Membrane filtration is a physical separation process that uses a semi-permeable membrane to separate suspended or dissolved substances in a fluid mixture based on their size, shape, or chemical properties. It is commonly used in industries such as water treatment, oil and water produced water, food and beverage production, pharmaceuticals, chemicals and biogas industry. With the help of membrane filtration, the overall production costs can be reduced while at the same time increasing product quality.
The membrane filters consist of either organic (polymeric) or inorganic (ceramic) materials. The two defined factors of separation size and separation process influence the process efficiency of the various membranes.
BOLLFILTER types of membranes
BOLLFILTER offers two different types of membranes:
SiC Tubular membranes
For more details on the tubular membranes, please click here:
When it comes to membrane filtration possibilities, membrane filtration is typically categorized into four widely recognized types, based on the size of particles they are designed to separate from the feed liquid. These types, arranged by increasing pore size, are reverse osmosis, nanofiltration, ultrafiltration, and microfiltration.
Reverse Osmosis (RO): Reverse osmosis is a filtration process that uses a semi-permeable membrane to remove ions, molecules, and larger particles from water or other liquids. It is highly effective in separating dissolved salts, contaminants, and impurities, producing highly purified water.
Nanofiltration (NF): Nanofiltration is a filtration technique that removes dissolved substances, such as divalent and larger monovalent ions or organic molecules, while allowing smaller solutes like sodium and chloride to pass through. It is often used for water softening, partial desalination, and the removal of organic matter.
Ultrafiltration (UF): Ultrafiltration employs membranes with slightly larger pores to separate macromolecules, proteins, oils, and suspended solids from liquids. It is commonly used in applications such as wastewater treatment, protein recovery, and the food and beverage industry.
Microfiltration (MF): Microfiltration is a process that removes larger particles, such as bacteria, suspended solids, and some viruses, using membranes with relatively large pores. It is frequently used in sterilization, beverage production, and the separation of fine particulates.
Crossflow Filtration VS Dead-End Filtration principle
The filtration methods used depend on the type of membrane. There are two different types. One is the Dead-End Principle (plate membrane) and the other is the Crossflow Filtration Principle (tubular membrane).
Crossflow Filtration Principle
Crossflow Filtration principle involves liquid flowing parallel to the membrane surface, with part of it (the permeate) passing through. This prevents particle buildup, reduces fouling, and ensures consistent performance, as retained particles are carried away with the remaining liquid (the retentate). The process extends membrane lifespan, requires less maintenance, and delivers reliable filtration results, making it ideal for industrial applications with high solids or strict filtration demands.
Click on the button below to learn more about the application of the Crossflow principle with BOLL tubular membranes:
Dead-end filtration is a method where the liquid flows perpendicularly through the membrane, with all particles and impurities being retained on the membrane surface. Over time, this leads to the formation of a filter cake. The process is simple, cost-effective, and efficient for applications with low particle concentrations.
To get more information about the application of the Dead-End Filtration Principle with BOLL plate membranes,click here:
Silicon carbide (SiC) is among the hardest materials in the world. Our SiC ceramic membrane technology provides extreme durability combined with mechanical robustness. The material also stands for the highest flux, high permeability as well as a high level of hydrophilicity (water-loving material). Add to this it is resistant to corrosion too.
In addition to our SiC ceramic membranes, BOLL also offers aluminum oxide membranes (Al2O3) as a versatile solution for various filtration needs. While aluminum oxide membranes provide reliable performance, BOLL SiC membranes dominate in some categories, making them the superior choice for demanding applications.
Features
SiC
AI2O3
Polymer
Life time
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Flux
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Chemical resistance
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Cost savings
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Operating TMP
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Temperature resistance
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Fouling behavior
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Advantages of SiC-membranes
High Flux
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High Flux
High flux due to ultrathin membrane layer and high porosity substrate.
This results in:
High flow on small foot-print for more compact plants
Low pressure operations
Lower energy consumption
Anti Fouling
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Anti Fouling
Due to low zeta potential, SiC membranes have a remarkable anti fouling property.
This leads to:
Longer filtration cycles (without backwash)
Less maintenance for cleaning
Lower energy expenditure
Chemical resistant
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Chemical resistant
Silicon Carbide is almost universally chemical-resistant (pH 0-14).
This enables:
Treatment of highly corrosive feed water
More adaptability in cleaning
Thermal resistant
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Thermal resistant
SiC membranes are particularly resistant to rapid, shock-like temperature changes. Heat can be transferred fast and there are hardly any tensions in the membrane that could lead to damage.
Hydrophilic and Lipophobic
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Hydrophilic and Lipophobic
SiC membranes are very hydrophilic due to low contact angle between water and membrane surfaces. Combined with the lipophobical attribute, this alows an optimized oil-water emulsion separation.
