Rapid Adsorption of 2,4,6-trinitrotoluene by hierarchically porous indole-based aerogel

A hybrid hierarchically porous indole-based aerogel (HINFA) was successfully fabricated and modified with hydroxyl groups. The HINFA with hierarchically porous exhibited satisfactorily adsorptive properties to 2,4,6-trinitrotoluene (TNT) in water in light of synergistic effect of hydrogen bonding and dipole-π interaction. Several factors such as pH, adsorbent dosage, contact time, initial TNT concentration and temperature were systematically discussed. Adsorption kinetics, isotherms and thermodynamic parameters had been calculated from experimental results. The HINFA demonstrated significantly fast equilibrium time (1.5 h) to TNT in particular. The maximum adsorption capacity was 117.5 mg g−1 calculated by Langmuir model at 293 K. The adsorption-desorption cyclic results revealed that HINFA could be effectively regenerated by acetone, and the regenerated HINFA could be employed for repeated use without significant deterioration after 7 cycles. The excellent adsorption performance of HINFA may be in virtue of the interweave meso- and macroporous structures which can enhance mass transport and easier accessibility for TNT to the adsorption sites. Therefore, the HINFA can be used potentially to remove TNT from water samples in practical applications for environmental remediation. Furthermore, the proposed synergy is expected to be a new rationale for design of TNT adsorbent materials.