Mass transfer of trichloroethylene through the palladized iron coated reactive geomembrane

Palladized iron coated reactive geomembrane (Pd/Fe RGM) was developed to mitigate the mass transfer of chlorinated volatile organic compounds through HDPE geomembrane. It had good performance in mitigating the mass transfer of TCE at the preliminary study. This study focused on the effects of Pd/Fe coating on the mass transfer parameters and the reaction rate constant of RGM. Also, the effects of sulfide and aging on the RGM were evaluated. It was proved that the effect of Pd/Fe coating on partition and diffusion coefficients of toluene was not significant by batch immersion test results with student's t-test. The reactivity of Pd/Fe RGM had a linear correlation with an increase in the Pd/Fe loading rate on RGM. However, it was lower than the reactivity of the Pd/Fe powder by a factor of one hundred because the effective surface area of Pd/Fe was blocked partially by the geomembrane and the opportunity to contact Pd/Fe and TCE was reduced. The reactivity of Pd/Fe RGM decreased severely at 10mM sulfide concentration and with long-term aging of RGM in the atmosphere for three years. However, the reactivity of aged RGM was recovered slightly by acid treatment, but not completely.