Selective removal of trace 2-methylisoborneol in real waters via hydrophobic interface-driven adsorption

Taste-and-odor episodes caused by 2-methylisoborneol (2-MIB) remain a persistent challenge for drinking water utilities because effective removal must be achieved at trace concentrations under complex natural organic matter interference. Here, a rationally designed hydrophobic metal organic framework (MOF) adsorbent, MIL-53(Al)@C14, is developed to enable rapid and selective capture of 2-MIB far beyond the performance of conventional powdered activated carbon. A targeted hydrophobic surface modification using long-chain phosphonic acid was introduced, converting MIL-53(Al) into MIL-53(Al)@C14 while preserving its crystalline framework and one-dimensional channels. The modified material achieved >96% removal of 2-MIB, reducing residual concentrations to below the odor threshold in both pure water and real reservoir waters, with adsorption kinetics reaching equilibrium within ∼40 min.Under identical conditions, MIL-53(Al)@C14 consistently outperformed commercial PAC, which suffered severe efficiency loss due to pore blockage and competitive adsorption. Furthermore, MIL-53(Al)@C14 exhibited stable regenerability, retaining 97.1% of its initial adsorption capacity after five cycles. Hydrophobic C14 chains create preferential microdomains that expel water and NOM, accelerate mass transfer of 2-MIB into the pores, and strengthen adsorption through combined hydrophobic interactions, van der Waals forces, and hydrogen bonding. Competitive adsorption experiments confirm that this mechanism confers exceptional resistance against humic substances, polysaccharides, and proteins, even in multi-component systems. Moreover, MIL-53(Al)@C14 exhibits broad-spectrum removal of multiple odorants, with preferential affinity toward the most problematic hydrophobic compounds. Our study demonstrates that hydrophobic interface engineering is critical for achieving reliable trace-odor control in real waters. The results provide a generalizable design principle for next-generation MOF adsorbents targeting ultra-low-concentration micropollutants under realistic treatment conditions.