Preparation and methylene blue dye adsorption behavior of MIL-100 (Fe) by hydrothermal method

In this study, metal-organic framework MIL-100 (Fe) with porous polymer structure has been successfully synthesized by a simple hydrothermal method at low-temperature (140 degrees C) via the reaction of ferric chloride hexahydrate and trimesic acid (H3BTC). The synthesized MIL-100 (Fe) was systematically characterized by XRD, BET, XPS, FTIR, EDX and FESEM and used as the adsorbent to adsorb methylene blue dye (MB). Effects of adsorption conditions on the dye adsorption, as well as thermodynamics and kinetics of dye adsorption onto MIL-100 (Fe) were investigated. Langmuir mode is favorable for MB adsorption onto MIL-100 (Fe), which is a spontaneous and endothermic process driven by an increase in entropy. Adsorption kinetic studies show that MB adsorption follows a pseudo-second-order kinetic model. MIL-100 (Fe) has dye adsorption capacity of 622 mg/g due to its mesoporous structure and specific surface area as high as 497.89 m(2)/g. After five successive adsorption-desorption cycles, dye removal efficiency only decreases to 73.6% as compared with that for the first absorption. Thus, MIL-100 (Fe) has great potential application in dye removal of dye- contaminated wastewater due to its mild and environmentally benign synthesis conditions, high adsorption capacity and good recycling property.