Delonix regia biomass as an eco-friendly biosorbent for effective Alizarin Red S textile dye removal: Characterization, kinetics, and isotherm studies

Alizarin Red (ARS), a harmful dye known for its carcinogenic and mutagenic properties, is widely used in textile dyeing, posing a significant environmental concern due to its water-solubility and potential negative impact on aquatic life. This study explores the use of Delonix regia pods, obtained from the Gulmohar or Mayflower tree, as an eco-friendly adsorbent for ARS removal. The adsorption efficiency of Delonix regia pods was investigated by examining the effects of pH, dosage, initial concentration, and contact time. The optimal conditions for ARS removal were determined to be a pH of 2, a dosage of 2 g/L, and a contact time of 60 min, resulting in a significant 55 % removal of the dye. The experimental data exhibited a good fit with the Langmuir isotherm model (R2 = 0.9637), with the maximum adsorption capacity (qm) of the pods calculated as 4.4307 mg g- 1 and the binding energy constant (Kl) as -1.0732. These findings highlight the potential of Delonix regia pods as a promising and environmentally friendly option for effective ARS removal. The study emphasizes the significance of utilizing biomass-based adsorbents in addressing the environmental challenges associated with dye removal.