Recent Advances in Biomass-Derived Activated Carbon and Biochar for Tetracycline Removal from Water: A Comprehensive Review

Here, we review the recent advancements in the use of sustainable carbon materials, namely, activated carbon (AC) and biochar (BC), for the adsorption of tetracycline (TC) from aqueous media. The environmental persistence of TC and its role in promoting antimicrobial resistance have necessitated the development of efficient, scalable, and sustainable treatment solutions. AC and BC, synthesized from agricultural and industrial biomass waste, offer high specific surface areas, tunable porosity, and surface functionalities that make them highly effective for TC removal. This review presents a comprehensive evaluation of biomass selection, synthesis routes, activation strategies, and surface modifications that influence the structural and chemical characteristics of these adsorbents. Key adsorption mechanisms such as π–π electron donor–acceptor interactions, hydrogen bonding, electrostatic interactions, surface complexation, and pore filling are critically discussed in relation to environmental parameters, including pH, ionic strength, and contaminant speciation. In addition, adsorption kinetics and isotherm models are analyzed to elucidate the underlying transport and binding processes. Finally, we identify current challenges and future opportunities in optimizing AC and BC for real-world applications in wastewater treatment systems. This review aims to serve as a scientific foundation for the rational design of next-generation carbon-based materials for effective antibiotic removal and environmental protection.