Are Normal and N-doped Hydrochars Efficient Enough for Removal of Pb(II) from Contaminated Waters?

WATER pollution possesses a potential threat to the surrounding ecosystem. Thus, the current study investigates the efficiency of using two safe organic products, named hydrochar and N-doped hydrocar for removal of Pb(II) from contaminated waters. To attain this aim, sugarcane bagasse was collected then pyrolyzed (+/-NH3) in an electric furnace at 200 ̊C for 24 h. Thereafter, the efficiency of each organic product for removal of Pb(II) from a water artificially polluted with Pb(II) (55 mg Pb L-1) was tested individually. These hydrochars were added at a rate of 0.25g to purify 500 mL of contaminated water. Throughout the experimental period, water samples were collected periodically at 13 time periods starting from the zero time up to 360 min of contact with 30 min time intervals. Key results indicate that application of hydrochar remarkably diminished soluble Pb(II) concentrations. In this concern, Pb(II) sorption occurred from the beginning of contact with experiment up to 150 min of contact, recording approximately 70% Pb(II) removal efficiency. Thereafter significant increases in soluble Pb(II) occurred, which accounted for about 50% of the sorbed Pb(II) amount. On the other hand, N-doped hydrochar lessened considerably Pb sorption (≈3 folds) and, at the same time, accelerated its desorption. Kinetics of Pb(II) desorption by using both types of hydrochars followed the inverse third-order model. These results supported our main hypothesis, while raises doubts about the feasibility of using hydrochars for successful decontamination of waters polluted with Pb(II). Future perspectives are needed to find out better modifications of hydrochar for effective removal of contaminants from wastewaters and investigate the mechanisms beyond their modes of action.