End opened carbon nanotubes assimilated with polyacrylonitrile electrospun nanofibers were prepared by simple electrospinning method. The open tips oxidized carbon nanotubes were obtained by using elevated acid oxidation method. The successful electrospun nanofibers were prepared using horizontal electrospinning method. The properties and morphology of these prepared nanofibers were characterized by FT-IR, SEM, TGA, TEM, and dispersion phenomenon which showed that oxidize carbon nanotubes possess open tips with various organic functional groups and it can be effectively utilized in adsorption phenomenon. Successfully prepared and characterized nanofibers were tested for the adsorption of pyrene from aqueous solution. Results showed that, 2 wt% of oxidized open tips carbon nanotubes with respect to polyacrylonitrile polymer achieved 96% adsorption of pyrene in 30 min contact time at room temperature. The adsorption capacity was studied under different experimental conditions and their effects on adsorption such as temperature, amount of o-CNTs loading, and contact time were also studied. In addition, kinetics models were also determined. The regeneration and recyclability of composite nanofibers were also studied. (C) 2014 Elsevier B.V. All rights reserved.