Synthesis and characterization of a polyurethane-polyaniline macroporous foam material for methyl orange removal in aqueous media

In this work, it is reported the development of a polyurethane/polyaniline (PU-PANI) material that can be used as an adsorbent for azo dyes from aqueous solutions. This material was synthetized by incorporating PANI into the surface of a macroporous PU foam by an in situ chemical polymerization method. The characterization results of the material with SEM and FTIR confirmed the presence of PANI deposited on the surface of the macroporous PU foam. The adsorption capacity of the PU-PANI material was evaluated by performing experiments in batch mode using methyl orange (MO) at different pHs, interaction time and initial concentration. The adsorbed amount of MO in the first minutes of interaction is high, reaching a 32.5% of removal from its total capacity in just 5 min. The adsorption process in the material stabilizes after 30 h of interaction and the adsorption kinetics follows the Elovich and the intraparticular diffusion models. The PU-PANI material possesses a maximum experimental adsorption capacity of 255 mg/g at pH 5.0, following a Sips isotherm. The adsorption and desorption capacity of the material was evaluated, showing that it can be reused up to 10 cycles without significantly decreasing in its removal capacity. The results obtained in this work are compared with literature, it can be said that the PU-PANI material is a promising material for azo dyes removal in aqueous media.