Sustainable adsorptive removal of As (III) using Garcinia xanthochymus leaf extract mediated Fe2O3 nanoparticles, regeneration and real water assessment

Abstract Garcinia xanthochymus leaf extract mediated Fe 2 O 3 nanoparticles (GX-Fe 2 O 3 NPs) were successfully synthesized for As (III) adsorption. The pore volume and surface area were found to be 0.2923 cm 3 /g and 125.7 m 2 /g respectively, as revealed by BET analysis. The crystallinity of the sample was proven by XRD, with an average crystallite size of 25.47 nm. The measured lattice parameters were a = 5.03 Å and c = 13.93 Å. FTIR confirmed the occurrence of surface functional groups, while FESEM images showed a porous morphology. EDS and XPS confirmed the elemental composition and the adsorption of As (III), evidenced by characteristic binding energy at 44.63 eV, respectively. Batch adsorption studies revealed the optimized parameters as pH:10, dose: 0.5 g/L, initial concentration: 4 mg/L, and temperature: 30 ℃, achieving 71.9% removal efficiency at an equilibrium time of 180 min. The adsorption kinetics followed a PSO model, and the Freundlich isotherm was the best fit, representing multilayer adsorption occurring on a heterogeneous surface. Using the Langmuir isotherm model, the q m was found to be 11.12 mg/g, while the thermodynamic studies confirmed the spontaneity and endothermic nature of the adsorption process. Regeneration studies showed good reusability over five cycles, and the adsorbent was tested across different water matrices. Therefore, the GX-Fe 2 O 3 NPs demonstrate high efficiency and sustainability as a green adsorbent for As (III) uptake.