Evaluation of surface functionalized electrospun polyacrylonitrile nanofibers for heavy metal ions removal from synthetic wastewater
- Maqinana, Siphosethu Sesethu
- Authors: Maqinana, Siphosethu Sesethu
- Date: 2020-12
- Subjects: Nanofibers , Nanostructured materials
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20871 , vital:46680
- Description: Heavy metal ions are elements that are discharged into water streams from municipal or industrial waste. In abundance, they can be threating to the environment and human health. Amongst other several convention methods, adsorption has been proven to be the most effective method in the removal of heavy metal ions from wastewater. The aim of this research was to fabricate electrospun polyacrylonitrile (PAN) nanofibers and modify their surface to improve the adsorption efficiency for Chromium and Cadmium metal ions from synthetic wastewater. Electrospun nanofibers PAN nanofibers were fabricated via electrospinning process though careful monitoring of its parameters and modified via two-step process: hydrolysis with sodium hydroxide (NaOH), hydrochloric acid (HCl) and ethylenediamine (EDA). The morphologies, functional groups, thermal stability, chemical composition and crystallinities or amorphous structures of the nanofibers were characterised by Scanning electron microscopy (SEM), Fourier-Transform Infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD), respectively. The experiments were conducted in batch tests to analyse the effect to pH, contact time and initial concentration of the solution. Ultraviolet-Visible spectroscopy (UV-Vis) was used to analyse the concentration of metal ions. The adsorption equilibrium was reached after 120 min with a maximum adsorption capacity of 301.1 mg/g for Cd(II) ions and 195.02 mg/g for Cr(VI) ions. The adsorption capacity increased with increasing pH and initial concentration of the solution. The adsorption capacity of Cd(II) and Cr(VI) ions was higher at pH 8 and 10, respectively. The equilibrium data was best described using Freundlich isotherm with a maximum adsorption capacity for Cd(II) ions than Cr(VI) ions. Pseudo-second order kinetic model best fitted both heavy metal ions with R2 value of 0.99 for Cr(VI) ions and 0.67 for Cd(II) ions. Heavy metal ions were desorbed from the nanofibers after one regeneration cycle with an equilibrium concentration of 4.83 mg/L for Cr(VI) ions and 43.06 mg/L for Cd(II) ions. , Thesis (MSc) (Chemistry) -- University of Fort Hare, 2021
- Full Text:
- Authors: Maqinana, Siphosethu Sesethu
- Date: 2020-12
- Subjects: Nanofibers , Nanostructured materials
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20871 , vital:46680
- Description: Heavy metal ions are elements that are discharged into water streams from municipal or industrial waste. In abundance, they can be threating to the environment and human health. Amongst other several convention methods, adsorption has been proven to be the most effective method in the removal of heavy metal ions from wastewater. The aim of this research was to fabricate electrospun polyacrylonitrile (PAN) nanofibers and modify their surface to improve the adsorption efficiency for Chromium and Cadmium metal ions from synthetic wastewater. Electrospun nanofibers PAN nanofibers were fabricated via electrospinning process though careful monitoring of its parameters and modified via two-step process: hydrolysis with sodium hydroxide (NaOH), hydrochloric acid (HCl) and ethylenediamine (EDA). The morphologies, functional groups, thermal stability, chemical composition and crystallinities or amorphous structures of the nanofibers were characterised by Scanning electron microscopy (SEM), Fourier-Transform Infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD), respectively. The experiments were conducted in batch tests to analyse the effect to pH, contact time and initial concentration of the solution. Ultraviolet-Visible spectroscopy (UV-Vis) was used to analyse the concentration of metal ions. The adsorption equilibrium was reached after 120 min with a maximum adsorption capacity of 301.1 mg/g for Cd(II) ions and 195.02 mg/g for Cr(VI) ions. The adsorption capacity increased with increasing pH and initial concentration of the solution. The adsorption capacity of Cd(II) and Cr(VI) ions was higher at pH 8 and 10, respectively. The equilibrium data was best described using Freundlich isotherm with a maximum adsorption capacity for Cd(II) ions than Cr(VI) ions. Pseudo-second order kinetic model best fitted both heavy metal ions with R2 value of 0.99 for Cr(VI) ions and 0.67 for Cd(II) ions. Heavy metal ions were desorbed from the nanofibers after one regeneration cycle with an equilibrium concentration of 4.83 mg/L for Cr(VI) ions and 43.06 mg/L for Cd(II) ions. , Thesis (MSc) (Chemistry) -- University of Fort Hare, 2021
