Adsorption of Cu (II), Mn (II) and Zn (II) by Spirodela polyrhiza (L.) Schleiden: Equilibrium, kinetic and thermodynamic studies

The potential of the free floating freshwater macrophyte Spirodela polyrhiza (L.) Schleiden from the phoomdi of Loktak lake, India as an adsorbent to remove Cu (II), Mn (II) and Zn (II) ions from single, binary and ternary metal solution system was investigated. Metal adsorption was fast and equilibrium was attained within 120 min. Langmuir isotherm best described the equilibrium with maximum adsorption capacities (q(max)) of 52.6 mg g(-1) for Cu (II), 35.7 mg g(-1) for Mn (II) and 28.5 mg g(-1) for Zn (II) ions. Adsorption of the specific metal ions from binary and ternary metal solution system showed antagonistic nature due to screening effect and competition between the metal ions for active sites on the biomass. The present study showed that S. polyrhiza biomass could be used as an effective, low-cost adsorbent for Cu (II), Mn (II) and Zn (II) ions removal from wastewaters. (C) 2014 Elsevier B.V. All rights reserved.