Adsorption of Azo Dye on Magnetically Separable Fe3O4/CeO2 Nanocomposite: Kinetics, Isotherm, Mechanism

• Published in: Medžiagotyra Vol. 28; no. 2; pp. 242 - 252
• Main Authors: AN, Zhihao, ZHANG, Wenwen, MA, Jingying, ZENG, Ke, YUAN, Ming, CHEN, Donghui
• Format: Journal Article
• Language: English
• Published: Kaunas University of Technology 01.01.2022
• Subjects: acid black; adsorption mechanism; fe3o4/ceo2; separation
• ISSN: 1392-1320; 2029-7289
• DOI: 10.5755/j02.ms.28019

In this study, magnetically separable Fe3O4/CeO2 nanocomposite (F/CNc) was first synthesized in hydrothermal and sol-precipitation methods and characterized by techniques including SEM-EDS, XRD, BET, FT-IR and VSM. The adsorption experiments of acid black dye (AB210) onto F/CNc were carried out under the conditions of temperature (30 – 60 ℃), solution pH (1 – 11), Fe-Ce molar ratio (1:2.5 – 4) and initial dye concentrations (20 – 80 mg/L). The adsorption capacity of AB210 increased with increasing initial dye concentration and temperature, and decreased with increasing solution pH. The maximum adsorption capacity of F/CNc for AB210 reached 124.5 mg/g when Fe-Ce molar ratio was 1:3. Pseudo-first-order and pseudo-second-order models were then used to describe the kinetics of adsorption, of which the latter fitted the adsorption process well, and the adsorption process complied also with the intra-particle diffusion model. The isothermal adsorption was described using Langmuir, Freundlich and Temkin models and the Langmuir model matched. FT-IR and Zeta-potential measurement proved the physical adsorption process of AB210 onto F/CNc. The saturation magnetizations of Fe3O4 nanospheres and F/CNc were measured to be 69.1 emu/g and 22.9 emu/g respectively, indicating the coating layer reduced the magnetization of Fe3O4 nanospheres, but F/CNc were still separated easily by applying a magnetic field, keeping easy separability. Being easy to recover and remaining adsorption efficiency 90 % in comparison to the original even after four adsorption cycles, demonstrate the effectiveness and practical application of F/CNc as an adsorbent.