Synthesis and adsorption performance of a modified micro-mesoporous MIL-101(Cr) for VOCs removal at ambient conditions

In this study, dynamic adsorption behavior of different gaseous volatile organic compounds (VOCs) on a new modified M-MIL-101(Cr) was investigated with a great emphasis on gasoline adsorption. The M-MIL-101(Cr) was synthesized, along with comprehensive purification procedures, using a new linker to cluster molar ratio (2:1 instead of 1:1) and different modulators (i.e. HF and HNO3). All prepared adsorbents were characterized by XRD, FTIR, FE-SEM and N-2 adsorption-desorption at 77 K. The results showed that surface area and pore volume of the M-MIL-101@Free (i.e. modified MIL-101(Cr) with using any modulator) which were 4293 m(2)/g and 2.43 cm(3)/g, greatly elevated up to 37.2% and 71.6% against the MIL-101@HNO3 (i.e. the best case of usual MIL-101(Cr)). The dynamic adsorption behavior of various VOCs (i.e. gasoline, n-pentane, n-hexane, n-heptane, benzene, toluene and xylenes), dispersed into an air stream at atmospheric conditions, was studied using an in-house made apparatus. The M-MIL-101@Free greatly exhibited high adsorption capacity for all selected VOCs which was approximately 1.9-2.5 times more than MIL-101@HNO3. Furthermore, the M-MIL-101@Free possessed maximum gasoline uptake of 90.14 wt%, which was enhanced by 116% (41.7 wt%) and 260% (25 wt%), compared to MIL-101@HNO3 and commercially activated carbon. Besides the prominent adsorption capacity of M-MIL-101@Free, it was also succeeded to be regenerated in 23.5% shorter time, 7.8% lower temperature and 2.1% higher efficiency versus the MIL-101@HNO3 after 4 cycles.