• 关键词：钙基磁性生物炭  梯度Cr（VI）污染  钝化机制  土壤酶  微生物群落结构

• 基金项目：国家自然科学基金（No.42077185）

• 蒲生彦
• 成都理工大学，地质灾害防治与地质环境保护国家重点实验室，成都 610059;成都理工大学生态环境学院，国家环境保护水土污染协同控制与联合修复重点实验室，成都 610059

• 余东
• 成都理工大学，地质灾害防治与地质环境保护国家重点实验室，成都 610059;成都理工大学生态环境学院，国家环境保护水土污染协同控制与联合修复重点实验室，成都 610059

• 肖雨婷
• 成都理工大学，地质灾害防治与地质环境保护国家重点实验室，成都 610059;成都理工大学生态环境学院，国家环境保护水土污染协同控制与联合修复重点实验室，成都 610059

• 上官李想
• 成都理工大学，地质灾害防治与地质环境保护国家重点实验室，成都 610059;成都理工大学生态环境学院，国家环境保护水土污染协同控制与联合修复重点实验室，成都 610059

• 摘要：生物炭改性材料因具有活性官能团众多、吸附效能高等优势被广泛应用于土壤重金属污染修复治理中.本研究以稻谷壳为原料，采用 共沉淀法及CaCO₃浸渍法制备了钙基磁性生物炭（Ca-Fe-B），并使用电子扫描显微镜（SEM）、傅里叶红外光谱（FTIR）、X射线衍射分析（XRD）、X射线光电子能谱分析（XPS）进行表征.同时，通过梯度浓度Cr（VI）污染土壤实验考察Ca-Fe-B施入对土壤pH、Cr（VI）稳定化效果、土壤酶活性及微生物群落结构的影响，并阐述其钝化机理.结果表明：①Ca-Fe-B表面负载Fe₃O₄、γ-Fe₂O₃、Fe₃C及以方解石形式存在的CaCO₃，具有大量—OH、—O—C=O、Si—O—Si、C≡C及C≡N等官能团；②Ca-Fe-B可显著提升土壤pH，在Cr（VI）污染浓度为100、200、1000 mg·kg^-1时，90 d的 固定效率分别可达72.57%、67.07%及59.88%，并使土壤中部分可交换态Cr转化为可还原态及残渣态Cr；③Ca-Fe-B可促进土壤β-葡萄糖苷酶与几丁质酶酶活性，但磷酸酶对其响应不显著，也可显著提升土壤中Proteobacteria门菌相对丰度；④Ca-Fe-B表面形成Si—O—Ca—OH键可吸附Cr（VI）， Fe（Ⅱ）作为电子供体参与土壤Cr（VI）还原过程，并生成Cr₂O₃、Cr（OH）₃沉淀及（Cr_xFe_1-x）（OH）₃、Cr_xFe_1-xOOH络合沉淀，以—OH、 —C=C—、O—C=O为主的大量含氧官能团协同吸附络合土壤中的Cr（VI）.研究显示， Ca-Fe-B对Cr（VI）污染土壤具有良好的稳定性能，有望为土壤重金属污染修复提供一种新的研究思路和技术路线.

• Abstract：Biochar modified materials are known for their numerous active functional groups and high adsorption efficiency， and are widely used in the remediation and treatment of soil that are polluted by heavy metal. In this study， rice hulls were used as raw materials to prepare calcium-based magnetic biochar（Ca-Fe-B） by using co-precipitation and CaCO₃ impregnation methods. The scanning electron microscope（SEM）， Fourier infrared spectroscopy（FTIR）， and X-rays diffraction analysis（XRD） were used to illustrate the microscopic properties of this material. The soil contamination experiment was conducted under gradient Cr（VI） concentration conditions to investigate the influence of Ca-Fe-B application on soil pH， Cr（VI） stabilization effect， soil enzyme activity and microbial community structure， and their passivation mechanism was concluded in detail. The result shows that： ①When the surface of Ca-Fe-B was loaded with Fe₃O₄， γ-Fe₂O₃， Fe₃C and CaCO₃ in the form of calcite，which offer the material with a large amount of functional groups such as —OH， O—C=O， Si—O—Si， C≡C and C≡N， etc.②The experiment clearly showed that Ca-Fe-B can significantly increase soil pH. When Cr（VI） concentration was 100， 200， 1000 mg·kg^-1， fixation efficiency at 90^th day reach 72.57%， 67.07% and 59.88%， respectively， and Exchangeable Cr was transformed into reducible and residual Cr； ③Ca-Fe-B can promote enzyme activity of β-glucosidase and chitinase， however， phosphatase does not respond well to it. Furthermore， it can also significantly increase the relative abundance of Proteobacteria in soil； ④the Si—O—Ca—OH bond formed on the surface of Ca-Fe-B can easily adsorb Cr（VI） and as an electron donor Fe（Ⅱ） participates in the reduction of Cr（VI） and generate Cr₂O₃， Cr（OH）₃ precipitates and （Cr_xFe_1-x）（OH）₃， Cr_xFe_1-xOOH complex precipitates. A large number of oxygen-containing functional groups mainly —OH， —C=C—， O—C=O participated in the adsorption of Cr（VI） in soil. The Studies have shown that Ca-Fe-B can effectively stabilize the Cr（VI） contaminated soil which provides a new research approach and technical route for the remediation of heavy metal polluted soil.

• Key words：calcium-based magnetic biochar  gradient Cr（VI） pollution  passivation mechanism  soil enzymes  microbial community structure

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