Ultrahigh adsorption capacities of carbon tetrachloride on MIL-101 and MIL-101/graphene oxide composites

Hybrid composites of MIL-101(Cr) and graphene oxide (GrO) were prepared using a hydrothermal synthesis method. The synthesized materials were characterized using scanning electron microscopy, X-ray diffraction, FTIR spectroscopy, thermal analysis and nitrogen adsorption. Results indicated that the specific area and pore volume of MIL-101/GrO-0.25 was much higher than pure MIL-101, and the adsorption capacities of carbon tetrachloride on the MIL-101 (Cr)/GrO was also higher than MIL-101. Moreover, the Langmuir-Freundlich (L-F) equation gave a well fit to the adsorption isotherm data of carbon tetrachloride. The result showed that the adsorption capacity of carbon tetrachloride on the MIL-101 at 303 K was 2044.4 mg/g, and the adsorbing amount on the MIL-101/GrO-0.25 was up to 2368.1 mg/g, which increased by 16% in comparison with the original MIL-101. The synthesized MIL-101/GrO composites exhibited a higher carbon tetrachloride uptake capacity than normal MIL-101 owing to the increasing of specific area, dispersion forces and defects on the crystal surface. Furthermore, the carbon tetrachloride uptakes of MIL-101 and MIL-101/GrO composites were well above those of conventional adsorbents, such as activated carbons and zeolites. It was demonstrated that the MIL-101 and MIL-101/GrO composite are promising adsorbents for application in the field of chlorinated volatile organic compounds (Cl-VOCs) adsorption.