with the increase
of the biochar dosage from 5 to 15 g/L and remained almost constant
beyond 25 g/L (Fig. 2a). The amount of Pb2+ adsorbed per unit
adsorbent mass at equilibriumdecreased across the biochar dosage
range of 5–100 g/L (Fig. 2a). This trend may be caused by the aggregation
between biochar particles and subsequently the unsaturation
of adsorption sites on biochar surface at high solid
concentrations during the experiment