doi: 10.18178/ijesd.2025.16.5.1542
Low-Cost Activated Carbon for Methylene Blue Adsorption Using Inert Gas-Free Carbonization and Microwave Activation
Pornprapa Kongtragoul1
,
Kanchalar Keeratirawee2,* ,
Orasa Choola-aied3
- 1Department of Agricultural Technology, King Mongkut’s Institute of Technology Ladkrabang Prince of Chumphon Campus, Thailand
- 2Department of General Sciences, King Mongkut’s Institute of Technology Ladkrabang Prince of Chumphon Campus, Thailand
- 3Laboratory Services, King Mongkut’s Institute of Technology Ladkrabang Prince of Chumphon Campus, Thailand
- Manuscript receivedApril 14, 2025
- revisedMay 26, 2025
- acceptedMay 27, 2025
- publishedSeptember 18, 2025
Abstract
This study investigated the preparation of activated carbon from spent coffee grounds for methylene blue adsorption using inert gas-free carbonization and microwave activation. Spent coffee grounds were obtained from a local coffee shop in Pathio, Chumphon, Thailand. The coffee grounds were pretreated with 1M H<sub>2</sub>SO<sub>4</sub> before undergoing carbonization at 600 ºC for 3 h in a limited-oxygen atmosphere. The obtained carbon materials were chemically activated with zinc chloride (ZnCl<sub>2</sub>) and physically activated using a microwave-assisted method at 300 W for 180 seconds. The adsorption of methylene blue was evaluated using a batch method. Methylene blue adsorption contact time, effect of pH, and initial concentration were investigated. The maximum adsorption capacity of the activated carbon for methylene blue removal was found to be 29.24 mg/g. The prepared activated carbon exhibited a BET surface area of 70.08 m<sup>2</sup>/g and reached equilibrium in 120 min at the optimum pH of 9. The adsorption isotherm was consistent with the Freundlich model, while the adsorption kinetics followed a pseudo-second-order model. The findings indicate that activated carbon is a cost-effective and efficient adsorbent for methylene blue removal from aqueous solutions.
Keywords
- methylene blue
- coffee waste
- activated carbon
- microwave-assisted
- zinc chloride
How to Cite
Pornprapa Kongtragoul, Kanchalar Keeratirawee, and Orasa Choola-aied, "Low-Cost Activated Carbon for Methylene Blue Adsorption Using Inert Gas-Free Carbonization and Microwave Activation," International Journal of Environmental Science and Development, vol. 16, no. 5, pp. 338-344, 2025. https://doi.org/10.18178/ijesd.2025.16.5.1542
Copyright & License
Copyright © 2025 by the authors. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).