Synthesis of amino-functionalization magnetic multi-metal organic framework (Fe3O4/MIL-101(Al0.9Fe0.1)/NH2) for efficient removal of methyl orange from aqueous solution

An amino-functionalization magnetic multi-metal organic framework material (called Fe3O4/MIL-101(Al0.9Fe0.1)/NH2), synthesized by a versatile step-by-step assembly method, has been investigated as a convenient and effective adsorbent for methyl orange (MO). The synthesized nano-adsorbent was characterized by TEM, TGA, SEM, FTIR, VSM, XPS and BET, XRD, respectively. Various factors influencing the adsorption of MO such as the adsorbent dosage, initial concentration of MO, the contact time, pH value of the solutions and the temperatures were studied by batch experiments. The results indicated that it agreed well to the Langmuir adsorption model, and the maximum adsorption capacities of MO were found to be 355.8 mg/g at pH 6.0. Kinetic data showed good correlation with pseudo-second-order equation. The results of adsorption thermodynamic studies illustrate that the sorption is exothermic, spontaneous and decreased randomness of the system. Besides, good magnetic performance of Fe3O4/MIL-101(Al0.9Fe0.1)/NH2 makes it simply achieve the solid-liquid separation at low magnetic field within 5 min. In addition, compared with Fe3O4/MIL-101(Al)/NH2, the Fe3O4/MIL-101(Al0.9Fe0.1)/NH2 not only showed higher removal efficiency toward MO, but also had higher stability in aqueous solution. (C) 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.