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Mesoporous carbon nanofiber-ceramic hybrid materials for water treatment
Thesis (PhD)--Stellenbosch University, 2025.
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Stellenbosch : Stellenbosch University
2026
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| _version_ | 1867614139918057472 |
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| access_status_str | Open Access |
| author | Sibanda, David |
| author2 | Mallon, Peter |
| author_browse | Mallon, Peter Sibanda, David |
| author_facet | Mallon, Peter Sibanda, David |
| author_sort | Sibanda, David |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/134819 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:47:17.937Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/134819 Mesoporous carbon nanofiber-ceramic hybrid materials for water treatment Sibanda, David Mallon, Peter Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science. Water -- Purification Mesoporous materials Carbon nanofibers Photocatalysis Thesis (PhD)--Stellenbosch University, 2025. Sibanda, D. 2025. Mesoporous carbon nanofiber-ceramic hybrid materials for water treatment. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/fe6c9640-93b8-4aff-8575-93b8a14f932b ENGLISH ABSTRACT: This study investigates the synthesis, characterisation, and photocatalytic performance of nitrogen-doped porous carbon/TiO₂-CdS composite fibres using high-molecular-weight polyacrylonitrile-block-poly(butyl acrylate) (PAN-b-PBA) block copolymers synthesised via atom transfer radical polymerisation (ATRP). Block copolymer templates were utilised to control the nanostructure and porosity of the resulting carbon-ceramic hybrid fibres, enhancing their photocatalytic efficiency. The effects of polymer composition, processing conditions, and nanoparticle distribution on the morphology, surface chemistry, and photocatalytic activity were evaluated. The study examines the effects of varying PAN and PBA block lengths, as well as processing parameters, particularly solution ageing, on fibre, film, and particle morphology, as well as multi-porosity, particularly for fibres. High-molecular-weight PAN-Br is essential for obtaining a spinnable solution capable of forming nanofiber precursors, whereas low-molecular-weight precursors tend to form nanoparticles via electrospray. The results indicate that ageing the electrospinning solution increases the fibre diameter and transitions the structure from smooth-porous to rough-porous, likely due to physical crosslinking and intermolecular interactions in concentrated solutions. Photocatalytic degradation experiments using methylene blue (MB) as a model pollutant revealed that the carbon/TiO₂-CdS composite fibres show superior degradation rates compared to bare TiO₂ nanoparticle and nitrogen-doped carbon fibre systems. The hybrid structure facilitated enhanced charge separation and reduced electron-hole recombination, leading to improved photocatalytic activity under UV-light irradiation. The MB degradation efficiency decreased with increasing pollutant concentration, with a maximum removal of 57% at 5 mg/L MB concentration. Kinetic analysis indicated that the lowest MB concentration yielded the highest reaction rate (k = 0.00760 min⁻¹). Moreover, cycling experiments showed that the hybrid fibres maintained significant catalytic stability over three cycles, with a gradual efficiency decline from 57% to 32%. Comparative analysis with other photocatalytic materials highlighted the advantages of the carbon/TiO₂-CdS composite fibres in terms of stability, recyclability, and ease of recovery. Unlike slurry-based TiO₂-CdS nanoparticles, which require complex separation methods, the fibrous composites could be easily retrieved from aqueous solutions, making them a cost-effective alternative for wastewater treatment applications. Moreover, the block copolymer-templated approach provided a scalable method for synthesising high-surface-area photocatalysts with tunable composition and morphology. Overall, this study demonstrates that fine-tuning solution parameters and processing conditions enable control over the structure and properties of carbon nanofibers, providing valuable insights in “tailoring” multiporous carbon nanomaterials with specific morphologies. Additionally, the study shows that nitrogen-doped carbon/TiO₂-CdS composite fibres offer a promising photocatalytic platform for environmental remediation, with enhanced stability, reusability, and efficiency compared to conventional TiO₂ and TiO2-CdS systems. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Doctoral 2026-01-09T10:04:14Z 2026-01-09T10:04:14Z 2025-12 Thesis https://scholar.sun.ac.za/handle/10019.1/134819 Stellenbosch University xviii, 164 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Water -- Purification Mesoporous materials Carbon nanofibers Photocatalysis Sibanda, David Mesoporous carbon nanofiber-ceramic hybrid materials for water treatment |
| title | Mesoporous carbon nanofiber-ceramic hybrid materials for water treatment |
| title_full | Mesoporous carbon nanofiber-ceramic hybrid materials for water treatment |
| title_fullStr | Mesoporous carbon nanofiber-ceramic hybrid materials for water treatment |
| title_full_unstemmed | Mesoporous carbon nanofiber-ceramic hybrid materials for water treatment |
| title_short | Mesoporous carbon nanofiber-ceramic hybrid materials for water treatment |
| title_sort | mesoporous carbon nanofiber ceramic hybrid materials for water treatment |
| topic | Water -- Purification Mesoporous materials Carbon nanofibers Photocatalysis |
| url | https://scholar.sun.ac.za/handle/10019.1/134819 |
| work_keys_str_mv | AT sibandadavid mesoporouscarbonnanofiberceramichybridmaterialsforwatertreatment |