Facile synthesis of Cu-BTC@biochar with controlled morphology for effective toluene adsorption at medium–high temperature

The development of adsorbents suitable for volatile organic compounds (VOCs) adsorption at medium–high temperature is urgently required for the control of VOCs in coal-fired power plant flue gas. In this study, a size-controlled broccoli-like Cu-BTC-loaded biochar composite (Cu-BTC@biochar) was synthesized with a facile one-pot method. Cu-BTC@biochar showed hierarchical pore structure features and significantly improved BET surface area (728.5 m2/g) compared with raw biochar (10.0 m2/g). The results of fixed-bed adsorption experiments show that Cu-BTC@biochar has outstanding toluene (typical components of VOCs) adsorption performance at the medium–high temperatures of 60 °C and 150 °C, the adsorption capacities can reach 501.8 and 88.8 mg/g, respectively. Molecular simulations were used to reveal the toluene adsorption mechanism and the results show that the van der Waals interaction plays an important role in the toluene adsorption process, but the electrostatic interaction of Cu-BTC@biochar has a significantly higher proportion than that of Cu-BTC (31 % vs 7 %), which is more pronounced when the temperature increases. Our findings demonstrate that this low-cost Metal-organic frameworks (MOFs) composite material presents great potential as the adsorbent for VOCs at medium–high temperature.