Isotherm and kinetic modelling of Toluidine Blue (TB) removal from aqueous solution using Lemna minor

ABSTRACT

The aim of this study was to investigate the ability of Lemna minor for Toluidine Blue (TB) removal. Influence of the initial concentration over the removal process was considered. Experimental data have been analyzed using Langmuir, Freundlich, Dubinin–Radushkevich (D–R), and Elovich isotherm models. In addition, several kinetic models, pseudo-first-, pseudo-second-order, intraparticle and film diffusion models were considered. Langmuir and Freundlich isotherm suggested a favorable adsorption of TB by Lemna minor plants. From the D–R the mean free energy was calculated to be 11.18 kJ/mol, which indicates that TB adsorption was characterized by a chemisorption process. Kinetic studies showed that liquid film diffusion plays an important role during the process. Adsorption capacities of up to 26.69 mg/g and a high capacity of adaptation indicated that phytoremediation using Lemna minor could be a valuable alternative for dyes removal from wastewaters.

KEYWORDS:

• isotherm
• kinetics
• Lemna minor
• toluidine blue

Conflict of Interest

The authors declare that they have no conflict of interest.

Acknowledgments

The authors are grateful to Botanic Garden “Alexandru Borza” of Cluj Napoca, Romania for providing Lemna minor plants.

Compliance with Ethical Standards

For this type of study formal consent is not required. This article does not contain any studies with human participants or animals performed by any of the authors.

Additional information

Funding

No funding was received.