DECHLORINATION OF CARBON TETRACHLORIDE BY NANOSCALE IRON PARTICLES IN AQUEOUS SOLUTION HSING-LUNG LIEN WEI-XIAN ZHANG Department of Civil and Environmental Engineering, Lehigh University, Bethlehem, PA 18015 INTRODUCTION Recently, a method for the generation of very small (nanoscale) bimetallic particles has been reported [1,2]. These nanoscale metal particles typically have a diameter on the order of 1-100 nm and feature 0.06% by weight of palladium deposited on the surface of iron. Advantages of the nanoscale bimetallic system for treatment of chlorinated organic pollutants include: (1) High specific surface area. The nanoscale metal particles have a specific surface area around 35 m2/g. Tens to hundreds times higher than those of the commercial grade iron particles (used in conventional iron walls). (2) High surface reactivity. For example, values of surface-area-normalized rate coefficient (KSA) for the transformation of chlorinated ethylenes were about one to two-orders of magnitude higher than those reported in the literature for commercial grade iron particles [3]. Due to their small particle size and high reactivity, the nanoscale metal particles may be useful in a wide array of environmental applications. In the aqueous phase, the nanoscale iron particles remain suspended, almost like a homogenous solution. Theoretical calculations indicate that, for colloidal particles less than about 1 micrometer, gravity of the metal particles is insignificant to influence the particle movement. Brownian motion (thermal movement) tends to dominate the transport process in groundwater. Thus, we believe that the metal particles could be injected directly into contaminated soils, sediments and aquifers for in situ remediation of chlorinated hydrocarbons, offering a cost-effective alternative to such conventional technologies as pump-and-treat, air sparging or even conventional iron reactive walls. Design, construction and operation of such injectable systems should be reasonably straightforward.

DOI link for DECHLORINATION OF CARBON TETRACHLORIDE BY NANOSCALE IRON PARTICLES IN AQUEOUS SOLUTION HSING-LUNG LIEN WEI-XIAN ZHANG Department of Civil and Environmental Engineering, Lehigh University, Bethlehem, PA 18015 INTRODUCTION Recently, a method for the generation of very small (nanoscale) bimetallic particles has been reported [1,2]. These nanoscale metal particles typically have a diameter on the order of 1-100 nm and feature 0.06% by weight of palladium deposited on the surface of iron. Advantages of the nanoscale bimetallic system for treatment of chlorinated organic pollutants include: (1) High specific surface area. The nanoscale metal particles have a specific surface area around 35 m2/g. Tens to hundreds times higher than those of the commercial grade iron particles (used in conventional iron walls). (2) High surface reactivity. For example, values of surface-area-normalized rate coefficient (KSA) for the transformation of chlorinated ethylenes were about one to two-orders of magnitude higher than those reported in the literature for commercial grade iron particles [3]. Due to their small particle size and high reactivity, the nanoscale metal particles may be useful in a wide array of environmental applications. In the aqueous phase, the nanoscale iron particles remain suspended, almost like a homogenous solution. Theoretical calculations indicate that, for colloidal particles less than about 1 micrometer, gravity of the metal particles is insignificant to influence the particle movement. Brownian motion (thermal movement) tends to dominate the transport process in groundwater. Thus, we believe that the metal particles could be injected directly into contaminated soils, sediments and aquifers for in situ remediation of chlorinated hydrocarbons, offering a cost-effective alternative to such conventional technologies as pump-and-treat, air sparging or even conventional iron reactive walls. Design, construction and operation of such injectable systems should be reasonably straightforward.

DECHLORINATION OF CARBON TETRACHLORIDE BY NANOSCALE IRON PARTICLES IN AQUEOUS SOLUTION HSING-LUNG LIEN WEI-XIAN ZHANG Department of Civil and Environmental Engineering, Lehigh University, Bethlehem, PA 18015 INTRODUCTION Recently, a method for the generation of very small (nanoscale) bimetallic particles has been reported [1,2]. These nanoscale metal particles typically have a diameter on the order of 1-100 nm and feature 0.06% by weight of palladium deposited on the surface of iron. Advantages of the nanoscale bimetallic system for treatment of chlorinated organic pollutants include: (1) High specific surface area. The nanoscale metal particles have a specific surface area around 35 m2/g. Tens to hundreds times higher than those of the commercial grade iron particles (used in conventional iron walls). (2) High surface reactivity. For example, values of surface-area-normalized rate coefficient (KSA) for the transformation of chlorinated ethylenes were about one to two-orders of magnitude higher than those reported in the literature for commercial grade iron particles [3]. Due to their small particle size and high reactivity, the nanoscale metal particles may be useful in a wide array of environmental applications. In the aqueous phase, the nanoscale iron particles remain suspended, almost like a homogenous solution. Theoretical calculations indicate that, for colloidal particles less than about 1 micrometer, gravity of the metal particles is insignificant to influence the particle movement. Brownian motion (thermal movement) tends to dominate the transport process in groundwater. Thus, we believe that the metal particles could be injected directly into contaminated soils, sediments and aquifers for in situ remediation of chlorinated hydrocarbons, offering a cost-effective alternative to such conventional technologies as pump-and-treat, air sparging or even conventional iron reactive walls. Design, construction and operation of such injectable systems should be reasonably straightforward.