Thin Film Composite Membrane with Nano-Bubbles for Reverse Osmosis
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Solution Overview
Problem
Current thin film composite membranes used in reverse osmosis suffer from low water permeability and susceptibility to fouling, with existing methods failing to enhance both water permeability and salt rejection to desired extents.
Innovation Solution
The creation of nano-sized bubbles in the membrane's separating layer through the use of additives such as bicarbonate salts, CuO nanoparticles, or soluble gases, combined with interfacial polymerization and post-treatment, to improve membrane permeability without compromising mechanical strength or stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional thin film composite membranes are used for reverse osmosis, then salt rejection is maintained, but water permeability is low
Solution Approach 1:
The patent introduces nanopores into the polyamide active layer by controlling interfacial polymerization conditions (pH, temperature, monomer concentration) to create a porous structure that maintains selective salt rejection while enabling enhanced water transport through the membrane
Solution Approach 2:
The patent creates a composite structure by integrating a porous polyamide active layer with a porous substrate, where the dual-porous architecture synergistically enhances water permeability while maintaining the selective separation function for salt rejection
2Productivity
If membrane structure is optimized for higher water permeability, then productivity increases, but susceptibility to fouling increases
Solution Approach 1:
The patent applies local quality modification by creating specific pore size distributions and surface properties in different regions of the active layer, where the porous structure is optimized locally to balance water transport efficiency with antifouling characteristics through controlled monomer composition and polymerization conditions
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 enhances water permeability and salt rejection while maintaining membrane stability, reducing fouling and improving antifouling properties, with a simple and cost-effective process.
Implementation Method 1
the thin film composite membranes are generally fabricated via interfacial polymerization of an aqueous solution comprising at least an amine monomer and an organic solution comprising at least an acid chloride monomer at or near a porous substrate
Implementation Method 2
Reverse osmosis is a water purification technology in which water with unwanted constituents is passed through a semipermeable membrane under certain applied pressure to remove ions, particles and molecules from it
Data Source
AI summary
Thin film composite membrane with nano-sized bubbles having enhanced membrane permeability, preparation methods and uses thereof are provided. The method of preparation of a thin film composite membrane, comprising: a) an aqueous solution containing at least an amine, and b) an organic solution containing at least a polyfunctional acyl halide, an additive or soluble gas being present in a) and/or b), or a nano-bubble generator or ultrasound are used to generate nano-bubbles in a) and/or b). Interfacial polymerization of a) and b) occurs at or near the surface of a porous support membrane. The advantage of creating nano-sized bubbles in the separating layer of membrane is that it can reduce membrane resistance without sacrificing the mechanical strength and stability of the membrane so as to improve its water permeability, salt rejection and antifouling. In addition, the process is simple to adopt while performance improvement of the membrane is remarkable.