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Photocatalytic activity and antibacterial properties of Ag/N-doped TiO2 nanoparticles on PVAE-CS nanofibre support
- Authors: Ocwelwang, Atsile Rosy
- Date: 2012
- Subjects: Nanocomposites (Materials) , Nanofibers , Electrospinning
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: vital:11337 , http://hdl.handle.net/10353/d1006794 , Nanocomposites (Materials) , Nanofibers , Electrospinning
- Description: Lack of potable water is one of the major challenges that the world faces currently and the effects of this are mainly experienced by people in developing countries. This has therefore propelled research in advanced oxidation technologies AOTs to improve the current water treatment methods using cost effective, non toxic and efficient treatment methods. Hence, in this study the sol-gel synthesis method was used to prepare TiO2 nanoparticles that were photocatalytically active under UV and visible solar light as well as possessing antibacterial properties. Silver and nitrogen doping was carried out to extend the optical absorption of TiO2. For easy removal and reuse of the photocatalyst the nanoparticles were immobilized on chitosan and poly (vinyl-alcohol-co-ethylene) using the electrospining technique. The synthesized nanomaterials were characterized by FTIR, XRD, SEM/EDS, TEM, DRS, and TGA. FTIR and EDS analysis confirmed the formation and composition of TiO2 nanopowders for the doped and undoped nanoparticles. XRD analysis showed that the anatase phase was the dominant crystalline phase of the synthesized nanopowders. SEM and TEM respectively illustrated the distribution and size of the electrospun nanofibers and the nanoparticles of TiO2. DRS results showed that there was a significant shift in the absorption band edge and wavelength of Ag-TiO2 to 397 nm, followed by N-TiO2 at 396 nm compared to the commercial titania which was at 359 nm. The photocatalytic activities and antibacterial properties of these materials were tested on methylene blue dye and E.coli microorganism respectively. Ag-TiO2 immobilized on nanofibers of chitosan and PVAE had the highest photocatalytic activity compared to N-TiO2. Similar results were observed when the biocide properties of these materials were tested on E. coli.
- Full Text:
- Authors: Ocwelwang, Atsile Rosy
- Date: 2012
- Subjects: Nanocomposites (Materials) , Nanofibers , Electrospinning
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: vital:11337 , http://hdl.handle.net/10353/d1006794 , Nanocomposites (Materials) , Nanofibers , Electrospinning
- Description: Lack of potable water is one of the major challenges that the world faces currently and the effects of this are mainly experienced by people in developing countries. This has therefore propelled research in advanced oxidation technologies AOTs to improve the current water treatment methods using cost effective, non toxic and efficient treatment methods. Hence, in this study the sol-gel synthesis method was used to prepare TiO2 nanoparticles that were photocatalytically active under UV and visible solar light as well as possessing antibacterial properties. Silver and nitrogen doping was carried out to extend the optical absorption of TiO2. For easy removal and reuse of the photocatalyst the nanoparticles were immobilized on chitosan and poly (vinyl-alcohol-co-ethylene) using the electrospining technique. The synthesized nanomaterials were characterized by FTIR, XRD, SEM/EDS, TEM, DRS, and TGA. FTIR and EDS analysis confirmed the formation and composition of TiO2 nanopowders for the doped and undoped nanoparticles. XRD analysis showed that the anatase phase was the dominant crystalline phase of the synthesized nanopowders. SEM and TEM respectively illustrated the distribution and size of the electrospun nanofibers and the nanoparticles of TiO2. DRS results showed that there was a significant shift in the absorption band edge and wavelength of Ag-TiO2 to 397 nm, followed by N-TiO2 at 396 nm compared to the commercial titania which was at 359 nm. The photocatalytic activities and antibacterial properties of these materials were tested on methylene blue dye and E.coli microorganism respectively. Ag-TiO2 immobilized on nanofibers of chitosan and PVAE had the highest photocatalytic activity compared to N-TiO2. Similar results were observed when the biocide properties of these materials were tested on E. coli.
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