By Dr. Brian Rodenhausen, Senior Product Specialist at Anton Paar
Filtration membranes have a wide range of applications, from wastewater treatment and desalination to screening proteins and biomolecules in pharmaceutical manufacturing. It is because of their broad reach across so many scientific fields that the frustration of membrane fouling is so universally understood.
Fouling reduces the throughput across a membrane, and scientists lose countless hours to surface maintenance and regeneration, as well as immeasurable amounts of money replacing membranes lost to excessive fouling or repeated harsh surface treatments. These problems might be prevented through more effectively designed membranes and treatments, but that demands a better understanding of the complex mechanisms that cause fouling and a more precise means of measuring them.
Membranes are most often characterized through techniques such as contact angle, AFM, scratch and indentation testing, and Raman spectroscopy. However, none of these address surface charge, which is important because electrostatic attraction leads to fouling while electrostatic repulsion prevents it. This article will explore and emphasize the role of surface charge as a function of pH in membrane fouling, and how zeta potential measurements will help scientists evaluate product performance and pretreatment and regeneration efficacy.