Plumeria alba (white frangipani) leaf powder as a biomass-based adsorbent for removal of methylene blue in water

ABSTRACT

The present study focused on the adsorption of cationic dye, methylene blue (MB) onto Plumeria alba (White frangipani) leaf powder (WFLP) from aqueous solution in batch experiments. The effects of contact time, solution pH, adsorbent dosage, initial dye concentration, and temperature on the adsorption of MB on WFLP were investigated. The morphology of adsorbent and interactions of MB and WFLP were characterized by SEM, EDX, FTIR, TGA, and Zeta analysis, respectively. The adsorption capacity of WFLP for the removal of MB was found from the kinetic and Langmuir isotherm model. For MB solution of dye concentration, 30 mg/L, and biosorbent loading of 3.5 g/L, the maximum dye removal was 37.22% with a monolayer adsorption capacity of 45.45 mg/g. The adsorption data fitted the isotherm models of Langmuir, Freundlich, and Temkin, in line with both first- and second-order kinetics, but the second-order kinetics gave a better fit. Both ΔH^° and ΔG^° decreased for the adsorption process that appeared to be both exothermic and spontaneous. Thus, WFLP could be converted to a potential and promising bioadsorbent for the removal of cationic dyes like MB from wastewater solution.

KEYWORDS:

• Plumeria alba leaves
• methylene blue
• isotherm
• kinetic
• adsorption

Acknowledgements

The authors acknowledge the authorities of Gauhati University (Department of Chemistry) and MC College, Barpeta, Assam (India) for providing the necessary facilities for this research.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.