A kinetic approach on the estimation of iron uptake by Apium nodiflorum plants

Abstract

A kinetic approach was developed to indicate the inherent capacity of aquatic plants to absorb heavy metals. The concept was based on the hypothesis that heavy metal uptake by plants follows a first‐order mathematical model depending on the heavy metal concentration in the biomass of this plant. This method enabled the evaluation of two parameters: (i) the specific metal uptake rate (k) and (ii) the maximum specific content (E_pl,8) of this metal in the aquatic plant. The specific uptake rate coefficient of the metal depended upon the concentration of the metal in the liquid phase, as can be seen from a Michaelis‐Menten‐type equation. This equation has two constants: (i) a maximum specific metal uptake rate (k_max) and (ii) a K_s coefficient. The maximum specific uptake rate coefficient was useful in the evaluation of the ability of different aquatic plants to absorb specific heavy metal, as well as in the evaluation of the selectivity of absorption between two or more metals by the plant. The maximum specific heavy metal content can be used for quantitative evaluation of an aquatic plant's ability to select this heavy metal. The ability of an aquatic plant to clean its aquatic environment from the metal can be evaluated in terms of the K_s‐coefficient. An example of this kinetic approach is given by using Apium nodiflorum. Experimental data from an aquatic system of Apium nodiflorum were collected and applied to the proposed kinetic approach for the estimation of parameters E_pl,8 k_max and K_s of the proposed kinetic model, whereas the adequacy of the model was examined by simulating a real process and comparing the predicted and measured values using χ²‐test.

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