Cross-Linked Nanofiltration Membrane for Acid Solvent Stability
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Solution Overview
Problem
Current membranes lack sufficient stability in aggressive environments, such as extreme pH levels, high concentrations of acids, and organic solvents, which limits their effectiveness in industrial applications requiring chemical and solvent resistance.
Innovation Solution
A polymeric semipermeable nanofiltration membrane is developed with a cross-linked skin formed on a base polymer, using reactive pendant groups and a hydrophilic polymer like polyethylenimine to enhance chemical and solvent stability, allowing the membrane to withstand aggressive conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymeric membrane is used in aggressive environments, then it provides filtration function, but it lacks sufficient stability in extreme pH levels, high concentrations of acids, and organic solvents
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of the base polymer through cross-linking reactions. The cross-linking degree and network density are adjusted to achieve optimal stability in aggressive environments while maintaining filtration performance. This transforms the membrane from a simple polymeric structure to a cross-linked network structure with enhanced chemical resistance.
Solution Approach 2:
The patent creates a composite structure by forming a cross-linked skin layer on the base polymer matrix. This composite architecture combines the filtration capabilities of the porous base polymer with the chemical stability of the cross-linked surface layer, achieving both functionality and durability in aggressive conditions.
2Reliability
If the membrane structure is modified to enhance chemical stability, then solvent and acid resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs preliminary action by incorporating reactive pendant groups into the base polymer structure during membrane fabrication. These pre-installed reactive groups are then activated through cross-linking reactions to form the stable skin layer. This approach simplifies the overall process compared to attempting to modify the membrane structure after fabrication.
Solution Approach 2:
The patent uses cross-linking agents as intermediaries to bridge the base polymer chains and form the cross-linked network. These intermediary substances facilitate the formation of stable chemical bonds between polymer chains, enabling enhanced solvent and acid stability without requiring direct modification of the base polymer structure itself.
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 membrane exhibits improved stability and performance in acidic and solvent environments, maintaining flux and selectivity even after exposure to harsh conditions, making it suitable for industrial applications like copper separation and wastewater treatment.
Implementation Method 1
A polymeric semipermeable nanofiltration membrane including a base polymer which is modified by forming a cross-linked skin onto a surface of the base polymer
Implementation Method 2
polymeric semipermeable nanofiltration membrane
Data Source
Figure 1~2B
Figure 3A~3B
Figure 4A~4B
AI summary
Solvent and acid stable ultrafiltration and nanofiltration membranes including a non-cross-linked base polymer having reactive pendant moieties, the base polymer being modified by forming a cross-linked skin onto a surface thereof, the skin being formed by a cross-linking reaction of reactive pendant moieties on the surface with an oligomer or another polymer as well as methods of manufacture and use thereof, including, inter alia separating metal ions from liquid process streams.