ANAMARIA TOROK, BOLDIZSAR NAGY, SZENDE TONK, ERZSEBET BUTA, ROBERT SZEP, CORNELIA MAJDIK, ALEXANDRA GABRIELA NICULAE CRYSTAL VIOLET DYE REMOVAL FROM AQUEOUS SOLUTIONS USING ELODEA CANADENSIS AS BIOFILTER The phytoremediation of Crystal violet dye was developed using the aquatic plant Elodea canadensis as biofilter. We analyzed the role of functional groups in phytoremediation by aquatic plants using the Fourier transform infrared spectroscopy (FTIR). The aquatic plant’s abiotic stress responses were evaluated under exposure of 20 - 90 mg/L initial dye concentration, where a significant decrease of the photosynthetic pigments content suggests the plant’s biosynthesis deregulation at higher concentrations. We determined the effect of operational parameters such as contact time, plant quantity initial concentration, initial pH and temperature on the removal efficiency. Data were analysed using the kinetic (pseudo-first- and second-order) and isotherm (Langmuir, Freundlich and Dubinin-Radushkevich) models. Our results show that the phytoremediation process follows the pseudo-second-order kinetic model, meaning that it takes places as chemisorption. The Crystal violet uptake was successfully described using the Freundlich isotherm model as a multilayer adsorption with heterogeneous energetic distribution of active sites.