Amine-Modified Porous Membrane for CO2 Separation
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Solution Overview
Problem
Current CO2 separation technologies face challenges such as high energy consumption, economic inefficiency, and environmental pollution due to the use of amine solvents and ionic liquids, which also result in membrane liquid loss and complex operation steps in supported liquid membrane systems.
Innovation Solution
Amination modification of porous membrane materials with amine-containing groups is introduced, where silane coupling agents are used to graft amine groups onto inorganic porous materials, allowing for a stable water-supported liquid membrane that enhances CO2 separation efficiency and avoids liquid loss, using environmentally friendly and cost-effective water as a solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ionic liquids are used in supported liquid membranes to achieve high CO2 dissolution selectivity, then CO2 separation selectivity is improved, but membrane liquid loss increases due to high requirements on pore size and inability to withstand high transmembrane pressure difference
Solution Approach 1:
The patent changes the physical-chemical parameters of the membrane liquid by replacing ionic liquids with amino acid salts, which have different properties including lower volatility, lower cost, and different surface tension characteristics. This parameter change allows the system to maintain CO2 separation selectivity while reducing membrane liquid loss and making the system more economically viable
Solution Approach 2:
The patent adopts amino acid salts as membrane liquids that are cheaper and more environmentally friendly than ionic liquids. Although amino acid salts may require more frequent replacement due to potential degradation, their low cost and biodegradability make them economically and environmentally superior to expensive ionic liquids
2Measurement precision
If ionic liquids are used in supported liquid membranes, then CO2 dissolution selectivity is improved, but economic efficiency deteriorates due to high cost of ionic liquids
Solution Approach 1:
The patent replaces expensive ionic liquids with much cheaper amino acid salts as membrane liquids. Amino acid salts are derived from renewable resources, have low production costs, and are biodegradable, making them economically viable while maintaining the required separation performance
Solution Approach 2:
The patent changes the economic parameters of the system by selecting membrane liquids with different cost structures. Amino acid salts offer a favorable balance between performance and cost, enabling economically efficient CO2 separation without sacrificing dissolution selectivity
3Productivity
If amine solvents are used for CO2 adsorption to achieve effective CO2 capture, then CO2 separation efficiency is improved, but energy consumption increases due to heating requirements for desorption and equipment corrosion
Solution Approach 1:
The patent replaces the thermal-driven amine absorption system with a membrane-based separation system that operates at ambient conditions. The supported liquid membrane uses dissolution-diffusion mechanism rather than chemical absorption followed by thermal desorption, eliminating the need for energy-intensive heating and cooling cycles
Solution Approach 2:
The patent exploits the phase behavior of gases in the liquid membrane, where CO2 dissolves in the amino acid salt membrane liquid and permeates through the membrane under partial pressure gradient. This phase transition-based separation occurs at ambient temperature, avoiding the thermal energy requirements of conventional amine systems
4Device complexity
If membrane separation is used to achieve CO2 separation, then equipment complexity is reduced, but CO2 purity deteriorates as it cannot exceed the Robeson upper bound
Solution Approach 1:
The patent changes the separation mechanism from conventional polymer membrane diffusion to supported liquid membrane dissolution-diffusion. By using amino acid salts as membrane liquids, the system achieves enhanced CO2 selectivity beyond typical polymer membrane limits, while maintaining the simplicity of membrane module configuration
Solution Approach 2:
The patent creates a composite structure combining porous membrane support with amino acid salt liquid phase. This composite supported liquid membrane system integrates the mechanical strength of solid membranes with the high selectivity of liquid membranes, achieving both high CO2 purity and equipment simplicity
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 modified membrane material achieves improved CO2 separation with increased permeation flux and selectivity, reduces membrane liquid loss, and simplifies operation by allowing easy repair and reuse, while being environmentally friendly and cost-effective.
Implementation Method 1
amination modification of a membrane material for improving separation of CO2 by a water-supported liquid membrane
Implementation Method 2
The modified membrane material achieves improved CO2 separation with increased permeation flux and selectivity
Data Source
AI summary
A membrane modification method for improving liquid membrane separation of carbon dioxide (CO2) includes grafting an organic substance containing an amine group on a porous membrane material, and loading water into pore channels of the porous membrane material to prepare a supported liquid membrane for a gas mixture separation experiment of CO2. In the method, the amine group is introduced through chemical grafting to make the water being alkaline when used as membrane liquid. Compared with an alkaline solution as the membrane liquid, the method can avoid the loss of active alkaline substances and increase the permeation flux of CO2.