(606e) Electrodialysis/Reverse Osmosis to Recover Dissolved Organics from Seawater

The dissolved organic matter (DOM) in seawater is estimated to contain about 700 gigatons of carbon although the concentration is only in the ppm range. The composition, origin, and fate of marine DOM has a significant impact on issues such as the global carbon balance and is therefore of great interest to scientists in a number of fields. A major obstacle has been isolating sufficient quantities of DOM from seawater for analysis of this chemically complex material. Ultrafiltration (UF) has been used for DOM recovery from seawater but a significant fraction of DOM is lost due to the molecular weight cutoff of UF membranes. We present electrodialysis combined with reverse osmosis as a gentle but rugged technique to relatively quickly recover significant amounts of a much larger fraction of DOM than previously possible while simultaneously removing salt. A planned research cruise in the Atlantic Ocean (Summer 2006) will demonstrate the feasibility of the technique on shipboard.