Selahle, S. K.Nephiphidi, Aluwani Sharon2026-06-172026-06-172026-05-19Nephiphidi, A.S. 2026. Magnetic solid phase microextraction and adsorptive removal of emerging pollutants from water samples by carbon adsorbents synthesized from agricultural waste materials,. . .https://univendspace.univen.ac.za/handle/11602/3197M.Sc. in ChemistryDepartment of ChemistryEmerging pollutants (EPs) are synthetic or naturally occurring chemicals that are not routinely monitored or regulated in the environment, posing potential risks to both ecological and human health. Many of these pollutants have been released without adequate recognition, particularly affecting communities that rely on untreated water sources. Anthropogenic activities, such as industrial discharges and agricultural practices, significantly contribute to this issue. Emerging pollutants encompass a range of substances, including pharmaceuticals, personal care products (PCPs), pesticides, UV filters, and antibiotics. Monitoring these pollutants presents challenges due to their continuous release into the environment at trace concentrations and their complex matrices, which limit the efficacy of conventional analytical techniques. Therefore, this study aimed to synthesize magnetic activated carbon (MAC) from agricultural waste for the microextraction and preconcentration of parabens (methylparaben, ethylparaben, and butylparaben) and the adsorptive removal of non-steroidal anti-inflammatory drugs (NSAIDs) (aspirin and ibuprofen) from wastewater samples. The carbon-based adsorbents were synthesized from avocado seeds and potato peel wastes. The obtained carbons were activated using various concentrations of potassium hydroxide (10%, 30% and 50%) , followed by magnetization using Fe3O4. The synthesized magnetic carbon adsorbents derived from agricultural waste materials offered several advantages, including cost-effectiveness, ease of separation, and environmental friendliness. Characterization of the synthesized magnetic carbon bioadsorbents was conducted, and they exhibited well-developed surface properties, as confirmed by Brunauer–Emmett–Teller (BET) analysis, with surface areas ranging from 30 - 57.96 m²/g and pore volumes of approximately 0.099 - 0.1 cm³/g. Scanning Electron Microscopy (SEM) revealed that the incorporation of iron oxide into the activated carbon resulted in the formation of small, well-defined pores. Energy Dispersive X-ray (EDX) analysis confirmed the presence of carbon, oxygen, iron, sodium, and potassium. Fourier Transform Infrared (FTIR) spectroscopy identified key functional groups, including carboxylic acid, iron oxide, and aromatic compounds. These characteristics indicate that the magnetic activated carbon, particularly that prepared with 30% KOH, is a promising and effective biosorbent. High-performance liquid chromatography coupled with a photodiode array detector was used for the detection and quantification of the targeted parabens and NSAIDs. Using the Dispersive Magnetic Solid-Phase Microextraction (DMSPME) technique, the optimum parameters for the extraction and preconcentration of parabens were 22.5 mg of bioadsorbent at pH 6.5, with 875 μL of methanol as the elution solvent. A batch adsorptive removal experiment was conducted for NSAIDs, with optimal conditions of an initial concentration of 10 mg/L, pH 7, and an adsorbent mass of 20 mg. Under these conditions, the removal efficiencies for NSAIDs were 96% and 94%, respectively, and the relative recoveries for the parabens ranged from 80.0% to 101%. The adsorption studies indicated that the data fitted well with the Langmuir isotherm model and followed the pseudo-first-order kinetics. A significant decline in reusability and regeneration percentage removal were observed after the fourth cycle for the removal of NSAIDs; also, the adsorption percentage recoveries significantly decreased after the seventh cycle for the extraction and preconcentration of parabens. The MACs prepared with 30% KOH demonstrated high adsorption efficiency for both NSAIDs and parabens. The biosorbents synthesized from agricultural waste were indicated to be effective sorbents for water treatment under the optimized conditions.1 online resource (xx, 141 leaves): color illustrationsenUniversity of VendaUCTDDissertationNephiphidi AS. Magnetic solid phase microextraction and adsorptive removal of emerging pollutants from water samples by carbon adsorbents synthesized from agricultural waste materials,. []. , 2026 [cited yyyy month dd]. Available from:Nephiphidi, A. S. (2026). <i>Magnetic solid phase microextraction and adsorptive removal of emerging pollutants from water samples by carbon adsorbents synthesized from agricultural waste materials,</i>. (). . Retrieved fromNephiphidi, Aluwani Sharon. <i>"Magnetic solid phase microextraction and adsorptive removal of emerging pollutants from water samples by carbon adsorbents synthesized from agricultural waste materials,."