What are the factors that affect the flux of microporous filtration membranes, and what substances a

The flux or flow rate of the microporous filtration membrane is the key parameter that determines its efficiency and performance, and it is also an important indicator that must be paid attention to during the membrane selection process. So, what are the factors that affect the membrane flux?

2. Membrane thickness, thicker membranes generally have higher resistance to flow, which results in lower flux.
The following is a comparison of typical thickness ranges of microporous filtration membranes and their corresponding flow rates.
Film Thickness Range: 0.1 - 1.0 microns, Flow Rate: 1 - 100 ml per minute
Film Thickness Range: 1.0 - 10.0 microns, Flow Rate: 0.1 - 10 mL per minute
Film Thickness Range: 10.0 - 100.0 Microns, Flow Rate: 0.01 - 1 mL/min
These are general ranges for reference and actual flow rates will also take into account factors such as membrane porosity, fluid viscosity and pressure gradient across the membrane.

3. Operating conditions, temperature, pressure and cross-flow velocity are important factors affecting flux. Higher temperatures generally increase flux due to a decrease in fluid viscosity, while higher pressure also increases flux by forcing more fluid through the membrane. However, excessive pressure can lead to membrane fouling and damage. Proper cross-flow velocities help minimize concentration polarization and fouling, which would otherwise reduce flux.

4. Fouling, the accumulation of some particles, colloids or biological substances on the membrane surface or in the pores will lead to a decrease in flux. Particles such as dirt, dust, and other debris Biological matter including bacteria, algae, and fungi, etc. Organic matter such as proteins, polysaccharides, and lipids Organic compounds, including some inorganic matter such as calcium, magnesium, and iron, Chemicals such as surfactants , solvents, and other contaminants can accumulate on the surface of the membrane, reducing its effectiveness and resulting in poor performance. Regular cleaning of membranes and use of proper pretreatment methods can help minimize fouling.

Usually, in order to test the flux of microporous filtration membranes, substances such as water, alcohol, dyes or specific solutes are used. For example, pure water flux is a common parameter used to evaluate membrane performance, and other substances, such as dextran, proteins, or salt solutions, can be used to evaluate the separation efficiency and selectivity of membranes.

Citation

1.Kim, J. H., Kim,H. C., & Kim, J. Y. (2013). Flux enhancement and fouling control inmembrane filtration processes: A review. Journal of Industrial and EngineeringChemistry, 19(1), 1-11. https://doi.org/10.1016/j.jiec.2012.07.014

2.Liao, B. Q., Jin,W., & Wang, P. (2018). Recent advances in the development of high-fluxmembranes for water treatment. Journal of Membrane Science, 554, 98-118.https://doi.org/10.1016/j.memsci.2018.02.026

3.Su, Y., &Chung, T. S. (2019). Recent advances in membrane surface modification forenhanced membrane filtration performance. Journal of Membrane Science, 572,163-181. https://doi.org/10.1016/j.memsci.2018.09.047

4.Wang, K., Li, X.M., Chen, J. X., & Wang, J. Y. (2017). Enhancement of membrane filtrationperformance by modifying membrane surface with nanoparticles: A review. Journalof Colloid and Interface Science, 498, 85-104. https://doi.org/10.1016/j.jcis.2017.02.026