Phycoremediation of heavy metals in ashes

Conference poster, 2014

A growing problem in today’s society is the increasing amount of ash from the production of electricity and heat. Ash contains heavy metals that may be harmful to the environment. By using algae as ion exchangers, the ashes can be purified from certain heavy metals before deposit and its environmental impact is decreased [1]. Algal cell wall contains functional groups, such as amino-, carboxyl-, hydroxyl- and suphate groups, to which the various metal ions can bind bind [3]. An ion exchange of bound metal ions toward heavy metal ions can occur when the cell wall comes in contact with, for example, leachate from the ashes [1]. The process of using algae for environmental remediation is called phycoremediation. Within this project, we study the potential of microalgae for remediating ash from heavy metals, by measuring the metal binding capacity by three phytoplankton species: Chlorella salina, Dunaliella salina and Scendesmus obliquus. The heavy metals assayed are divalent ions of mercury (Hg), cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn). The effect of pH has been investigated as well as total binding over time. To apply the method on a more authentic situation, the binding of metals from combustion ash was investigated.