461312 Advanced Redox-Based Electrochemical Separations for Wastewater Treatment

Wednesday, November 16, 2016: 1:00 PM
Union Square 14 (Hilton San Francisco Union Square)
Xiao Su1, Timothy Jamison2 and T. Alan Hatton1, (1)Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, (2)Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA

Water scarcity is one of the principal challenges for the 21st century, both from a geographical and an economic standpoint. Developing novel, more energetically efficient technologies for wastewater treatment, retreatment and reuse is crucial for long-term water sustainability. One of the principal challenge for water remediation, both in the U.S. and worldwide, is to target contaminants of emerging concern, such as complex organic molecules including pharmaceuticals, chemical precursors, endocrine inhibitors and pesticides.[1] These originate from chemical processes and organic synthesis, the food industry, electronic manufacturing among others. Many of these pollutants disperse in remote locations, such as agricultural locations, in which large-scale purification systems cannot be implemented. Electrochemical methods are particularly attractive for addressing these problems due to their modularity, fast kinetics and integration with renewable energy sources.[2]

We have developed an redox-mediated separation method based on organometallic-functionalized electrodes (e.g. ferrocene or cobaltocene) for the sorption and release of specific ions from the liquid-phase under oxidizing and reducing conditions.[3] Many of the organic contaminants are anionic in nature (e.g. carboxylates, sulfonates or phosphonates), thus selectivity based on chemical interactions with their functional groups is essential in chemical design. Rather than rely solely on charge or size, our immobilized redox-centers targets these compounds through the activation of a specific chemical binding. Moreover, in the charging and discharging steps, electrochemical charge can be stored by ion-selective adsorption onto the porous electrodes, thus dramatically decreasing energetic costs.

This modular system can then be easily implemented at the point-of-exit in chemical manufacturing and wastewater treatment. Here, we present a complete asymmetric redox-system in both batch and flow for (1) water remediation, through the specific separation of anionic and cationic contaminants in water, (2) tandem energy recovery due to pseudocapacitive charge storage and (3) increasing sustainability in chemical processes, through the recovery of expensive synthesis products from complex organic reactions, thus reducing organic waste and decreasing water usage during separation steps.

References

[1] a) Gilliom R.; Hamilton P. U.S. Geological Survey. 2014. (USGS fact sheet: http://pubs.usgs.gov/fs/2006/3028/

). b) Doughton, C.G. and Thomas, A. T. (1999). Pharmaceuticals and personal care products in environment: agents of suble change? EHP 107 (6), 907-938.

[2] Suss, M. E.; Porada, S.; Sun, X.; Biesheuvel, P. M.; Yoon, J.; Presser, V. Energy & Environmental Science 2015. Zhao, R.; Satpradit, O.; Rijnaarts, H. H.; Biesheuvel, P. M.; van der Wal, A. Water Res 2013, 47, 1941.

[3] Su, X.; Kulik, H; Jamison, T.F.; Hatton, T. A. 2016. Anion-selective redox electrodes: electrochemically-mediated separation with organometallic interfaces. Advanced Functional Materials. Advance Article Online. DOI: 10.1002/adfm.201600079


Extended Abstract: File Not Uploaded
See more of this Session: Advanced Treatment for Water Reuse and Recycling II
See more of this Group/Topical: Environmental Division