Tailored Bombax ceiba-based activated carbons for enhanced rhodamine B removal: A sustainable approach to industrial effluent remediation
Dibyashree Shrestha
Abstract
Bombax ceiba wood waste-derived activated carbon (AC) provides a low-cost, sustainable, and efficient solution for rhodamine B (RhB) dye removal from industrial wastewater through eco-friendly adsorption techniques. This study reports the synthesis of ACs from B. ceiba wood dust using three different chemical activating agents – phosphoric acid, potassium hydroxide, and sodium carbonate – followed by carbonization at an optimized temperature determined through thermogravimetric (TG) analysis and differential scanning calorimetry. The optimal carbonization temperature was identified as 400°C. AC samples were prepared through a one-step chemical impregnation and carbonization process under nitrogen flow. Comprehensive characterization using X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller surface area analysis confirmed the formation of amorphous carbon structures with abundant oxygenated surface functional groups and porous architectures. Among the three samples, phosphoric acid-activated carbon (Bc-H) exhibited the highest surface area (1,451.2 m²/g) and a well-developed micro–mesoporous structure. Batch adsorption experiments showed that Bc-H achieved 99.9% RhB removal under optimized conditions (20 ppm initial dye concentration, pH 8.5, 0.03 g adsorbent, 10 min). Its superior performance is attributed to its large surface area and rich surface functionalities. Notably, Bc-H also outperformed commercial AC under identical conditions, demonstrating faster kinetics and higher removal efficiency. These findings underscore B. ceiba wood dust as a low-cost and sustainable precursor for high-performance AC production. The work contributes to waste biomass valorization and offers a scalable, eco-friendly solution for industrial wastewater treatment, particularly relevant to textile and dyeing effluents in resource-limited settings such as Nepal.