Evaluation Of Biochar Derived from Mango and Banana Peels for The Removal of Selected Endocrine-Disrupting Compounds from Wastewater
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Date
2026-01-31
Authors
Kasambala, Hildegard R.
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Publisher
Nelson Mandela African Institution of Science and Technology.
Abstract
Wastewater pollution by endocrine-disrupting compounds poses a significant environmental and public health risk due to their ability to interfere with hormonal systems in living organisms even at trace levels. Conventional removal methods of endocrine-disrupting compounds from wastewater often fail to effectively eliminate these pollutants, encouraging the search for sustainable and eco-friendly alternatives. This study evaluated the potential of biochar derived from banana and mango peels, both in mono- and hybrid forms, to remove progesterone and bisphenol A from synthetic and real wastewater. It also examined the impact of the coexistence of progesterone and bisphenol A on hybrid biochar removal efficiency. Biochar was produced through pyrolysis at temperatures of 300, 550, 700 and 800°C for a duration of two hours. Batch adsorption experiments in varying conditions revealed that biochar produced at 700°C yielded the most effective adsorbent. Optimal removal was achieved with a 0.5 g dose of biochar, pH 8, an adsorbate concentration of 12.50 mg L⁻¹, a temperature of 25°C and agitation of 140 rpm. Under these conditions, the hybrid biochar demonstrated the highest removal efficiency of 97.80% of progesterone and 91.80% of bisphenol A, compared to banana peels biochar (92.80% and 87.90%) and mango peels biochar (80.50% and 90.40%), respectively. Adsorption kinetics followed a pseudo-second-order model, indicating chemisorption as the rate-limiting step. Isotherm models showed that bisphenol A followed the Freundlich model (R² = 0.99), indicating multilayer adsorption on heterogeneous surfaces, while progesterone fit the Langmuir model (R² = 0.98), indicating monolayer adsorption. The hybrid biochar had a Brunauer-Emmett-Teller surface area of 652 m² g⁻¹, outperforming banana (481 m² g⁻¹) and mango (562 m² g⁻¹) biochar. Fourier Transform Infrared Spectroscopy confirmed the presence of functional groups and Scanning Electron Microscopy revealed a highly porous structure that facilitates the entrapment of pollutants. Thermodynamic analysis showed that adsorption was spontaneous, endothermic and involved both strong physisorption and weak chemisorption. The hybrid biochar maintained high performance over four reuse cycles, although it shows slightly less efficiency in real wastewater due to the presence of competing solutes. Therefore, hybrid agro-waste biochar is a promising, reusable material for removing endocrine-disrupting compounds. Further research is recommended to optimize its properties and evaluate its performance against a broader range of organic pollutants in full-scale field applications
Description
This Thesis was published by Nelson Mandela African Institution of Science and Technology.
Keywords
Wastewater pollution, organic pollutants, biochar derived, living organisms