Fast kinetics and high adsorption capacity of green extract capped superparamagnetic iron oxide nanoparticles for the adsorption of Ni(II) ions

[Display omitted] •Fast kinetics and a high adsorption capacity of 227.20mg/g is obtained.•Less expensive synthesizing route with use of limited chemicals.•Superparamagnetic iron oxide nanoparticles facilitated easy magnetic separation.•Smaller particle size and a high BET surface area helped in enhanced adsorption. Superparamagnetic iron oxide nanoparticles were synthesized using co-precipitation technique by dissolving required stoichiometric proportions (1:2) of Fe2+ and Fe3+ salts in water. Lantana camara extract and ammonia solution were used as the stabilizing and precipitating agents, respectively. The prepared particles were characterized using FTIR, TGA, PSA, SEM–EDAX and zeta potential analysis. This material was successfully adopted for the removal of Ni(II) ions from aqueous solution and the process parameters were optimized. The results indicated the faster kinetics and a remarkably higher adsorption capacity of 227.20mg/g at a pH of 6.0 and an adsorbent dose of 0.05g.