Development of open-pore polymer and ceramic foams/Guefoams with tunable fluid-dynamic properties: Application in highly efficient water bacteria removal

Abstract

The usual replication method for preparing open-pore metal foams using NaCl as a template cannot be successfully applied to the fabrication of foams using either water-based ceramic slurries in which NaCl can be dissolved during processing, or liquid polymers that wet NaCl and leave no interconnecting windows between pores. In this work, we propose to modify the replication process by including a second template, paraffin, which is deposited over the NaCl and serves a dual purpose: (i) it acts as a barrier to dissolution of the NaCl with the matrix precursor, and (ii) it creates size-controllable binding collars between the particles that ensure the formation of interconnecting windows in the foam. The usefulness of the process described here is illustrated by the fabrication of two types of materials: low porosity epoxy and cement matrix foams and Guefoams. As proof of concept, epoxy-based Guefoams were developed for the removal of Escherichia coli in water using iodine-impregnated activated carbon particles as the guest phase. The results indicate that the Guefoams outperform conventional bactericidal particle beds in several aspects, including their ease of handling and their tunable fluid-dynamic properties that enable high bacteria annihilation efficiency.