Feasible synthesis of nickel ferrite using Uncaria gambir Roxb. leaf extract for removal of phosphate from aqueous solution

Nickel ferrite nanoparticles (NiFe 2 O 4 ) are promising materials for environmental applications, particularly in resource recovery and pollution management, due to their unique magnetic, chemical, and surface properties. In this study, we reported a successful synthesis of nickel ferrite nanoparticles via green synthesis approach using Uncaria gambir Roxb. (UGR) leaf extract by hydrothermal method. The synthesized nanoparticles were characterized for crystallinity, morphology, particle size, and magnetic properties. Functional group analysis was performed to investigate interactions between the nanoparticles and the plant extract, comparing samples prepared with and without UGR. Morphological analysis using transmission electron microscope (TEM) revealed the formation of cubic and triangular nanoparticles with average sizes of 35 nm and 55 nm for samples synthesized with and without UGR, respectively. Particle size analyzer (PSA) confirmed these findings, with measured sizes of 19.9 nm and 51.2 nm, indicating the UGR extract's efficacy in maintaining stable, smaller particle sizes. XRD confirmed the formation of spinel inverse NiFe 2 O 4 , with a reduction in crystallite size from 54 nm to 36 nm for UGR-assisted synthesis. FTIR analysis identified Ni–O and Fe–O vibrations at 511 and 623 cm⁻ 1 , respectively. The saturation magnetization (Ms) values were 37.35 emu/g and 23.95 emu/g for nanoparticles synthesized with and without UGR, respectively, highlighting the enhanced magnetic properties conferred by the extract. The nanoparticles exhibited exceptional phosphate removal efficiency of up to 98% in solution using 1 g/L of material, demonstrating their potential for environmental remediation. These findings underscore the feasibility and potency of UGR-assisted NiFe 2 O 4 synthesis for developing effective materials in pollution management.