Efficient Phytoremediation of Methyl Red and Methylene Blue Dyes from Aqueous Solutions by <i>Juncus effusus</i>

The contamination of water with dyes stemming from the discharge of industrial waste poses significant environmental risks and health concerns. In this study, the phytoremediation potential of the wetland plant <i>Juncus effusus</i> was investigated (as a function of plant biomass, pH, contact time, and initial dye concentration) for the removal of methylene blue and methyl red dyes from wastewater. The experimental adsorption capacities under the optimum conditions were found to be 1.421 and 1.038 mg g^-1 plant wet weight for methylene blue and methyl red, respectively. Pseudo-first-order and pseudo-second-order models were employed to determine the kinetics of the phytoremediation adsorption process. The pseudo-second-order model was found to be the most suitable for both methylene blue and methyl red. The results were found to conform to the Freundlich equilibrium isotherm, with a correlation of <i>R</i> ² ≥ 0.99 for removal of both dyes. Confirmation of dye uptake by the plant was determined by using Fourier transform infrared spectroscopy (FTIR). Additionally, direct analysis in real time-high-resolution mass spectrometry (DART-HRMS) analysis of plant roots is reported here for the first time as a means to investigate dye degradation by plant roots.