Real time monitoring of whey foulants adsorption on polyethersulfone surface

The worldwide growing demand for whey proteins and derivatives requires more efficient and sustainable whey protein production processes. Whey is an important by-product from cheese manufacturing. In whey industry membrane processes such as microfiltration, ultrafiltration, nanofiltration and reverse osmosis are well-established to concentrate, fractionate and purify whey proteins as well as whey derivatives in large scale.
In particular, ultrafiltration is used to separate whey proteins and derivatives in aqueous mixtures in an energy efficient way under mild process conditions maintaining the natural properties of the proteins. However, membrane fouling is one of the key challenges when applying membrane processes in the whey industry. Fouling occurs because of adsorption of e.g. whey proteins onto the membrane, which results in a decrease of permeate flux over the filtration time and a formation of a fouling layer on top of the membrane surface, which can alter separation performance. Frequent cleaning with chemical cleaning agents or enzymes is standard in the industry to overcome fouling but results in plant downtime, reduction of membrane lifetime as well as costs for cleaning agents and water/wastewater.
In order to gain a deeper understanding of the complexity of membrane fouling, the adsorption process and viscoelastic properties of the fouling layer formed by whey proteins over time on the surface of polyethersulfone were studied. Polyethersulfone is the most common ultrafiltration membrane material in the dairy industry. The adsorption was studied by real-time monitoring techniques such as quartz crystal microbalance with dissipation (QCM-D) and surface plasmon resonance (SPR).
The results obtained will help to gain further understanding of the fouling behavior and thus to develop tailored cleaning strategies to minimize/overcome fouling. Furthermore, the knowledge gained might also support development of new membrane materials to minimize/eliminate fouling.
The work reflects on and builds upon previous work in the field [1, 2] with the aim to provide further information on the adsorption and desorption of whey proteins and other whey foulants onto polyethersulfone surfaces to support the broad employment of membranes in food processing.