Phytoremediation of methylene blue dye (triarylmethane) and Congo red (diazo) by T.ammiL.: kinetic studies

Phytoremediation developed as a green-clean, solar-driven and innovative technique for the eradication of contaminants from the environment from last two decades. In the present research work, phytoremediation potential of an ornamental plant Trachyspermumammi L. was examined for the removal of a triarylmethane-methylene blue and diazo-Congo red dye. The various parameters such as initial dye concentration, contact time, and pH were focused to explore the dye removal capability of T.ammi L. in wastewater. The increase in initial dye concentration affects the phytoremediation potential of the T.ammi L. and found to be reduced with enhancing the initial dye concentration of both the dyes. The plant achieved condition of equilibrium after 40 h of contact time with both Methylene blue and Congo red dyes. The kinetics of phytoremediation reaction with both Methylene blue and Congo red dyes were studied with the help of pseudo-first order, pseudo-second order, and Elovich models, and the results were well appropriated to pseudo-first order with the correlation value R-2 >= 0.99 for methylene blue and R-2 >= 0.97 for Congo red. The Langmuir and Freundlich isotherms studies of phytoremediation reaction found in favor of Freundlich equilibrium isotherm with correlation R-2 >= 0.99 for both methylene blue and Congo red dyes. The finding of analytical studies disclosed that the phytoremediation mechanisms of Methylene blue and Congo red by T.ammi L. involves phytosorption through electrostatic interaction and hydrogen bonding and also degradation of dyes occur through desulfurization and denitrification.