Classification and Introduction of Water Purifiers

This comprehensive guide provides an in-depth introduction to water purifiers and their classifications. Learn about the main purification technologies, including reverse osmosis, ultrafiltration, activated carbon filtration, softening, and mineralization, as well as their advantages, limitations, and applications in household and industrial water treatment.

Clean and safe drinking water is essential to health, comfort, and industry. However, water sources often contain contaminants such as suspended solids, heavy metals, microorganisms, and organic pollutants. Modern water purifiers employ various physical, chemical, and membrane separation technologies to ensure water safety and improve its taste and quality.

Depending on the treatment method, water purifiers can be divided into 11 main types, each designed to target specific impurities and meet different water quality needs.

The water softening method removes or reduces water hardness by eliminating calcium and magnesium ions responsible for scale formation. Softened water prevents scaling in pipes and appliances but does not improve overall water purity since it does not remove organic or chemical contaminants.

Distillation involves boiling water, collecting the vapor, and condensing it into pure water. The resulting distilled water is free of bacteria and most inorganic substances. However, it lacks essential minerals, leading some experts to question its long-term health benefits. Distillation also consumes significant energy and cannot remove volatile organic compounds.

The boiling method is one of the oldest and simplest ways to disinfect water. Boiling effectively kills most bacteria and viruses, but it does not remove heavy metals or chemical pollutants. Therefore, while safer than untreated tap water, boiled water may still contain harmful residues.

Magnetized water treatment exposes water to a magnetic field, theoretically altering its molecular structure to reduce scaling. However, this method remains controversial and lacks strong scientific validation. It is not widely adopted in professional or international water purification systems.

Mineralization enhances purified water by adding beneficial minerals such as calcium, magnesium, and zinc. This process aims to improve taste and health benefits. While some purifiers use maifan stone or mineral cartridges, the scientific effectiveness of artificial mineralization is still debated.

Both ozone and ultraviolet (UV) disinfection methods effectively kill bacteria and viruses but do not remove heavy metals, chemicals, or dissolved solids. Moreover, dead microorganisms can remain in the water, making secondary filtration necessary.

Developed in Japan, electrolyzed water purifiers produce alkaline and acidic water through electrolysis. Alkaline water is believed to benefit human metabolism, while acidic water can be used for skincare. However, scientific consensus on these claims remains uncertain, and further research is ongoing.

Activated carbon is one of the most effective materials for adsorbing organic pollutants, chlorine, odor, and taste from water.
There are several types:

• Granular Activated Carbon (GAC): Derived from coconut shells, coal, or wood, GAC has a large surface area that traps contaminants through physical and chemical adsorption.
• Silver-Impregnated Activated Carbon: Combines filtration with antibacterial properties, preventing bacterial growth inside the purifier.
• Activated Carbon Fiber (ACF): A newer form of activated carbon with higher efficiency in removing organic compounds and trace metals.

These filters are widely used in both household water purifiers and industrial pre-treatment systems.

Reverse Osmosis (RO) is the most advanced and widely used purification method today. It uses a semi-permeable membrane with pore sizes around 0.0001 micrometers, allowing only water molecules to pass while rejecting impurities such as heavy metals, bacteria, viruses, and dissolved salts.

RO systems produce pure, great-tasting water suitable for direct drinking, cooking, and industrial use. They are commonly used in households, hotels, hospitals, and laboratories.

Advantages of RO Systems:

• Removes over 99% of contaminants
• Produces clear, odor-free, and great-tasting water
• Reduces scaling and extends appliance life
• Ideal for soft, pure drinking water

Modern RO systems often combine silver-loaded activated carbon filters and ultra-low pressure membranes for enhanced efficiency and longer service life.

Both microfiltration (MF) and ultrafiltration (UF) are membrane separation technologies used to remove suspended particles, bacteria, and colloids.

• Microfiltration membranes have larger pores and are used as pre-filters.
• Ultrafiltration membranes can remove macromolecules, bacteria, and viruses with pore sizes between 0.01–0.1 microns.

UF systems are often used before RO units to extend membrane lifespan and improve overall purification efficiency.

When one method alone cannot achieve desired purity, composite water purifiers combine multiple technologies—such as activated carbon, UV sterilization, ultrafiltration, and reverse osmosis.
This multi-stage design enhances water quality and ensures comprehensive purification, making it ideal for domestic and commercial applications.

The classification of water purifiers reflects the diversity of technologies developed to ensure safe, high-quality drinking water. From traditional boiling and activated carbon adsorption to advanced reverse osmosis and ultrafiltration, each method serves unique needs.

Modern composite water purifiers that integrate membrane technology and adsorption filtration offer the best combination of safety, convenience, and performance. Choosing the right purifier depends on your local water quality, health needs, and budget.

For most households, reverse osmosis (RO) systems provide the best balance between purification efficiency, taste, and cost-effectiveness.

Mineralized water contains beneficial elements but may not be essential if you maintain a balanced diet. RO-purified water is still perfectly safe and healthy.

Boiling kills microorganisms but does not remove heavy metals or chemical contaminants. For complete purification, a filtration system is recommended.

Ultrafiltration removes smaller particles, including viruses, while microfiltration targets larger particles like bacteria and sediments.

Typically, filters should be replaced every 6–12 months, depending on usage and local water quality.

Xi’an CHIWATEC Water Treatment Technology is a high-tech enterprise specialized in various water processing devices. Aside from these individual products, which cover a number of types and series, we can also help with related comprehensive engineering projects. Thanks to our hard work and dedication upon our founding, we are now one of the fastest-developing water treatment equipment manufacturers in Western China.

Further reading:

• Overview of water purifier
• Knowledge about water purifier
• Classification and introduction of water purifiers
• Functional characteristics and application of reverse osmosis water purifier
• Features of reverse osmosis water purifier system and introduction of filter element use