Hydrophobic mesoporous adsorbent based on cyclic amine–divinylbenzene copolymer for highly efficient siloxane removal

Abstract

This paper presents a new class of octamethylcyclotetrasiloxane (D4 siloxane) adsorbent based on the copolymer of divinylbenzene and a novel methacrylate monomer. The novel cyclic amine based methacrylate monomer was synthesized employing click chemistry and was polymerized to form a mesoporous adsorbent under solvothermal conditions and tested for siloxane removal. The D4 adsorption capacity of the novel adsorbent is 2220 mg g⁻¹, which is greater than the adsorption capacities of mesoporous poly(divinylbenzene) and commercial activated charcoal. The adsorbent retains 47% regeneration capacity after 10 usage cycles. The high specific adsorption is due to a combination of physisorption, caused by the mesoporosity and pore volume and chemisorption, as evidenced by spectroscopic results. The incorporation of functional groups into a mesoporous structure with significantly enhanced specific adsorption offers future opportunities towards tailored polymer properties for efficient industrial applications in siloxane removal.