Mudzielwana, R.Pindihama, G. K.Tshotheli, Happiness2026-06-182026-06-182026-05-19Tshotheli, H. 2026. Synthesis of carbon nanotubes from tyre rubber waste for application in the removal of pharmaceutical contaminants in aquatic ecosystems. . .https://univendspace.univen.ac.za/handle/11602/3233Master of Environmental SciencesDepartment of Geography and Environmental SciencesThe presence of pharmaceutical contaminants in aquatic ecosystems is a growing environmental concern due to their significant impacts. This study was designed to assess the occurrence of amoxicillin, aspirin, efavirenz, and levonorgestrel in effluent of selected wastewater treatment plants (WWTPs) in Vhembe and Mopani Districts, as well as in their respective receiving streams. The study further evaluated the feasibility of synthesising carbon nanotubes (CNTs) from tyre rubber waste for the adsorption of prevalent pharmaceutical contaminants. The first chapter of results focused on assessing the presence of amoxicillin, aspirin, efavirenz, and levonorgestrel in wastewater effluent and the respective streams of the Vhembe and Mopane districts. A total of 42 samples collected in duplicate over a three-month period (July, August, and September) were subjected to solid-phase extraction (SPE), followed by analysis with a High-Performance Liquid Chromatograph (HPLC) coupled with a photodiode array (PDA) detector. The observed concentration range of the analysed compounds were 1.70×10-3 to 4.16×10-2 mg/L (effluent) and 4.0×10-4 to 1.68×10-2 mg/L (surface water) for efavirenz, 3.19×10-3 to 5.34×10-2 mg/L (effluent) and 1.0×10-3 to 2.44×10-2 mg/L (surface water) for levonorgestrel, 0.14 to 4.07 mg/L (effluent) and 0.52 to 4.13 mg/L (surface water) for amoxicillin, 0.46 to 4.75 mg/L (effluent) and 4.70×10-2 5 to 1.19 mg/L (surface water) for aspirin. Based on the results, amoxicillin was prevalent, with the highest concentrations in both the effluent and receiving streams. Owing to the dominance of amoxicillin in all treatment plants, the second chapter focused on the synthesis of CNTs from tyre rubber waste for the adsorption of amoxicillin from water. The CNTs were produced by pyrolysis of carbonised tyres, with ferrocene as a catalyst. For the characterisation of the CNTs, Fourier Transform Infrared Spectroscopy (FTIR) revealed functional groups typical of carbon nanotubes, including C=O, C–H, and C=C bonds. Additionally, Brunauer–Emmett–Teller (BET) analysis indicated a surface area of 90.16 m²/g. Scanning Electron Microscopy (SEM) identified fibrous features, while Transmission Electron Microscopy (TEM) revealed nearly spherical amorphous structures, which were concluded to be SWCNTs. Lastly, the particle size analyser recorded a particle size of 25.53 μm. Batch experiments were conducted to evaluate the removal efficiencies of amoxicillin by CNTs from water under various conditions. The maximum removal efficiency of 96.91% was achieved under the following conditions: a contact time of 90 min, a pH of 8, and an adsorbent dose of 60 mg at 35 °C. Furthermore, the adsorption process better fits the Freundlich isotherm model, indicating a heterogeneous surface influences multilayer adsorption. The adsorption capacity of amoxicillin was determined to be 25.46 mg/g for the synthesised CNTs. Additionally, the kinetics were better described by a pseudo-second order model, suggesting the dominance of a chemisorption mechanism. Adsorption isotherm studies revealed that amoxicillin adsorption on CNTs was endothermic and non-spontaneous. Furthermore, the material remained stable throughout 9 regeneration cycles, with efficiency decreasing to below 80% in the 8th cycle. The maximum amoxicillin removal efficiency from real water samples was 69.99%. From the observed results, the synthesised material has potential for application in the removal of amoxicillin from water In conclusion, amoxicillin, aspirin, efavirenz, and levonorgestrel were present in both wastewater effluent and receiving streams. Amoxicillin was detected at higher concentrations in the samples, prompting an investigation into its removal using in-house-synthesised CNTs derived from tyre rubber waste. This revealed significant potential to source adsorbents from environmental waste. This study further recommends (i) The inclusion of pharmaceutical contaminants in the routine monitoring of contaminants in essential water streams by relevant authorities, (ii) Further studies focusing on tertiary treatment methods targeting pharmaceutical compounds.1 online resource (xiv, 97 leaves)enUniversity of VendaPharmaceutical compoundsSynthesisCarbon nanotubes (CNTs)AdsorbentTyreRubber wasteDissertationTshotheli H. Synthesis of carbon nanotubes from tyre rubber waste for application in the removal of pharmaceutical contaminants in aquatic ecosystems. []. , 2026 [cited yyyy month dd]. Available from:Tshotheli, H. (2026). <i>Synthesis of carbon nanotubes from tyre rubber waste for application in the removal of pharmaceutical contaminants in aquatic ecosystems</i>. (). . Retrieved fromTshotheli, Happiness. <i>"Synthesis of carbon nanotubes from tyre rubber waste for application in the removal of pharmaceutical contaminants in aquatic ecosystems."