Polyaniline nanofibers formed by seed polymerization through heat treatment for synergistic enhancement of Cr(VI) removal

[Display omitted] •Preparing uniform polyaniline nanofibers with high surface area through seed polymerization.•Forming more absorption sites for the nanofibers by removing ammonia.•Achieving the synergistic enhancement on the Cr(VI) uptake with the capacity of up to 275.46 mg/g. Owning to the high toxicity and mobility of hexavalent chromium (Cr(VI)), the removal has caused tremendous attention recently. In this study, an obvious improvement on Cr(VI) removal can be achieved for polyaniline nanofibers (PANFs) by removing ammonia via heating treatment. The as-prepared PANFs manifest high removal capacity of 275.46 mg/g, being more than 10% and 50% increase compared to PANFs obtained without ammonia removal and general chemically synthesized particles. The excellent removal performances can be ascribed to the synergistic effect between uniform morphology, high specific surface area and good conductivity, which can provide large amount of active sites for Cr(VI) uptake. Benefiting from the easy control of morphology and structure as well as large–scale production, the present approach exhibits great promising to develop low–cost absorbents for removing heavy metal ions with high efficiency and multiple reuses to enhance their applicability on an industrial scale.