Formatted Title
ZVI and Activated Carbon Integration Led to the Emergence of the Synergy Sought but not Found in ZVI Mixtures
Background/Objectives
BOS 100® is a significant improvement on ZVI alone and on mixtures of ZVI and activated carbon. When iron and activated carbon are mixed, a halogenated molecule can either be adsorbed to the activated carbon or be reduced by the ZVI. The halogenated compound adsorbed by the activated carbon is protected from interaction with nZVI, which is outside the activated carbon grain. This is an antagonistic relationship. The original patent for a mixture of activated carbon and iron was never commercialized. The research on which the patent was based showed that activated carbon’s failure to desorb adsorbed halogens eliminates it as an effective additive with nZVI (Huo, 2001). BOS 100® overcomes this issue. It is a unique integration. The ZVI is within and throughout the structure of the activated carbon. Having the ZVI inside the activated carbon places the adsorbed contamination in the location of the iron. ZVI within the micropores of the activated carbon produces a surface on which molecules are brought in proximity such that reactions that do not occur on ZVI will occur within BOS 100. BOS 100 can degrade contaminants such as vinyl chloride, methylene chloride, and 1,1 DCA. Chemicals not typically degraded by ZVI. The protected ZVI is not sensitive to oxygen, nitrate, or sulfate. BOS 100 continues to function for years in the subsurface. Finally, the kinetic rate of contaminant degradation exceeds ZVI.
Approach/Activities
Through laboratory studies and significant field data spanning over 20 years, BOS 100’s characteristics will be compared with ZVI. Site studies will include BOS 100 sites installed by in situ injection and barriers. Field data will be presented showing BOS 100 longevity that exceeds nine years. Both field and laboratory calculations will be given to demonstrate degradation rates. Similarly, field and laboratory data will present the range of contaminants BOS 100 is known to degrade. Finally, biological mechanisms conjoined to the BOS 100 technology will be briefly presented.
Results/Lessons Learned
It is evident from both field and laboratory data that BOS 100 overcomes several issues associated with ZVI alone and ZVI mixed with activated carbon. Additionally, BOS 100 has broader chemical applications than ZVI and BOS 100 has superior longevity. BOS 100 is a significant improvement to ZVI technology.