Nanofiltration Membrane Coating for Divalent Ion Rejection
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Solution Overview
Problem
Current direct lithium extraction (DLE) methods are inefficient and environmentally unfriendly, particularly due to the high frequency of regeneration and shortened lifespan of ion exchange resins, which struggle to separate divalent ions from monovalent ions at high purity.
Innovation Solution
The use of a membrane-based separation process, including a nanofiltration membrane with a coating, to reduce the ratio of divalent ions to a target monovalent ion in an aqueous solution, improving the efficiency and reducing the number of stages required in the extraction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ion exchange resins are used to separate divalent ions from monovalent ions, then separation is achieved, but the resins require high frequency regeneration and have shortened lifespan
Solution Approach 1:
The patent changes the separation mechanism from ion exchange to nanofiltration membrane separation, altering the physical and chemical parameters of the separation process. The nanofiltration membrane uses size exclusion and charge-based rejection to separate ions, eliminating the need for resin regeneration and extending operational lifespan while maintaining separation capability
Solution Approach 2:
The patent replaces the chemical ion exchange resin system with a physical nanofiltration membrane system. This substitution eliminates the chemical saturation and regeneration cycle inherent in ion exchange resins, providing continuous operation without frequent downtime for regeneration
2Reliability
If ion exchange resins are used for ion separation, then separation occurs, but the frequency of regeneration increases and downtime increases
Solution Approach 1:
The patent replaces the chemical ion exchange resin system with a physical nanofiltration membrane system. This substitution eliminates the chemical saturation and regeneration cycle inherent in ion exchange resins, providing continuous operation without frequent downtime for regeneration
Solution Approach 2:
The nanofiltration membrane system enables continuous separation operation without the periodic interruptions required for resin regeneration. The membrane maintains its separation function indefinitely under proper operating conditions, ensuring uninterrupted production and maximizing operational continuity
3Quantity of substance
If traditional lithium extraction from brines is used, then lithium can be extracted, but the process is time-consuming and requires huge amount of chemicals
Solution Approach 1:
The patent extracts and isolates the nanofiltration membrane separation step from the traditional multi-step extraction process. By using the membrane to selectively reject divalent ions while permitting monovalent lithium ions to pass, the process achieves rapid separation without requiring lengthy evaporation periods or multiple chemical addition steps
Solution Approach 2:
The patent replaces chemical-based separation methods with physical membrane filtration. This substitution eliminates the need for adding huge amounts of chemicals for precipitation and separation, reducing both chemical consumption and processing time while maintaining effective lithium extraction
4Productivity
If direct lithium extraction is used, then extraction speed improves, but the number of stages remains high and efficiency is low
Solution Approach 1:
The patent extracts and isolates the nanofiltration membrane separation step from the traditional multi-step extraction process. By using the membrane to selectively reject divalent ions while permitting monovalent lithium ions to pass, the process achieves rapid separation without requiring lengthy evaporation periods or multiple chemical addition steps
Solution Approach 2:
The nanofiltration membrane performs multiple functions simultaneously: it acts as a prefiltration device, a separation membrane for divalent/monovalent ion separation, and a concentration device. This multi-functionality consolidates what would traditionally require multiple separate stages into a single integrated unit, reducing overall process complexity
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 enhances the extraction efficiency of lithium and other monovalent ions by reducing the divalent ion interference, leading to improved metal extraction performance, reduced operating costs, and a more environmentally friendly process.
Implementation Method 1
a nanofiltration separation portion operable to receive the optionally prefiltered source aqueous solution and form an intermediate aqueous solution having a lower ratio of divalent ions to the target monovalent ion than the optionally prefiltered source aqueous solution
Implementation Method 2
the membrane comprises a membrane substrate and a coating arranged over at least a part of the membrane substrate
Data Source
AI summary
A separation portion for use in an apparatus for reducing the ratio of divalent ions to a monovalent ion in an aqueous solution from a source aqueous solution that contains a higher ratio of divalent ions to the target monovalent ion. The separation portion includes a membrane having a membrane substrate and a coating arranged over at least a part of the membrane substrate. An apparatus including the separation portion and a process for reducing the ratio of divalent ions to a monovalent ion in an aqueous solution.