Characterization and use of chemically activated Butea monosperma leaf dust for mercury(II) removal from solutions

The objective of this study was to investigate the potential use of chemically activated Butea monosperma leaf dust for the removal of Hg(II) from laboratory prepared aqueous solutions at room temperature. The Hg(II) sorption was pH dependent, and maximum removal was observed at a pH of 6.0. The metal uptake capacity of the biosorbent was found to be 88.67 and 95.41 mg/g for an initial concentration of 100 and 150 mg/L Hg(II) respectively, for an average particle size of 0.5125 mm. The biosorption was calculated to be endothermic with a heat value of 157.1 and 215.8 kJ/kmol for 100 and 150 mg/L Hg(II) initial concentration respectively. Sorption-desorption results revealed that the biosorbent can be effectively reused. A two stage biosorber indicated a saving of 18.91% of the biosorbent. External mass transfer coefficient was calculated and sophisticated instrumental analysis such as TGA, FTIR, SEM and CHNS of the biosorbent were also carried out.