Functionalisation of polymer nanofibres and track-etched membrane removal of organic and and inorganic pollutants from water

Philosophiae Doctor - PhDOrganic and inorganic pollutants are two broad classes of pollutants in the environment with their main sources from waste waters that are indiscriminately dumped from chemical related industries. Among the organic pollutants are dyes that come as effluents from the textile industries. Toxic metals are the main inorganic pollutants with their sources from industries such as mining, electroplating, batteries etc. The presence of both classes of pollutants in the aquatic environment poses a serious threat to aquatic organisms and humans who depend on these waters for domestic purpose. Therefore, this research focused on the fabrication of materials and designing of methods for removal of both classes of pollutants from their aqueous solutions

Fabrication of silver‑coated PET track‑etched membrane as SERS platform for detection of acetaminophen

In this study, silver nanoparticles (AgNPs) were immobilized on the surface of polyethylene terephthalate (PET) membrane using diethylenetriamine (DETA) as a chemical linker. The molecule of DETA was attached to the surface of PET via an amide bond following scission of the polyester ester bond on the PET surface. The AgNPs were immobilized on the surface of diethylenetriamine-modifed PET membrane via a silver-nitrogen covalent bond. The silver-coated, DETA-modifed and unmodifed PET membranes were characterized by Fourier transform infrared (FTIR), x-ray photoelectron spectroscopy (XPS), ulltraviolet-visible spectroscopy (UV–Vis), and scanning electron microscopy (SEM). The results showed that the size of AgNPs also increased with time of immobilization. The percentage of elemental silver also increased with increase in time of immobilization of AgNPs on the surface of DETA-modifed PET membrane. The AgNP-coated PET membrane was used as SERS platform to detect acetaminophen in water. The SERS results showed that acetaminophen molecules could be detected with high Raman scattering intensity arising from adsorption of acetaminophen molecules on the silver nanoparticles of the SERS platform

Surface-modified polyacrylonitrile nanofibers as supports

Polyacrylonitrile nanofibers (PAN-nfs) are one of the most studied nanofibres because of their excellent characteristics, such as good mechanical strength, chemical resistance, and good thermal stability. Due to the easy dissolution in polar organic solvents, PAN-nfs are mostly produced via electrospinning technique. The electrospun PAN-nfs surfaces are relatively in-active and hydrophobic, and, therefore, hinder some potential applications; however, chemical surface modification reactions, such as amination, reduction, hydrolysis, and amidoximation, have been carried out on them. These reactions bring about functional groups, such as amine, hydroxyl, carboxylic, imine etc, to the surface PAN-nfs and invariably make their surfaces active and hydrophilic. The surface-modified PAN-nfs have been used as supports for organic compounds, enzymes, and antibodies in biological studies. They have also been used for immobilization of various organic ligands for adsorption of metal ions in water. Furthermore, because of their ability to complex metal ions, several surface-modified PAN-nfs have also been used as supports for transition metal catalysts in Fenton’s chemistry.IS