Toward Deep Dehydration of Tetrahydrofuran: Preparation and Application of a Microporous/Mesoporous Composite Adsorbent

Water content restricts high-value tetrahydrofuran (THF) applications (e.g., polymerization, Grignard reactions), which demand levels below 10 mg/kg, yet commercial or purified THF typically exceeds this. In this study, a series of microporous/mesoporous composite adsorbents were synthesized under industrially feasible execution conditions and evaluated for deep dehydration of THF. Structural characterization indicated the coexistence of a crystalline LTA-type microporous phase and an amorphous mesoporous phase, enabling investigation of the influence of hierarchical pore architecture on adsorption behavior. The optimal composite adsorbent reduced the water content in THF from 70 mg/kg to 7 mg/kg (mean value of triplicate measurements, RSD < 5%), while the 3A molecular sieve could only reduce it to 23 mg/kg. The improved dehydration performance may be attributed to the combined contribution of microporous adsorption sites and mesoporous transport pathways, which could enhance water removal by improving access to active sites and alleviating diffusion limitations. Adsorption kinetic and isotherm analyses suggested complex adsorption behavior that was well described by a double-exponential model and a combined Langmuir and Dual-Site Langmuir-Freundlich (DSLF) model, respectively. Density functional theory (DFT) calculations further indicated stronger interaction of the composite adsorbent with water than with THF. In addition, regeneration tests showed stable performance after six cycles. These results indicate that the integration of microporous and mesoporous features may be a feasible approach for deep solvent dehydration, while also providing experimental and theoretical insights into how hierarchical pore structures influence the dehydration performance of composite porous adsorbents.