Nele Daels

Filtration performance of electrospun polyamide nanofibres loaded with bactericides

Electrospinning is a process to generate nanofibrous nonwovens. With these nonwovens, many applications can be targeted, such as water filtration. In this paper, polyamide nanofibrous membranes are evaluated for their pore size, a key parameter in water filtration, and for their removal of microorganisms. To increase the removal efficiency to values exceeding the state of the art, innovative functionalization of the nanofibres is studied. The nanofibrous membranes are functionalized using a one step method. Different functionalization chemicals are investigated which are Ag nanoparticles and bactericides. Ag functionalized nanofibres are used as a reference medium to compare with a novel bactericide based functionalization system. It is seen that nanofibrous membranes functionalized with the bactericides exceed the normal removal efficiencies obtained by microfiltration membranes. Furthermore, knowledge is built up on how these bactericides are inserted in the nanofibres themselves.

Structure changes and water filtration properties of electrospun polyamide nanofibre membranes

Nanofibre membranes are studied extensively in water treatment. Inappropriate storage, however, could alter their performance, e.g. regarding water filtration. This shows the need for investigating this effect in more detail so as to offer a solution for long-term behaviour and stability. In this study, polyamide nanofibre membranes were treated under different conditions, simulating the diverse storage conditions and to simulate their use in water filtration systems. Under all these different settings, nanofibre properties (scanning electron microscope pictures, dimensional changes, tensile strength) and water filtration performance (clean water permeability (CWP), bacterial removal) were investigated. The results demonstrate that, as soon as the dimensional change of a membrane is >2%, the CWP, tensile strength and bacterial removal significantly decrease. These dimensional changes occurred when the membrane became dry after it had been in contact with water. As such, it is important to keep the membrane either in dry or in wet conditions to store its unique properties. When heat-treated, the membrane had a higher tensile strength and kept its morphology and characteristics better during storage.