Capacitive Deionization Water Purification System
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laboratory-scale water purification systems face challenges in reducing pressure requirements and increasing water recovery, as they typically operate at lower efficiency and higher water wastage due to the limitations of reverse osmosis technology, especially when dealing with high hardness forming ions in feedwater.
Innovation Solution
The method employs capacitive deionization (CDI) in multiple stages with alternating charging and discharging cycles to progressively reduce conductivity, using two CDI modules with different capacities and operational modes to achieve high purity water with reduced pressure and increased recovery, avoiding the need for high-pressure reverse osmosis systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reverse osmosis is used for water purification, then purification effectiveness is improved, but pressure requirements increase and water recovery decreases
Solution Approach 1:
The patent replaces the mechanical reverse osmosis system (which requires high pressure) with an electrochemical capacitive deionization system. The CDI modules use electrical fields to remove ions from water through electrostatic attraction to charged electrodes, eliminating the need for high-pressure pumps and mechanical membrane filtration while achieving effective purification.
Solution Approach 2:
The patent changes the fundamental operating parameter from mechanical pressure (reverse osmosis) to electrical potential (capacitive deionization). By applying voltage cycles to the CDI modules, ions are selectively removed from water during charging phases, and the system operates at atmospheric pressure throughout, resolving the pressure-effectiveness contradiction.
2Reliability
If reverse osmosis is used for water purification, then purification effectiveness is improved, but water recovery decreases
Solution Approach 1:
The patent replaces the mechanical reverse osmosis system with an electrochemical capacitive deionization system. The CDI process selectively removes ions from water without the need for high-pressure filtration, allowing much higher water recovery rates since only the dissolved ions are removed in the concentrate stream while the majority of water is recovered as purified product.
3Loss of substance
If multiple reverse osmosis modules are used to increase water recovery, then water recovery is improved, but pressure requirements increase and efficiency decreases
Solution Approach 1:
The patent divides the water purification task into multiple separate CDI modules operating in parallel or sequence, each handling a portion of the feedwater. This segmentation allows the system to achieve high overall water recovery without requiring high pressure, as each module operates independently at atmospheric pressure and the results are combined.
4Stress or pressure
If capacitive deionization is used instead of reverse osmosis, then pressure requirements are reduced and water recovery is increased, but multiple modules with alternating cycles are needed
Solution Approach 1:
The patent employs periodic alternating cycles where CDI modules switch between charging (purification) and discharging (regeneration) modes. During charging, modules purify water by attracting ions to charged electrodes; during discharging, they release accumulated ions to a concentrate stream. This periodic operation allows continuous purification while simplifying the overall system architecture compared to multiple permanent filtration stages.
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 significantly increases water recovery to over 70% of the input, achieving ultrapure water with conductivity below 20 μS/cm, while reducing energy consumption and eliminating the need for high-pressure equipment, thus improving efficiency and cost-effectiveness in laboratory settings.
Implementation Method 1
circulating the feed water in the first storage tank one or more times through a first purification re-circulation loop including a first capacitive deionisation module in a charging mode to provide a first purified water stream having a conductivity less than the feed water
Implementation Method 2
circulating the water in the second storage tank one or more times through a first concentration re-circulation loop including the first capacitive deionisation module in a discharging mode to provide a first concentrate water stream
Data Source
AI summary
There is described a method of treating potable mains feed water to provide a purified water stream of conductivity <20 μS/cm, comprising at least the steps of: (a) providing the potable mains feed water into a first storage tank; (b) circulating the feed water in the first storage tank one or more times through a first purification re-circulation loop including a first capacitive deionisation module in a charging mode to provide a first purified water stream having a conductivity less than the feed water; (c) circulating the first purified water stream one or more times through a second purification re-circulation loop including a second capacitive deionisation module in a charging mode to provide a second purified water stream having a conductivity less than the first purified water stream.