Capacitive Deionization Process for Resource Recovery
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Solution Overview
Problem
Current capacitive deionization technologies primarily focus on purifying water by removing ions, but they face challenges in efficiently recovering valuable resources and managing high-concentration wastewater, leading to environmental and cost issues.
Innovation Solution
A capacitive deionization process that crystallizes ions of valuable resources by concentrating them to a supersaturated state using a capacitive deionization apparatus, involving a charging step, a discharging step, and a crystal recovery step, which allows for the recovery of high-purity crystals with low energy consumption and eliminates the need for post-processing high-concentration wastewater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If capacitive deionization is used to purify water by removing ions, then water quality is improved, but valuable resources are lost and high-concentration wastewater is generated
Solution Approach 1:
The patent converts the harmful concentrated brine waste product into a valuable resource by crystallizing target ions (such as lithium ions) to obtain high-purity crystal products. The charging process concentrates ions that would otherwise be waste, and the discharging process with saturated solution enables crystal precipitation, transforming the waste disposal problem into a resource recovery opportunity
Solution Approach 2:
The patent changes the concentration parameter of the solution by using a saturated solution during the discharging step. This parameter change enables the supersaturation condition necessary for crystal formation, allowing target ions to precipitate as high-purity crystals rather than remaining dissolved in the brine waste
2Manufacturing precision
If conventional water purification methods are used, then dissolved ions are removed from feed, but energy consumption increases and wastewater disposal costs rise
Solution Approach 1:
The patent employs periodic charging and discharging cycles to the capacitive deionization electrodes. During charging, ions are adsorbed; during discharging with saturated solution, ions are released and crystallize. This periodic operation enables continuous resource recovery while maintaining low energy consumption compared to conventional continuous purification methods
Solution Approach 2:
The patent utilizes the phase transition from dissolved ions in solution to solid crystal form during the discharging step. By introducing a saturated solution and maintaining supersaturation conditions, target ions precipitate as crystals, enabling easy separation and recovery while consuming minimal energy compared to thermal evaporation or other high-energy separation methods
3Loss of substance
If ions are concentrated to supersaturated state for resource recovery, then valuable resources are recovered as crystals, but the process complexity increases
Solution Approach 1:
The capacitive deionization apparatus performs multiple functions: it acts as both a water purification device during charging and a resource crystallization device during discharging. The same electrodes and membranes used for ion removal are utilized for ion concentration and crystal formation, eliminating the need for separate processing equipment and reducing overall system complexity
Solution Approach 2:
The saturated solution serves as an intermediary medium that facilitates crystal formation. By introducing this saturated solution during the discharging step, the system enables supersaturation and subsequent crystallization of target ions without requiring complex precipitation chemicals or additional processing stages, simplifying the overall process
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 process effectively recovers valuable resources like lithium ions as high-purity crystals, reducing environmental and cost burdens associated with traditional methods, and enables efficient reuse of valuable materials from wastewater, such as lithium carbonate or lithium hydroxide, with minimal energy expenditure.
Implementation Method 1
concentrating ions of valuable resources contained in feed water to a supersaturated state
Implementation Method 2
crystallizes by concentrating ions of valuable resources contained in feed water to a supersaturated state
Implementation Method 3
removing various types of dissolved ions from the feed through capacitive adsorption
Implementation Method 4
anion exchange membrane is a membrane having selectivity to pass and retain only anions, and the cation exchange membrane is a membrane having opposite property and is a membrane having selectivity to pass and retain only cations
Implementation Method 5
anions among the inorganic salts contained in the feed are electrically attracted to the anode so that the anions pass through the anion exchange membrane and are retained in the anode region. In contrast, cations in the feed are attracted to the cathode so that the cations are retained in the anode region
Data Source
AI summary
A capacitive deionization process is provided. The capacitive deionization process includes a charging step of applying power to a capacitive deionization apparatus in a charging state and supplying charge water containing target dissolved ions to be precipitated to the capacitive deionization apparatus for a predetermined period of time, a discharging step of applying power to the capacitive deionization apparatus in a discharging state and supplying discharge water in which the target dissolved ions are in a saturated state to the capacitive deionization apparatus for a predetermined period of time, and a crystal recovery step of recovering a crystal of the target dissolved ions precipitated in the capacitive deionization apparatus and/or the discharge water.