Removal of PCP-Na from aqueous systems using monodispersed pompon-like magnetic nanoparticles as adsorbents

Novel monodispersed pompon-like magnetite/chitosan (Fe₃O₄/CS) composite nanoparticles were synthesized by a solvothermal method and used as adsorbents for the removal of toxic sodium pentachlorophenate (PCP-Na) from aqueous media. The adsorption behavior of PCP-Na on Fe₃O₄/CS obeyed the Langmuir isotherm and fitted the pseudo-second-order kinetics model. Thermodynamic parameters showed that the adsorption process was exothermic and spontaneous. Moreover, the adsorption was strongly pH-dependent. The results of XPS, thermodynamics, pH-dependent and desorption studies suggested that electrostatic attraction, hydrogen bonding and π-π interactions were all believed to play a role in PCP-Na adsorption on Fe₃O₄/CS. Having a saturation magnetization of 22.2 emu · g⁻¹, the Fe₃O₄/CS can be easily separated from water with magnets within 2 min. The adsorption equilibrium was achieved quite rapidly (within 30 min) and the maximum removal of PCP-Na (91.5%) was obtained at 25 °C and pH 6.5. The Fe₃O₄/CS investigated can be used to remove PCP-Na and other contaminants from wastewater.