Development and assessment of surfactant modified sorbents to measure inorganic and organic contaminant fluxes using passive flux meter
Abstract
The use of contaminant flux and contaminant mass loading as robust metrics has gained increasing acceptance for assessment of risks at contaminated sites, and for evaluating the performance of site remediation efforts. Passive Flux meter (PFM), an innovative approach to simultaneously measure groundwater and contaminant fluxes, has been demonstrated for organic contaminants at diverse sites. This study focused on extensions to the PFM technology to assess contaminant fluxes at sites contaminated with perchlorate (used as solid rocket propellant) and other inorganic anions. Natural zeolite (clinoptilolite) and silver-impregnated, granular, activated carbon (SI-GAC), and granular activated carbon (GAC) were modified with the cationic surfactant, hexadecyltrimethyl ammonium (HDTMA), to enhance the anion exchange capacity of the sorbents. Newly developed sorbent matrices, surfactant-modified, silver-impregnated, granular activated carbon (SM-SI-GAC), surfactant-modified zeolite (SMZ) and surfactant-modified, granular activated carbon (SM-GAC) were evaluated in laboratory and field studies for measuring anion fluxes. SM-SI-GAC, SMZ and SM-GAC were evaluated at two field sites. SM-SI-GAC was tested for perchlorate flux measurements at a site located at the Indian Head Naval Surface Warfare Center (IHDIV-NSWC) in Maryland. The new method with SM-SI-GAC compares favorably with the conventional method for perchlorate and groundwater flux measurements. SMZ and SM-GAC were successfully field-demonstrated for flux measurements of PCE and by-products at a dry cleaner site located at Crawfordsville, Indiana. This study advanced PFM technology to measure inorganic as well as organic contaminant fluxes and measure both of them simultaneously with SMZ and SM-SI-GAC as a sorbent. Further, SMZ and SM-SI-GAC can be used as a sorbent to remove inorganic and organic contaminants in other applications such as wastewater treatment and permeable reactive barriers (PRBs). In addition, the concept of modification of sorbent extends the selection of sorbent of PFM for target contaminants.
Degree
Ph.D.
Advisors
Rao, Purdue University.
Subject Area
Environmental engineering
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