人工纳米材料在污水中的稳定特性研究

With the rapid development in nano-technology, the increasing use of nanomaterials raises concerns about their environmental impacts. The wastewater treatment plants are important controlling gate to protect the natural water safety from the nano-pollution, therefore, it is important and necessary to study how nanomaterials affect the wastewater activated sludge in biological treatment system. In this paper, we took the metal oxide nanoparticles of zinc oxide and titanium dioxide as our experimental targets. According to the results of DLS, the nanoparticles dispersed very well in the wastewater samples maintaining their diameters of 300 to 400 nm. Dissolved organic matter (NOM) was confirmed to be the main factor for the stability of nanoparticles in wastewater. Further studies showed that the humic acid, which maybe stem from the extracellular polymeric substances (EPS) of bacteria, maybe the culprit leading to the stability of nanoparticles. It was found that divalent calcium ion had no effect on the stability of nanoparticles which meant that the electric double layer compression didn't cause the distability of the nanoparticles in wastewater, which was totally different from the previously reported traits of nanoparticles in the nature water bodies.