(572e) Formaldehyde Adsorption Performance of Selected Metal-Organic Frameworks from High-Throughput Computational Screening

Authors: 
Li, W., HuaZhong University of Science and Technology
Volatile organic compounds (VOCs) have caused severe air pollutions due to their harmfulness to human health. Among the most popular VOCs, formaldehyde (HCHO), is very allergenic and carcinogenic even at very low concentrations. As an emerging class of porous crystalline materials, Recently, metal–organic frameworks (MOFs), a class of crystalline nanoporous materials composed of inorganic metal nodes and organic ligands, have attracted increasing research interest due to their high specific surface areas and pore volumes, well-defined porosity, and tunable pore properties, which has been utilized for gas storage, separation, and catalysis. So, the utility of MOFs for formaldehyde removal is an intersting and meaning research topic. With the rapidly increasing number of reported metal-organic frameworks (MOFs), high-throughput computational screening (HTCS) strategy based on grand canonical Monte Carlo (GCMC) simulation is proposed to quickly explore the top-performing MOFs with high adsorption capability towards formaldehyde. In this work, the computation-ready experimental (CoRE)-MOF database consisting of 2932 MOF structures carrying density derived electrostatic and chemical (DDEC) charges obtained from density function (DFT) theory calculations, were employed in high-throughput GCMC simulations for formaldehyde adsorption from the air. The structure-property relationship from HTCS revealed that the MOF candidates with high formaldehyde uptakes exhibited small pore sizes, relatively high selectivity and moderate heat of adsorption (Qst). Afterwards, the top MOFs with both high uptake and selectivity towards formaldehyde were chosen for further experimental evaluation. Three selected MOFs Y-BTC, ZnCar and Ni-BIC were successfully synthesized and characterized by Powder X-ray diffraction (PXRD) and BET surface area analysis. In order to validate our HTCS strategy, the representative Cu-BTC and activated carbon (AC) were also adopted as controls. The formaldehyde adsorption test was performed in a sealed container with the formaldehyde concentration of 100 mg/m­3 at 298 K. After 24 h adsorption, the formaldehyde uptakes of the adsorbents were obtained according to the concentration changes prior to and after formaldehyde exposure by UV-vis spectrometer. It was found that the adsorption capacities of Y-BTC, ZnCar and Ni-BIC are 0.38, 0.25 and 0.11 mol/kg, respectively, which were remarkably higher than Cu-BTC (0.08 mol/kg) and AC (0.06 mol/kg). The recyclability of the best performer Y-BTC was also verified. These findings open up the possibility of employing HTCS strategy for highly efficient exploration of MOF adsorbents for formaldehyde removal.