Removal of Cr(VI) from aqueous solutions using polymer nanotubes

The self-assembled polymer nanotubes were obtained by a simple solvothermal method. Its physicochemical properties were characterized by SEM, BET, TGA, FT-IR, XPS, and solid-state 13 C magnetic resonance. The effects of initial pH, dosage, and coexisting ions were evaluated for its Cr(VI) adsorption performances. The result showed that polymer nanotubes surface had a large number of organic functional groups and porous structures. In 140 mg/L Cr(VI) solution, polymer nanotubes obtained the largest Cr(VI) adsorption capacity of 147.81 mg/g. Adsorption kinetics and isotherms agreed well with the pseudo-second-order and Redlich–Peterson models, respectively. The desorption process showed that the polymer nanotubes were easy to regenerate in strong polarity solution and had a high removal efficiency. Ionic strength played an important role in the adsorption and the adsorption interaction contained electrostatic interaction, reduction, and chelation in this work. The self-assembly method will constitute a highly efficient adsorbent.