Graphene oxide (GO), a graphene nanomaterial with great application potential, possesses promising adsorption abilities towards various water contaminants due to the ultra-large surface area and the nature of electric charge on the surface. However, ultrahigh centrifugation for a prolonged time is strongly needed to collect the highly dispersed GO in the recovery process. In this study, a GO-based polymeric composite particle with core–shell structure was fabricated by a facile method. Polyethersulfone (PES) was chosen as the shell to enwrap GO through a liquid–liquid phase inversion process, since the PES shell presented high porosity, good mechanical property and easily modified ability. Methylene blue (MB), a cationic dye, was chosen as the adsorbate to investigate the adsorption capabilities, kinetics and isotherms of the prepared particles. The PES@GO core–shell particles displayed an adsorption capacity as high as 352.11 mg g⁻¹ for MB dye, and the adsorption rates could be improved by modifying the PES shells with hydrophilic fillers. The MB adsorption behavior fitted the pseudo-second-order kinetic model and the Langmuir isotherm very well, and the adsorption process was controlled by the intra-particle diffusion. In addition, a particle column was used to further study the removal ability of environmental toxins, and the results revealed that the composite particles had great potential to remove cationic dyes for wastewater treatment on an industrial scale.