What is the Difference Between Deionized Water and Demineralized Water

The key difference between deionized water and demineralized water is that deionized water is formed from the removal of all the ionic species from water, whereas demineralized water is formed from the removal of all the mineral particles from water.

Sometimes, the terms deionized water and demineralized water are used interchangeably though there is a slight difference between them. Deionized water may contain uncharged particles, while demineralized water has no charged or uncharged mineral particles.

CONTENTS

1. Overview and Key Difference
2. What is Deionized Water  
3. What is Demineralized Water
4. Deionized Water vs Demineralized Water in Tabular Form
5. Summary – Deionized Water vs Demineralized Water

What is Deionized Water?

Deionized water is the water from which ions are removed. In other words, deionized water does not contain ionic species. We can get deionized water by passing the water through an ion exchange process, from which the ions are removed from the water. The ion exchange process results in high-quality, ion-free water that is suitable for research purposes. Deionized water is also abbreviated as DI water in common.

Usually, tap water contains a number of ions that come from the soil, including sodium cations and calcium cations as the major cations. Moreover, tap water may also contain ions coming from the pipes through which water passes, e.g. ferrous ions and cuprous ions. When we remove these ions, we get deionized water.

What is Demineralized Water?

Demineralized water is the purest form of water that does not contain any charged or uncharged mineral particles that come from the soil. We can also name it purified water. This form of water can be produced from mechanical filtration to remove impurities, which makes it suitable for use. Although people often use the terms demineralized water and distilled water interchangeably, they are different from each other because distilled water may contain some particles due to the less efficient process from which it is produced, i.e., distillation process.

When producing demineralized water, we can use a range of processes, including capacitive deionization, reverse osmosis, carbon filtering, microfiltration, ultrafiltration, ultraviolet oxidation, and electro-deionization. Moreover, we can use some of these techniques in combination to produce “ultrapure water”.

There are many different uses of demineralized water, which include the production of pharmaceutical products, food industry, laboratory uses for research studies, beverage industry, lead-acid battery production, semiconductor productions, automotive cooling systems, etc.

What is the Difference Between Deionized Water and Demineralized Water?

Often, the terms deionized water and demineralized water are used interchangeably though there is a slight difference between them. The key difference between deionized water and demineralized water is that deionized water is formed from the removal of all the ionic species from water whereas demineralized water is formed from the removal of all the mineral particles from water. Moreover, we can easily produce deionized water from ion exchange processes while forming demineralized water requires more complicated techniques such as capacitive deionization, reverse osmosis, carbon filtering, microfiltration, ultrafiltration, ultraviolet oxidation or electro-deionization.

The below infographic presents the differences between deionized water and demineralized water in tabular form for side by side comparison

Summary – Deionized Water vs Demineralized Water

Often, the terms deionized water and demineralized water are used interchangeably though there is a slight difference between these terms. The key difference between deionized water and demineralized water is that deionized water forms from the removal of all the ionic species from water whereas demineralized water forms from the removal of all the mineral particles from water. Further, Deionized water may contain uncharged particles while demineralized water has no charged or uncharged mineral particles.

Reference:

1. Campbell, Brian. “What Is Deionized Water? (2021 Ultimate Guide).” WaterFilterGuru.com.

Image Courtesy:

1. “Cation anion ion exchange” By Z22 – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Aquafina…” By Diego Torres Silvestre (CC BY 2.0) via Flickr