Rational Construction of Flexible-Rigid β-Cyclodextrin Cross-Linked Porous Microspheres for High-Efficiency Oil Absorption

Abstract

Oil spills and toxic organic solvent leakage damage aquatic environments and human health, while traditional polymer oil adsorbents feature disconnected pores, weak recyclability, and conflicting adsorption capacity and structural stability. Herein, renewable β-cyclodextrin (β-CD) was esterified into a multivinyl cross-linker (β-CD-A), and flexible-rigid balanced porous DBP microspheres were synthesized via one-pot suspension copolymerization. Gradient monomer screening identified 35 mol % rigid comonomer 4-tert-butylstyrene (PTBS) as the optimal dosage. Dodecane served as a porogen to build interconnected hierarchical macro/meso/micropores, endowing DBP with high adsorption capacities of 135.6, 128.8, and 115.1 g g–1 for CCl4, CHCl3, and toluene. Adsorption obeys pseudo-first-order kinetics, driven by capillary force and van der Waals force. After 10 adsorption–desorption cycles, the microspheres reserve over 75% initial capacity, perform steadily from −20 to 60 °C, and lose less than 6% mass in water, concentrated acid, and alkali. This work demonstrates a flexible-rigid synergistic approach for fabricating hierarchically porous β-CD adsorbents. The scalable material shows potential for marine oil spill remediation and industrial organic wastewater treatment.