Flux-Enhancing Inclusion Complexes for Thin Film Composite Membranes

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Solution Overview

Problem

Thin film composite (TFC) membranes used for nanofiltration and reverse osmosis face challenges in achieving high water flux while maintaining or improving salt rejection, particularly in purifying seawater, due to fouling and limitations in chemical additives that enhance flux without compromising rejection characteristics.

Innovation Solution

The process involves incorporating a flux-enhancing inclusion complex during membrane formation, comprising a host component like crown ether and a guest component with a metal chelate, which is interfacially polymerized with a polyamine and polyfunctional acyl halide on a porous support membrane to create a highly permeable reverse osmosis membrane with improved flux and anti-fouling properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If chemical additives are added to increase water flux, then membrane permeability improves, but salt rejection characteristics deteriorate

Engineering Contradiction:

Improvewater fluxVSAvoidsalt rejection

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent uses inclusion complexes as intermediary substances that mediate between the conflicting requirements of high flux and high rejection. The host molecule (cyclodextrin or crown ether) forms inclusion complexes with specific additives, creating a controlled delivery mechanism that allows flux enhancement while maintaining rejection properties through steric hindrance and selective binding.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates composite membrane structures by incorporating inclusion complexes formed from host molecules and guest additives into the membrane matrix. This composite approach combines the flux-enhancing properties of chemical additives with the structural integrity and selectivity of the host molecule, achieving both high permeability and high rejection simultaneously.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If membrane flux is increased, then energy efficiency improves, but membrane fouling increases

Engineering Contradiction:

Improveenergy efficiencyVSAvoidmembrane fouling

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potentially harmful effect of high flux (which causes fouling) into a beneficial outcome by using inclusion complexes to control the flow characteristics. The host-guest interactions create a structured flow regime that enhances water permeability while the inclusion complex structure itself prevents contaminant accumulation, thus converting the fouling risk into improved anti-fouling performance.

Inventive Principle:

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

3Reliability

If standard high-pressure systems are used for seawater desalination, then salt rejection is maintained, but operating costs increase

Engineering Contradiction:

Improvesalt rejectionVSAvoidoperating costs

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The invention changes the fundamental parameters of membrane performance by incorporating inclusion complexes that alter the membrane's permeability and selectivity characteristics. This allows operation at lower pressures while maintaining high salt rejection, directly reducing the energy input required and thereby lowering operating costs without sacrificing rejection reliability.

Inventive Principle:

Principle #35Parameter changes

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 resulting membranes exhibit increased water flux and maintained or improved salt rejection, essential for energy-efficient seawater desalination, reducing operating costs compared to standard high-pressure systems.

Implementation Method 1

The flux enhancing inclusion complex includes a host component having a cavity, and guest component within the cavity

Methodology Applied

Scientific EffectInclusion complex formation:

Implementation Method 2

the guest component includes a metal chelate containing a metal atom or metal ion and a bidentate ligand

Methodology Applied

Scientific EffectMetal chelation:

Implementation Method 3

reverse osmosis membranes for treating tap water, brackish water and sea water

Methodology Applied

Scientific EffectReverse osmosis: Reverse Osmosis

Implementation Method 4

TFC membranes are used where flux and substantial rejection characteristics are required

Methodology Applied

Scientific EffectSelective permeation: Semipermeable Membrane

Implementation Method 5

interfacial polymerization of a monomer in a nonpolar (e.g., organic) phase together with a monomer in a polar (e.g., aqueous) phase on a porous support membrane

Methodology Applied

Scientific EffectInterfacial polymerization:

Data Source

PatentEP3322514B1A process for preparing a thin film composite membrane, thin film composite membrane prepared according to the process and method of purifying tap water or seawater or brackish water using the membrane

Publication Date: 2023.03.29 LG NANOH2O INC

AI summary

Provided are flux enhancing inclusion complexes for preparing highly permeable thin film composite membranes, and processes that include adding the flux enhancing inclusion complexes to the organic phase or aqueous phase prior to interfacial polymerization of the thin film composite membrane. The thin film composite membranes are suitable for nanofiltration, and reverse and forward osmosis. The provided processes can include contacting a porous support membrane with an aqueous phase containing a polyamine to form a coated support membrane, and applying an organic phase containing a polyfunctional acid halide and a flux enhancing inclusion complex to the coated support membrane to interfacially polymerize the polyamine and the polyfunctional acid halide to form a discrimination layer to form thin film composite membranes.