Silk Nanofiber Interlayer for High-Permeance Nanofiltration Membranes

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Solution Overview

Problem

Current nanofiltration membranes suffer from low water permeance and membrane stability, leading to high energy consumption and inefficiencies in water filtration applications, such as seawater desalination and wastewater treatment.

Innovation Solution

Development of nanofiltration membranes incorporating a silk layer, optionally with a porous substrate and selective layer, which significantly enhances water permeance and ion removal efficiency, utilizing silk nanomaterials like fibroin fibers with specific structural and chemical properties to improve mechanical stability and selectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If commercial nanofiltration membranes are used, then ion removal efficiency is maintained, but water permeance is low leading to high energy consumption

Engineering Contradiction:

Improveenergy consumptionVSAvoidwater permeance

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent employs a composite membrane structure consisting of a porous substrate layer combined with a silk fibroin-based selective layer. This composite architecture integrates the mechanical strength and porosity control of synthetic substrates with the superior water permeability and ion rejection properties of silk fibroin, achieving both high water permeance and effective ion removal while reducing energy consumption

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent utilizes porous silk fibroin materials with controlled pore structures in the selective layer. The porous architecture allows efficient water transport through the membrane while the pore size distribution and surface properties provide selective ion rejection, thereby achieving high water permeance without sacrificing ion removal efficiency

Inventive Principle:

Principle #31Porous materials

2Productivity

If membrane thickness is reduced to improve permeance, then water permeance increases, but mechanical stability decreases

Engineering Contradiction:

Improvewater permeanceVSAvoidmembrane stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The composite structure separates the mechanical support function (handled by the thicker porous substrate) from the selective separation function (handled by the thin silk fibroin layer). This allows the selective layer to be sufficiently thin for high permeance while the substrate provides the necessary mechanical strength and stability

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Different regions of the membrane have different thicknesses and properties: the porous substrate layer has greater thickness for mechanical stability, while the silk fibroin selective layer is thin for high permeance. This local differentiation of properties resolves the contradiction between thickness, stability, and permeance

Inventive Principle:

Principle #3Local quality

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 membranes demonstrate improved water permeance, up to 5-fold that of commercial membranes like DuPont FilmTec™ NF270 and NF90, and high ion rejection rates, resulting in reduced energy consumption and enhanced filtration efficiency across various water treatment processes.

Implementation Method 1

Nanofiltration membranes having improved water permeance... a silk layer... silk nanomaterials... fibroin fibers

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

nanofiltration offers many benefits including low operation cost, reduced energy consumption... high ion removal efficiency... ion rejection rates

Methodology Applied

Scientific EffectSize exclusion:

Implementation Method 3

high ion rejection rates... removal efficiency against a wide spectrum of contaminants, such as sulfate, magnesium, calcium

Methodology Applied

Scientific EffectElectrostatic repulsion: Ion Repulsion/Attraction

Data Source

PatentUS20240058754A1Super-high-permeance thin-film composite nanofiltration membrane incorporating silk nanofiber interlayer

Publication Date: 2024.02.22 THE UNIVERSITY OF HONG KONG

AI summary

Nanofiltration membranes and methods of using and making thereof are disclosed. The nanofiltration membranes contain a silk layer, a porous substrate, and a selective layer. The silk layer is an interlayer sandwiched between the porous substrate and selective layer. The nanofiltration membranes have high performance for filtering water, such as improved water permeance and/or high ion removal rate. For example, the nanofiltration show a water permeance that is at least 2-fold, such as about 5-fold, of the water permeance of a commercially available nanofiltration membrane, such as DuPont FilmTec™ NF270 and/or DuPont FilmTec™ NF90, and an ion rejection of at least 70% against a target ion, such as a divalent or multivalent ion. The greatly improved water permeance of the nanofiltration membranes can result in up to a magnitude lower energy consumption in water filtration applications.