Preparation of polyethersulfone-modified sepiolite hybrid particles for the removal of environmental toxins

Abstract In this study, sepiolite (SEP) was modified by acid and heat treatment (AH-SEP), and organic treatment (OAH-SEP). Then, polyethersulfone (PES)/AH-SEP and PES/OAH-SEP hybrid particles were prepared by using a liquid–liquid phase separation technique, and then used for the removal of environmental toxins. The morphology structure of the particle was characterized by scanning electron microscopy (SEM). Detailed studies on the adsorption for ethidium bromide (EB, ionic toxin) and bisphenol A (BPA, non-ionic toxin) by the PES/modified-SEP (PES/mSEP) hybrid particles were carried out. The results indicated that the PES/AH-SEP hybrid particles had good adsorbability for ionic toxin, while the PES/OAH-SEP hybrid particles were more suitable for adsorbing non-ionic toxin. In addition, three simplified kinetic models (pseudo-first-order, pseudo-second-order and intraparticle diffusion model) and adsorption isotherms (Langmuir and Freundlich) were used for the analysis of the EB and BPA adsorption processes, respectively. It was found that the diffusion in macro-pores was significant at the initial period for EB adsorption; while, the boundary layer diffusion was dominant at the beginning for BPA adsorption. For both EB and BPA adsorption, the intraparticle diffusion controlled the adsorption rate at the final stage.