Removal of Crystal Violet by Using Reduced-Graphene-Oxide-Supported Bimetallic Fe/Ni Nanoparticles (rGO/Fe/Ni): Application of Artificial Intelligence Modeling for the Optimization Process

• Published in: Materials 2018-05, Vol.11 (5), p.865
• Main Authors: Ruan, Wenqian, Hu, Jiwei, Qi, Jimei, Hou, Yu, Cao, Rensheng, Wei, Xionghui
• Format: Article
• Language: English
• Subjects: Adsorption; Artificial intelligence; Artificial neural networks; Bimetals; Composite materials; Dyes; Endothermic reactions; Enthalpy; Free energy; Genetic algorithms; Gibbs free energy; Graphene; Iron; Nanoparticles; Neural networks; Nickel; Particle swarm optimization; Scanning electron microscopy; Spectrum analysis; Swarm intelligence; X ray photoelectron spectroscopy; X-ray diffraction
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma11050865

Reduced-graphene-oxide-supported bimetallic Fe/Ni nanoparticles were synthesized in this study for the removal of crystal violet (CV) dye from aqueous solutions. This material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), Raman spectroscopy, N₂-sorption, and X-ray photoelectron spectroscopy (XPS). The influence of independent parameters (namely, initial dye concentration, initial pH, contact time, and temperature) on the removal efficiency were investigated via Box⁻Behnken design (BBD). Artificial intelligence (i.e., artificial neural network, genetic algorithm, and particle swarm optimization) was used to optimize and predict the optimum conditions and obtain the maximum removal efficiency. The zero point of charge (pH ) of rGO/Fe/Ni composites was determined by using the salt addition method. The experimental equilibrium data were fitted well to the Freundlich model for the evaluation of the actual behavior of CV adsorption, and the maximum adsorption capacity was estimated as 2000.00 mg/g. The kinetic study discloses that the adsorption processes can be satisfactorily described by the pseudo-second-order model. The values of Gibbs free energy change (Δ ⁰), entropy change (Δ ⁰), and enthalpy change (Δ ⁰) demonstrate the spontaneous and endothermic nature of the adsorption of CV onto rGO/Fe/Ni composites.