Biomass-derived magnetically tuned carbon modified Sepiolite for effective removal of Congo red from aqueous solution

• Published in: Desalination and water treatment Vol. 184; pp. 326 - 339
• Main Authors: Vahidhabanu, Shappur, Swathika, Irulappan, Adeogun, Abideen Idowu, Roshni, Ramakrishnan, Babu, B. Ramesh
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-04-2020
• Subjects: Adsorption; Biomass; Congo red; Isotherms; Kinetics; Magnetic; Sepiolite; Magnetic; Congo red; Adsorption; Isotherms; Biomass; Kinetics; Sepiolite
• ISSN: 1944-3986; 1944-3986
• DOI: 10.5004/dwt.2020.25319

Biomass-derived carbon-based magnetic tuned Sepiolite nanocomposite, Fe3O4-Sepiolite/C was synthesized and characterized using scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, vibrating sample magnetometer, Fourier transform infrared spectroscopy as well as atomic force microscopy techniques. The adsorbent was used for adsorption removal of Congo red dye from synthetic wastewater in a batch process, the effects of operating parameters such as; initial concentrations (10–50 ppm), contact time (0–240 min) and pH were investigated. Data from the kinetic study were analyzed with pseudo-first-order and pseudo-second-order, while the mechanism was analyzed using Elovich and intra-particle diffusion models. The equilibrium data were evaluated using Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherm models. The adsorption kinetics of the dye removal followed pseudo-first-order with constant rate increases from 0.031 to 0.068 min–1 as the initial concentration increases from 50 to 200 mg L–1. Equilibrium data fitted well with all the isotherm data were investigated, the Langmuir model showed that the maximum adsorption capacities of the adsorbent were 199.0 mg g–1. The negative ΔG° values obtained from thermodynamic studies showed that the adsorption spontaneous, while positive ΔH° value of 6.549 kJ mol–1 and entropy change ΔS° revealed an increased activity at the solid/liquid interface. The results obtained from this study showed that Fe3O4-Sepiolite/C is an excellent adsorbent with good surface morphology and magnetic property for effective removal of Congo red dye from an aqueous solution and recyclability.