HR: 10:40h
AN: H22A-02    [Abstracts]
TI: Use of Carboxymethyl-beta-cyclodextrin (CMCD) as Flushing Agent for Remediation of Metal Contaminated Soil
AU: * Skold, M E
EM: mskold@mines.edu
AF: Department of Geology and Geological Engineering, Colorado School of Mines, 1500 Illinois St, Golden, CO 80401 United States
AU: Thyne, G D
EM: gthyne@mines.edu
AF: Department of Geology and Geological Engineering, Colorado School of Mines, 1500 Illinois St, Golden, CO 80401 United States
AU: Thyne, G D
EM: gthyne@mines.edu
AF: Environmental Science and Engineering Division, Colorado School of Mines, 1500 Illinois St, Golden, CO 80401 United States
AU: McCray, J E
EM: jmccray@mines.edu
AF: Environmental Science and Engineering Division, Colorado School of Mines, 1500 Illinois St, Golden, CO 80401 United States
AU: Drexler, J W
EM: John.Drexler@colorado.edu
AF: Geological Sciences, University of Colorado at Boulder, University of Colorado at Boulder, Boulder, CO 80309 United States
AB: One of the major challenges in remediating soil and ground water is the presence of mixed organic and inorganic contaminants. Due to their very different behavior, research has to a large extent focused on remediation of either organic or inorganic contaminants rather than mixed waste. Cyclodextrins (CDs) are a group of non-toxic sugar based molecules that do not sorb to soil particles and do not experience pore size exclusion. Thus, they have good hydraulic properties. CDs enhance the solubility of organic compounds by forming inclusion complexes between organic contaminants and the non-polar cavity at the center of the CD. By substituting functional groups to the cyclodextrin molecule it can form complexes with heavy metals. Previous studies have shown that carboxymethyl-beta-cyclodextrin (CMCD) can simultaneously complex organic and inorganic contaminants. The aim of this study is to compare how strongly CMCD complexes several common heavy metals, radioactive elements and a common divalent cation. Results from batch experiments show that CMCD has the ability to complex a wide array of heavy metals and radioactive elements. The solubility of metal oxalates and metal oxides clearly increased in the presence of CMCD. Logarithmic conditional formation constants ranged from 3.5 to 6 for heavy metals and from 3 to 6 for radioactive elements. Calcium, which may compete for binding sites, has a logarithmic conditional formation constant of 3.1. Batch experiments performed at 10 and 25 degrees C showed little temperature effect on conditional formation constants. Results from batch experiments were compared to results from column experiments where Pb was sorbed onto hydrous ferric oxide coated sand and subsequently removed by a CMCD solution. The results indicate that CMCD is a potential flushing agent for remediation of mixed waste sites.
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: Fall Meeting 2005