Cycle 1 (2011 Deadline)
Investigation into persulfate/peroxymonosulfate oxidation of micro-contaminants towards water sustainability: mechanism, kenetics, and implementation
PI: Antoine Ghauch, American University of Beirut
US Partner: Richard Luthy, Stanford University
Project Dates: May 2012 - April 2015
Professor Antoine Ghauch presenting his PEER Science project results at the American Chemical Society meeting, New Orleans, April 2013.
Persulfate activation has attracted great interest within the scientific community as a way of producing short-lived sulfate radicals. These radicals are powerful oxidants that are more selective toward organic contaminants than the hydroxyl radicals that are often used for water and waste treatment. Using this approach, it may be possible to remove recalcitrant organic contaminants from water that are difficult to oxidize with existing treatment methods. The development of novel approaches for contaminant oxidation is critical to future efforts to secure water supplies in rapidly growing countries in arid climates. The issue of water quality is particularly important to Lebanon, where water shortages strike the Lebanese capital during August through November each year.
In this study, organic compounds that pose risks to human health and aquatic systems will be subjected to treatment with persulfate activated in various ways: thermally, photochemically (via sunlight) and chemically. This project will take several variables into account, such as ionic strength, sunlight intensity, concentrations of organic compounds, and chemical activators. Catalysts for persulfate activation will be developed using various metals and minerals, including some collected from Lebanese soils and waterways. These new chemical activators should be able to progressively activate persulfate and peroxymonosulfate into sulfate radicals in order to destroy organic micro-contaminants. This project should not only contribute to Lebanon's interests in educating its population but also help promote economic development, environmental protectoin, and capacity building among Lebanese researchers.
Summary of Recent Activities
Dr. Ghauch and his research group obtained new data on the removal of pharmaceutical compounds and benzene from water by thermal and chemical activation during the summer of 2013. The team continued their experiments using industrial iron waste for the degradation of ranitidine and their study of the effect of additives like Br-, Cl-, and bicarbonate on the degradation rate of this pharmaceutical. The team also tested columns filled with sand/iron for water purification using ibuprofen and phenacetin as pharmaceutical probes. Some of these results have been published or accepted for publication in peer-reviewed international journals. Dr. Ghauch has made a scientific visit to the University of California, Berkeley in August 2013, where he made a presentation to the research group of his U.S. co-partner Dr. David Sedlak. During this visit, he was also able to follow up on the research activities of graduate student Ghada Ayoub, who has spent the summer at Berkeley working under Dr. Sedlak’s supervision. During her summer visit, Ghada undertook experiments using strong oxidants like persulfate for the remediation of recalcitrant contaminants such as benzene that are hazardous wastes found in different sites throughout the world. The PI has also met with a National Instruments engineer to follow up on enhancements to the solid substrate room temperature phosphorescence (SS-RTP) instrument previously installed in Dr. Ghauch’s lab, as well as assignment of an engineer to work on software development aspects for the instrument’s improved operation.
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