Synthesis of polyaniline micro/nanospheres by a copper(ii)-catalyzed self-assembly method with superior adsorption capacity of organic dye from aqueous solution

Hollow and core-shell polyaniline (PANI) micro/nanospheres have been fabricated by a simple copper(II)-catalyzed self-assembly method under different reagent concentrations. In this synthesis system, the copper(II) salt and the template composed of aniline monomers were two key factors in the formation of PANI spherical products. The molecular structure of the PANI prepared by the copper(II)-catalyzed self-assembly method is similar to that of PANI prepared by traditional methods as demonstrated by X-ray diffraction, Fourier-transform infrared and Raman spectroscopy. The synthesized PANI hollow spheres and fiber/sheets were used to adsorb methyl orange from aqueous solution. The results showed that the adsorption/desorption kinetics and isotherms followed pseudo-second-order and Langmuir models. Importantly, the as-synthesized PANI hollow spheres exhibited a superior adsorption capacity (384.62 mg g−1) compared with other absorbents. The excellent adsorption characteristic of the hollow PANI microsphere will render it an ideal candidate for removal of organic dye from wastewater.