<p>The lignocellulosic biorefinery sector holds significant potential to play a pivotal role in advancing global carbon neutrality goals. However, the efficient utilization of waste lignin remains a critical bottleneck, severely impeding the sustainable development of this industry. This study used a two-step method to prepare zinc and nitrogen activated lignin (Zn/N-lignin), and investigated its removal performance, influencing factors, and potential mechanisms for hexavalent chromium Cr(VI) in water. Results indicated that Cr(VI) removal process conformed to the Langmuir adsorption isotherm model and pseudo-second-order kinetic model. At an initial Cr(VI) concentration of 10&#xa0;mg·L⁻¹ and an adsorbent dosage of 400&#xa0;mg·L⁻¹, the maximum adsorption capacity at 298&#xa0;K was 284.61&#xa0;mg·g⁻¹. Low concentrations (less than 0.1&#xa0;mmol·L⁻¹) of cations Ca²⁺and Mg²⁺, as well as competitive anions H₂PO₄⁻ and NO₃⁻, have little effect on the removal of Cr(VI). Zn/N-Lignin possessed a good regeneration performance, and the removal efficiency still reached more than 80% after five adsorption and desorption times. Spectral analysis and density functional theory calculations indicated that the main mechanisms of Zn/N-Lignin for removing Cr(VI) from water were electrostatic adsorption, hydrogen bonding and chemical reduction. In order to investigate the environmental impact of the preparation process of Zn/N-Lignin, a life cycle assessment (LCA) was conducted and the contribution of each component to the production of Zn/N-Lignin was analyzed. These results show that Zn/N-Lignin is not only an effective pathway for lignin resource utilization, but also an economically efficient adsorbent for Cr(VI) removal.</p> Graphical Abstract <p></p>