One-Step Preparation of Indole-Based Porous Magnetic Composite via Cation-π Interaction-Driven and -Induced Strategy

Abstract A strategy driven and induced by cation-π interaction was employed to obtain magnetic porous composite material with a uniform dispersion of ferroferric oxide (Fe 3 O 4 ). Ferroferric oxide/indole-based porous composite (Fe 3 O 4 /PIN) was prepared in a one-step process. Cation-π interaction dispersed iron ions (Fe 3+ ) next to the indole groups in the indole-based porous polymer (PIN), and subsequently, after the in-situ reaction, Fe 3 O 4 was uniformly distributed around the indole groups within PIN. At 298 K, Fe 3 O 4 /PIN displayed remarkable adsorption effectiveness, attaining 290.697 mg/g, and within 1 hour, had achieved 74% of the highest capacity. In addition, due to the excellent magnetic properties of Fe 3 O 4 /PIN, it exhibited rapid recovery characteristics for TNT. Despite five cycles of adsorption-desorption, with acetone as the eluent, the adsorption capacity of Fe 3 O 4 /PIN for TNT still remains at 90% of its highest potential. Hence, Fe 3 O 4 /PIN is anticipated to serve as an effective adsorbent for TNT. The uniform distribution of Fe 3 O 4 in porous materials through the driving and inducing effects of cation-π is an unprecedented innovation, providing a new perspective and approach for the preparation and application of similar composite materials.