Heat-responsive gels used to coat MF/UF membranes

Applying thermoresponsive microgels to micro- and ultrafiltration (MF and UF) membranes can allow flow to be influenced by temperature variations, according to new research from RWTH Aachen University and DWI-Leibniz Institute for Interactive Materials in Germany.

In a paper Temperature-Modulated Water Filtration Using Microgel-Functionalized Hollow-Fiber Membranes published in the journal Angewandte Chemie (16 Apr 2014 DOI: 10.1002/anie.201400316), the authors describe how they used Pentair X-Flow MF and UF hollow-fiber membranes coated with poly(N-vinylcaprolactam)-based microgels. Both inside-out and outside-in filtration in dead-end mode were tested.

The researchers monitored the clean-water permeability and stability of the membranes not only as a function of time but also of temperature. Their finding was that the microgel-modified membranes exhibited a reversible thermoresponsive behavior in that both the resistance and the retention increased with decreasing temperature.

However, application of the gel did significantly reduce the permeability of the membranes.