An adsorbent silica biogel material was developed via silica gel encapsulation of Pseudomonas sp. NCIB 9816-4, a bacterium that degrades a broad spectrum of aromatic pollutants. The adsorbent matrix was synthesized using silica precursors methyltrimethoxysilane and tetramethoxysilane to maximize the adsorption capacity of the matrix while maintaining a highly networked and porous microstructure. The encapsulated bacteria enhanced the removal rate and capacity of the matrix for an aromatic chemical mixture. Repeated use of the material over four cycles was conducted to demonstrate that the removal capacity could be maintained with combined adsorption and biodegradation. The silica biogel can thus be used extensively without the need for disposal, as a result of continuous biodegradation by the encapsulated bacteria. However, an inverse trend was observed with the ratio of biodegradation to adsorption as a function of log Kow, suggesting increasing mass-transport limitation for the most hydrophobic chemicals used (log Kow > 4).
Bibliographical noteFunding Information:
We thank Dr. Guillermo Marques for support with confocal microscopy and Sujin Yeom for assistance in growing cell cultures. This work was funded in part, by a MnDRIVE seed grant, the Institute on the Environment and an OVPR Transdisciplinary MnDRIVE grant from the University of Minnesota. Parts of this work were carried out in the Characterization Facility at the University of Minnesota, which receives partial support from the National Science Foundation through the MRSEC program. Confocal microscopy was done with the help of the University Imaging Centers at the University of Minnesota.
© 2017 American Chemical Society.