Abstract

Duckweed was used to study adsorption of several metal ions (Fe²⁺,Cu²⁺, Zn²⁺ and Pb²⁺)  from wastewater under different conditions .The dried leaves of duckweed were used at different adsorbent/metal ion ratios. The experimental conditions which includes, pH, contact time, initial concentration, and loading weight on the removal process were investigated. Bach adsorption was studied in a room temperature. The efficiency of adsorption depends on pH value, it increases with the increase of pH value at (2 to 8 ) in range time between  60 to 90  min. The most percentage of removal in the main way of loading weigh was 1.5 gm and 50 ml mixed metal ions solution at 50 ppm concentration of each metal ion. The study of isothermal showed that data was confirmed with temkin isotherm model. The removal order was found to be Pb²⁺< Zn²⁺< Cu²⁺< Fe²⁺. The potential of application for the treatment of solutions containing these heavy metals in multimetal solutions is indicated. The characterization (the infrared) for the surface of duckweed showed the presence of many function groups which can be binding with metal cations.

Key words: Duckweed, heavy metals, adsorption, removal of metals, adsorption isotherm, adsorption from aqueous solution.