Evaluation of Kinetic and Equilibrium studies for Phytoremediation of Methylene Blue Dye (Triarylmethane) and Congo Red (Diazo) using Trachyspermum Ammi L.

Abstract

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 Trachyspermum ammi L. (T. ammi) was examined for the removal of a triarylmethane-Methylene blue (MB) and di-azo-Congo red (CR) dye. The various parameters such as initial dye concentration, contact time, and pH were focused to explore the dye removal capability of T. ammi. The increase in initial dye concentration affects the decolorization potential of the T. ammi. The decolorization potential of T. ammi found to be reduced with enhancing the initial dye concentration of both the dyes. The plant achieved condition of equilibrium after the 40 h of contact time with both MB and CR dye. The favorable pH for T. ammi for the MB dye was observed as 5 while for CR dye was 6. The kinetics of phytoremediation reaction with both MB and CR dyes were studied with 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 R2 ≥ 0.95 for MB and R2 ≥ 0.97 for CR. The Langmuir and Freundlich isotherms studies of phytoremediation reaction found in favor of Freundlich equilibrium isotherm with correlation R2 ≥ 0.99 for both MB and CR dyes. The mechanism of T. ammi for removal of dyes was supported with the help of analytical techniques such as Fourier Transform-Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM).