Using Sea Shells to Remove Heavy Metals from Water


Photo: Flickr, CC

Researchers in Vietnam have recently completed tests on a new way to remove heavy metals from water. The secret? No, it's not some high tech materials... It's the good ol' sea shell. "In factories on the outskirts of Ho Chi Minh City, Stephan Kohler of the Graz University of Technology in Austria and a team of researchers have cleansed water tainted with toxic metals like cadmium, zinc, lead and iron." This could save countless lives in developing countries. Read on for more details. From Discovery News:

Kohler's team has found that pouring metal and acid-laden water over a bed of crushed clam or mussel shells provides an easy fix. The shells are made of aragonite, a form of calcium carbonate (CACO3) that readily swaps out its calcium atoms in favor of heavy metals, locking them into a solid form. The shells are naturally basic, too -- when dissolved they have a pH of 8.3. [...]

The team's technique stems from work in 2003 by Manuel Prieto of Oviedo University in Spain, who first showed that shells effectively remove cadmium from water.
"The idea of using aragonite shells arose because abiogenic aragonite is not an extremely abundant mineral," Prieto wrote in an email to Discovery News. "Moreover, in the North of Spain we have a very important seafood canning industry (cockles, mussels, clams, etc.) and shells are the most important wastes of that industry."

Of course, the next step is actually to stop dumping heavy metals in water in the first place, but while we get to that point, using sea shells to clean up the mess sounds like a pretty clever thing to do (and most important, it's inexpensive enough for poorer countries). Kudos.

Via Discovery News
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