Adsorption and reduction of trichloroethylene by sulfidated nanoscale zerovalent iron (S-nZVI) supported by Mg(OH)2.

Sulfidated nanoscale zerovalent iron (S-nZVI) supported on a flower spherical Mg(OH)2 with different Mg/Fe ration were successfully synthesized. The synthesized materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS). The results showed that S-nZVI particles were well dispersed on the petals of the flower spherical Mg(OH)2. The influence of factors, including the initial solution pH, Mg/Fe, S/Fe were studied. The trichloroethylene (TCE) adsorption data on Mg(OH)2 and S-nZVI @Mg(OH)2 fit well to a Langmuir isotherm model, and the maximum adsorption of S-nZVI @Mg(OH)2 was 253.55 mg/g, which was 2.6-fold of S-nZVI. Meanwhile, the S-nZVI @Mg(OH)2 composite expanded the pH selection range of S-nZVI from 2 to 11. Cycling experiments showed that removal rate was 58.3% for the 5th cycle. TCE removal was due to synergistic action of reduction coupled with adsorption. During this process, 65.43% of total remove TCE from ion chromatography data was reduced and 34.57% of total remove TCE was adsorbed finally. At the same time, adsorption favors reduction. These observations indicated that the S-nZVI @Mg(OH)2 can be considered as potential adsorbents to remove TCE for environment remediation.