Bimetallic Nanoparticles - Nanotechnologies for Water Environment Applications - page 184

7.4 Conclusions

In this chapter, emphasis has been focused on the environmental applications of
bimetallic aluminum-based microparticles and bimetallic iron-based nanoparticles.
Although bimetallic iron nanoparticles are among the most successful nano-sized
reactive media in groundwater remediation, bimetallic aluminum-based particles have
shown their unique feature that is worthy of being explored. Because of the presence of
zero-valent aluminum, bimetallic Fe/Al particles successfully prevent the formation of a
passive layer at the iron surface and thus maintain the reactivity of iron. Bimetallic
Cu/Al particles are capable of dechlorinating dichloromethane that cannot be degraded
by bimetallic iron nanoparticles or conventional ZVI.

Bimetallic nanoparticles have many specific features, including a small particle
size (1-100 nm in diameter), high specific surface areas, and the bimetallic structure
with catalytic functionality. Based on these characteristics, they have been demonstrated
to have many advantages in subsurface remediation. In this chapter, the use of bimetallic
Pd/Fe nanoparticles for effective treatments of various chlorinated aliphatic
contaminants is presented. A systematic study on the formation of long-chain
hydrocarbons that may involve surface-mediated reactions similar to the
Fischer-Tropsch process is discussed since the concurrent formation of long-chain
hydrocarbons during the course of dechlorination by bimetallic iron nanoparticles has
long been ignored. In situ formation of bimetallic iron nanoparticles is discussed from
both the theoretical and practical aspect of groundwater remediation. In situ formation of
bimetallic iron nanoparticles may be achieved when monometallic iron nanoparticles are
implemented for remediation of mixed contamination with both chlorinated organic
contaminants and heavy metals. Overall, the nanoparticle technology is considered well
suited for in-situ treatment of contaminated hot-spots given its high reactivity, portability,
and flexible deployment in the field.

7.5 References

Alowitz, M. J., and Scherer, M. M. (2002). “Kinetics of nitrate, nitrite, and Cr(VI)
reduction by iron metal.” Environ. Sci. Technol ., 36, 299-306.
Arnold, W. A., and Roberts, A. L. (1998). “Pathways of chlorinated ethylene and
chlorinated acetylene reaction with Zn(0).” Environ. Sci. Technol., 32,
3017-3025.
Baltruschat, H., Beltowska-Brzezinska, M., and D Ü lberg, A. (1993). “Reactions of
halogenated hydrocarbons at platinum group metals. part I: A DEMS study of the
adsorption of CH 3 CCl 3 .” Electrochimica Acta., 38, 281-284.