Construction of polyurethane/chitosan hybrid foam for dihydroxylammonium 5, 5′-bistetrazole-1, 1′-diolate removal

Dihydroxylammonium 5, 5′-bistetrazole-1, 1′-diolate (TKX-50) is a new high-energy and insensitive material with broad application prospects. However, the discharge of TKX-50 wastewater from its production and applications not only causes the waste of high-value explosives, but also pollutes the environment. The traditional used adsorbents are poor adsorption efficiencies and recyclability performance in pratical applications. In this study, we successfully prepared a porous polyurethane/chitosan hybrid foam (PUF) with chitosan (CTS) as the active adsorption component by the semi-prepolymerization/acidification method. The compressive strength of the PUF can reach up to 8.83 kPa, and the static adsorption capacity of TKX-50 can reach 39.32 mg/g. The TKX-50 adsorption process and mechanism were further studied by the adsorption kinetics, isotherm and thermodynamics. The adsorbed TKX-50 was effectively recovered by NaOH solution, with a desorption rate exceeding 94 %. The dynamic adsorption investigation indicates that the PUF is suitable for industrial continuous flow wastewater treatment process in practical engineering. In all, our work has explored a new construction strategy of chitosan composited recyclable polyurethane hybrid foam materials with high TKX-50 adsorption efficiencies, and the obtained hybrid foam exhibits great application potentials for the treatment of TKX-50-containing wastewaters.