Investigating the adsorption behavior and mechanisms of swine manure-derived biochar in tetracycline removal

This study primarily focused on the simple preparation of an efficient adsorbent from swine manure (SM) for removing tetracycline (TC) from water. SM-biochar (SM-BC), which was produced at varying temperatures (300–900 °C), showed increases in surface area and pore volume as the temperature increased, with BC-900 reaching 558.75 m²/g and 0.51 cm³/g, respectively. BC-700 and BC-900 achieved high adsorption capacities (423–437 mg/g), comparable to commercial activated carbons (110–362 mg/g). Kinetic and isotherm experiments revealed strong chemisorption, involving pore filling, H-bonding, π–π stacking interaction and π–π electron donor-acceptor interactions driven by the formation of a graphite-like structure and increased presence of aromatic compounds. Moreover, spent SM-BCs demonstrated effective chemical regeneration, highlighting their potential for practical water treatment applications.