Maximising E-waste leachate adsorption: multi-component isotherm models and mechanisms with scalable mesoporous sugarcane bagasse-derived biochar

Al-Gailani, Amthal; Bongosia, Julius G.; Hornsby, Karl; Taylor, Martin J.

Abstract

Heavy metal contamination is a primary environmental and health concern contributing to organ damage, neurological disorders and developmental issues. Adsorption is an efficient, cost-effective method for removing heavy metals from contaminated water. In this study, the adsorption of five metals (Cu2+, Ni2+, Pb2+, Ag+ and Mn2+) into mesoporous sugarcane bagasse-derived biochar (surface area: 1061.77 m2 g−1) was investigated using multi-component isotherm models, including Extended Langmuir (EL), Extended Freundlich (EF), Modified Competitive Langmuir (MCL) and Extended Sips (ES). The biochar was synthesised via KOH activation (1, 1 w/w) followed by pyrolysis at 800 °C. The ES model was found to best describe the competitive adsorption behaviour. Among the tested metals, Pb2+ exhibited the highest adsorption capacity (605.45 mg/g), followed by Cu2+ (501.77 mg/g). Kinetic analysis using pseudo-first-order and pseudo-second-order models confirmed chemisorption superiority, specifically for Cu2+, Mn2+, and Pb2+. The rate-limiting step was temperature-dependent; intraparticle diffusion dominated at 25 °C, while chemisorption prevailed at 55 °C. The thermodynamic analysis (ΔH > 0, ΔG < 0) confirmed that the adsorption process is endothermic and spontaneous under the tested conditions. After three regeneration cycles, the biochar structure stability is confirmed with evidence of full adsorbate removal.

Citation

Al-Gailani, A., Bongosia, J. G., Hornsby, K., & Taylor, M. J. (2025). Maximising E-waste leachate adsorption: multi-component isotherm models and mechanisms with scalable mesoporous sugarcane bagasse-derived biochar. Journal of Water Process Engineering, 75, Article 107979. https://doi.org/10.1016/j.jwpe.2025.107979

• Journal Article Type: Article
• Acceptance Date: May 18, 2025
• Online Publication Date: May 20, 2025
• Publication Date: 2025-06
• Deposit Date: May 21, 2025
• Publicly Available Date: May 21, 2025
• Print ISSN: 2214-7144
• Electronic ISSN: 2214-7144
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 75
• Article Number: 107979
• DOI: https://doi.org/10.1016/j.jwpe.2025.107979
• Public URL: https://hull-repository.worktribe.com/output/5179784