Diamond-like Carbon Reverse Osmosis Membrane via Sputtering
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Solution Overview
Problem
Conventional porous carbon membranes used in ultrafiltration face challenges in balancing impermeable and permeable rates, making it difficult to effectively separate materials based on their size, particularly in reverse osmosis applications.
Innovation Solution
A method involving the formation of a carbon membrane with a diamond-like-carbon structure using high power impulse magnetron sputtering under an atmosphere containing rare gases and nitrogen, which is then coated on a porous support substrate and dissolved to create a reverse osmosis membrane that allows specific materials to permeate while rejecting others.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pore diameter of a porous carbon membrane is reduced to improve the impermeable rate, then the separation performance improves, but the permeable rate is remarkably decreased according to Hagen-Poiseuille's law
Solution Approach 1:
The invention changes the fundamental parameter of the membrane structure from a porous ultrafiltration type to a dense reverse osmosis type with a diamond-like-carbon structure. This structural parameter change enables simultaneous achievement of high separation performance and high permeable rate by allowing diffuse permeation of water molecules through the dense carbon layer while blocking ions.
Solution Approach 2:
The invention creates a composite membrane structure combining a porous support substrate (ultrafiltration layer) with a dense carbon membrane layer (reverse osmosis active layer). The porous support provides mechanical strength and initial filtration, while the dense carbon layer provides the reverse osmosis function, achieving both high separation and high permeation.
2Device complexity
If a porous carbon membrane is used as an ultrafiltration membrane for size-based sieving, then the membrane structure is simple, but it becomes theoretically difficult to balance improvement of the impermeable rate with improvement of the permeable rate
Solution Approach 1:
The invention fundamentally changes the membrane structure from a porous ultrafiltration type to a dense reverse osmosis type with a diamond-like-carbon structure formed by physical vapor deposition. This structural parameter change enables simultaneous achievement of high separation performance and high permeable rate by allowing diffuse permeation of water molecules through the dense carbon layer while blocking ions.
Solution Approach 2:
The invention uses a porous support substrate as the base layer to provide mechanical strength and initial filtration function, then forms a dense carbon membrane on top. The porous structure is retained in the support layer while the active layer becomes dense, combining advantages of both porous and dense structures.
3Manufacturing precision
If a dense carbon membrane is formed to achieve reverse osmosis function, then the separation performance improves, but the manufacturing process becomes more complex requiring physical vapor deposition
Solution Approach 1:
The invention changes the fundamental parameter of the membrane structure from a porous ultrafiltration type to a dense reverse osmosis type with a diamond-like-carbon structure. This structural parameter change enables simultaneous achievement of high separation performance and high permeable rate by allowing diffuse permeation of water molecules through the dense carbon layer while blocking ions.
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 reverse osmosis membrane effectively separates materials by allowing water molecules to permeate while preventing ions like sodium and chloride from entering, achieving high salt rejection rates and maintaining durability and chlorine resistance.
Implementation Method 1
a carbon membrane forming step of forming a carbon membrane having a diamond-like-carbon structure including nitrogen atoms on the coating membrane by a high power impulse magnetron sputtering that deposits carbon as a target material under an atmosphere where rare gas and nitrogen gas are contained
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
the carbon membrane is configured to be diffusely permeated with a particular material contained in a solution and to separate the particular material as an object targeted for removal
Implementation Method 4
a removing-by-dissolving step of removing the coating membrane by immersing the coating membrane in the predetermined solvent to dissolve the same in the solvent after formation of the carbon membrane
Data Source
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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.