Methylene blue dye adsorption on Ghana’s activated clay from Teleku Bukazo

Abstract

In this work, a clay sample from Teleku Bukazo in the Western Region of Ghana was activated by an acid activation process and the material used for adsorbing methylene blue from wastewater. Zeta potential, scanning electron microscopy, X-ray diffraction analysis, and Fourier transform infrared spectroscopy, analysis were used to characterize the material. To ascertain the impact of temperature, pH, contact time, starting concentration, and adsorbent dosage on the adsorbent, kinetic and thermodynamic experiments were conducted. The optimal dosage required for the removal of MB was 0.1 g in 50 mg/L for 80 min at a pH of 9. The maximum adsorption capacity and removal efficacy were found to be 35 mg/g and 98%, respectively. With an R² value of 0.9992, the adsorption data most closely matched the Freundlich isotherm. The nature of the adsorption process is pseudo-second-order as confirmed by the correlation (R² = 0.9982). A spontaneous adsorption process is shown by the negative change in Gibbs free energy at all temperatures (ΔG⁰ = −1.83 KJ/mol to −1.92 KJ/mol). The decrease in enthalpy change (ΔH⁰ = −1.08 KJ/mol) indicates an exothermic process. Statistical analyses, including ANOVA in Microsoft Excel, were employed to assess the impact of various parameters such as time, pH, concentration, dosage, and temperature on adsorption. Notably, all tested parameters exhibited statistically significant effects on dye removal (p < 0.05), emphasizing their substantial influence on the adsorption process.

Graphical Abstract

Keywords:

• Methylene blue
• adsorption
• activated clay
• kinetic and thermodynamic

Acknowledgments

We acknowledge the technical support from the Central Laboratory, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi-Ghana, and Regional Water and Environmental Sanitation Centre, KNUST, Kumasi-Ghana for characterizing the materials.

Disclosure statement

The authors have granted their approval for this manuscript to be published in this journal and declare that they have no conflicting interests in its publication.

Data availability

This research article’s data originated from our experiments. The research-supporting data are contained in the paper and are also available from the corresponding author upon request.