The use of indigenous coal reserves for the removal of lead(II) from the aquatic environment by adsorption

Activated carbon was prepared as an adsorbent from low cost Lakhra coal (LC) (Lignite grade) by chemical activation for the removal of Pb(II) from aqueous solution. The variables of pH, adsorbent dose, agitation time, ionic strength and temperature were investigated. The sorption process followed pseudo-first-order kinetics, intra-particle diffusion and Langmuir isotherm models. Evaluation of thermodynamic parameters affirmed the spontaneity of the process. The study also included the surface properties of activated Lakhra coal (ALC) by FTIR, scanning electron microscope and energy dispersive spectroscopy. The maximum Pb(II) removal capacity of ALC was 758 ± 8 mg g−1 at 32 °C, approximately 300 times higher than without activation. This value was higher than other previously reported values. Thus, this study demonstrated that indigenous LC has excellent potential to be used as an economically feasible adsorbent after activation for the treatment of wastewater bearing Pb(II).