标题：Kinetic and Isotherm Studies of Ni<sup>2+</sup> and Pb<sup>2+</sup> Adsorption from Synthetic Wastewater Using <i>Eucalyptus camdulensis</i>—Derived Biochar
摘要：The production of biosorbents by waste biomass has attracted considerable attention due to the low cost and abundance of the raw materials. Here biochar produced from <i>Eucalyptus camdulensis</i> sawdust (<i>EU</i>-biochar) via pyrolysis at 600 °C was used as a potential biosorbent for Ni<sup>2+</sup> and Pb<sup>2+</sup> metal ions from wastewater. Characterization experiments indicated the formation of C- and O-bearing functional groups on the <i>EU</i>-biochar surface, while shifts and changes in the shape of C–H bands suggested the adsorption of Ni<sup>2+</sup> and Pb<sup>2+</sup> onto <i>EU</i>-biochar by interacting with surface carboxylic groups. Pb<sup>2+</sup> was adsorbed more quickly than Ni<sup>2+</sup>, indicating a faster and stronger interaction of Pb<sup>2+</sup> with <i>EU-</i>biochar compared to Ni<sup>2+</sup>. As the initial concentrations of both metal ions increased, the percentage removal decreased, whereas increasing the <i>EU</i>-biochar dose improved the percentage removal but impaired the adsorption capacity for Ni<sup>2+</sup> and Pb<sup>2+</sup>. The adsorption capacity could only be improved without affecting the percentage removal of both ions by increasing the pH of the metal solutions. The sorption efficiency of <i>EU</i>-biochar and the removal mechanism of Ni<sup>2+</sup> and Pb<sup>2+</sup> were further explored using non-linear and linear forms of kinetic and isotherm models.
关键词：adsorption capacity; biochar; Eucalyptus camdulensis; removal mechanism; heavy metals; removal efficiency; kinetic model; isotherm model
