Abstract：Laboratory scale experiments were conducted to investigate the sedimentation and delivery properties in the three vehicles, i.e. water, sodium dodecyl sulfate (SDS) solution and SDS foam. Experimental results showed that the stability of NZVI in SDS solution was much greater than that in water; the optimum foam capability to carry NZVI and the uniformity of NZVI in foams were observed at 3000 r/min stirring speed; the presence of NZVI has slightly influence on foam stability. The maximum delivery distances for NZVI suspension, SDS-NZVI suspension and NZVI-laden foam were 0.8m, 7.9m, and 2.1m, respectively. Therefore, the transport of NZVI in porous media was enhanced apparently by SDS solution and SDS foam. The impact zones for SDS-NZVI suspension (33.5%) and NZVI-laden foams (42.5%) were icreased compared with the bare NZVI suspension (12.8%). Due to gravity, vertical transport of NZVI carried by SDS solution was prior to horizontal transport, and the horizontal delivery distance was limited; NZVI carried by SDS foam could transport in both horizontal and vertical directions, and the distribution of NZVI was more uniform. Additionally, compared with water and SDS solution, SDS foam was an ideal vehicle to deliver NZVI particles and had a promising application in contamination sites.
