Fe3O4-chitosan nanocomposite hollow fibers were prepared via impregnation of Fe3O4 nanoparticles on dry-wet spun chitosan hollow fibers (CS-HFs) and its performance in the removal of selenium(IV) from water was investigated. The prepared nanocomposite was characterized using XRD, SEM and TEM analyses confirming the formation of Fe3O4 nanoparticles throughout the heterogeneous surface of CS-HFs. Response surface methodology (RSM) was utilized to optimize Se(IV) adsorption and investigate operational parameters including nanocomposite amount, Se(IV) concentration, pH and contact time. The polynomial second order regression, which is conventionally developed in RSM for describing the process, did not accurately fit the experimental data owing to significant lack of fit. However, in modified polynomial third order regression, all model evaluation criteria had been confirmed the accuracy of the developed model. The adsorption of Se(IV) on prepared Fe3O4-CS HFs followed from pseudo-second-order kinetics with participating both intraparticle and boundary layer diffusion in the rate-controlling step. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.