Amine-Functionalized Graphene Oxide Membranes for Antifouling

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Solution Overview

Problem

Current membrane technologies for water desalination and wastewater treatment face significant challenges with fouling, which reduces membrane flux and operational efficiency, and existing methods for synthesizing graphene oxide (GO) have drawbacks such as NOx emissions and incomplete oxidation.

Innovation Solution

A modified Hummers' method for synthesizing high-oxidation, NOx-free graphene oxide (GO) is developed, and amine-functionalized GO (GO-DDA) is used as a filler in polysulfone membranes to enhance antifouling and antibacterial properties, achieved through a temperature-assisted flux technique and incorporation via phase inversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional Hummers' method is used to synthesize graphene oxide, then graphene oxide can be produced, but NOx emissions occur and oxidation is incomplete

Engineering Contradiction:

Improveoxidation completenessVSAvoidNOx emissions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the oxidation parameters by replacing nitrate-based oxidants with potassium permanganate and adjusting the oxidation potential to achieve complete oxidation without NOx emissions, transforming the chemical parameters of the synthesis process

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful NOx emissions of conventional Hummers' method into a benefit by using an alternative oxidation system that produces no harmful gases, while maintaining effective oxidation of graphite to graphene oxide

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Productivity

If graphene oxide is added to membranes to enhance performance, then flux and rejection improve, but fouling resistance is limited

Engineering Contradiction:

Improvewater fluxVSAvoidfouling resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent creates a composite material by combining graphene oxide with polysulfone polymer matrix, integrating the high flux characteristics of GO with the mechanical stability and fouling resistance of the polymer to achieve balanced membrane performance

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies graphene oxide specifically to the active filtration layer of the membrane where it locally enhances flux and selective rejection properties, while the bulk polymer matrix maintains structural integrity and antifouling characteristics

Inventive Principle:

Principle #3Local quality

3Productivity

If membrane fouling occurs, then separation efficiency decreases, but washing methods can restore performance

Engineering Contradiction:

Improveseparation efficiencyVSAvoidoperational difficulty

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent incorporates graphene oxide into the membrane structure beforehand to create an antifouling surface that preliminarily resists contaminant adhesion, preventing fouling rather than requiring subsequent washing treatments

Inventive Principle:

Principle #9Preliminary anti-action

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 GO-DDA membranes exhibit improved antifouling properties with a 37.8% increase in flux recovery ratio against protein fouling and 13.1% against organic fouling, along with enhanced antibacterial activity, demonstrating effective fouling resistance and bacterial inhibition.

Implementation Method 1

Graphite can be oxidized to GO using several approaches. Brodie's method reported in 1859 was the first one using nitric acid (HNO3) and potassium chlorate (KClO3) as the intercalant and oxidant. However, several drawbacks associated with this approach have been reported. In 1958, Hummers eliminated the flaws associated with Brodie's method by using sulfuric acid (H2SO4) with Sodium nitrate (NaNO3) and Potassium permanganate (KMnO4) to oxidize graphite.

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

Membrane treatment for desalination and wastewater is one of the promising solutions to produce affordable clean water. These technologies include distillation, membrane filtration, ion exchange, and aqueous adsorption.

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 3

The present disclosure also provides a process of incorporating raw GO and dodecylamine-functionalized GO (GO-DDA) in polysulfone (PSF) via phase inversion technique.

Methodology Applied

Scientific EffectPhase inversion: Phase Change

Data Source

PatentUS20230183072A1Nanofillers, membranes thereof, preparation thereof, and use thereof

Publication Date: 2023.06.15 QATAR FOUND FOR EDUCATION SCI & COMMUNITY DEV

AI summary

A high-oxidation and NOx-free synthesis of graphene oxide (GO) from natural graphite using the modified Hummers' method is described. The amine-functionalized GO using dodecylamine (DDA) is used as a filler for membranes for the first time. Antifouling and antibacterial properties of UF membranes are achieved using amine functionalization of GO. A process of incorporating raw GO and dodecylamine-functionalized GO (GO-DDA) in polysulfone (PSF) via phase inversion technique is disclosed.