</i> ., , 2026.TY - Dissertation AU - Nephiphidi, Aluwani Sharon AB - Emerging pollutants (EPs) are synthetic or naturally occurring chemicals that are not routinely monitored or regulated in the environment, posing potential risks to both ecological and human health. Many of these pollutants have been released without adequate recognition, particularly affecting communities that rely on untreated water sources. Anthropogenic activities, such as industrial discharges and agricultural practices, significantly contribute to this issue. Emerging pollutants encompass a range of substances, including pharmaceuticals, personal care products (PCPs), pesticides, UV filters, and antibiotics. Monitoring these pollutants presents challenges due to their continuous release into the environment at trace concentrations and their complex matrices, which limit the efficacy of conventional analytical techniques. Therefore, this study aimed to synthesize magnetic activated carbon (MAC) from agricultural waste for the microextraction and preconcentration of parabens (methylparaben, ethylparaben, and butylparaben) and the adsorptive removal of non-steroidal anti-inflammatory drugs (NSAIDs) (aspirin and ibuprofen) from wastewater samples. The carbon-based adsorbents were synthesized from avocado seeds and potato peel wastes. The obtained carbons were activated using various concentrations of potassium hydroxide (10%, 30% and 50%) , followed by magnetization using Fe3O4. The synthesized magnetic carbon adsorbents derived from agricultural waste materials offered several advantages, including cost-effectiveness, ease of separation, and environmental friendliness. Characterization of the synthesized magnetic carbon bioadsorbents was conducted, and they exhibited well-developed surface properties, as confirmed by Brunauer–Emmett–Teller (BET) analysis, with surface areas ranging from 30 - 57.96 m²/g and pore volumes of approximately 0.099 - 0.1 cm³/g. Scanning Electron Microscopy (SEM) revealed that the incorporation of iron oxide into the activated carbon resulted in the formation of small, well-defined pores. Energy Dispersive X-ray (EDX) analysis confirmed the presence of carbon, oxygen, iron, sodium, and potassium. Fourier Transform Infrared (FTIR) spectroscopy identified key functional groups, including carboxylic acid, iron oxide, and aromatic compounds. These characteristics indicate that the magnetic activated carbon, particularly that prepared with 30% KOH, is a promising and effective biosorbent. High-performance liquid chromatography coupled with a photodiode array detector was used for the detection and quantification of the targeted parabens and NSAIDs. Using the Dispersive Magnetic Solid-Phase Microextraction (DMSPME) technique, the optimum parameters for the extraction and preconcentration of parabens were 22.5 mg of bioadsorbent at pH 6.5, with 875 μL of methanol as the elution solvent. A batch adsorptive removal experiment was conducted for NSAIDs, with optimal conditions of an initial concentration of 10 mg/L, pH 7, and an adsorbent mass of 20 mg. Under these conditions, the removal efficiencies for NSAIDs were 96% and 94%, respectively, and the relative recoveries for the parabens ranged from 80.0% to 101%. The adsorption studies indicated that the data fitted well with the Langmuir isotherm model and followed the pseudo-first-order kinetics. A significant decline in reusability and regeneration percentage removal were observed after the fourth cycle for the removal of NSAIDs; also, the adsorption percentage recoveries significantly decreased after the seventh cycle for the extraction and preconcentration of parabens. The MACs prepared with 30% KOH demonstrated high adsorption efficiency for both NSAIDs and parabens. The biosorbents synthesized from agricultural waste were indicated to be effective sorbents for water treatment under the optimized conditions. DA - 2026-05-19 DB - ResearchSpace DP - Univen KW - UCTD LK - https://univendspace.univen.ac.za PY - 2026 T1 - Magnetic solid phase microextraction and adsorptive removal of emerging pollutants from water samples by carbon adsorbents synthesized from agricultural waste materials, TI - Magnetic solid phase microextraction and adsorptive removal of emerging pollutants from water samples by carbon adsorbents synthesized from agricultural waste materials, UR - ER -