Simultaneous adsorptive removal of organic and inorganic pollutants from aqueous solutions: kinetic, equilibrium and thermodynamic studies

• Published in: Desalination and water treatment Vol. 162; pp. 207 - 219
• Main Authors: Saeedi, Reza, Mozaffari, Shahla, Beigi, Elham, Khaloo, Shokooh Sadat
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-09-2019
• Subjects: Cobalt; Magnetic graphene; Methylene Blue; Removal; Toluidine Blue; Removal; Methylene Blue; Toluidine Blue; Cobalt; Magnetic graphene
• ISSN: 1944-3986
• DOI: 10.5004/dwt.2019.24122

There is an increasing need for clean water to support human societies and other living organisms. Ferrite-based magnetic nano-materials are an important class of metal oxide composite with unique physicochemical properties which make them as a powerful candidate for water purification. In this study, MnFe2O4-graphene oxide nano-composite (MNC) was synthesized and characterized by scanning electron microscopy, energy dispersive spectroscopy, thermogravimetric analysis, vibrating sample magnetometer and X-ray diffraction techniques. MNC was used for adsorptive removal of organic (Methylene Blue, Toluidine Blue) and inorganic (Co and Ni) pollutants, simultaneously. The adsorptive removal efficiency of MNC for organic and inorganic pollutants was optimized with respect to different factors such as pH, contact time, adsorbent dose, the initial pollutant concentration and temperature. The results of the adsorption process were well fitted with the Langmuir isotherm and pseudo-second-order kinetic model (R2 > 0.99). The maximum adsorption capacity according to the Langmuir isotherm model (qm) was 37.0, 46.7, 125.0 and 110.0 mg g–1 for Co(II), Ni(II), MB and TB, respectively. The negative values of ΔG° (–25.1 to –31.1 kJ mol–1) and positive values of ΔH° (46.8–118.7 kJ mol–1) suggested that the adsorption process is spontaneous and endothermic. The adsorption capacities of MNC in five cycles of consecutive adsorption–desorption experiments approved that the sorbent could keep 97% of the capability in adsorptive removal of the mentioned pollutants then the prepared MNC was introduced as a highly efficient multifunctional, magnetically separable and reusable adsorbent for water remediation.