You are here:
Applications Of Nanomaterials In Risk Management Of Environmental Pollutants: The Use Of Bimetallic Systems
Citation:
AL-ABED, S. R., H. Choi, S. AGARWAL, AND D. D. DIONYSIOU. Applications Of Nanomaterials In Risk Management Of Environmental Pollutants: The Use Of Bimetallic Systems. Presented at First International Conference from Nanoparticles and Nanomaterials to Nanodevices and Nanosystems (First IC4N), Halkidiki, GREECE, June 15 - 19, 2008.
Impact/Purpose:
To discuss the applications of Fe/Pd and Mg/Pd bimetal systems for the remediation of PCBs-contaminated sediments and soil.
Description:
Remediation of sediments and water contaminated hydrophobic organic chemicals (HOCs) such as polychlorinated biphenyls (PCBs) remains a scientific and technical challenge. PCBs-contaminated sediments are ubiquitous despite the production and use of PCBs was banned in 1979 due to their toxicity and persistence in the environment. In addition to the high stability of PCBs, their low solubility in water and high affinity to organic substances make it difficult to treat PCBs using conventional methods. The use of reactive zerovalent metals such as iron and magnesium has been well documented to work efficiently for the dechlorination [1,2]. Metals are oxidized to produce electrons while PCBs are reduced to release chloride ions. Alternatively, the released electrons can produce hydrogen from electrolysis or water, which can be activated and ultimately used to dechlorinate PCB. Two main strategies have been focused to increase the reactivity. Fe and Mg are oxidized more rapidly when attached with less active metals (Pd, Pt, Ni, Ag). Thus, the overall reactivity can be significantly increased by depositing a thin and discontinous layer (i.e., islands) of noble metals on Fe and Mg surface. Studies also suggested that dechlorination of PCBs is facilitated through Pd-mediated hydrogenation. In addition, dechlorination of PCBs using zero-valent iron/Pd (ZVI/Pd) systems can be improved by introducing nanoscale ZVI particles and Pd nano-islands on the ZVI. The small size and high surface to volume ratio of nanoscale Fe make it attractive for PCBs dechlorination, compared to those of conventional micron size Fe [3]. In this presentation, we will discuss the versatile applications of these Fe/Pd and Mg/Pd bimetal systems for the remediation of PCBs-contaminated sediments and soil. This includes i) synthesis of nanoscaling of Fe/Pd and Mg/Pd particles, ii) immobilization of nano-islands of bimetals on granular activated carbon for the simultaneous adsorption and dechlorination of PCBs, and iii) comparison between Fe/Pd and Mg/Pd bimetal systems.