Zwitterionic and Photocatalytic Janus Membrane Based on Diethylamine N-Oxide Group and WS₂ Nanosheets for Dye Removal in Forward Osmosis

Abstract

The search for innovative materials with unique properties to aid in the remediation of polluted water effluents is increasingly imperative. Herein, we present the fabrication of a Janus membrane operated in forward osmosis mode that combines the advantages of polymeric and semiconducting materials. This membrane was prepared postmodifying a polysulfone backbone with the zwitterionic group amine N-oxide (DEAO). Then, a thin layer of WS 2 nanosheets was deposited over the membrane to incorporate a photosensitive layer. The fabricated membranes were thoroughly characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), surface Zpotential, and water contact angle (CA). The performance of the prepared membranes was assessed in terms of the water permeance and their ability to degrade a model dye (rhodamine B (RhB)). The results suggest the photodegradation of the RhB above 92% and 98% after 8 and 12 h, respectively. These degradation performances are almost 20% higher than the control membranes, and reactive oxygen species (ROS) are likely formed by the WS 2 nanosheets, which accelerates the degradation process. These results are encouraging, as this technology may open the door to fabricating membranes with dual functions.

Medicinal Chemistry of Drugs with N-Oxide Functionalities

“…It makes polymeric N -oxides interesting for applications not only in the biomedical field but also in (salt)­water purification. The latter has been demonstrated with the preparation of superwetting membranes which can be used for the separation of oil–water emulsions and textile wastewater dye removal. − A possible drawback of polymeric N -oxides for applications in healthcare is their limited thermal stability, which was mentioned in Chapter 2. Decomposition reactions typically start at around 120–150 °C.…”