Reactive barrier membranes with environmental applications

Abstract

Addition of reactive groups to a barrier membrane can increase lag time for specific contaminants. Loading polyvinylalcohol (PVA) with a cesium-selective crystalline silicotitanate (CST) is shown to greatly increase lag time for cesium ion when upstream concentration is constant. Experiments are reproducible. Results can be generalized to real-world environmental applications. Loading powdered activated carbon (PAC) to PVA is shown to greatly increase lag time for 1,2,4-trichlorobenzene (1,2,4-TCB), a model for polychlorinated biphenyls (PCBs). Flow-through diffusion cell tests are performed challenging a PAC loaded barrier membranes with varying upstream concentrations. Desorption from a loaded PAC barrier membrane is shown to depend on the square root of time. Theoretical models are derived for four cases where a reactive volume degrading a contaminant in series with a sorbing, carbon-containing volume. Reactions following first-order kinetics allow more contaminant to escape from the modeled systems than reactions following zero-order kinetics. Results are summarized and potential future work is suggested.