This research has been carried out for assessing phytoremediation of contaminated soils with 4 concentrations of arsenic by three plants, namely Vetiver grass (Vetiveria zizanioides), Chara algae (Chara vulgaris) and Water hyacinth (Hyacintus orientalis). The experimental results showed that at least two sampling times were significantly different. In addition, at least two plants were also significantly different in terms of percentages of total arsenic that were removed from the soil of the pots, as well as significant interactions between plant and arsenic concentrations. The results obtained from the thermodynamic studies show that, obtained by zero Gibbs free-energy, the process reached an equilibrium on the 60th day of the experiment, and, in fact, the adsorption of arsenic after the 60th day would be negligible.
Keywords: Arsenic; Chara algae; Contaminated Soils; Phytoremediation; Vetiver grass; Water hyacinth.