- Title
- Fabrication of a photocatalytic PAN supported C-TiO2-CFA nanocomposite for use in water treatment
- Creator
- Mpelane, Amkelwa
- Subject
- Photocatalysis
- Date Issued
- 2020
- Date
- 2020
- Type
- Thesis
- Type
- Masters
- Type
- MSc (Chemistry)
- Identifier
- http://hdl.handle.net/10353/18744
- Identifier
- vital:42729
- Description
- The goal of this study was to fabricate a visible light responsive composite of C-TiO2-CFA. The prepared nanocomposite (C-TiO2-CFA) was immobilized on poly(acrylonitrile) membrane to address the drawback of recovering the nanosized photocatalyst from water after photodegradation experiments. The C-TiO2-CFA nanocomposites were fabricated using a modified sol-gel method, while the C-TiO2-CFA/PAN membranes were prepared via the phase inversion technique. The nanocomposites were fully characterized using FTIR, XRD, SEM-EDX, TEM, DRS, and BET surface area analysis. The prepared C-TiO2-CFA/PAN membranes were evaluated in the photodegradation of methyl orange and the golden yellow dyes, as well as the photoreduction of lead and cadmium heavy metals in synthetic wastewater. UV-Visible spectroscopy was used to follow the changes in the concentration of organic dyes, while inductively coupled plasma optical emission spectroscopy was used to follow changes in the concentration of the heavy metals. FTIR analysis confirmed the presence of functional groups expected on the prepared C-TiO2- CFA/PAN membranes and EDX analysis accounted for the elements expected. The prepared membranes all exhibited an asymmetric structure as depicted by cross-sectional view study via SEM analysis. TEM and SEM analyses revealed that the prepared C-TiO2-CFA nanocomposite was roughly spherical in shape with an estimate particle size of 10.94 nm according to TEM and 11.62 nm according to XRD using Scherrer equation. The incorporation of carbon into the lattice structure of titanium dioxide resulted in a reduction in bandgap from 3.19 eV to 2.78 eV through introduction of mid-band states, allowing visible light utilization. The best nanocomposite was obtained by doping TiO2 with 4% carbon and having a C-TiO2 to CFA ratio of 4:1 respectively. The C-TiO2-CFA nanocomposite exhibits a crystalline structure with a mixture of rutile and anatase phases. The parameters investigated in the evaluation of photocatalytic performance of C-TiO2- CFA/PAN were effect of photocatalyst load on PAN membrane, initial dye concentration, pH and light source in the activation of photocatalyst. For both dyes (methyl arrange and golden yellow), it was observed that photodegradation efficiencies increased with an increase in catalyst load. In the photodegradation of MO and GY using the membrane with 1% C-TiO2- CFA, removal efficiencies of 73.3% and 59.99% were attained respectively, while the membrane with 2% C-TiO2-CFA achieved MO and GY photodegradation efficiencies of 99.8% and 99.2% respectively. Photodegradation efficiencies of MO and GY were observed to decrease with an increase in dye concentration. Low pH (3) was observed to favour the photodegradation of MO and GY azo dyes. Photodegradation efficiencies of 99.8% and 99.2% were attained where obtained at lower MO and GY initial concentration. The modified photocatalyst (C-TiO2-CFA/PAN) exhibited better photoactivity under sunlight irradiation compared to strict UV light irradiation. Evidently, the C-TiO2-CFA/PAN membranes can be 4 Final Submission of Thesis, Dissertation or Research Report/Project, Conference or Exam Paper utilized as a sustainable and stable photocatalyst to efficiently eliminate methyl orange and golden yellow dyes. A PAN membrane with 2 wt% C-TiO2-CFA revealed enhanced cadmium and lead removal efficiencies in comparison to PAN membranes with 1 wt% and 1.5% C-TiO2-CFA. A Cd2+ removal efficiency of 95% was obtained using 2 wt% C-TiO2-CFA/PAN nanocomposite membranes. Cadmium removal efficiencies of 92.5% and 91% were obtained using the 1.5 wt% and 1 wt% C-TiO2-CFA/PAN nanocomposite membranes. A lead removal efficiency of 97% was obtained using PAN membrane with 2 wt% C-TiO2-CFA. Pb2+ removal efficiencies of 90.9% and 94.6% were obtained using the 1.5 wt% and 1 wt% C-TiO2-CFA/PAN nanocomposite membranes. The photoreduction activity was observed to decrease with an increase in cadmium and lead initial concentrations. A cadmium and lead removal efficiencies of 95% and 97% were observed at lower Cd2+ and Pb2+ initial concentrations (20 ppm), respectively. The removal efficiencies varied marginally with changes in pH values. The fouling activity of the C-TiO2 modified PAN asymmetric membranes and pure PAN was investigated by carrying out pure water filtration tests as well as bovine serum albumin (BSA) filtration tests. A bovine serum albumin rejection of 98% was obtained utilizing the 2 wt% CTiO2-CFA/PAN membrane.
- Format
- 123 leaves
- Format
- Publisher
- University of Fort Hare
- Publisher
- Faculty of Science and Agriculture
- Language
- English
- Rights
- University of Fort Hare
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UFH Department of Chemistry
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