Study on the adsorption performance of toluene by bimetallic doped MOFs with high adsorption capacity

In this study, Cr-MIL-101-M doped with metal ions (Ce3+, Fe3+, Al3+) was synthesized by hydrothermal method for toluene adsorption. The physical and chemical properties of the adsorbent were studied by XRD, SEM, EDS, BET, CO2-TPD, TG and other characterization methods. The results show that doping metal ions can effectively improve the toluene adsorption capacity of Cr-MIL-101, with aluminum being the optimal doping metal and the best doping ratio being 20%. Under these conditions, Cr-MIL-101- 20% Al has more basic adsorption sites, a larger specific surface area (3106.37 m(2)/g) and pore volume (1.85 cm(3)/g), which provides more active sites for toluene adsorption. Therefore, Cr-MIL-101-20%Al possesses the highest saturation adsorption capacity (486.05 mg/g). Kinetic analysis indicated that both physical and chemical adsorption significantly contributed to the uptake of toluene by bimetallic MOFs, and the doping of 20% Al markedly enhanced the adsorption rate, achieving the optimal adsorption effect.