Methods to Reduce Membrane Fouling
There are three main factors that contribute to membrane fouling:
- Feed stream properties. This includes characteristics such as concentration, pH and ionic strength, dissolved solid content, suspended solid content, etc.
- Membrane material and its physical-chemical properties. Membrane pore size, porosity and pore distribution, and membrane surface charge and hydrophobicity in certain pH and ionic strength conditions can contribute to fouling.
- Processing variables. Transmembrane pressure, temperature, and cross-flow velocity have a big impact on membrane fouling.
With a better understanding of these factors, several approaches can be taken to minimize membrane fouling:
- Optimize pH and ionic strength of the feed solution to minimize the adsorption or deposition of the feed materials.
- Select an appropriate pre-filtration procedure or other means to remove large molecules, since the presence of larger molecules or particles could cause a steric hindrance to the passage of smaller molecules through the membrane.
- Select a membrane with an optimum pore size to result in good separation performance as well as optimized permeate flux.
- Optimize the operating conditions. This includes increasing transmembrane pressure to maximize flux without introducing more fouling potential.
- Increase the cross-flow velocity, which generally results in an improvement in permeate flux.
- Definition of a Membrane
- Membrane Materials: Organic vs. Inorganic
- Pressure-Driven Membrane Filtration Processes
- Concentration Polarization in Pressure-Driven Processes
- Degrees of Membrane Separation
- Flux Behavior in Membrane Processes