Eco-friendly tassel-derived activated carbon for efficient dye removal in wastewater treatment

This study introduces a sustainable method for wastewater treatment by creating activated carbon from the fast-growing tassels of Phragmites australis, an invasive and low-cost biomass source. Its novelty lies in being the first to use the tassel part (inflorescence) of Phragmites australis as a precursor for activated carbon, demonstrating its excellent ability to remove Alizarin Red S (ARS), an anionic dye not previously studied with any Phragmites australis-based adsorbent. The resulting tassel-activated carbon (TAC) showed a high surface area (1166.16 m²/g), pore volume (1.5038 cm³/g), and abundant oxygen- and nitrogen-containing functional groups, confirmed by FTIR and XPS analyses. These structural features greatly improved its adsorption capacity for hazardous dyes like ARS and Methylene Blue (MB). The maximum adsorption capacities reached 541 mg/g for ARS and 860 mg/g for MB. Kinetic studies followed the pseudo-second-order model, indicating chemisorption, while equilibrium data fit the Langmuir isotherm, indicating monolayer adsorption. Thermodynamic results showed spontaneous and endothermic adsorption for ARS and spontaneous and exothermic adsorption for MB. TAC maintained high stability and reusability, retaining over 85% efficiency after seven adsorption-desorption cycles. Additionally, TAC effectively removed dyes from real water samples, including tap, Nile, and sewage water, demonstrating its practical potential. These findings position TAC as a promising, scalable, and eco-friendly adsorbent for industrial wastewater treatment, supporting sustainable waste valorization and cleaner aquatic environments.