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%.

Trivalent chromium (Cr(III)) can form stable soluble complexes with organic components, altering its adsorption properties in the water-soil environment. This increases the risk of Cr(III) migrating to deeper soils and transforming into toxic Cr(VI) due to the presence of manganese oxides in sediments. In this study, Citric Acid (CA) was selected as a representative organic ligand to prepare and characterize Cr(III)-CA complexes. The characteristics, mechanisms and environmental factors influencing the adsorption of Cr(III)-CA on porous media (silts and fine sands) were investigated in the study. The results show that Cr(III) coordinates with CA at a 1:1 molar ratio, forming stable and soluble Cr(III)-CA complexes. Compared to Cr(III) ions, the equilibrium adsorption capacity of Cr(III)-CA is an order of magnitude lower in silts and fine sands. The adsorption of Cr(III)-CA in silts and fine sands is dominated by chemical adsorption of monolayers, following the pseudo-second-order kinetic equation and the Langmuir isotherm adsorption model. Varying contents of clay minerals and iron-aluminum oxides prove to be the main causes of differences in adsorption capacity of Cr(III)-CA in silts and fine sands. Changes in solution pH affect the adsorption rate and capacity of Cr(III)-CA by altering its ionic form. The adsorption process is irreversible and only minimally influenced by ionic strength, suggesting that inner-sphere complexation serves as the dominant Cr(III)-CA adsorption mechanism.