Kinetics of Manganese Uptake by Wetland Plants

Abstract

The aim of this study was to assess the kinetics of Mn removal by broad-leaved cattail, soft stem bulrush, soft rush and wool grass plants from contaminated wastewater under laboratory conditions. The approach used was based on a first order kinetic model which depended on the initial heavy metal concentration in the wastewater and allowed for the evaluation of the specific metal uptake rate and the maximum specific content of the metal in each plant species. The results showed that the model is capable of predicting the experimental data with relatively high confidence (R² = 0.88). The specific Mn uptake rate and the maximum amount of Mn that can accumulate in each plant species were affected by the initial Mn concentration in the wastewater and the plant species. As the initial concentration of Mn in the water increased, the specific Mn uptake rate of each species decreased showing signs of toxicity. Broad-leaved cattail displayed the highest specific Mn uptake rates followed by soft stem bulrush, soft rush and wool grass. The maximum amount of Mn that accumulated in each species also increased as the initial Mn concentration in the wastewater increased. Broad-leaved cattail and soft stem bulrush plants would accumulate the highest amount of Mn in their tissues followed by soft rush and wool grass.