Ceramic membranes are divided into two types: tubular ceramic membranes and flat ceramic membranes. The walls of tubular ceramic membranes are densely packed with micropores. Under pressure, the raw liquid flows either inside or outside the membrane tube. Small molecules (or liquids) pass through the membrane, while larger molecules (or solids) are retained by the membrane, thus achieving the purposes of separation, concentration, purification, and environmental protection. The surface of flat ceramic membranes is also densely packed with micropores. Based on permeation within a specific pore size range as the filtration medium, under certain pressure, only water, inorganic salts, and small molecules are allowed to pass through the membrane, while suspended solids, colloids, and microorganisms in the water are blocked.
The preparation processes for tubular ceramic membranes and flat ceramic membranes are different. Tubular ceramic membranes are made by casting molds inside tubes and then applying a layer of ceramic membrane coating. This preparation process allows tubular ceramic membranes to have higher flux and better mechanical strength.
Flat ceramic membranes are made directly on flat sheets, making the preparation process relatively simple. However, due to the thicker membrane layer of flat ceramic membranes, their flux is relatively lower.
Flux is one of the important indicators for measuring the performance of ceramic membranes. Due to the higher mechanical strength and thinner membrane layer of tubular ceramic membranes, their flux is much higher than that of flat ceramic membranes.
The smaller pore size of tubular ceramic membranes provides better rejection for tiny particles and organic substances. Therefore, tubular ceramic membranes are more resistant to fouling compared to flat ceramic membranes.
Both tubular ceramic membranes and flat ceramic membranes are types of ceramic membranes used in fields such as water treatment, juice clarification, and dairy production.
Tubular ceramic membranes generally operate at pressures between 1-5 bar and are widely used in situations where high turbidity and high viscosity liquids need to be treated, such as in food and beverage processing and wastewater treatment. Flat ceramic membranes are typically used for the clarification and purification of low-viscosity liquids, such as dairy products, juices, and alcoholic beverages.
Tubular ceramic membranes are easier to maintain compared to flat ceramic membranes, being easier to clean and replace when damaged.
In summary, both tubular ceramic membranes and flat ceramic membranes have their respective application fields and characteristics. Tubular ceramic membranes are suitable for treating high-turbidity and high-viscosity liquids, offering higher flux and better anti-fouling properties; whereas flat ceramic membranes are suitable for the clarification and purification of low-viscosity liquids, with simpler preparation processes. When choosing which type of ceramic membrane to use, it is important to consider the characteristics of your industry and the treatment goals you need to achieve.