RO Membrane Composition and Flushing for Scale Fouling Control
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Solution Overview
Problem
Existing reverse osmosis membrane systems face issues with scale adhesion, particularly calcium and silica scales, leading to membrane fouling and performance deterioration, which are not effectively addressed by current methods that require chemical adjustments or operational changes.
Innovation Solution
The use of a reverse osmosis membrane device with a membrane element comprising carbon nanotubes and cellulose nanofibers, combined with a feed channel spacer containing carbon nanotubes, and the addition of a scale dispersant such as 2-phosphonobutane-1,2,4-tricarboxylic acid, along with periodic flushing without pressurization, to suppress scale adhesion and fouling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If acidic conditions are used to suppress scale adhesion, then scale formation rate decreases, but blocking performance deteriorates and chemical costs increase
Solution Approach 1:
The patent introduces carbon nanotubes as an intermediary substance incorporated into both the RO membrane structure and feed channel spacer. These nanotubes act as a mediator that prevents scale adhesion through their unique surface properties and flow characteristics, eliminating the need for acidic conditions while maintaining blocking performance. The nanotubes create a hydrophobic surface that scales cannot easily adhere to, and their presence enhances cross-flow velocity to prevent fouling.
2Object-affected harmful factors
If chemical agents are added to control pH, then scale formation is suppressed, but operational complexity and chemical costs increase
Solution Approach 1:
The patent implements a self-service mechanism where the carbon nanotube-modified membrane and spacer automatically prevent scale formation through their inherent physical properties. The nanotubes create a surface that repels scale components and enhance cross-flow velocity naturally, eliminating the need for external chemical agents or pH control operations. The system serves itself by preventing fouling through its structural design rather than requiring ongoing chemical treatment.
3Productivity
If conventional RO membranes are used, then initial flux is achieved, but membrane fouling occurs over time due to scale adhesion
Solution Approach 1:
The patent employs composite materials by incorporating carbon nanotubes into both the RO membrane matrix and the feed channel spacer material. This creates a hybrid structure that combines the filtration capabilities of the RO membrane with the anti-fouling properties of carbon nanotubes. The composite structure maintains high flux rates while providing long-term resistance to scale adhesion and membrane fouling, extending the operational lifespan of the membrane system.
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
This approach significantly reduces scale adhesion and stabilizes membrane performance by preventing scale nuclei formation and facilitating their removal, thereby maintaining high flux rates over time.
Implementation Method 1
reverse osmosis membrane device for treating water to be treated which contains a scale component with the reverse osmosis membrane device
Implementation Method 2
a dense layer of the reverse osmosis membrane includes carbon nanotubes and cellulose nanofibers
Implementation Method 3
adding a scale dispersant to the water to be treated
Data Source
AI summary
Provided is a method for operating a reverse osmosis membrane device which has a reverse osmosis membrane element and in which treated water is obtained by passing water to be treated that contains a scale component through the reverse osmosis membrane device, said method being characterized in that: the reverse membrane element includes a reverse osmosis membrane and a feed channel spacer; a dense layer of the reverse osmosis membrane contains carbon nanotubes and cellulose nanofibers; the feed channel spacer contains carbon nanotubes; and a scale dispersant is added to the water to be treated.