Introduction to Electrodeionization (EDI)
Presently, high-purity water is required in industries, hence need to look for effective and sustainable solutions in water treatment processes. One such advanced technology is Electrodeionization (EDI), a continuous and chemical-free process water purification technology. EDI systems have emerged and been considered as an integral element in industries including pharmacy, electronics, energy, and many others. Here in this blog, we’ll explore what electrodeionization is; how EDI systems function, and the benefits they offer to industrial water treatment processes.
What is Electrodeionization (EDI)?
EDI is a water purification process that uses ion exchange resins and electrical membranes to allow the removal of the ionized species from the water. This means that the system does not employ chemical regeneration as is the case with some other desalination systems and is therefore eco-friendly. EDI is mainly applied for further treatment of reverse osmosis (RO) permeate water, obtaining water with a resistivity of up to 18m cm. 2 MΩ. Cm is a standard required in mission-risky ones like microelectronic and pharma products manufacturing.
How Does the Electrodeionization System Work?
The electro-deionization system works using the ion exchange and the electrodialysis processes:
- Ion Exchange Resin: Water first undergoes mixed-bed ion exchange by passing the water through a resin which removes positive ions and replaces them with hydrogen ions and negative ions and replaces them with hydroxide ions. This resin bed is useful in removing soluble salts from the water being treated.
- Membranes: It then moves through some hydrophilic semi-permeable membranes which are connected in a manner where they are combined in cation-exchange and anion-exchange fashion. These membranes can let through only certain ions depending on their charge.
- Electric Current: Two electrodes located at the opposite ends of the EDI system form an electric field. This field manages ion transport in the ion-exchange resin and membranes needed in the separation process. Ions and other cations will be attracted to the negative terminal referred to as the cathode, while anions will be attracted to the positive terminal called the anode.
- Regeneration: The constant DC maintains the selective ion exchange resin perpetually regenerated, making it possible for uninterrupted service without regeneration or the use of drastic chemicals.
This leads to an achievement of high-purity water with low dissolved ions in the water stream. It is very effective and is designed to eliminate dissolved salts as well as organic impurities present in water.
Applications of Electrodeionization Systems
EDI systems are employed in a variety of industries where ultra-pure water is required. Below are some key applications:
- Pharmaceuticals: The pharmaceutical industry needs water that meets a certain quality to be used in the production of medicine and other products. EDI systems support the production of water that meets USP and other requirements.
- Power Generation: In power plants, water used in boiler and turbine systems feed water must be free from impurities which cause scaling and corrosion. EDI systems ensure that water qualifies the general specifications necessary for any process hence eradicating operational hitches.
- Microelectronics: According to the New York Times article, water used to manufacture semiconductors and other electronic parts must be free from any contaminants. Despite this, any form of impurity, no matter how small, can lead to some form of flaw in the final product, thus making an EDI system instrumental in maintaining water used in the process extremely clean.
- Laboratories: The use of high-purity water is very important when doing research and analysis in scientific experiments. EDI systems assist laboratories in achieving the water quality that is required for experiments and analysis work.
Challenges of EDI Systems
Despite their numerous advantages, EDI systems also come with certain challenges:
Feed Water Quality: Electrical Discharge Ionisation (EDI) systems are very sensitive to the quality of the water it treats. Therefore, they are mainly applied as a final step after reverse osmosis (RO). Rinsing is required if the EDI components are to perform to the best of their capabilities and to prevent fouling of the elements.
Initial Cost: The capital cost of an EDI system can be high and is generally higher than a conventional ion exchange system cost. However, the payback is achieved in terms of lower chemical consumption, frequent maintenance, and overall operating costs after a few years of operation.
Conclusion: Why Choose EDI Electrodeionization?
Electrodeionization systems are an efficient, innovative, and environmentally friendly solution for industries that need high-purity water. EDI is a future-oriented technology for water treatment for the following reasons: it does not use chemical regenerants, provides continuous operation, and achieves the required level of water purity.
In case they plan on implementing a new EDI system in the water treatment process, they should involve manufacturers who have adequate knowledge regarding the system and the process required for its implementation. HINADA for example is a company that offers effective and high-performing EDI systems that can capacity different industries while offering reliable solutions to sustainable water purification.
