Huang Kangping, Zheng Tianwen, Li Xinyue, Yang Ziyin, Li Ruoxi, Liu Yizhou, Wei Wenxia, Sang Yimin, Wang Heming
State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum, Beijing, 102249, China.
Beijing Key Laboratory of Remediation of Industrial Pollution Sites, Institute of Resources and Environment, Beijing Academy of Science and Technology, Beijing, 100089, China.
Environ Res. 2025 Jun 25;284:122222. doi: 10.1016/j.envres.2025.122222.
Nano-zero-valent iron (nZVI) is commonly used as a reactive material for trichloro-ethylene (TCE) remediation in groundwater systems, and the long-term removal capacity serves as a critical indicator for evaluating the material efficacy. In this study, a novel sustained-release iron-carbon composite (BC@nZVI-βCD) was synthesized by the integration of biochar (BC) matrix and β-cyclodextrin (βCD) encapsulation, and the materials before and after modification were analyzed by various characterization methods. Subsequently, the kinetics of TCE removal by different materials were investigated, and the sustained-release properties of BC@nZVI-βCD were explored by batch and column experiments. Finally, the long-term TCE removal mechanism was discussed carefully. The results showed that the incorporation of BC increased the specific surface area and dispersion of nZVI, while βCD successfully encapsulated nZVI and formed abundant nanocracks on the surface. The removal of TCE by BC@nZVI-βCD was in accordance with the pseudo-second-order kinetic equation, and the removal rate of TCE was as high as 97 % within 3 h, and 92.7 % of TCE was degraded within 14 d. Moreover, BC@nZVI-βCD maintained a stable removal efficiency of TCE in long-term sand column experiments, with the removal rate remaining above 94 % for the first 32 d, and the removal rate also reached 78.6 % by 86 d. In conclusion, the synergistic effect of both BC and βCD breaks through the limitation of pure nZVI, improves the sustained-release performance of the BC@nZVI-βCD composite and the degradation effect of TCE, which can have great application prospects on the long-term remediation of TCE contaminated sites.
纳米零价铁（nZVI）通常用作地下水系统中三氯乙烯（TCE）修复的反应材料，其长期去除能力是评估材料效果的关键指标。在本研究中，通过生物炭（BC）基质和β-环糊精（βCD）包封的整合合成了一种新型缓释铁碳复合材料（BC@nZVI-βCD），并通过各种表征方法对改性前后的材料进行了分析。随后，研究了不同材料对TCE的去除动力学，并通过批次和柱实验探索了BC@nZVI-βCD的缓释性能。最后，仔细讨论了TCE的长期去除机制。结果表明，BC的加入增加了nZVI的比表面积和分散性，而βCD成功地包封了nZVI并在表面形成了丰富的纳米裂纹。BC@nZVI-βCD对TCE的去除符合准二级动力学方程，TCE的去除率在3小时内高达97%，14天内92.7%的TCE被降解。此外，在长期砂柱实验中，BC@nZVI-βCD对TCE保持了稳定的去除效率，前32天去除率保持在94%以上，86天时去除率也达到了78.6%。总之，BC和βCD的协同作用突破了纯nZVI的限制，提高了BC@nZVI-βCD复合材料的缓释性能和TCE的降解效果，在TCE污染场地的长期修复方面具有广阔的应用前景。
