Removal of mercury ion by the moss Pohlia flexuosa

Abstract

The moss Pohlia flexuosa was obtained as the protonema from its matured capsules. It was grown by shaking in modified Murashige-Skoog's medium, and the dry weight obtained was 40 mg per 20 ml medium after 15 d. The mature protonema removed Hg²⁺ from aqueous solutions. The higher the initial Hg²⁺ concentration, the higher the amount of Hg²⁺ removed, and the concentration factor, which is an indicator of the ability to remove heavy metals, was 2000 ml/g of dry moss at 50 μg/ml of HgCl₂. The optimal pH and temperature for Hg²⁺ removal were 7.0 and 25°C, respectively. Sodium azide and dinitrophenol at 0.1 mM inhibited Hg²⁺ removal up to a relative removal of 81 and 77%, respectively. The importance of two processes, bioaccumulation and adsorption, in the removal of Hg²⁺ by this moss is discussed.