Study On The Synthesis Of Magnetic Polystyrene Based Macroporous Resins And Their Adsorption Performance To Metal Ions In Aqueous Solution

The magnetic micro/nano materials, a kind of adsorbent used to remove the harmful organic compounds and metal ions in aqueous solution has been developed as a new energy saving and efficient water treatment technology. Among all of them, magnetic chelating resins have received world-wide attention due to its regeneration properties and the selective characteristics for heavy metal ions.In this study, the hydrophilic polystyrene based macroporous resins were prepared by using organic reagents contained amino and hydroxyl groups for the surface modifier of chloromethylation polystyrene. Subsequently, in-situ macroporous resins composites were prepared by co-precipitation method using FeCl3·6H2O and FeSO4-7H2O as precursors. The prepared resins were characterized by means of Scanning electron microscope(SEM), Fourier infrared spectrum(FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy(XPS), Vibrating sample magnetometer(VSM) and specific surface area analyser(BET), as well as the adsorption property of Hg2+in aqueous solution was investigated by batch methods. Adsorption of Hg2+from aqueous solutions was carried out under different experimental conditions by varying pH, contact time, initial concentration, the mass of adsorbent and temperature. The pseudo-first-order equation, pseudo-second-order equation and intra-particle diffusion model were used to fit the adsorption kinetics data, the Langmuir and Freundlich isothermal model were used to evaluate the adsorption isothermal model, the adsorption thermodynamics was studied by calculating the△G°,△H°and△S°of adsorption process.The results showed that the macroporous resins with magnetic Fe3O4were prepared successfully, the structure of macroporous resins was not destroyed after magnetism modification, the saturation magnetization of magnetic macroporous resins was enough to realize the magnetic separation of solid and liquid after adsorption. The mercury ions could be successfully adsorbed on magnetic resins with a removal rate over90%, the adsorption process tended to balance after720min and the magnetic resins were more suitable for Hg2+adsorption in acid aqueous environment. The adsorption kinetics had a better agreement with pseudo-second-order equation, and equilibrium studies showed that the data of Hg2+adsorption followed the Freundlich model. Adsorption process was spontaneous endothermic reaction, and high temperature was helpful for the adsorption reaction.