Removal of 1,2,3-Trichloropropane from groundwater using Graphene Oxide-Modified Nano Zero-Valent Iron Activated Persulfate

Abstract

Graphene Oxide (GO), nanoscale Zero-Valent Iron (nZVI) and GO-modified nZVI (GO-nZVI) composite materials were prepared by the Hummer and polyphenol reduction method, respectively, and Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) were used to characterize the morphology and phase composition of these materials. A series of batch experiments were then conducted to investigate the performance and influencing factors of GO-nZVI activating peroxydisulfate (SPS) for the degradation of 1,2,3-trichloropropane (TCP). Finally, an in-situ oxidation reaction zone was created by GO-nZVI-activated SPS in a one-dimensional simulated system to study the remediation of TCP contamination under different aquifer conditions. The results showed that the GO-nZVI composite exhibited a porous, fluffy structure, with spherical nZVI particles loaded onto the surface and folds of the GO sheets. Compared with unmodified nZVI particles, the GO-nZVI composite significantly enhanced the removal efficiency of TCP by activated SPS, achieving a removal rate of 67.2% within an hour - 78.2% higher than that of the unmodified system. The SPS dosage and the C/Fe ratio in GO-nZVI were found to significantly affect the degradation efficiency of TCP. The removal rate of TCP increased with higher SPS concentration, and a 10% carbon addition, yielded the best activation effect. The one-dimensional simulation results indicated that the removal rate of TCP ranged from 30.1% to 73.3% under different conditions. A larger medium particle size and higher concentrations of reactants (SPS and GO-nZVI) improved pollutant degradation efficiency, increasing TCP removal by 62.1%, 23.8%, and 3.7%, respectively. In contrast, a higher groundwater flow velocity was not conducive to the removal of pollutants, with the TCP removal rate decreasing by approximately 41.9%.