A novel and inexpensive method for producing activated carbon from waste polyethylene terephthalate bottles and using it to remove methylene blue dye from aqueous solution

Abstract

The current study aims to present a novel and inexpensive method for producing activated carbon using waste polyethylene terephthalate (PET) bottles in order to remove methylene blue (MB) dye from aqueous solution. Here, a novel method for producing activated carbon is developed by utilizing KOH and combining the carbonation and activation processes. Besides, the inert gases are not used in the production process. In order to determine the characteristics of the produced activated carbon texture, N₂ gas adsorption at 77 K and scanning electron microscope are used. The adsorption isotherms of MB have been studied using Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin models. The specific surface area and the total volume of the generated activated carbon pores are 353.307 m²/g and 0.288 cc/g, respectively. In addition, q_max for adsorption of MB dye is obtained as 404.089 mg/g. Obtained results show that the Langmuir isotherm model has the best fitness. The values of R², the sum of squares of the errors percentage, and χ² for this model are measured as 0.996, 3.878, and 0.109, respectively. The present study shows that PET bottles are appropriate precursors for producing activated carbon. Besides, the present proposed method is effective and inexpensive.

Keywords:

• Waste polyethylene terephthalate bottles
• Activated carbon
• Methylene blue
• Isotherm

Acknowledgments

The authors are grateful to the Iranian nuclear science and technology research center (Razi laboratory) and especially to the environmental chemistry laboratory of Shiraz University of Medical Sciences. Besides, Research improvement center of Shiraz University of Medical Sciences, Shiraz, Iran and Ms. A. Keivanshekouh are highly appreciated for their significant aids in preparing this project.