AIChE Annual Meeting: Pittsburgh, Pennsylvania

Measuring Diffusion of Trichlorethylene Breakdown Products in Polyvinylalginate

October 29, 2018

Trichloroethylene (TCE), a toxic and carcinogenic contaminant, presents unique challenges for cleanup because of its water solubility, density, and volatility. Bioremediation of TCE is a promising cleanup method; however, metabolism of TCE results in acid generation that inhibits remediating microorganisms. Calcium alginate(CA)-polyvinylalcohol (PVA) hydrogels show promise for protecting remediating microbes, however diffusion of TCE or its byproducts through these polymers is unknown. To measure the effective diffusion coefficient of TCE and byproducts through hydrogel membranes, we used a modified diaphragm cell. Measured effective diffusion coefficient of each species was (cm ² /s × 10⁶ ): 14.0 ± 1.91 for H⁺ ions, 12.4 ± 1.64 for TCE, 7.83 ± 0.54 for cis-1,2-dichloroethylene (DCE), and 4.68 ± 4.14 for vinyl chloride. These results aid in engineering biobeads and suggest that CA-PVA hydrogel blends are effective in slowing diffusion of protons, buffering acids produced by trichloroethylene metabolism, and remains suitable for encapsulation of microorganisms involved in bioremediation.