Adsorption of Reactive Black 5 azo dye from aqueous solution by using amine-functioned Fe3O4 nanoparticles with L-arginine: Process optimisation using RSM

In the present study, the efficiency of amine-functioned Fe3O4 magnetic nanoparticles with L-arginine (Fe3O4@L-arginine) for the removal of RB5 azo dye from aqueous solution was investigated. Box-Behnken design was used to design the experiments and optimise the adsorption parameters. The results showed that Fe3O4@L-arginine nanoparticles were synthesised successfully. Optimum conditions for dye adsorption were obtained at a dye concentration of 50 mg/L, adsorbent dose of 0.8 g/L and pH 3 with an efficiency of 97.6% that was close to the model's prediction percentage (96.8%), which confirms the validity of the model. The RB5 dye adsorption followed the pseudo-second-order kinetic model and the Temkin isotherm model, and the adsorption was a spontaneous endothermic process. The results illustrated that the Fe3O4@L-arginine nanoparticles can be used for RB5 dye adsorption by maintaining high efficiency for several times. Therefore, Fe3O4@L-arginine nanoparticles because of their high performance, easy synthesis and use and ease of separation are suitable adsorbents to remove dye from the coloured wastewater.