Enhanced removal efficiency of Pb ²⁺ from wastewater using MgO/ZnO/N-doped biochar-derived from waste building wooden template in the fixed bed and fluidized bed systems

The MgO/ZnO/N-doped biochar is prepared using the waste building wooden template as the feedstock for Pb ²⁺ removal from wastewater, which is investigated in the fixed bed and fluidized bed systems. The characterization analysis exhibits that the MgO/ZnO/N-doped biochar has high surface area and nitrogen-containing functional groups, contributing to Pb ²⁺ removal from wastewater using the X-ray diffraction, fourier transform infrared spectroscopy and N₂ adsorption-desorption analyzer. The Pb ²⁺ adsorption behavior is investigated by the Pseudo-second order and Langmuir models with Pb ²⁺ adsorption amount of 296.45 mg/g and excellent reusability. Besides, the Pb ²⁺ can be quickly removed from wastewater in the fluidized bed system compared to the fixed bed system. The Pb ²⁺ adsorption mechanism includes surface complexation and electrostatic attraction, based on characterization analysis. The co-existing substances have little influence on Pb ²⁺ removal. Besides, the MgO/ZnO/N-doped biochar can be used as an extensive adsorbent for the removal of other pollutants from wastewater. The waste building wooden template is converted into an efficient MgO/ZnO/N-doped biochar for Pb ²⁺ wastewater treatment.