A novel N-doped porous graphitized biochar (NPGBC) with a large specific surface area (950.52 m²/g), partly graphitized structure, and high nitrogen (N) doping (3.61%) was prepared by co-carbonization of alfalfa, ferric chloride (FeCl₃), and potassium hydroxide (KOH). This biochar was used as an adsorbent with excellent methylene blue (MB) (326.90 mg/g) and methyl orange (MO) (906.52 mg/g) sorption capacities from wastewater. The sorption of MB and MO by NPGBC followed pseudo-second-order kinetics and Sips models. Density functional theory (DFT) calculations showed that the pyrrole N and pyridine N played decisive roles in the elimination of MO. When the content of pyridine N was more than 6.67%, or the content of pyrrole N was more than 3.00% in the calculation model, it was conducive to the sorption of MO. The interactions between NPGBC and organic dyes included π–π stacking and electrostatic and hydrogen-bonding interactions. The above results provide important reference values for the preparation and application of high-efficiency organic dye adsorbents.

通过紫花苜蓿，三氧化二铁的共碳化，制备了一种新型的氮掺杂多孔石墨生物炭（NPGBC），具有较大的比表面积（950.52 m ² / g），部分石墨化结构和高氮（N）掺杂（3.61％）。氯化物（FeCl ₃）和氢氧化钾（KOH）。该生物炭用作吸附剂，具有极佳的亚甲基蓝（MB）（326.90 mg / g）和甲基橙（MO）（906.52 mg / g）吸附能力。NPGBC对MB和MO的吸附遵循伪二级动力学和Sips模型。密度泛函理论（DFT）计算表明，吡咯N和吡啶N在消除MO中起决定性作用。在计算模型中，当吡啶N的含量大于6.67％，或吡咯N的含量大于3.00％时，有利于MO的吸附。NPGBC与有机染料之间的相互作用包括π-π堆积以及静电和氢键相互作用。以上结果为高效有机染料吸附剂的制备和应用提供了重要的参考价值。