Sequestration of Heavy Metals from Water by Aegle marmelos (Bael) Leaves as Promising Biomaterial: Kinetic and Equilibrium Studies

Abstract

Heavy metals abatement from polluted water through the use of green biosorbents is a growing research area due to its renewability and inexpensive. This study investigates the idea of utilizing Aegle marmelos (Bael) leaves as a biosorbent for the removal of heavy metal ions Cd(II), Pb(II) and Cr(VI) from simulated wastewater. The surface area, functionality, surface morphology and elemental analysis of biosorbent were analyzed by BET, FTIR, FE-SEM with EDX, respectively. Batch studies were done for biosorption of heavy metal ions. The maximum biosorption capacity of heavy metal ions were optimized by varying the pH (2-9), metal ions concentration (20-80 mg/L), biosorbent dose (0.02-0.2 g/L) and contact time (30-210 min). The Langmuir adsorption isotherms and pseudo-second order kinetics models were the most suitable for the biosorption of heavy metal ions and the maximum adsorption capacity was 11.85, 10.35 and 8.55 mg/g for Pb(II), Cd(II) and Cr(VI) heavy metals, respectively at optimized time 120 min. Thermodynamics studies revealed that biosorption of Pb(II), Cd(II) and Cr(VI) on A. marmelos biosorbent was exothermic and spontaneous in nature. Finally, the removal efficiency of A. marmelos biosorbent against the all three metals were found maximum for Pb(II) followed by Cd(II) and Cr(VI) due to the variations in hydration energy of these heavy metals.