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
Between September and December 2013, the project team continued to generate data on how well a column filtration system using various thermal and chemical processes removed various pharmaceutical compounds from water. The experiment focusing on naproxen has shown high potential for using thermally-activated persulfate to mineralize organic contaminants found in hospital effluents. The tests aimed at reducing ranitidine contamination focused on the effect of additives on the persulfate/water matrix in the presence of trace amount of industrial iron collected from an automotive repair shop. Over the same period, Dr. Ghauch and his group have conducted benzene remediation experiments at AUB, paralleling a University of California, Berkeley experiment executed between June and August, 2013. They have achieved some very promising results, which have been disseminated for publication in several peer-reviewed international journals.
In the next few months, the team will be testing the suitability of the first components of the solid substrate room temperature phosphorescence (SS-RTP) instrument. A consultancy agreement has been prepared for an engineer to develop the software and user interface. The project team will be making a presentation on the water purification testing apparatus at the American Chemical Society’s National Meeting & Exposition in August 2014. .
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