Visible-Light Self-Cleaning Nanofiltration Membrane for Organic Pollutants

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Solution Overview

Problem

Existing nanofiltration membranes suffer from fouling by organic pollutants, which is challenging to remove and requires high energy and solvent treatments, and photocatalytic nanomaterials like TiO2 need UV irradiation, limiting their real-life application.

Innovation Solution

A nanofiltration membrane with a polysulfone/polyethylene terephthalate support and an active layer containing a diacyl chloride compound, tetra-amine compound, and a graphitic carbon nitride-polypyrrole nanocomposite that is activated by visible light for self-cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional nanofiltration membranes are used, then water filtration is achieved, but membrane fouling by organic pollutants occurs and requires high energy cleaning treatments

Engineering Contradiction:

Improvemembrane performance stabilityVSAvoidcleaning energy requirement

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent incorporates photocatalytic nanomaterials (TiO2, ZnO, or ZnS) into the membrane structure during manufacturing, enabling the membrane to perform self-cleaning function before fouling becomes severe. The photocatalytic active layer is pre-formed with specific pore structures and material compositions that provide ongoing anti-fouling protection during operation, reducing the need for intensive post-fouling cleaning treatments

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The membrane system performs self-cleaning through photocatalytic degradation of organic pollutants on its surface when exposed to UV or visible light. The photocatalytic nanomaterials generate reactive oxygen species that automatically decompose foulants, allowing the membrane to maintain itself without external chemical cleaning interventions, thereby reducing energy and chemical consumption

Inventive Principle:

Principle #25Self-service

2Ease of operation

If TiO2 photocatalytic nanomaterial is used, then photocatalytic self-cleaning is achieved, but UV irradiation is required which limits real-life application

Engineering Contradiction:

Improveself-cleaning activation conditionVSAvoidlight source compatibility

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent modifies the optical properties of photocatalytic nanomaterials by incorporating metal nanoparticles (Ag, Au, Cu) or metal oxide nanoparticles (Fe2O3, Fe3O4, CuO) as co-catalysts or modifiers. These modifications change the light absorption characteristics from UV-only to visible light-responsive, expanding the operational wavelength range and enabling activation by ambient visible light sources

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates composite photocatalytic systems combining multiple nanomaterials (e.g., TiO2-Ag, ZnO-Au, ZnS-CuO) where the combination of materials produces synergistic effects. The composite structure allows the base photocatalytic material to work with visible light through plasmonic resonance or band structure modification by the metal components, enhancing both visible light absorption and photocatalytic activity

Inventive Principle:

Principle #40Composite materials

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 achieves effective self-cleaning under visible light, reducing fouling and maintaining high permeate flux and salt rejection, without the need for UV activation.

Implementation Method 1

a nanocomposite including graphitic carbon nitride and polypyrrole... activated by visible light for self-cleaning

Methodology Applied

Scientific EffectPhotocatalysis: Catalysis

Implementation Method 2

activated by visible light... without the need for UV activation

Methodology Applied

Scientific EffectVisible light absorption: Absorption (EM radiation)

Implementation Method 3

nanofiltration membranes (NFMs) have potential for advanced industrial saline wastewater treatment

Methodology Applied

Scientific EffectNanofiltration: Semipermeable Membrane

Implementation Method 4

The foulants adsorb on the membrane surface through various interactions such as electrostatic interactions, hydrophobic interaction and hydrogen bonding

Methodology Applied

Scientific EffectElectrostatic interactions: Electrostatics

Data Source

PatentUS12440810B1Method for photocatalytic degradation of organic pollutants

Publication Date: 2025.10.14 KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS

AI summary

A membrane including a polysulfone/polyethylene terephthalate (PSf/PET) support and an active layer on an outer surface of the PSf/PET support. The active layer comprises reacted units of a diacyl chloride compound, a tetra-amine compound, and a nanocomposite including graphitic carbon nitride and polypyrrole. The membrane of the present disclosure is self-cleaning following exposure to radiation and finds application in water decontamination and de-salination.