Abstract:
Due to the wide presence of nanoparticles (NPs) and heavy metals (HMs) in the environment, especially in porous media like soil, their fate and transport behaviors and hence the environmental impacts will greatly depend on their speciation, the impacts of natural organic matter (NOM) and how they interact with each other. Most correlative studies select typical NPs, HMs and NOM as the model subjects and conduct a series of adsorption-desorption batch experiments and NPs-HMs co-transport experiments in porous media to systematically study the NPs-HMs co-behaviors. Both thermodynamic and kinetics models have been applied to describe the interfacial reaction and transport/retention data obtained from experiments. The parameters were well compared, simulated and interpreted in order to achieve a complete picture of the effects of NOM on the fate of NPs-HMs. To reveal the mechanisms of NPs surface adsorption and the metal ions immobilization by NPs between soil grains, a big series of characterization analysis methods can be employed, such as Transmission Electron Microscopy (TEM), X-ray Diffractomer (XRD), X-ray Photoelectron Spectrometer (XPS), Fourier Transform Infrared Spectrometry (FTIR) and X-ray Absorption Near Edge Structure Spectrometry/Extended X-ray Absorption Fine Structure Spectrometry(XANES/EXAFS). Some of these methods working together are believed as a very effective and efficient approach in modern study. Understanding how the NPs impact on the leachability and bioavailability of heavy metals in subsurface porous media is of fundamental importance to the accurate assessment of environmental and ecological impacts of NPs. The results also have great significance to well comprehend the mechanisms of nano soil remediation.