Reactive orange 12 dye adsorption onto magnetically separable CaFe2O4 nanoparticles synthesized by simple chemical route: kinetic, isotherm and neural network modeling

Abstract

Abstract Industrial wastewaters laden with toxic dyes are required to be treated prior to their disposal in view of their adverse effect on human health and aquatic ecosystems. Thus in this research, CaFe2O4 nanoparticles were prepared and used as adsorbent for elimination of reactive orange 12 dye (RO12) from aqueous medium. The CaFe2O4 nanoparticles exhibit specific surface area of ∼230 m2/g and average pore diameter of ∼2.5 nm. Maximum RO12 removal of 77% was observed at solution pH 2.0 with uptake capacity of 276.92 mg/g. The electrostatic interaction between CaFe2O4 nanoparticles and RO12 was the main driving force behind this adsorption. The kinetic modeling reveals that this adsorption process obeyed the pseudo-second-order kinetic model accurately (R2: 0.988–0.994), indicating chemisorption behavior. The adsorption experimental data firmly followed the Langmuir isotherm model (R2: 0.997), confirming monolayer adsorption. Thermodynamic study suggests that the adsorption process is spontaneous (ΔG0 = −8.76 to −3.19 kJ/mol) and exothermic in nature (ΔH0 = –71.86 kJ). A neural network model (optimum topology of 4–7–1) was developed for precise forecasting of RO12 removal (%). The developed model with very high correlation coefficient (0.986) and very low mean squared error (0.00185) was successful for accurate prediction of experimental data.