Mg/K-13X Zeolite for Deep Removal of Oxygenates from α-Olefins Derived from Fischer–Tropsch Synthesis

Linear α-olefins derived from Fischer–Tropsch (FT) synthesis serve as critical feedstocks for high-grade polyolefin production, yet residual oxygenated compounds severely compromise polymerization efficiency and product quality. This study reports the modification of 13X zeolite via Mg/K bimetallic ion exchange to enhance its adsorptive performance for deep oxygenate removal. It is found that Mg/K modification enhances surface polarity and acid sites without destroying the zeolite framework. Adsorption capacity follows the order of Mg/K-13X > Mg-13X > 13X. The process fits the Langmuir isotherm and pseudo-second-order kinetics, indicating monolayer chemical adsorption. Thermodynamic results reveal spontaneous and exothermic adsorption. In fixed-bed tests with 1-hexene and 1-octene, oxygenates are reduced below 5 ppm within 270 min. Breakthrough curves are well-fitted by the Thomas model, with aldehydes breaking through first and alcohols last, owing to polarity-driven adsorption selectivity. After 40 regeneration cycles, the oxygenate removal efficiency remains above 90.72%, confirming exceptional stability and reusability. Mg/K-13X thus represents a highly efficient and robust adsorbent for the deep purification of FT-derived α-olefins.