Research on Foam’s Carrying Capacity of Two Types of nZVI

Special physical and chemical properties of nanoscale zero valent iron (nZVI), such as small particle size and high reactivity, make it a good choice as a remediation agent. nZVI is widely used in the remediation of various contaminants, including heavy metals and persistent organic pollutant. However, the immobilization of nanoparticles in porous medium limits the application in soil environmental remediation. Foam instead of water is used as the carrier of nanoparticles in in-site soil remediation process, which is a new idea, to improve sweep efficiency of nanoparticles. In this paper, the foam’s carrying ability of two types of nanoscale zero valent iron is studied. One of nZVI is purchased from a reagent Company, the other one is obtained by chemical precipitation method. In addition, the influence factors, the type and concentration of surfactant, foam quality and the initial concentration of nZVI are also discussed. The results demonstrate that foam has a 73% carrying capacity of nZVI-M, while much less capacity (33%) of nZVI-P under certain conditions. Surfactant can be used as dispersant to improve the stability of nZVI suspension. Besides, nZVI has no significant effect on the stability of foam, which provide the premise for foam as carrier. Influencing degree of these factors followed the order of the surfactant type > surfactant concentration > initial concentration of nZVI > foam quality under the experimental conditions.