Four kinds of Fe/N co-doped porous hydrochar were prepared by one/two-step N-doping schemes using microwave/traditional pyrolysis methods for removing Cr(VI) from aqueous phase. Heterocyclic-N was introduced through CO(NH₂)₂-based hydrothermal carbonization process, which could adjust the electronic structure of the hydrochar framework. Furthermore, Fe⁰ and Fe₃O₄ were embedded into hydrochar via carbothermal reduction reaction using FeCl₃ as the precursor, which improved the reducibility and magnetism of the material. The modified hydrochar exhibited pH-dependency and rapid kinetic equilibrium, and the maximal adsorption amount of magnetic porous hydrochar obtained by microwave-assisted one-step N-doping (MP₁HC_MW) reached 274.34 mg/g. Meanwhile, the modified hydrochar had a high tolerance to multiple co-existing ions and the removal efficiency maintained above 73.91 % during five regeneration cycles. Additionally, MP₁HC_MW efficiently removed Cr(VI) via pore filling, electrostatic attraction, ion exchange, reduction, complexation, and precipitation. Summarily, Fe/N co-doped porous hydrochar was a feasible adsorbent with outstanding remediation potential for Cr(VI)-contaminated water.

采用微波/传统热解方法通过一步/两步氮掺杂方案制备了四种 Fe/N 共掺杂多孔水炭，以去除水相中的 Cr(VI)。通过CO(NH ₂ ) ₂水热碳化工艺引入杂环-N，可以调节水热炭骨架的电子结构。此外，以FeCl ₃为前驱体，通过碳热还原反应将Fe ⁰和Fe ₃ O ₄嵌入水炭中，提高了材料的还原性和磁性。改性水炭表现出pH依赖性和快速动力学平衡，微波辅助一步氮掺杂得到的磁性多孔水炭的最大吸附量(MP ₁ HC _MW )达到274.34 mg/g。同时，改性水炭对多种共存离子具有较高的耐受性，在五个再生周期内去除效率保持在73.91%以上。此外，MP ₁ HC _MW通过孔隙填充、静电吸引、离子交换、还原、络合和沉淀有效去除 Cr(VI)。总之，Fe/N 共掺杂多孔水炭是一种可行的吸附剂，对 Cr(VI) 污染水体具有突出的修复潜力。