Reverse Osmosis Membrane Formed by Physical Vapor Deposition
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Solution Overview
Problem
Porous carbon membranes used in ultrafiltration struggle to balance permeable and impermeable rates due to their pore diameter, leading to inefficiencies in filtration processes, particularly in separating materials based on size.
Innovation Solution
A method of forming a reverse osmosis membrane by depositing carbon through physical vapor deposition under an atmosphere containing rare gases and nitrogen, allowing for the selective permeation of water molecules while retaining ions by forming a carbon membrane on a porous support substrate with a coating layer that can be dissolved, enhancing the membrane's permeability and separation capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a porous carbon membrane is used as an ultrafiltration membrane to separate materials by size, then the separation capability is improved, but the permeable rate decreases remarkably as the pore diameter becomes smaller
Solution Approach 1:
The invention changes the fundamental parameter of the membrane structure from having defined pores (ultrafiltration) to having no pores (dense structure). This transforms the separation mechanism from size-based sieving to density-based separation, allowing water molecules to pass through while blocking ions through differences in molecular size and density, thereby achieving both high separation capability and maintained permeable rate
Solution Approach 2:
The invention uses a composite structure combining a porous support substrate with a dense carbon membrane layer. The support substrate provides mechanical strength and porosity for water transport, while the dense carbon membrane layer provides the separation function. This composite approach allows the system to achieve both high permeable rate through the support and high separation capability through the dense carbon layer
2Productivity
If the pore diameter of a porous carbon membrane is increased to improve the permeable rate, then the permeable rate increases, but the probability that targeted materials pass through increases
Solution Approach 1:
The invention changes the structural parameter from having controllable pore sizes to having a completely dense structure with no pores. This eliminates the trade-off between pore size and separation performance, as the separation is achieved through the dense carbon membrane's molecular-level filtering capability rather than physical pores, allowing high permeable rate while maintaining excellent separation capability
Solution Approach 2:
The invention replaces the mechanical sieving mechanism (physical pores blocking larger molecules) with a molecular-level separation mechanism (dense carbon membrane blocking ions based on molecular size and density). This substitution eliminates the need for large pores and achieves separation through the inherent properties of the dense carbon structure
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 method results in a reverse osmosis membrane that effectively separates targeted materials from solutions, such as sodium chloride aqueous solutions, by allowing water molecules to permeate while preventing ions from entering, thereby improving both permeable and impermeable rates.
Implementation Method 1
a carbon membrane forming step of forming a carbon membrane on the coating membrane by a physical vapor deposition that deposits carbon as a target material
Implementation Method 2
water molecules can be taken into the carbon membrane, as if the water molecules dissolve in the carbon membrane, and diffusely travel through the carbon membrane
Implementation Method 3
a removing-by-dissolving step of removing the coating membrane by dissolving the same in the solvent
Data Source
AI summary
A method of forming a reverse osmosis membrane 1 of the present invention includes a coating membrane forming step of forming a coating membrane which is soluble in a predetermined solvent on a surface of a porous support substrate 2 that is insoluble in the solvent, a carbon membrane forming step of forming a carbon membrane 3 on the coating membrane by a physical vapor deposition which deposits carbon as a target material under an atmosphere where rare gas and nitrogen gas are contained, and a removing-by-dissolving step of removing the coating membrane by dissolving the same in the solvent after formation of the carbon membrane 3.