Revealing the role of parallel benzene rings in full phenolic recovery by Zr-based metal organic framework

Liquid-phase adsorption is a critical technology for environmental sustainability, resource management, and the advancement of biotechnology and materials science. The development of materials capable of efficient and highly selective adsorption from aqueous media is essential. In this study, we investigate the adsorption of phenolic compounds (guaiacol, creosol, and homocresol) from aqueous solutions using a stable hydrophobic metal-organic framework (MOF), namely MIL-140C. Synthesized via fast microwave-assisted hydrothermal conditions within 40 min, MIL-140C exhibits high efficiency in liquid-phase separations, achieving full recovery of these compounds upon complete pore occupancy. Our results highlight that the adsorbent with one-dimensional (1D) channels featuring parallel benzene rings is superior; the micropore filling degree of the adsorbent directly affects the recovery efficiency of the adsorbate. Theoretical calculations and Fourier transform infrared spectroscopy (FTIR) analysis further confirm the adsorption with minimal chemical bonding. This study underscores the potential of MOFs of benzene rings parallel to the 1D channel for sustainable phenolic recovery and efficient separations of aromatic containing molecules, reflecting the decisive importance of micropore occupancy in determining recovery efficiency.