Synthesis Of Sub-micron-sized Polystyrene-supported Core-shell Composites And Its Application For Arsenate And Copper Removal

Adsorption is one of the widely used methods of heavy metal treatment. The widely used adsorbents are generally microsized, and the capacity and adsorption rate is still far from satisfaction. In our research we develop two materials sub-micron size materials. We study the performance of the removal of heavy metals and discuss the related mechanism, which provides a certain theoretical basis and method guidance for the development and application of sub-micron sized adsorbents.Based on the electrostatic assembly method, we synthesized a nano-sized magnetic core-shell adsorption material (PS-Fe3O4) via the heterogeneous coacervation method. The resultant adsorbent greatly increase the capacity of the bulky Fe3O4while maintain the solid-liquid magnetic separation, Transmission electron microscopy and X-ray diffraction were adopted to characterize the microstructure of the material. Batch and column adsorption of As(V) was performed by the core-shell material as a function of solution pH, concentration, time, and the competitive ion. The maximum adsorption capacity of PS-Fe3O4was139.3mg/g Fe3O477.7%greater than that of bulky Fe3O4.More attractively, it can be readily separated from water under a low magnetic field (<0.035T). Continuous adsorption-desorption cyclic results demonstrated that arsenate-loaded PS-Fe3O4can be effectively regenerated by NaOH solution, and the regenerated composite beads could be employed for repeated use without significant capacity loss.To further accelerate the adsorption rate and to improve the utilization of chitosan (CS) for heavy metal ion removal, sub-micron-sized polystyrene supported chitosan thin film was synthesized by the electrostatic assembly method. The thin chitosan film was well coated onto the surface of the polystyrene (PS) beads, as characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). Its adsorption toward Cu(II) ions was investigated as a function of solution pH, degree of cross-linking, equilibrium Cu(II) ions concentration and contact time. The maximum adsorptive capacity of PS-CS was99.8mg/g. More attractively, adsorption equilibrium could be achieved within only10min, with much faster rate than most of the reported adsorbents. Continuous adsorption-desorption cyclic results demonstrated that Cu(II)-loaded PS-CS could be effectively regenerated by the HCl solution. The regenerated composite beads could be employed for repeated use without significant capacity loss. XPS spectra confirmed the formation of the metal complexes with chitosan.Generally, PS beads could be employed as a promising host to fabricate efficient composites that originated from chitosan or other biosorbents for environmental remediation.