Facile synthesis of mesoporous FeNi-alloyed carbonaceous microspheres as recyclable magnetic adsorbents for trichloroethylene removal

Abstract

Magnetic mesoporous FeNi/CS composites (FeNi alloy embedded in a porous carbon sphere) have been synthesized via a facile one-pot hydrothermal carbonization method, using metal nitrates and glucose as magnetic particle precursors and the carbon source, respectively. The properties of FeNi/CS were characterized with X-ray diffraction (XRD), Raman spectroscopy, a scanning electron microscopy (SEM) system, transmission electron microscopy (TEM), thermo-gravimetric analysis (TGA), nitrogen adsorption/desorption isotherms and a magnetic property measurement system (SQUID-VSM). FeNi/CS derived at different pyrolysis temperatures of 500, 700, 900 °C (FeNi/CS-500, FeNi/CS-700, FeNi/CS-900, respectively) could serve as novel magnetic carbonaceous adsorbents for removing trichloroethylene from aqueous media. FeNi/CS produced at 700 °C has the best removal capacity among all, mainly due to its large surface area, a wider range of pore size distribution, and suitable carbonized extent. The pseudo-second order model is well fitted to the kinetic data, indicating that chemisorption is the primary mechanism of TCE adsorption onto FeNi/CS. Moreover, the obtained magnetic porous composites could be easily separated from solution by using a permanent magnet after adsorbing TCE and used as efficient and recyclable adsorbents in the successive removal of TCE from wastewater.