Dried Composite Semipermeable Membrane Production Process
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Solution Overview
Problem
Conventional semipermeable membranes experience deterioration in water permeability and salt-blocking performance after drying, and removal of unreacted components complicates the production process, leading to purity issues and reduced membrane efficiency.
Innovation Solution
A process involving a moisturizing treatment with organic acid metal salts and hydrophilization agents applied to the porous support surface, followed by a protective treatment on the skin layer, before drying, to maintain water permeability and salt-blocking rates while minimizing unreacted components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sufficient washing is given to remove unreacted components from the membrane, then purity of the targeted compound is improved, but washing operation takes long time and reduces membrane flux performance
Solution Approach 1:
The patent applies preliminary action by conducting the polyfunctional aromatic amine treatment during the membrane formation process itself, before the membrane is fully cured and before drying. This timing allows unreacted components to be removed while the membrane structure is still forming, eliminating the need for separate post-forming washing operations and preserving membrane flux performance while achieving high purity
2Ease of operation
If a composite semipermeable membrane is dried to improve subsequent workability and preservability, then ease of operation is improved, but salt-blocking performance and permeation flux deteriorate
Solution Approach 1:
The patent applies preliminary action by removing unreacted polyfunctional aromatic amine components through the polyfunctional aromatic acid halide treatment step, before drying occurs. This preliminary removal prevents the unreacted components from interfering with the drying process, allowing the membrane to be dried without significant loss of salt-blocking performance or permeation flux
Solution Approach 2:
The patent applies parameter changes by controlling the concentration and conditions of the polyfunctional aromatic acid halide treatment to simultaneously achieve removal of unreacted amine components and preservation of the membrane's functional properties. The treatment parameters are optimized so that unreacted components are removed while the crosslinked structure maintaining salt-blocking performance is preserved
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 treated membranes exhibit improved water permeability, salt-blocking performance, and durability, with reduced content of unreacted components, enabling stable operation and high purity of permeated liquids.
Implementation Method 1
a skin layer includes a polyamide obtained by interfacial polymerization of a polyfunctional aromatic amine and a polyfunctional aromatic acid halide
Implementation Method 2
washing the composite semipermeable membrane
Implementation Method 3
unreacted components eluted or flowing out from parts constituting the membrane
Implementation Method 4
a hydrophilization treatment for the purpose of solving the problem
Data Source
AI summary
The present invention aims at providing a process for producing a dried composite semipermeable membrane having extremely small content of unreacted components, outstanding water permeability and salt-blocking rate even after drying treatment, and outstanding contamination resistance and durability. The present invention relates to a process for producing a dried composite semipermeable membrane comprising the steps of: preparing a composite semipermeable membrane having a skin layer including a polyamide resin obtained by reaction between a polyfunctional amine component and a polyfunctional acid halide component formed on the surface of a porous support; washing the composite semipermeable membrane; contacting a moisturing solution including a moisturizer and a hydrophilization agent only to the surface of the porous support of the washed composite semipermeable membrane and contacting a protecting solution only to the surface of the skin layer of the washed composite semipermeable membrane; and drying the treated composite semipermeable membrane.