Question

Bioremediation (will be discussed further in class on 3/22): Isopropyl propionate (IPP- C6H12O2) has been considered as an electron donor source to support the biodegradation of tetrachloroethene (PCE) or trichloroethene (TCE) to ethene. IPP has been shown to undergo hydrolysis (transformation due to reaction with water) to form propionic acid and isopropyl alcohol. Ultimately, these byproducts are also transformed to yield H2 and CO2 in the following complete balanced chemical reaction with water:

0. C6H12O2 + 10H2O → 16H2 + 6CO2

   1. What volume of a 5mM (typical concentration used in groundwater remediation) IPP solution will be needed to provide enough reducing equivalents (amount of chemical species [in this case H2] which transfer the equivalent of one electron in a redox reaction) to completely biotransform a 5 L spill of pure/neat PCE?

   2. What if it was a 55 gallon drum of pure/neat trichloroethene (TCE) that was spilled; what volume of 5mM IPP would be need to carryout bioremediation to ethene? Note that 4 moles of H2 is need to transform 1 mole of PCE to ethene (i.e., 4 reducing equivalents) and 3 moles of H2 is need to transform 1 mole of TCE to ethene (i.e., 3 reducing equivalents).

TCE Properties
Molecular weight (MW) = 131.4 g/mole
Liquid density (ρL) = 1.46 g/cm3
Vapor pressure (VP) = 57.8 mm Hg
Aqueous solubility (Csol) = 1,100 mg/L
Henry’s Law dimensionless constant (H) = 0.335 OC partition coefficient (Koc) = 155 mL/g

PCE Properties
Molecular weight (MW) = 165.8 g/mole
Liquid density (ρL) = 1.62 g/cm3
Vapor pressure (VP) = 12 mm Hg
Aqueous solubility (Csol) = 180 mg/L
Henry’s Law dimensionless constant (H) = 0.47 OC partition coefficient (Koc) = 363 mL/g

Answer 1