Green Aloe-vera leaf waste functionalized magnetic nanoparticles as a bio-adsorbent for the removal of the cationic dye from aqueous solution

Aloe-vera Leaf Waste Magnetically Modified (AMNP) was prepared and applied as a bio-adsorbent for crystal violet (CV) dye removal from aqueous solution. The material was characterized by ultraviolet–visible spectroscopy (UV), field emission scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), Zeta potential analysis, Brunauer–Emmett–Teller surface area analysis (BET) and Vibrating sample magnetometry (VSM) confirming its porous structure, functional groups, and magnetic properties. Batch adsorption studies showed a maximum CV removal of 96.4% with a Maximum adsorption capacity of 58 ± 5.75 mg/g at pH 8. The adsorption followed the Freundlich isotherm (R2 = 0.95), suggesting multilayer uptake, and the pseudo-second-order kinetic model (R2 = 0.99), indicating chemisorption. Thermodynamic analysis revealed the process to be spontaneous and endothermic with ΔH° = 11.5 ± 0.94 kJ/mol. Desorption experiments confirmed that AMNP remained reusable over several cycles with moderate efficiency. Compared with other reported bio-adsorbents, AMNP exhibited competitive capacity, low cost, and reusability. These findings demonstrate AMNP as a sustainable and eco-friendly material for treating dye-contaminated wastewater. Synthesis of magnetically modified aloe vera using ferric oxide (Fe3O4) nanoparticles for removal of crystal violet dye.