Zinc adsorption from aqueous solution on biosorbent from urban pruning waste

In this study, urban pruning waste biosorbent after thermal activation process was used to remove zinc ion from aqueous solution. The zinc adsorption was fast, with values above 98.0% removal after 5 min. The maximum removal achieved was 99.4% in 360 min, at 30°C, pH 5.0, and initial zinc concentration of 10 mg L^-1. The adsorption process was adequately described by the pseudo-second-order kinetic model (R² = 1.000), and data obtained from batch adsorption experiments fitted well with the Langmuir isotherm model. The maximum adsorption capacity of zinc onto urban pruning waste biosorbent was 18.382 mg g^-1 at 30°C. Thus, it is concluded that urban pruning waste can be used as a low-cost alternative biosorbent to remove zinc in aqueous solutions.