Removal of N-Nitroso Dimethylamine from Aqueous Solution by Nano Zero Valent Iron–Copper Bimetallic Composite Supported on Granular Activated Carbon

Granular activated carbon-supported nano zero-valent iron-copper bimetallic composite(nZVI-Cu@GAC) was synthesized using the chemical liquid-phase reduction method. The morphology and physicochemical properties of the material were analyzed using scanning electron microscopy (SEM), a fully automatic specific surface area analyzer (BET), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The removal efficiency of N-nitrosodimethylamine (NDMA) by different materials was compared, and the adsorption process was further investigated using adsorption kinetics and isotherm models. The results showed that nZVI-Cu was well dispersed on the surface and in the pores of GAC. Among the tested materials, nZVI-Cu@GAC (Fe/Cu = 1/0.05, m/m) demonstrated the best NDMA removal efficiency, achieving a removal rate of 85.8%. The degradation process of NDMA by the composite material followed pseudo-second-order kinetics and the Freundlich model, indicating that the removal process was predominantly chemical adsorption and characterized by bimolecular layer adsorption on a heterogeneous surface. The nZVI-Cu@GAC (Fe/Cu = 1/0.05, m/m) composite exhibited the fastest adsorption rate, muscular adsorption capacity, and facile adsorption process. The removal of NDMA by nZVI-Cu@GAC was accomplished through the combined effects of GAC adsorption and nZVI-Cu chemical reduction. In conclusion, the nZVI-Cu@GAC composite material can effectively remove NDMA from water and holds better application prospects.