How to produce ultrapure water

The production of ultrapure water requires multiple water treatment steps to remove impurities, minerals, bacteria, particles, etc. in the water to ensure that its purity reaches extremely high standards.

The main steps of ultrapure water production process:

Step 1: Raw water pretreatment

Coarse filtration: First, the raw water passes through a coarse filter to remove large particles of impurities, such as sand, soil, and suspended solids.

Activated carbon adsorption: Organic matter, chlorine, odor, etc. in the water are adsorbed by activated carbon. This step helps to remove organic pollutants and residual chlorine in the water.

Softened water: Raw water usually contains more hardness ions (such as calcium, magnesium, etc.). Softening treatment is carried out through ion exchange resin to remove these minerals and prevent them from affecting subsequent equipment.

Step 2: Reverse osmosis treatment

Reverse osmosis is a key technology for removing impurities such as dissolved salts, particles, and bacteria from water. In the reverse osmosis stage of the ultrapure water machine, water is forced to pass through a semipermeable membrane, which can effectively remove most of the dissolved inorganic salts, organic matter, heavy metals, and bacteria. The water after reverse osmosis treatment is close to pure water, but it may still contain trace amounts of ions and impurities.

Step 3: Deionization

The water after reverse osmosis undergoes a deionization process, using ion exchange resins to further remove cations and anions (such as sodium, chloride, sulfate, etc.) in the water. Deionization usually uses two types of ion exchange resins: cation resin and anion resin. After this step, the ions in the water are completely removed.

Step 4: Precision Filtration

Precision filtration usually uses filters with a pore size of 0.1 microns or less to further remove particles, microorganisms, etc. in the water. This step ensures that the particle content of ultrapure water meets industry standards.

Step 5: UV Sterilization

Ultraviolet sterilization is used to disinfect microorganisms such as bacteria and viruses in water. UV light can destroy the DNA structure of microorganisms, thereby effectively killing or inhibiting their growth. This process is usually the last sterilization step in the Ultrapure water purification system to ensure that the water quality is sterile.

Step 6: Inspection

After all water treatment steps are completed, the water quality needs to be monitored and tested to ensure that it meets the ultrapure water standards. Common indicators include conductivity, total organic carbon (TOC) content, microbial content, etc. Ultrapure water usually has very low conductivity and its TOC content must also be extremely low.

Step 7: Storage and Distribution

Finally, the ultrapure water that has undergone multiple treatments will be stored in a dedicated water tank and distributed through a pipeline system to laboratories, production lines, or other locations. During the storage and distribution process, it is also necessary to prevent the water from being contaminated again, so storage and delivery systems made of stainless steel or other high-purity materials are often used.

The production of ultrapure water is a highly sophisticated and multi-stage process, and each link requires precise control to ensure the purity and quality of the water. By using ultrapure water filtration equipment, the resulting ultrapure water can be widely used in semiconductor manufacturing, pharmaceuticals, electronics industry, laboratory research and other fields.