Purification of dye-contaminated wastewater has always been a research hotspot, yet also a challenge, due to high concentration and species diversity of pollutants. The present study designs an efficient nitrogen-doped 3D carbon nanosheets (N-3DCNs) adsorbent with 2592.50 m² g⁻¹ of specific surface area and 2.68 m³/g of average pore volume based on nitrilotriacetic acid trisodium salt by combining calcination and activation techniques. Microstructure and surface potential of N-3DCNs indicate that a large number of N heteroatoms in the lattice of main material can effectively optimize Zeta potential from 1.53 to −31.08 mV with solution pH increases from 3 to 11. So, as-prepared N-3DCNs possesses necessary conditions for efficient and selective adsorption of cationic dyes due to the abundant adsorption sites and strong electrostatic interactions. When 700 mg/L of cationic rhodamine and anionic methyl orange are respectively used as high concentration industrial dye-contaminated wastewater, N-3DCNs shows 97.97 % and 89.13 % of removal efficiency within 60 min. Furthermore, the adsorption capacity of N-3DCNs displays a wider pH tolerance at 1000 mg/L of cationic concentration, with a maximum adsorption capacity of 4888.70 mg/g at pH = 7 and a minimum value of 4203.77 mg/g at pH = 3, only 14 % of attenuation rate. The kinetics mechanism of dye adsorption could be well explained by pseudo-second-order kinetic model, suggesting chemisorption behavior, while fitting better with the linear Langmuir isothermal model. The groundbreaking and exceptional adsorption performances of N-3DCNs can be attributed primarily to the high specific surface area and negatively charged active sites, facilitating synergistic adsorption.

中文翻译：

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N 掺杂三维碳纳米片：简便合成和高浓度染料吸附


由于污染物的高浓度和物种多样性，染料污染废水的净化一直是一个研究热点，但也是一个挑战。本研究基于次氮基三乙酸三钠盐，通过结合煅烧和活化技术，设计了一种高效的氮掺杂 3D 碳纳米片 （N-3DCN） 吸附剂，比表面积为 2592.50 m^{2 g-1}，平均孔体积为 2.68 m³/g。N-3DCNs 的微观结构和表面电位表明，当溶液 pH 值从 3 增加到 11 时，主体晶格中的大量 N 杂原子可以有效地优化 1.53 至 −31.08 mV 的 Zeta 电位。因此，由于丰富的吸附位点和较强的静电相互作用，所制备的 N-3DCNs 具有高效和选择性吸附阳离子染料的必要条件。当 700 mg/L 阳离子罗丹明和阴离子甲基橙分别用作高浓度工业染料污染废水时，N-3DCNs 在 60 min 内显示出 97.97% 和 89.13% 的去除效率。此外，N-3DCNs 的吸附容量在 1000 mg/L 阳离子浓度下表现出更宽的 pH 耐受性，在 pH = 7 时最大吸附容量为 4888.70 mg/g，在 pH = 3 时最小吸附容量为 4203.77 mg/g，仅为衰减速率的 14%。染料吸附的动力学机制可以用准二级动力学模型很好地解释，表明化学吸附行为，同时更好地拟合线性 Langmuir 等温模型。N-3DCN 的开创性和卓越的吸附性能主要归因于高比表面积和带负电荷的活性位点，促进了协同吸附。