The present research study investigates the potential use of the novel polyethylene terephthalate (PET) nanofibers extracted from waste bottles. The electrospinning process creates nanofibers, which are then impregnated with dibenzo-18-crown-6 (DB18C6) (crown ether) to obtain a modified PET nanofiber. The use of modified PET nanofibers to remove methylene blue (MB) from aqueous solutions at different contact times, temperatures and initial dye concentrations is the prime concern of the present study. The amount of MB adsorbed at equilibrium (qe) is calculated at different temperatures (303, 313, and 323 K) and different concentrations (5, 10, 15 mg/g). The Kinetic and equilibrium studies of MB removal are carried out. The results indicate that the adsorption kinetics of MB can be described by the pseudo-second-order model. The activation energy value is below 40 kJ/mol and this gives an idea about the physisorption process.