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Groundwater Sampling at ISCO Sites: Binary Mixtures of Volatile Organic Compounds and Persulfate
Citation:
HULING, S. G., S. Ko, AND B. Pivetz. Groundwater Sampling at ISCO Sites: Binary Mixtures of Volatile Organic Compounds and Persulfate. GROUNDWATER MONITORING AND REMEDIATION. National Ground Water Association, Westerville, OH, 31(2):72-79, (2011).
Impact/Purpose:
binary mixtures comprised of sodium persulfate (2.5 g L-1) and volatile organic compounds (VOCs) (benzene, toluene, m-xylene, perchloroethylene, trichloroethylene) (500 – 1100 µg L-1) were investigated to assess whether the quality of the sample was impacted by an oxidant.
Description:
In-situ chemical oxidation involves the introduction of a chemical oxidant into the subsurface for the purpose of transforming ground-water contaminants into less harmful byproducts. Due to oxidant persistence, ground water samples collected at hazardous waste sites may contain organic contaminants and the oxidant in a “binary mixture”. Here, binary mixtures comprised of sodium persulfate (2.5 g L-1) and volatile organic compounds (VOCs) (benzene, toluene, m-xylene, perchloroethylene, trichloroethylene) (500 – 1100 µg L-1) was investigated to assess whether the quality of the sample was impacted by the oxidant. Significant reduction in the concentration of VOCs (49 – 100%) was measured in samples using either gas chromatography (GC) purge and trap, or GC mass spectroscopy (MS) headspace methods. Oxidative transformation of VOCs in the binary mixture was attributed to the direct reaction with the persulfate anion and the sulfate radical which formed as a result of persulfate activation. Preservation of the binary mixture samples was achieved through the addition of ascorbic acid (99-100% VOC average recovery). High concentrations of ascorbic acid (42 – 420 mM) did not interfere in the measurement of the VOCs, favored the reaction between persulfate and ascorbic acid while limiting the reaction between persulfate and VOCs, and did not negatively impact the instruments used in VOC analyses.
URLs/Downloads:
Groundwater Sampling at ISCO Sites: Binary Mixtures of Volatile
Abstract
GWMR Website
10317 HULING JOURN ART.PDF (PDF, NA pp, 2952 KB, about PDF)