Application of silicon carbide ceramic membrane in drinking water treatment



At present, our daily drinking water is based on groundwater or surface water as raw water, however the surface water is easily polluted by various external factors and become a micro-polluted source of drinking water. In order to provide clean, safe and healthy drinking water for human beings, the research of water treatment technology is very important.

Compared with the traditional water treatment process, membrane filtration technology, as a new and effective treatment process, its application in water treatment will be more extensive, which can effectively remove bacteria, algae, particles, heavy metals, oil and other substances.

With its performance advantages, the application of silicon carbide ceramic membrane in drinking water can better solve the problem that the traditional process couldn’t reach the higher water quality standards and meet people's pursuit of high-quality drinking water.

How does silicon carbide ceramic membrane process drinking water?


Silicon carbide ceramic membrane separation of pollutants is roughly divided into the following three stages:

1.In the initial stage of filtration, the particles with a smaller particle size are adsorbed in the membrane pore due to various forces, which reduces the effective diameter of the membrane pore.

 2. When the adsorption in the membrane pore tends to be saturated, the particles block at the entrance of the membrane pore.

3. More particles are adsorbed and accumulated on the surface of the membrane, thus forming a cake layer.

Thus, the separation mechanism of silicon carbide ceramic membrane can be divided into two mechanisms: surface interception and internal interception.

The surface interception mechanism of SiC ceramic membrane can be divided into below three types:

1) Sieving. Particles, microorganisms and macromolecular organic matter with a particle size larger than the membrane pore size can be intercepted in the membrane surface.
2) Adsorption. that is, depending on van der Waals force, chemical bond force or electrostatic gravitation, pollutants are adsorbed on the membrane surface and pores, and pollutants with a particle size smaller than the membrane pore size can be removed.
3) Bridging. That is, the interaction between pollutants is bridged into a whole, which is intercepted by the membrane.


On the other hand, the internal interception can be entered by particles smaller than the membrane pore and adsorbed in the membrane pore, so as to reduce the inner diameter of the membrane pore and enhance the interception effect.


What are the advantages of SiC ceramic membrane in the treatment of drinking water?

Compared with organic membrane and traditional inorganic ceramic membrane, silicon carbide ceramic membrane is becoming more and more popular in the field of water treatment, its high quality, easy handling, durability, ability to work in a worse environment and effectiveness of organic pollution removal,so as to produce high-quality drinking water, and can shorten the technological process, easy to achieve automatic operation.
Except the advantages of high flux, easy cleaning, high recovery rate and long service life, silicon carbide ceramic membrane is more suitable for drinking water treatment process with oxidants, and it is not easy to be broken or damaged.

What are the main applications of SiC ceramic membranes in drinking water treatment?

1. Seawater desalination pretreatment.image.png
Reverse osmosis seawater desalination has become one of the most important methods of seawater desalination. In order to avoid pollutants in seawater seriously affecting the performance and life of reverse osmosis membrane, the pretreatment of reverse osmosis seawater desalination project is an essential step, which mainly includes multi-media filtration and organic membrane ultrafiltration / microfiltration.
Compared with the above two methods, silicon carbide ceramic membrane has the advantages of narrow pore size distribution, high porosity, thin separation layer, low filtration resistance, high treatment capacity per unit surface area, large water production capacity and stable chemical properties. it can operate stably in seawater for a long time, which is more suitable for seawater desalination pretreatment.

image.png2.Surface water treatment.
SiC ceramic ultrafiltration membrane can effectively remove microorganisms, suspended solids and other pollutants in surface water, and SiC ceramic membrane material will not be dissolved in water, which ensures the safety of effluent and improves the water quality, consequently meet the new requirements of drinking water purification technology. For example, coagulation-membrane filtration process has been widely used in the process of surface water purification.


3. Recovery of backwashing water from ultrafiltration and sand filtration.

image.pngThe backwash water of the waterworks is generally allowed to discharge after being treated to meet the standards, and the backwash water of the filter of the waterworks accounts for about 1.5% ~ 5% of the water production, and the recycled water has positive meanning for urban water supply and saving.
At present, there are two main processes for the recovery of backwash water: 1 traditional method (coagulation-sedimentation-filtration) 2 membrane filtration.
The traditional method will have an impact load on the main process of the waterworks, at the same time, the supernatant still contains much organic matter, microorganisms and heavy metals, therefore,there is a risk of water quality safety. While silicon carbide ceramic membrane filtration technology occupies less land and can safely remove parasites, it only takes one step to treat backwashing water into drinking water.


To maintain the safety of drinking water is to ensure the health of the people and promote economic and social development. Due to the proposal of the new standard for drinking water treatment and the irreparable shortcomings of the traditional drinking water treatment technology, and compared with the traditional hollow fiber membrane and alumina and other materials membrane, the characteristics and application advantages of silicon carbide ceramic membrane are the major reasons why it is becoming more and more popular and concerned. It is believed that it will become the application trend of membrane separation technology.