Interfacial Polyamide Membrane Formation for Low-Pressure Solute Rejection
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Solution Overview
Problem
Existing membrane-based solution concentration systems face limitations such as low efficiency, low concentration limits, high expense, and undesired fouling and scaling, particularly in processes like forward osmosis and reverse osmosis.
Innovation Solution
A method involving interfacial polymerization of low concentrations of optionally-substituted m-phenylenediamine and trimesoyl chloride in specific ratios with optional polar co-solvents to form a polymer layer in a porous medium, which achieves an intermediate solute rejection range without post-formation modification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional membrane formation methods are used, then membranes can be produced, but they exhibit low efficiency, low concentration limits, high expense, and undesired fouling and scaling
Solution Approach 1:
The patent changes the chemical parameters of membrane formation by using interfacial polymerization with specific monomer concentrations (m-phenylenediamine and trimesoyl chloride) and adding polar co-solvents to control polymerization kinetics. This creates membranes with optimized pore structures that achieve higher concentration limits while reducing fouling and scaling through controlled hydrophilicity and surface properties.
Solution Approach 2:
The patent creates composite membrane structures by forming polymer layers through interfacial polymerization that combine organic polyamide networks with controlled pore structures. The resulting composite material integrates selective barrier properties with transport channels, achieving both high concentration limits and resistance to fouling through the synergistic combination of dense polymer matrices and porous architectures.
2Manufacturing precision
If high solute rejection is achieved through conventional membrane formation, then separation performance improves, but hydraulic pressure requirements and energy costs increase
Solution Approach 1:
The patent utilizes porous membrane structures formed through interfacial polymerization with controlled monomer concentrations and polar co-solvents. The porous architecture provides transport channels that reduce hydraulic pressure requirements while maintaining solute rejection through size exclusion and selective permeability mechanisms in the pore structures.
Solution Approach 2:
The patent optimizes the balance between solute rejection and pressure requirements by controlling polymerization parameters including monomer concentration ratios, reaction time, and polar co-solvent content. These parameter changes create membranes with optimized pore size distributions that achieve intermediate solute rejection at lower hydraulic pressures compared to conventional dense membranes.
3Productivity
If membrane formation uses high monomer concentrations, then polymer layer formation is rapid, but manufacturing variance increases and requires post-formation modification
Solution Approach 1:
The patent introduces polar co-solvents as intermediary substances that mediate the interfacial polymerization reaction between m-phenylenediamine and trimesoyl chloride. These co-solvents control the reaction kinetics and polymer precipitation rates, enabling rapid polymer layer formation while maintaining uniform membrane structures and reducing manufacturing variance without requiring post-formation modifications.
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 membranes with improved solute rejection and water permeance, reducing hydraulic pressure requirements and energy costs, while maintaining durability and reducing manufacturing variance.
Implementation Method 1
at least some of the optionally-substituted m-phenylenediamine and at least some of the optionally-substituted trimesoyl chloride undergo a polymerization reaction to form a polymer layer
Data Source
AI summary
Methods of forming porous media (e.g., membranes for liquid separations or parts thereof) via polymerization, and related articles, are generally described. In some instances, two components are combined such that a polymerization (e.g., interfacial polymerization) reaction occurs, resulting in the formation of polymer layer (e.g., an active layer). In some instances, the two components include a first solution including water and a relatively low concentration of a first monomer (e.g., an amine-containing monomer such as optionally-substituted m-phenylenediamine) and a second solution including a nonpolar organic liquid and a relatively low concentration of a second monomer (e.g., an acid halide-containing monomer such as an optionally-substituted trimesoyl chloride).