Remediation of a nonachloro biphenyl congener with zero-valent iron in subcritical water

Dechlorination of a nonachloro biphenyl congener with zero-valent iron in w ater under high temperature and pressure was investigated over time. Temper ature has the main influence on the speed of dechlorination. Determination of polychlorinated biphenyls (PCBs) according to the grade of chlorination was performed by gas chromatography with mass selective detection in single ion monitoring mode. Dechlorination results in a variety of lower chlorina ted biphenyls. The level of chlorination decreases with time. The amount of PCB molecules decreases to one-third within 90 min at 250 degrees C and 10 0 atm. However, no increase of biphenyl could be detected over time. A firs t-order kinetic model fitted the data obtained.