Fu Mingming, Ma Yingdi, Yang Fengrui, Xiao Ziyu, Wang Mei, Bai Shaoyuan, Zhang Qin, Liu Huili, Xu Dandan, Zhang Yanan
College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China.
Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541006, China.
Toxics. 2025 Jul 25;13(8):623. doi: 10.3390/toxics13080623.
Low-concentration NO (≤5%) emissions from agricultural fields and waste treatment facilities in China reach 7.333 × 10 t annually, making them a significant but inadequately controlled contributor to global warming. Agricultural wastes were selected as precursors to prepare biochar, including pecan shell (SH), poplar sawdust (JM), wheat straw (XM), and corn straw (YM), which were subsequently acid-modified with 0.1 mol L HCl. The objectives were (i) to quantify the enhancement in NO capture achievable by acid treatment, (ii) to elucidate the underlying chemisorption mechanism, and (iii) to identify the most efficient feedstock for practical deployment. Acid modification increased the oxygen content, specific surface area, and the number of hydroxyl and carboxyl groups on the biochar surface. Both modified and unmodified biochar followed the pseudo-second-order kinetic model (R ≥ 0.960), indicating chemisorption-dominated processes. The adsorption performance ranked as XM > JM > SH > YM, with XM exhibiting the highest adsorption capacity (26.000 mol/kg unmodified, 43.088 mol/kg modified, 65.72% increase). The Langmuir model provided a better fit for NO adsorption, suggesting dynamic multilayer heterogeneous adsorption. The findings demonstrate that acid-modified biochar derived from agricultural waste is a scalable, economical, and environmentally friendly adsorbent for mitigating low-concentration NO emissions.
中国农田和废物处理设施排放的低浓度一氧化氮（≤5%）每年达7.333×10吨，使其成为全球变暖的一个重要但未得到充分控制的因素。选择农业废弃物作为制备生物炭的前驱体，包括山核桃壳（SH）、杨木锯末（JM）、小麦秸秆（XM）和玉米秸秆（YM），随后用0.1 mol/L盐酸对其进行酸改性。目的是：（i）量化酸处理可实现的一氧化氮捕获增强效果；（ii）阐明潜在的化学吸附机制；（iii）确定实际应用中最有效的原料。酸改性增加了生物炭表面的氧含量、比表面积以及羟基和羧基的数量。改性和未改性生物炭均遵循准二级动力学模型（R≥0.960），表明过程以化学吸附为主。吸附性能排序为XM＞JM＞SH＞YM，其中XM表现出最高的吸附容量（未改性为26.000 mol/kg，改性为43.088 mol/kg，增加65.72%）。朗缪尔模型对一氧化氮吸附的拟合效果更好，表明为动态多层非均相吸附。研究结果表明，源自农业废弃物的酸改性生物炭是一种可扩展、经济且环保的吸附剂，可以减少低浓度一氧化氮排放。
