What Is Water Demineralization?

Water demineralization is the process of removing minerals and other dissolved substances from water, leading to a reduction in the water's hardness. Commonly, water demineralization refers to the elimination of inorganic minerals such as calcium and magnesium ions. These impurities in drinking water can lead to health problems, and in industrial processes, they can cause damage to equipment and reduce operational efficiency.

Water demineralization can be achieved through various methods such as distillation, reverse osmosis, and ion exchange. The ion exchange process is a cost-effective method for water demineralization and is widely used in industrial processes.

What are the target ions for water demineralization?

The target ions for water demineralization are typically calcium (Ca²⁺), magnesium (Mg²⁺), sodium (Na⁺), and potassium (K⁺), as well as various anions including chloride (Cl^-), sulfate (SO₄^2-), and bicarbonate (HCO₃^-).

How does demineralization work?

Demineralization works by using an ion exchange resin, which is a material that attracts and binds to certain ions. The resin is typically made of small plastic beads that are coated with a negatively charged substance. As water containing ions flows through the resin, the negatively charged beads attract and bind to positively charged ions like calcium and magnesium. These ions are removed from the water, which is then considered "softened".

The ion exchange resin used in demineralization can be regenerated by rinsing it with a solution of salt water. The salt water displaces the minerals that were removed from the water, allowing the resin to be used again.

Although water demineralization and water softening work similarly, water demineralization targets a wider range of contaminants, covering all mineral salts (except trace sodium ions and colloidal silica).

What is the difference between desalination and demineralization?

Water desalination and water demineralization are two different processes used to purify water.

Water desalination is the process of removing salts and minerals from seawater or brackish water to make it suitable for human consumption or agricultural purposes. It is usually done through a process called reverse osmosis, which involves forcing seawater through a semipermeable membrane that traps salt and other impurities while allowing clean water to pass through.

Water demineralization, on the other hand, is the process of removing most or all of the minerals and dissolved solids from freshwater to make it suitable for laboratory, medical, or industrial purposes. Demineralization is typically done through the use of ion exchange resins or distillation, which remove cations and anions from the water. This process is often used to create ultra-pure water for industries such as electronics, pharmaceuticals, and cosmetics.

Related Ion Exchange Products

Some of the ion exchange resins and membranes available from Alfa Chemistry for water demineralization are listed below for your quick selection. Our chemical experts are ready to develop the most suitable solution for your demineralization processing system needs.