Objective Wastewater containing lead has a significant destructive impact on human health and the environment. Adsorption is a well-established lead removal technology. However efficient adsorption of Pb 2+ still faces many challenges such as high costs and low adsorption capacities of biochar adsorbents. Selecting appropriate adsorbent materials and improving adsorption efficiency through modification methods are crucial. Methods Nitrogen-doped biochar derived from food waste digestate was prepared by carbonization and subsequent nitrogen doping. The adsorption performance of nitrogen-doped digestate biochar for Pb 2+ was investigated under different initial solution pH values adsorption times and initial Pb 2+ concentrations. The adsorption mechanisms were analyzed and explored using various characterization techniques including scanning electron microscopy SEM Brunauer-Emmett-Teller BET analysis Fourier-transform infrared spectroscopy FTIR and X-ray photoelectron spectroscopy XPS . Results The results showed that nitrogen doping generated more mesopores or micropores in the digestate biochar increasing the total specific surface area and pore volume. The complexation of oxygen-containing and nitrogen-containing functional groups was the main mechanism for Pb 2+ adsorption. The nitrogen-doped biochar exhibited better adsorption performance for Pb 2+ compared to the raw digestate biochar which indicates that nitrogen doping can effectively enhance the adsorption capacity of biochar for Pb 2+ . The Langmuir adsorption isotherm model and pseudo-second-order kinetic equation better describe the adsorption characteristics suggesting monolayer adsorption and chemisorption as the primary adsorption mechanisms. Conclusion Nitrogen doping is an effective method to improve the adsorption capacity of digestate biochar for lead ions and has promising application prospects.