R1 PM Nanotechnology Environmental Remediation, Fate, and Transport
Thursday, 17 November 2005: 1:50 PM - 5:30 PM in Ballroom 1

(BRA-1117-722831) Transport of different nanosized aluminum particles through sand columns.

Doshi, Reeti¹, Braida, Washington¹, Christodoulatos, Christos¹, O'Connor, Gregory², ¹ Stevens Institute of Technology, Hoboken, NJ, USA² US Army, Environmental Technology Division, Picatinny Arsenal, NJ, USA

ABSTRACT- Nanoaluminum is used as an energetic material. The fate and transport of nanosized aluminum particles, once they are released into the environment, has not yet been addressed. As part of an ongoing research effort, the transport of two types of nanosized aluminum particles through sand columns has been studied. The Al particles are 100 nm in size and are coated with a thin layer of aluminum oxide or an organic carboxylic ligand. The transport behavior of the nanoaluminum particles was compared with the transport behavior of micron sized oxide coated-Al particles. Two experimental setups were used; i) columns fed with aqueous nanoaluminum suspension at different pHs and ii) deposit a layer of nanoaluminum particles at the top of the sand in the column and pump water at different pHs through it. The columns amended with nanoaluminum particles clogged after a few pore volumes of liquid passed through (faster clogging at pH 4 than at pH 7), suggesting the agglomeration of nanosized particles. Micron sized-Al amended sand columns clogged, but at much slower rate. Concentrations as high as 15 mg/L in the effluent were measured. Those are far larger than the World Health Organization guideline for Al in drinking water (0.2 mg/L). The total amount of aluminum leached from the columns follows the order: organic coated-pH 4>oxide coated-pH4 >> organic coated-pH 7oxide coated-pH 7. The distribution of aluminum through the column profile was measured and XRD analysis was performed to characterize the aluminum particles after exposure to the environment. The results of the research suggest that surface phenomena (i.e., changes in point of zero charge, agglomeration, etc.) play a major role in the transport of nanoaluminum particles. Furthermore, our results add to the basic knowledge necessary to predict the fate and transport of nanoparticles in the environment.

Key words: nanaoaluminum, fate & transport, sand columns