1. Precipitation and filtration method
It relies on the sinking of the particulate impurities in the water to achieve the purpose of separation. This is the most primitive filtration method, which is often used in the treatment of large impurity particles in water.
2. Distillation
It is to heat water and turn it into gas, separate out the low-boiling point components or droplets mixed into the gas phase, put the low-boiling point gas in the atmosphere, and the non-volatile impure substances remain in the liquid phase, and then discharge them as concentrated liquid.
This method consumes a lot of electricity and water, and needs someone to guard it, so it is inconvenient to use.
3. Membrane microfiltration method
This method includes three forms: depth filtration, screen filtration, and surface filtration.
Depth filtration is a matrix made of woven fibers or compressed materials, using inert adsorption or capture methods to retain particles, such as commonly used multimedia filtration or sand filtration.
The sieve filter membrane is basically a consistent structure, just like a sieve, which keeps particles larger than the pore size on the surface, such as the security filter used in the terminal of the ultrapure water machine.
Surface filtration is a multi-layer structure. When the solution passes through the filter membrane, the particles larger than the internal pores of the filter membrane will be left and mainly accumulated on the surface of the filter membrane. Such as commonly used PP fiber filter.
4. Activated carbon adsorption method
Activated carbon relies on adsorption and filtration to mainly remove organic impurities such as color, odor, residual chlorine, and residual disinfection in water.
5. Electrodialysis
For example, two brines with different concentrations are separated by a permeable membrane, and the solutes in the brine with high concentration, such as inorganic salt ions, permeate into the brine with low concentration through the membrane. This phenomenon is called dialysis. If you want to speed up this speed, you can add electrodes on both sides of the membrane, which is called electrodialysis. Electrodialysis consumes a lot of power, and the dialysis membrane is fragile. After the appearance of reverse osmosis technology, it is rarely used.
6. Ion exchange method
The principle of the ion exchange method is to exchange the anions and cations of inorganic salts in raw water, such as calcium ions, magnesium ions, sulfate ions, etc., with ion exchange resins, so that the anions and cations in the water exchange with the anions and cations in the resin, so that the water Get softened or purified.
7. Ultrafiltration method
Microporous membranes rely on the size of the filter aperture to remove heat particles, while ultrafiltration membranes are like a molecular sieve, which uses the molecular size as a benchmark to allow the solution to pass through extremely fine pores to achieve the purpose of separating molecules of different sizes in the solution.
8. Ultraviolet light, sampling sterilization method
The 254nm ultraviolet light emitted by the ultraviolet lamp is an effective sterilization method, and the DNA and protein in the bacteria will be irradiated and die.
Ozone sterilization method: adding ozone to pure water, the sterilization effect is very good.
9. Reverse Osmosis
With pressure as the driving force, the reverse osmosis membrane can only permeate water but not solute. Its desalination rate is as high as 99%, and its sterilization rate is greater than 99.5%, which can remove impurities such as inorganic salts, sugars, amino acids, bacteria and viruses in water.
10. EDI method
Also known as continuous electric desalination technology, the EDI device fills the ion exchange resin between the anion and cation exchange membranes to form an EDI unit. This method does not need to regenerate the resin with acid and alkali, and is environmentally friendly.
