A simple approach to prepare isoxazoline-based porous polymer for the highly effective adsorption of 2,4,6-trinitrotoluene (TNT): Catalyst-free click polymerization between an in situ generated nitrile oxide with polybutadiene

Abstract

• Click polymerization was used for efficient adsorption of TNT. • The synergistic effect of dipole-π interaction and π-π interaction was applied. • The maximum adsorption capacity at 298 K was up to 177.3 mg/g within 4 h. • The isoxazoline-based porous polymer was reversible and could be reused. • No metal ion catalyst was added to the reaction to avoid secondary contamination. This paper presents the application of click polymerization between an in situ generated nitrile oxide and polybutadiene leading to an isoxazoline-based porous polymer for the adsorption of 2,4,6-trinitrotoluene (TNT). Because the synergistic effect of dipole–π interaction and π–π interaction enlarges the binding area between the organic porous polymer and TNT, the resulting adsorbent exhibited efficient adsorption of TNT in water. The adsorption kinetics fit well with the pseudo-second-order model, and adsorption equilibrium could be achieved in 4.0 h. The Langmuir model exhibited better correlation for equilibrium data analysis, and the maximum adsorption capacity at 298 K was as high as 177.3 mg/g. The adsorption capacity remained relatively high after five desorption–adsorption cycles for acetone eluent. Additionally, no metal ion catalyst was added to this reaction, thereby avoiding secondary pollution. This click polymerization provides a simple, yet highly effective, method for the preparation of porous organic polymers to be used in the efficient adsorption of TNT, and the synergistic effect is believed to be a novel rationale for the design of TNT adsorption materials.