TiO2 functionalized nanofibrous membranes for removal of organic (micro)pollutants from water

Abstract

Abbreviations 1 1 PA 6: polyamide 6, MB: Methylene Blue, IL: inline, DC: dip-coating, H: hydrophilic 2 ABSTRACT Titania has already proven its added value for air and water treatment. The higher the surface-to-volume area, the better the performance of the TiO2 photocatalyst. These nanoparticles are typically applied in a slurry form. The use of titania nanoparticles in suspension has, however, multiple disadvantages such as a high turbidity and complex recovery of the photocatalyst after use. Therefore, immobilization of titania nanoparticles on a porous support such as a nanofibrous membrane, can be highly valuable for water treatment. These TiO2 functionalized nanofibrous membranes may be used not only in a membrane separation reactor, but also in a contact reactor. In this study, TiO2 nanoparticles were immobilized on both polymer (polyamide 6) and ceramic (silica) nanofibrous membranes. Polymer nanofibers are chosen as they are the state-of-the-art material, silica nanofibers on the contrary are less studied but show additional advantages due their excellent chemical and thermal stability and can thus offer a clear benefit for a wider range of applications. Two immobilization techniques were used, namely inline functionalization and dip-coating. Inline functionalization showed to be the preferred method for polyamide 6 nanofibrous membranes, dip-coating for silica nanofibrous membranes. Complete degradation of isoproturon, an actual concern in water treatment, is shown. Even the widely available commercial TiO2 nanoparticles allowed for a complete isoproturon removal as the result of a correct immobilization process on nanofibrous materials. This clearly opens up the high value of TiO2 functionalized nanofibrous membranes for organic (micro)pollutants removal.

Solvent-Free Process for the Development of Photocatalytic Membranes

“…Titanium dioxide (TiO 2 ) is the most commonly used material for the fabrication of photocatalytic membranes due to its high reactivity, chemical and thermal stability, low cost, reusability, and high photocatalytic performance [7][8][9].…”

Solution mixing preparation of PVDF/ZnO polymeric composite films engineered for heterogeneous photocatalysis

“…Comparatively, there are studies that report on the potential of polymer matrices . For example, the authors Ren et al .…”

Silica Nanofibrous Membranes for the Separation of Heterogeneous Azeotropes

“…A (super)hydrophobic membrane, which is characterized by a high water contact angle and low contact angle hysteresis, has potential applications in, for instance, microfluidics, as water‐repellent textile, in membrane distillation units, and in oil–water separation . On the other hand, a (super)hydrophilic membrane is beneficial for a whole range of other applications in which a water‐rich stream has to pass through the membrane structure with a low pressure drop and high flux, such as particle‐size‐based separation or photocatalytic degradation of organic micropollutants . This behavior is dependent on a subtle balance between the surface chemistry and the morphology of the membrane structure, such as pore size, pore size distribution, and surface roughness, and can be tuned by various functionalization strategies …”