Discipline: Chemistry and Chemical Sciences
Subcategory: Materials Science
Bethzaely Fernandez-Reyes - University of Puerto Rico Mayaguez Campus
Co-Author(s): Arturo J. Hernandez-Maldonado and Karen M. González-Ramos, University of Puerto Rico-Mayaguez, Mayaguez, PR
Contaminants of emerging concern (CECs) such as pharmaceutical and personal care products (PPCPs) enter wastewater treatment plants and even the environment every day, and most do in an unnoticed fashion. Many CECs are considered toxic, particularly those that are metabolites of source compounds such as medicinal drugs, endocrine disrupting chemicals (EDCs) and so on. Furthermore, the vast majority of CECs are not removed by treatment facilities due to the lack of proper technology to achieve this. A potential platform to develop such technology is that of porous adsorbents, which should be capable of selectively removing CECs in a non-energy intensive way. Although activated carbons are commonly used in water treatment due to hydrophobicity, large adsorption capacity and relative low cost, the lack of tailored functionality limits the potential for selective adsorption of targeted contaminants. Zeolites, on the other hand, possess flexible surface chemistry that allows for ease of functionalization, but suffer from limited hydrophobicity. However, a combination of these materials in the form of a porous carbon/zeolite composite might hold the answer to develop a suitable adsorbent to remediate CECs or at least families of CECs. This project focuses on the synthesis and characterization of such composites by imprinting a synthetic Faujasite zeolite onto the pores of an amorphous activated carbon (Darco KB-G) or a 3-dimensionally ordered mesoporous carbon (3DOm carbon). The first composite variant, namely an amorphous activated carbon-zeolite (CFAU), was successfully prepared, characterized, functionalized and tested for the adsorption of salicylic acid, carbamazepine and caffeine from water. In general, the composite adsorbent shows better capacity than the individual constituents (i.e., Faujasite and activated carbon). Inclusion of transition metal further enhances the interactions between the composite and the CECs. The results suggest that hydrophobicity, electrostatic interaction and complexes between adsorbent and CECs play an important role in the adsorption process. When using copper as the active site (i.e., Cu-CFAU), the adsorption selectivity increases as follows: salicylic acid < caffeine < carbamazepine. On going work is focusing on optimization of the preparation of the said composite plus the development of synthetic protocols to imprint the zeolite onto 3DOm carbons as well as the performance on the presence of other CECs.
Funder Acknowledgement(s): This material is based upon work supported by the National Science Foundation (NSF) under Award No. HRD-1345156 (CREST Phase 2 Program).
Faculty Advisor: Arturo J. Hernandez-Maldonado, email@example.com
Role: In house preparation of copper zeolite/carbon composite via in situ nanoseeding based crystal growth; carbamazepine and caffeine adsorption test.