Efficient removal of trichloroethylene in surfactant amended solution by nano Fe-0-Nickel bimetallic composite activated sodium persulfate process

摘要

Trichloroethylene (TCE) is chloride organic solvent used in industrial process and frequently detected as one of contaminants in groundwater. In present study, nano zero valent iron-nickel composite (nZVI-Ni) was prepared successfully by ion exchange process and investigated as a proficient sodium persulfate (SPS) activator for the removal of TCE in Fenton-like oxidation system. The physico-chemical characteristics, structure, and surface morphology of the prepared nZVI-Ni nanocomposite was analyzed through energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), N-2 adsorption-desorption, transition electron microscopy (TEM), X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). The experimental results obtained from batch tests in lab showed that more than 95% of TCE could be removed efficiently at nZVI-Ni/SPS/TCE molar ratio of 4/4/1 within 120 min at 20 degrees C. Further scavenging tests were designed to examine the presence of HO%, SO4 center dot- and O-2(-center dot) radicals and verified the major role of HO center dot radical in the nZVI-Ni/SPS system for the complete removal of TCE. Moreover, the generation of HO center dot radicals in the system was confirmed through electrons paramagnetic resonance (EPR) of nZVI-Ni composite. The influence of surfactants on TCE removal was tested and the results showed that the percentage removal of TCE was recorded as 97.75%, 95.63% and 77.50% in the presence of Tween-80, BRIJ-35 and TX-100 surfactants at the nZVI-Ni/SPS/TCE molar ratio of 80/80/1, respectively. Results of TCE degradation in real groundwater revealed that nZVI-Ni can be applicable and is a promising catalyst for TCE removal in in-situ chemical oxidation (ISCO) practice. In Summary, these significant findings strongly demonstrate the feasibility and potential of nZVI-Ni activated SPS process as an alternative technique for TCE contaminated groundwater remediation.