Question

5. Bioremediation (will be discussed further in class on 3/22): Isopropyl propionate (IPP CoH1202) 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: CoH1202 10H20 16H2 6CO2 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? What if it was a 55 gallon drum of pure/ncat trichlorocthene (TCE) that was spilled; what volume of 5mM IPP would be need to carryout bioremediation to ethenc? Note that 4 moles of H2 is need to transform 1 mole ofPCE to ethene (i.e., 4 reducing equivalents) and 3 moles of H2 is need to transform I mole of TCE to ethene (i.e., 3 reducing equivalents) a. b.

Answer 1

For one of PCE, four moles ofhydrogen is required, whereas for TCE, only three moles of hydrogen is required The balanced reaction of bioremediation is as follows: C^H,,O2+10H,0- 16H2+6 CO2 a. To calculate the volume of 5 mM IPP solution for complete reduction of biotransform of5 L solution by using the dilution law MV -M,V, is as follows: ми-м, 5x103 molxV x16 molx 5 L (4 3) 4 |x16 тоl x5L (4 3) V 5x10 mol -3 =9.14 x103 L Therefore, the required volume of IPP solution is 9.14 x103 L

b. 3.785L = 208.175 L Convert the 55 gallon into L as follows: 55galx. 1gal To calculate the volume of5 mM IPP solution for complete reduction of biotransform of 208.175L solution by using the dilution law MV=M,V, is as follows: ми-му, 3 x16 mol x 208.175L 5x 10 mol xV = (4 3) 3 x16 molx 208.175L (4 3) V = 5x103 mol 2.85x105 L Therefore, the required volume of IPP solution is 2.85x105 L