Adsorption of methylene blue from aqueous solution by chemically treated water hyacinth

Abstract

Water hyacinth (WH), an aquatic plant macrophyte, was investigated for its ability to perform as a suitable adsorbent for methylene blue (MB) from aqueous solution. The non-living biomass of WH was subjected to several chemical treatments, namely, washing with hot water, washing with hot dilute HCl, soaking in NaOH, soaking in HNO₃, and sulfonation. The system variables studied also include pH and MB concentration. The Langmuir isotherm was found to represent the measured adsorption data well except for WH soaked in NaOH, which was found to be better represented by the Freundlich isotherm. Values of the dimensionless separation factor, K _R, indicated that the adsorption systems in this study are all favorable. Values of the first layer of adsorption were calculated by the non-linear multilayer adsorption model, and the specific surface area values were found to be high and comparable to commercially activated carbons.

Keywords:

• adsorption
• dye
• methylene blue
• water hyacinth
• biosorption

Acknowledgments

The author thanks Prof. Dr R.R. Zaharn for providing the laboratory facilities. The authors are also grateful to the Egyptian Academy for Scientific Research and Technology for financial support. Also, thanks are due to Mohamed Nasr for his participation in the experimental work.

Notes

^†Undergraduate research participant.

Additional information

Notes on contributors

Hossam El-Din Samy†

†Undergraduate research participant.