Forward Osmosis Membrane with Carbon Nanotube Support

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Solution Overview

Problem

Conventional forward osmosis membranes are prone to erosion by organic contaminants due to their polymeric materials, which reduces their service life and efficiency in extreme environments.

Innovation Solution

A forward osmosis membrane design featuring a hydrophilic support layer with nanostructures comprising carbon nanotubes coated with hydrophilic films, such as polydopamine, sandwiched between a backing layer and a selective layer, preventing the selective layer from penetrating and enhancing chemical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If polymeric materials are used in forward osmosis membranes, then the membrane structure can be formed and supported, but the membrane becomes prone to erosion by organic contaminants in extreme environments

Engineering Contradiction:

Improvemembrane structural supportVSAvoidchemical resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent employs a composite structure consisting of a polymeric support layer providing mechanical strength and a carbon nanotube-based selective layer providing chemical resistance. The carbon nanotubes are coated with hydrophilic materials to enhance contaminant rejection while maintaining structural integrity in extreme environments, thus resolving the contradiction between structural support and chemical resistance.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies different materials with specific properties to different layers of the membrane: the polymeric support layer provides mechanical strength where needed, while the carbon nanotube selective layer provides chemical resistance and filtration functionality where required. This localized application of material properties resolves the contradiction by assigning each material to its optimal functional role.

Inventive Principle:

Principle #3Local quality

2Productivity

If the selective layer is formed on a polymeric support layer, then the membrane can function for water purification, but the polymeric support layer may be eroded by organic contaminants

Engineering Contradiction:

Improvewater purification functionVSAvoiderosion by organic contaminants

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a carbon nanotube-based intermediate layer between the selective layer and the polymeric support layer. This intermediate layer acts as a protective barrier that prevents direct contact between the polymeric support layer and organic contaminants, thereby eliminating erosion while maintaining water purification functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The carbon nanotube layer forms a porous structure that allows water molecules to pass through while blocking organic contaminants. The porous nature enables water purification function while the carbon nanotube material provides resistance to chemical erosion, resolving the contradiction between productivity and harmful factor resistance.

Inventive Principle:

Principle #31Porous materials

3Ease of manufacture

If conventional polymeric membranes are used, then the membrane can be manufactured with standard processes, but the service life is reduced due to erosion in extreme environments

Engineering Contradiction:

Improvestandard manufacturing processVSAvoidservice life

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The patent applies a hydrophilic coating to the carbon nanotubes before assembling the complete membrane structure. This preliminary action enhances the chemical resistance and contaminant rejection capabilities of the membrane, ensuring long service life in extreme environments while maintaining compatibility with standard manufacturing processes.

Inventive Principle:

Principle #10Preliminary 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 membrane exhibits improved chemical resistance and higher water flux while maintaining effective rejection of organic contaminants, with a favorable water flux to reverse salt flux ratio, suitable for water purification in extreme conditions.

Implementation Method 1

a hydrophilic support layer including a plurality of nanostructures, each of which includes a carbon nanotube and a hydrophilic film coated around the carbon nanotube

Methodology Applied

Scientific EffectHydrophilic coating: Coatings

Implementation Method 2

no external pressure is necessary in a forward osmosis process, which utilizes an osmotic pressure gradient formed by a concentration difference of solutes in solution on two sides of a forward osmosis membrane for purifying water

Methodology Applied

Scientific EffectOsmosis: Osmosis

Data Source

PatentUS11148101B2Forward osmosis membrane having high chemical resistance

Publication Date: 2021.10.19 NATIONAL TSING HUA UNIVERSITY

AI summary

A forward osmosis membrane having a high chemical resistance includes a backing layer, a selective layer, and a hydrophilic support layer sandwiched between the backing layer and the selective layer. The hydrophilic support layer includes a plurality of nanostructures, each of which includes a carbon nanotube and a hydrophilic film coated around the carbon nanotube, and has an outer layer defined by the hydrophilic films of the nanostructures to prevent the selective layer from penetrating into the hydrophilic support layer.