Feasibility and assessment of the phytoremediation potential of duckweed for triarylmethane dye degradation with the emphasis on some physiological responses and effect of operational parameters

Phytoremediation is a low-cost and effective technology that removes pollutants, such as dye-containing effluents, from the environment through the use of plants. In the present study, the potential of Lemna minor L. for decolorization and degradation of the triarylmethane dye malachite green was investigated. The results revealed that the decolorization ability of the plant species is as high as 88%. The effect of some operational parameters (initial dye concentration, temperature, pH, and amount (weight) of plant) on the efficiency of biological decolorization process was determined. The metabolic fate of the dye was proposed by identifying 8 intermediate compounds produced during this process by gas chromatography-mass spectrometry. Some physiological responses of the plant were evaluated under 10 and 20 mg/L of the dye, with notable increases in superoxide dismutase and peroxidase activities at high concentrations. The results suggested that dye treatment induced oxidative stress and demonstrated duckweed's capacity to upregulate its antioxidative defense.