Transforming invasive weeds Typha angustifolia into NaOH-functionalized carbon for efficient tetracycline antibiotic removal: Experimental and theoretical validation

• Invasive weed cattail was NaOH functionalized to high Surface area Ty-AC . • Ty-AC exhibited maximum adsorption capacity of 382.166 mg/g for TC antibiotic. • MM2 simulations validated NaOH-induced surface hydroxylation enhanced the TC removal. • Ty-AC retained 97.8% of the removal efficiency after 10 reusable cycles. Eutrophication-driven invasive weeds represent a major ecological challenge but also an underutilized biomass resource. In this study, narrow-leaf cattail ( Typha angustifolia ) was valorized into an NaOH-functionalized activated carbon (Ty-AC) for the efficient removal of tetracycline (TC) antibiotics from water. The optimized Ty-AC (Typha:NaOH= 1:3) exhibited a high BET surface area of 1324.022 m 2 /g, a total pore volume of 2.12 m 3 /g, and an average pore width of 2.3 nm. The highest removal efficiency was achieved with an initial TC concentration of 100 ppm at pH 7 and a temperature of 50°C within 8 hours of time. TGA studies suggested thermal stability with a strong graphitic structure, while FTIR analysis confirmed enrichment of oxygenated functional groups (–OH, –COOH, –COO⁻) responsible for increased surface polarity and adsorption affinity. Effective alkali species incorporation was confirmed by the EDX analysis. Adsorption isotherm, kinetic data, and thermodynamic data for TC confirmed Langmuir and pseudo-second-order models as the best-fit models and the adsorption process as endothermic and spontaneous. The Langmuir equation also revealed the maximum adsorption capacity of 382.166 mg/g, underscoring the adsorbent’s excellence in TC removal. Computational molecular mechanics (MM2) simulations validated that NaOH-induced surface hydroxylation enhances TC adsorption by intensifying hydrogen bonding and electrostatic interactions. The adsorbent demonstrated excellent regeneration and stability by retaining 97.8% of the removal efficiency even after ten adsorption-desorption cycles. This work introduces a sustainable route for transforming invasive water blooms into high-performance adsorbents, offering a scalable and economical strategy for antibiotic pollution remediation in water systems.