(575d) Silica-Polymer Mixed Matrix Membranes for Mercury and Silver Sorption

Mercury contaminated waters, from lakes and rivers to mine runoff and other contaminated streams, poses a serious public health hazard. Similarly, silver sorption is often desired as a cost-recovery mechanism for various industries, including mining.  Novel functionalized silica particles have been synthesized with a Hg(II) sorption capacity of up to 85 mg/g (200 ppm Hg feed concentration at pH ~ 5.5).  However, like many sorbent particles, use of these materials in a packed bed or slurry has some drawbacks, such as internal mass transfer limitations as well as handling of hazardous and/or potentially valuable microparticles.  Novel functionalization techniques allow for mechanically stable mixed matrix membranes (MMM).  These are synthesized with higher loadings of sorbent (up to 50 wt% sorbent) than has been reported for previous silica/polymer MMM (30 wt% sorbent).  Functionalized silica/polymer MMM offer advantages for the efficient sorption of these ions onto the novel silica particles.  Synthesis of these MMM disperses the sorbent particles into a polymer matrix, so that the active sites are more exposed.  Convective flow used in the membrane processes exploits this dispersion for increased mass transfer and access to the active sorption sites.  Finally supporting the sorbent particles within a membrane matrix allows for facile handling, whether for disposal or adsorbate recovery. This work is supported by NEI Corporation.