Synthesis of CaCO3 supported nano zero-valent iron-nickel nanocomposite (nZVI-Ni@CaCO3) and its application for trichloroethylene removal in persulfate activated system

Nano zero-valent (nZVI) based composite have been widely utilized in environmental remediation. However, the rapid agglomeration and quick deactivation of nZVI limited its application on large scale. In this work, CaCO 3 supported nZVI-Ni catalyst, namely nZVI-Ni@CaCO 3 was prepared and used for the efficient removal of trichloroethylene (TCE) in PS oxidation process. The successful disbursement of nZVI-Ni on CaCO 3 support material not only increased the surface area of nZVI-Ni@CaCO 3 (69.45 m 2 /g) with respect to CaCO 3 (5.92 m 2 /g) and bare nZVI (13.29 m 2 /g) but also improved the catalytic activity . XRD, XPS and FTIR analysis confirmed the successful formation of nZVI-Ni@CaCO 3 nanoparticles . The nZVI-Ni@CaCO 3 nanoparticles combined with PS had achieved complete removal of TCE (99.8%) with dosage of 36 mg/L and 1.34 mM respectively. These results showed that the use of CaCO 3 as support material for nZVI-Ni could have significant influence on contaminant removal process. Scavenging and EPR tests validated the existence of SO 4 •– , OH • and O 2 •– radicals in PS/nZVI-Ni@CaCO 3 system and highlighted the dominant role of SO 4 •– radicals in TCE removal process. HCO 3 ˉ ions and humic acid have shown adverse effect on TCE removal due to radical scavenging and buffering effect. Owing to improved catalytic activity and easy preparation, the nZVI-Ni@CaCO 3 nanoparticles could be served as an alternative strategy for environmental remediation.