Facile additive-free synthesis of iron oxide nanoparticles for efficient adsorptive removal of Congo red and Cr(VI)

• Published in: Applied surface science 2014-02, Vol.292, p.174-180
• Main Authors: Hao, Tao, Yang, Chao, Rao, Xuehui, Wang, Jide, Niu, Chunge, Su, Xintai
• Format: Article
• Language: English
• Subjects: Adsorption; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Congo red; Cr(VI); Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Iron oxide nanoparticles; Iron oxides; Mathematical analysis; Nanoparticles; Physics; Surface area; Surface chemistry; Synthesis; Transmission electron microscopy; Water treatment; X-ray diffraction
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2013.11.108

•The iron oxide is gained via a facile, green, and economical synthesis process.•The promising adsorptive applications in water treatment are investigated.•Congo red removal capacity is 253.8mgg−1, and commercial α-Fe2O3 is 42.4mgg−1.•The maximum adsorption capacity for Cr(VI) is 17.0mgg−1. The iron oxide nanoparticles had been successfully synthesized via an additive-free hydrolysis process at 75°C for 12h. The product was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and N2 adsorption–desorption. The results of XRD and N2 adsorption–desorption demonstrated that the as-prepared product was mainly α-Fe2O3 with a large surface area of 164.1m2g−1. The TEM images illustrated that the as-prepared product was found to consist of a mixture of irregular spherical nanoparticles (a diameter of ∼50nm) and nanowhiskers (a diameter of ∼50nm and uneven length). The as-prepared product was used to investigate its promising applications in water treatment. Due to its small size and large surface area, the maximum adsorption capacities of Congo red and Cr(VI) have been determined using the Langmuir equation and found to reach up to 253.8 and 17.0mgg−1, respectively. The facile synthesis method and the superior adsorption performance derived from the iron oxide nanoparticles display the potential applications for the removal of Congo red and Cr(VI) from aqueous solution.