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September 1, 2015


Crab Shells Remove Copper and Cadmium from Contaminated Water


Scientists in Malaysia have found that crab shells are effective in removing copper and cadmium from contaminated waters.


Copper and cadmium exist naturally in the environment, but human activities including industrial and agricultural processes can increase their concentrations.  At high concentrations, copper can cause unwanted health effects such as nausea, while cadmium can be toxic to the kidneys.


In a study published in the Pertanika Journal of Science and Technology, researchers at the Universiti Putra Malaysia tested the effectiveness of crushed shells from the mud crab (Scylla serrata) as biosorbents.  The calcium carbonate in their shells removes copper and lead by forming strong bonds with them, and the chitin in their shells absorbs dissolved cadmium and copper.


The research team carried out several tests in water conditions similar to mining or metal refining wastewater, using five different concentrations of copper and cadmium ranging from 1 to 20 percent.  The scientists found that crab shells could remove up to 95 per cent of the copper and 85 per cent of the cadmium after six hours.  Based on these results, the team concluded that “crab shells are undeniably suitable adsorbents for heavy metals from industrial wastewater.”


Information: Ahmad Zaharin Aris, Associate Professor, Environmental Forensics Research Centre, Faculty of Environmental Studies, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia (email, phone +603 8946 7455, mobile +6012 474 0304, webpage


Source: NewsMaker.  Pertanika Journal: Purifying Contaminated Water With Crab Shells.  August 31, 2015.

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