Heavy Metal Stabilization in Contaminated Soil.....

HEAVY METAL STABILIZATION IN CONTAMINATED SOIL USING CROSSLINKED BIOPOLYMERS WITH INTERPENETRATING POLYMER NETWORK (IPN) STRUCTURESSpeaker:Shawntine Lai
Environmental Engineer
URS CorporationAbstract:
U.S. Department of Defense has many outdoor small arms firing ranges for weapons training, essential for its mission. Their use, however, generates soil contamination primarily with Pb, which is a characteristic hazardous waste. With common total Pb levels in range soils of 50,000 mg/kg or more, there is an acute need for efficient permanent stabilization technologies. The study proposed the use of biopolymers for Pb stabilization in soils. The concept is based on biopolymers' well-known abilities to bind metals, soil particles and to create the crosslinking networks (interpenetrating polymer networks, IPNs) in the presence of crosslinking agents. Consequently, the soil treatment with crosslinked biopolymer networks able to bind both Pb and soil particles in composites resistant to biodegradation may provide a permanent stabilization. There are several commercialized biopolymers and possible crosslinking agents available, such as guar gum, xanthan gum, chitosan, alginate, etc. Many of them have been widely adapted in soil remediation since they are renewable and cost-effective. They can be used as barriers to prevent the migration of hazardous wastes.The parameters used in this study included biodegradability of the IPNs, weight swelling ratio, and rheological properties of the IPNs. Lead in firing range soil was successfully stabilized up to 99% using crosslinked biopolymers at optimum conditions. The distribution of lead species in soil components was investigated using Selective Sequential Extraction (SSE) procedures, and was altered due to the formation of IPNs. This crosslinked biopolymer technology was also applied to synthetic polluted soil of other metals, such as Cr, Cu, and Fe, and showed remarkable results. This presentation will also provide general information on how to conduct and evaluate Environmental Site Assessments (ESAs) in engineering practice, such as Phase I ESA, Phase II ESA, and Preliminary Endangerment Assessment. The purpose of the ESAs is to identify existing or potential environmental hazards for a subject property. The assessments provide useful information for subsequent remedial action plans.

Location: Kaprielian Hall (KAP) - 156

Audiences: Everyone Is Invited

Contact: Evangeline Reyes