Selective adsorption of heavy metal ions from industrial effluent is important for healthy ecosystem development. However, the selective adsorption of heavy metal pollutants by biochar using lignin as raw material is still a challenge. In this paper, the lignin carbon material (N-BLC) was synthesized by a one-step hydrothermal carbonization method using paper black liquor (BL) as raw material and triethylene diamine (TEDA) as nitrogen source. N-BLC (2:1) showed excellent selectivity for Cr(VI) in the binary system, and the adsorption amounts of Cr(VI) in the binary system were all greater than 150 mg/g, but the adsorption amounts of Ca(II), Mg(II), and Zn(II) were only 19.3, 25.5, and 6.3 mg/g, respectively. The separation factor (SF) for Cr(VI) adsorption was as high as 120.0. Meanwhile, FTIR, elemental analysis and XPS proved that the surface of N-BLC (2:1) contained many N– and O– containing groups which were favorable for the removal of Cr(VI). The adsorption of N-BLC (2:1) followed the Langmuir model and its maximum theoretical adsorption amount was 618.4 mg/g. After 5th recycling, the adsorption amount of Cr(VI) by N-BLC (2:1) decreased about 15%, showing a good regeneration ability. Therefore, N-BLC (2:1) is a highly efficient, selective and reusable Cr(VI) adsorbent with wide application prospects.

选择性吸附工业废水中的重金属离子对于健康的生态系统发展具有重要意义。然而，以木质素为原料的生物炭选择性吸附重金属污染物仍然是一个挑战。以造纸黑液（BL）为原料，三乙烯二胺（TEDA）为氮源，采用一步水热碳化法合成木质素碳材料（N-BLC）。N-BLC(2:1)对二元体系中的Cr(VI)表现出优异的选择性，二元体系中Cr(VI)的吸附量均大于150 mg/g，但Ca(VI)的吸附量II)、Mg(II) 和 Zn(II) 分别仅为 19.3、25.5 和 6.3 mg/g。Cr(VI)吸附的分离因子(SF)高达120.0。同时，FTIR、元素分析和XPS证明N-BLC(2:1)表面含有许多含N和O的基团，有利于Cr(VI)的去除。N-BLC（2:1）的吸附遵循Langmuir模型，其最大理论吸附量为618.4 mg/g。经过第5次回收后，N-BLC（2:1）对Cr(VI)的吸附量下降了约15%，表现出良好的再生能力。因此，N-BLC（2:1）是一种高效、选择性、可重复使用的Cr(VI)吸附剂，具有广阔的应用前景。