Electrostatic Ion Pumping for Desalination
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Solution Overview
Problem
Conventional desalination methods, such as reverse osmosis, are energy-intensive, prone to scaling and fouling, and require costly maintenance, failing to meet the need for a robust, cost-effective, and efficient method for removing ions and impurities from water.
Innovation Solution
A desalination system utilizing synchronized periodic electric fields and oscillating fluid flow through a network of flow channels with conductive plates to direct ions from a feed fluid to a concentrate fluid, reducing energy consumption and avoiding membrane degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reverse osmosis is used for desalination, then ions and impurities are removed from water, but energy consumption increases significantly
Solution Approach 1:
The patent applies periodic electric fields that alternate in polarity to drive ion migration through the membrane. The electric field is applied in cycles, with each cycle consisting of a forward pulse that drives ions through the membrane and a reverse pulse that restores the field. This periodic action enables continuous ion removal while maintaining lower energy consumption compared to constant high-pressure reverse osmosis operation
Solution Approach 2:
The patent replaces the mechanical high-pressure pumping system of reverse osmosis with an electrostatic field-based ion pumping mechanism. Instead of using mechanical force to push water and ions through the membrane, the system uses synchronized electric fields to selectively drive ions through the membrane while allowing water to pass through by osmosis, significantly reducing energy requirements
2Reliability
If reverse osmosis membranes are used, then ion separation is achieved, but the membrane degrades over time requiring costly maintenance
Solution Approach 1:
The patent employs a dynamic electric field system that can be adjusted and reversed, allowing the membrane to operate under varying conditions. The periodic reversal of electric field polarity prevents permanent fouling and scaling by periodically flushing accumulated ions back through the membrane, extending its service life and maintaining separation capability over time
Solution Approach 2:
The system periodically reverses the electric field to discard accumulated ions from the membrane surface back into the feed stream, preventing permanent fouling. This recovery process allows the membrane to maintain its separation capability without requiring frequent replacement or costly cleaning operations
3Reliability
If conventional ion exchange is used, then water softening is achieved, but highly concentrated sodium chloride solution is produced requiring additional desalination
Solution Approach 1:
The patent applies localized electric fields across the membrane surface that create selective ion migration zones. The electric field is concentrated at the membrane interface where ion separation occurs, enabling precise control over which ions are removed and in what direction, thereby producing diluted effluent rather than concentrated brine
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 reduces energy use, minimizes scaling and fouling, and allows for continuous operation with lower capital and operating costs, making it suitable for brackish and seawater desalination while being modular and operator-friendly.
Implementation Method 1
applying a synchronized periodic electric field about each of the plurality of flow channels in conjunction with the oscillating fluid flow to enable a directed movement of predetermined ions from the first channel to the second channel
Implementation Method 2
oscillating a fluid flow therethrough a plurality of flow channels so as to fluidly communicate the first channel with the second channel
Data Source
AI summary
The present invention provides a new method and apparatus/system for purifying ionic solutions, such as, for example, desalinating water, using engineered charged surfaces to sorb ions from such solutions. Surface charge is applied externally, and is synchronized with oscillatory fluid movements between substantially parallel charged plates. Ions are held in place during fluid movement in one direction (because they are held in the electrical double layer), and released for transport during fluid movement in the opposite direction by removing the applied electric field. In this way the ions, such as salt, are “ratcheted” across the charged surface from the feed side to the concentrate side. The process itself is very simple and involves only pumps, charged surfaces, and manifolds for fluid collection.