In this study, the novel mesoporous carboxylated Mn2O3 nanofibers were synthesized by combination of electrospinning and sol-gel methods and in situ polymerization of acrylic acid monomer. The optimum amount of acrylic acid was determined by evaluating the results of microscopic and specific surface area analyses. The characteristic analyses exhibited the deposition of a layer containing silica and acrylic acid on the nanofiber surface. Also, Mn2O3 nanofibers showed a mesoporous structure which was maintained after the polymerization process. Although, the mean mesopore size on the nanofiber surface was decreased but the size of pores existing among the nanofibers increased because of increasing the nanofiber diameter. An investigation on the topography of nanofibers revealed that the average surface roughness values increased after the polymerization of acrylic acid. The coverage of Mn2O3 nanofiber surface by amorphous silica after the modification process was confirmed by X-ray diffraction (XRD) method. Moreover, the dye removal ability of synthesized nanofibers was evaluated and the effect of operational parameter including adsorbent dosage, pH, inorganic anions and initial dye concentration on dye removal was investigated. Adsorption isotherm and kinetic models were used to evaluate the adsorption mechanism and rate. To determine the best fit model for each system, non-linear regression along with error function were used. The results showed that the experimental data followed with Langmuir isotherm. Although the intra-particle diffusion was influenced on adsorption rate, the adsorption kinetic conformed to the pseudo-second order kinetic model. The result showed that synthesized nanofibers with high adsorption capacity might be a suitable alternative to remove dyes from colored aqueous solutions. (C) 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.