Sesbania Grandiflora Activated Carbon As a High-Efficiency Stable and Reusable Adsorbent for Sustainable Fluoride Removal Publisher



Sivakumar D¹ ; Selvan MP¹ ; Nouri J^{2, 3} ; Jabin MJ¹ ; Priyanka S¹ ; Madhubala G¹
Source: Global Journal of Environmental Science and Management Published:2025

Abstract

BACKGROUND AND OBJECTIVES: Excess fluoride in groundwater poses environmental and public health risks, causing skeletal and dental fluorosis. Standard defluoridation techniques encounter difficulties concerning their expense, efficiency, and potential for reuse. This study assesses the effectiveness of Sesbania grandiflora activated carbon as a reliable and reusable adsorbent for fluoride, emphasizing its characterization, ideal adsorption parameters, and reusability. METHODS: Sesbania grandiflora activated carbon was synthesized and characterized using fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive x-ray spectroscopy, and x-ray diffraction to assess structural integrity and surface interactions. Batch adsorption experiments were conducted by varying particle size (up to 2.360 millimeter), dosage (2–10 grams), agitation speed (100–500 revolution per minutes), and contact time (up to 140 minutes) to determine the optimal conditions for fluoride removal. Freundlich and Langmuir models were employed to analyze the adsorption isotherms and kinetics. Furthermore, the reusability was tested over five regeneration cycles with 0.1 mole sodium hydroxide. FINDINGS: Fourier transform infrared spectroscopy revealed interactions between fluoride ions and surface functional groups. The analysis using scanning electron microscopy indicated a porous structure characterized by pore sizes between 0.5 and 5 microns, which exhibited a smoother appearance following adsorption, thus validating the absorption of fluoride. Energy dispersive x-ray spectroscopy showed before treatment, Sesbania grandiflora activated carbon had 78.3 percent carbon and 16.5 percent oxygen, while after treatment, carbon increased to 78.8 percent, oxygen to 17.1 percent, and sodium rose to 2.1 percent, with phosphorus and sulphur undetected. X-ray diffraction confirmed that activated carbon from Sesbania grandiflora remained mostly amorphous, with crystallinity increasing from 17.2 percent to 17.4 percent. The study revealed that the best adsorption conditions include a particle size of 2.360 millimeters, a dosage of 8 grams, an agitation speed of 300 revolutions per minute, and a contact duration of 120 minutes, which together achieved a fluoride removal efficiency of 89.3 percent. Adsorption followed the Freundlich isotherm (coefficient of determination is 0.9976), suggesting a multilayer heterogeneous adsorption process. Pseudo second order kinetics (coefficnet of determination is 0.9988) confirmed chemisorption as the dominant mechanism. Sesbania grandiflora activated carbon maintained 78.3 percent efficiency after five regeneration cycles, demonstrating good reusability. CONCLUSION: The activated carbon obtained from Sesbania grandiflora is an exceptionally efficient and stable adsorbent for fluoride removal in groundwater, offering reusability while preserving its structural integrity and effectiveness. Its potential for scalable, sustainable water treatment warrants further study on scale-up, hybrid integration, and enhanced regeneration techniques. © (2025), (GJESM Publication). All rights reserved.