through standardized porous material synthesis methods.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent adjusts fabrication parameters such as oxidation degree, functionalization level, and assembly conditions to optimize the balance between permeability and fabrication ease. By controlling these parameters, leak-free porous structures can be produced more reliably.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If cleaning methods are applied to regenerate fouled membranes, then membrane performance is restored, but energy consumption and chemical usage increase

Engineering Contradiction:

Improvemembrane performanceVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary anti-action by pre-functionalizing graphene with hydrophilic groups before membrane fabrication. This preventive measure reduces fouling accumulation from the outset, minimizing or eliminating the need for subsequent cleaning operations and associated energy/chemical consumption.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The hydrophilic graphene surface exhibits self-cleaning properties where water flow naturally removes contaminants without requiring external cleaning interventions. The surface chemistry enables automatic resistance to fouling, reducing maintenance energy requirements.

Inventive Principle:

Principle #25Self-service

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 graphene-polymer composite membrane exhibits improved wettability, increased pure water flux, and enhanced antifouling properties, leading to more stable and efficient water filtration performance with reduced fouling, thus addressing the limitations of existing membranes.

Implementation Method 1

a graphene-polymer composite with amine functionalized graphene linked to a polymer containing an anhydride group

Methodology Applied

Scientific EffectCovalent bonding: Chemical Bonding

Implementation Method 2

enhances wettability and dispersibility, reducing fouling

Methodology Applied

Scientific EffectHydrophilic interaction: Hydrophile

Data Source

PatentUS11148099B2Graphene-based membrane and method of producing the same

Publication Date: 2021.10.19 NGEE ANN POLYTECHNIC

AI summary

A graphene-based membrane and a method of producing the same are disclosed. The graphene-based membrane may include a graphene-polymer composite, wherein the graphene-polymer composite may consist of an amine functionalized graphene and a polymer containing an anhydride group as a linker for linking the amine functionalized graphene to the polymer. The graphene-based membrane may be constructed of a single-layer. A method may include reacting a polymer containing an anhydride with an amine functionalized graphene in presence of a solvent to form an intermediate product; and thermal imidizing the intermediate product to form a graphene grafted polymer composite for use in fabricating a graphene-based membrane.