Biogenic fabrication of iron nanoadsorbents from mixed waste biomass for aqueous phase removal of alizarin red S and tartrazine: Kinetics, isotherm, and thermodynamic investigation

Present work deals with the facile and ecologically viable production of iron nanoadsorbents by utilizing different waste plant biomass, orange peel, flower waste, and environmentally harmful Alligator weed. The as-prepared nanoadsorbents were applied for the aqueous phase minimization of toxic dyes, alizarin red S and tartrazine. Different techniques, namely, X-ray diffraction, Fourier transform infra-red spectroscopy, scanning electron microscopy, dynamic light scattering and magnetic properties measurement system, were applied to characterize the synthesized material. Impact of various experimental conditions like pH, adsorbent dose, contact time, and temperature on removal trend was examined. The acidic medium positively favored the process of sorption. Kinetic analysis revealed that the adsorption of both the dyes followed pseudo-second-order kinetic model. Equilibrium sorption data were fitted better to Freundlich model as compared with Langmuir model. The maximum adsorption capacities at 50 degrees C were 42.58 and 68.78 mg g(-1) for alizarin red S and tartrazine at pH 4.0 and 2.0, respectively. Thermodynamic parameters exhibited that the sorption of both the dyes onto nanoadsorbent was spontaneous and endothermic with increased randomness at the solid-liquid interface. Desorption experiment demonstrated that the regenerated adsorbent can be recycled efficiently up to three times. Overall, the prepared nanomaterials exhibit remarkable removal competency for both dyes tested like alizarin red S and tartrazine.