Zeolite-like algal biochar nanoparticles for enhanced antibiotics removal: Sorption mechanisms and theoretical calculations

In the study, Sargassum horneri (S. horneri) was used to create a novel zeolite-like algal biochar (KSBC). KSBC with doping of N, O, S, Al, and Si, displayed zeolite-like properties, including well-developed porosity, a high specific surface area (1137.60 m²/g), and a large number of oxygen-containing functional groups. According to bath adsorption experiments, ciprofloxacin (CIP) and tetracycline (TC) had maximum adsorption capacities of 352.936 and 265.385 mg/g, respectively, on KSBC. The adsorption behavior of the two antibiotics on KSBC was consistent with the Freundlich isotherm model and the pseudo-first-order kinetic model. According to the density functional theory calculations, the -OH, Si, N, and Al in KOH could change the electronic structure and increase absorbability. Additionally, pore adsorption, hydrogen bonding, complexation, electrostatic interaction, and π-π electron-donor-acceptor (EDA) interaction were the adsorption mechanisms of CIP and TC via KSBC. S. horneri algal biochar demonstrated encouraging promise as an adsorbent for eliminating antibiotics from wastewater.