Abstract

CoFe2O4 nanoparticles were synthesized, functionalized with amine group, and used to adsorb Direct Red 80 (DR80), Direct Green6 (DG6), and Acid Blue 92 (AB92) dyes from aqueous solutions. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), zeta potential (ZP), and the Brunauer-Emmett-Teller (BET) were used to analyze the adsorbents surface characteristics. The effects of pH, adsorbent dosage, initial dye concentration and contact time on the dyes adsorption was studied at 25 °C. The Langmuir, Freundlich and Tempkin models were used for this study and the experimental results show that the Langmuir equation fits better than the other equations. At initial pH of 2, the adsorption capacity (Q0) for DR80, DG6, and AB92 was 333.33, 384.61, and 625 mg/g, respectively. Furthermore, pseudo-first-order, pseudo-second-order, and intra-particle diffusion adsorption kinetics of three dyes were studied and the rates of sorption were found to conform well to the pseudo-second-order kinetics (R2 > 0.99). © 2015 Taiwan Institute of Chemical Engineers.