</i> ., , 2026.TY - Dissertation AU - Tshotheli, Happiness AB - The presence of pharmaceutical contaminants in aquatic ecosystems is a growing environmental concern due to their significant impacts. This study was designed to assess the occurrence of amoxicillin, aspirin, efavirenz, and levonorgestrel in effluent of selected wastewater treatment plants (WWTPs) in Vhembe and Mopani Districts, as well as in their respective receiving streams. The study further evaluated the feasibility of synthesising carbon nanotubes (CNTs) from tyre rubber waste for the adsorption of prevalent pharmaceutical contaminants. The first chapter of results focused on assessing the presence of amoxicillin, aspirin, efavirenz, and levonorgestrel in wastewater effluent and the respective streams of the Vhembe and Mopane districts. A total of 42 samples collected in duplicate over a three-month period (July, August, and September) were subjected to solid-phase extraction (SPE), followed by analysis with a High-Performance Liquid Chromatograph (HPLC) coupled with a photodiode array (PDA) detector. The observed concentration range of the analysed compounds were 1.70×10-3 to 4.16×10-2 mg/L (effluent) and 4.0×10-4 to 1.68×10-2 mg/L (surface water) for efavirenz, 3.19×10-3 to 5.34×10-2 mg/L (effluent) and 1.0×10-3 to 2.44×10-2 mg/L (surface water) for levonorgestrel, 0.14 to 4.07 mg/L (effluent) and 0.52 to 4.13 mg/L (surface water) for amoxicillin, 0.46 to 4.75 mg/L (effluent) and 4.70×10-2 5 to 1.19 mg/L (surface water) for aspirin. Based on the results, amoxicillin was prevalent, with the highest concentrations in both the effluent and receiving streams. Owing to the dominance of amoxicillin in all treatment plants, the second chapter focused on the synthesis of CNTs from tyre rubber waste for the adsorption of amoxicillin from water. The CNTs were produced by pyrolysis of carbonised tyres, with ferrocene as a catalyst. For the characterisation of the CNTs, Fourier Transform Infrared Spectroscopy (FTIR) revealed functional groups typical of carbon nanotubes, including C=O, C–H, and C=C bonds. Additionally, Brunauer–Emmett–Teller (BET) analysis indicated a surface area of 90.16 m²/g. Scanning Electron Microscopy (SEM) identified fibrous features, while Transmission Electron Microscopy (TEM) revealed nearly spherical amorphous structures, which were concluded to be SWCNTs. Lastly, the particle size analyser recorded a particle size of 25.53 μm. Batch experiments were conducted to evaluate the removal efficiencies of amoxicillin by CNTs from water under various conditions. The maximum removal efficiency of 96.91% was achieved under the following conditions: a contact time of 90 min, a pH of 8, and an adsorbent dose of 60 mg at 35 °C. Furthermore, the adsorption process better fits the Freundlich isotherm model, indicating a heterogeneous surface influences multilayer adsorption. The adsorption capacity of amoxicillin was determined to be 25.46 mg/g for the synthesised CNTs. Additionally, the kinetics were better described by a pseudo-second order model, suggesting the dominance of a chemisorption mechanism. Adsorption isotherm studies revealed that amoxicillin adsorption on CNTs was endothermic and non-spontaneous. Furthermore, the material remained stable throughout 9 regeneration cycles, with efficiency decreasing to below 80% in the 8th cycle. The maximum amoxicillin removal efficiency from real water samples was 69.99%. From the observed results, the synthesised material has potential for application in the removal of amoxicillin from water In conclusion, amoxicillin, aspirin, efavirenz, and levonorgestrel were present in both wastewater effluent and receiving streams. Amoxicillin was detected at higher concentrations in the samples, prompting an investigation into its removal using in-house-synthesised CNTs derived from tyre rubber waste. This revealed significant potential to source adsorbents from environmental waste. This study further recommends (i) The inclusion of pharmaceutical contaminants in the routine monitoring of contaminants in essential water streams by relevant authorities, (ii) Further studies focusing on tertiary treatment methods targeting pharmaceutical compounds. DA - 2026-05-19 DB - ResearchSpace DP - Univen KW - Pharmaceutical compounds KW - Synthesis KW - Carbon nanotubes (CNTs) KW - Adsorbent KW - Tyre KW - Rubber waste LK - https://univendspace.univen.ac.za PY - 2026 T1 - Synthesis of carbon nanotubes from tyre rubber waste for application in the removal of pharmaceutical contaminants in aquatic ecosystems TI - Synthesis of carbon nanotubes from tyre rubber waste for application in the removal of pharmaceutical contaminants in aquatic ecosystems UR - ER -