4 research outputs found
Functionalisation of electrospun nanofibre for lanthanide ion adsorption from aqueous solution
Philosophiae Doctor - PhD (Chemistry)Rare earth elements (REEs) have widespread use and importance for industrial
applications due to their metallurgical, optical and electronic properties. Several
typical hydrometallurgical techniques such as adsorption, chemical precipitation,
filtration, ion exchange and solvent extraction techniques have been used for
separation and recovery of the rare earth metals from aqueous solutions. Adsorption
was recognised as one of the most promising methods due to its simplicity, high
efficiency and availability. Many adsorbents are being investigated but there are few
adsorbents containing specific functional groups in practical use for REEs recovery.
This aim of this study was to develop a nanofibre based adsorbent containing
glycolic acid functional groups for the recovery of rare earth metals. Polystyrene (PS)
and polyethylene terephthalate (PET) nanofibres were prepared by the
electrospinning technique, glycolic acid functional groups were grafted onto the PS
or PET nanofibres and the potential of the two modified nanofibre adsorbents for
adsorption of Ce3+ or Nd3+ from aqueous solution were investigated and compared.
The adsorption experiments were carried out to investigate the effect of different
adsorption parameters such as pH, contact time and initial concentration in a batch
system in order to achieve the objectives of this research
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
Adsorptive Recovery of Cu<sup>2+</sup> from Aqueous Solution by Polyethylene Terephthalate Nanofibres Modified with 2-(Aminomethyl)Pyridine
The accumulation of plastic waste products in the environment has adversely affected wildlife and human beings. Common plastics that accumulate in the environment are plastics that are made of polyethylene terephthalate (PET) polymer. PET plastic waste products can be recycled for beneficial use, which would reduce their negative impacts. In this study, modified PET or waste PET (WPET) from plastic bottles was blended with powder commercial 2-(aminomethyl)pyridine (SiAMPy) resin and electrospun into composite nanofibres and applied for Cu2+ adsorption. PET-SiAMPy or WPET-SiAMPy composite nanofibres fibre diameters from the HRSEM images were 90–140 nm and 110–155 nm, respectively. In batch adsorption experiments, PET-SiAMPy or WPET-SiAMPy composite nanofibres achieved Cu2+ adsorption equilibrium within 60 secs of contact time with 0.98 mmol/g (89.87%) or 1.24 mmol/g (96.04%) Cu2+ adsorption capacity. The Cu2+ complex formation rate (k) with WPET-SiAMPy was 0.0888 with the mole ratio of Cu2+ and WPET-SiAMPy nanofibres 1:2. The complex molecular formula formed was Cu(WPET-SiAMPy)2 with a square planar geometry structure. The WPET-SiAMPy nanofibres’ adsorption was best fitted to the Freundlich isotherm. WPET-SiAMPy composite nanofibres were considered highly efficient for Cu2+ adsorption from aqueous solution and could be regenerated at least five times using 5 M H2SO4
Metal Specific Functionalized Nanofibers
Functionalized nanofibers made by electrospinning technique. [...