Mesoporous MOF composite for efficient removal of uranium, methyl orange, methylene blue, and Congo red dyes from aqueous solutions

Abstract

AbstractThe metal‐organic framework (MOF) composites have significant applications in removing water pollutants and heavy metals from aqueous solutions. The MOF‐2@Al2O3 composite was synthesized using zinc nitrate, 1,4‐benzene dicarboxylic acid, and Al2O3 using an in‐situ one‐pot solvothermal method. Physicochemical properties of MOF‐2@Al2O3 are characterized by X‐ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy‐energy dispersive X‐ray spectroscopy (SEM‐EDX), and Brunauer–Emmett–Teller (BET). Batch mode adsorption studies were carried for uranium (VI) effectively from 5‐M HNO3 solution with maximum adsorption of 300.3 mg/g. Furthermore, methyl orange (MO), methylene blue (MB), and Congo red (CR) dyes were removed from the aqueous solution using the fixed‐bed column adsorption method at room temperature. The pseudo second‐order model was well fitted to uranium adsorption rate on MOF‐2@Al2O3 composite, which indicates that chemisorption is the primary mechanism for removing U (VI). Effects of parameters such as flow rate, bed height, initial concentration, time, and pH are studied for azo dyes and U (VI) adsorption. Experimental results indicate that MOF‐2@Al2O3 can efficiently remove uranium and azo dyes with good reusability up to five cycles.