• 关键词：生物炭  耐镉菌群  Cd²⁺  吸附机理

• 基金项目：广西重点研发科技项目（No.桂科AB18281002）

• 贺晓晗
• 华南理工大学环境与能源学院，广州 510006

• 郝鑫瑞
• 中国电建华东勘测设计研究院，杭州 311122

• 邓郁蓉
• 华南理工大学环境与能源学院，广州 510006

• 苏吉凯
• 华南理工大学环境与能源学院，广州 510006

• 易筱筠
• 华南理工大学环境与能源学院，广州 510006

• 党志
• 华南理工大学环境与能源学院，广州 510006

• 摘要：从广西某硫化尾矿中分离出一耐镉菌群，将其固定在生物炭上制成固定化菌剂.同时，探究了生物炭种类、添加量、溶液pH、Cd²⁺初始浓度对固定化菌剂吸附Cd²⁺性能的影响，并结合吸附动力学、吸附等温线、16S rDNA、SEM、FTIR、XPS等分析测试手段研究了固定化菌剂对Cd²⁺的吸附过程和作用机制.结果表明，竹生物炭制备的固定化菌剂（ZBCM）对Cd²⁺的吸附效果最佳，在Cd²⁺浓度为20 mg·L^-1、pH=6、生物炭投加量为3 g·L^-1的条件下，ZBCM对Cd²⁺的吸附率达89.49%，较生物炭和单菌群的吸附率分别提高了54.6%和53.51%.从属水平上看，菌群主要由 梭状芽孢杆菌、毛梭菌和产己酸菌构成，ZBCM吸附Cd²⁺后优势菌变为副梭菌、毛梭菌和贪铜菌，贪铜菌丰度的增长增强了ZBCM对Cd²⁺的 络合和生物积累作用.ZBCM对Cd²⁺的吸附过程符合伪二级动力学和Langmuir模型，说明吸附过程以单分子层内的化学吸附为主.结合FTIR和XPS结果来看，ZBCM对Cd²⁺的作用机制主要有离子交换、配位络合和阳离子-π键、生物积累.

• Abstract：In this study， a cadmium-tolerant bacterial flora was isolated from a sulfide tailings in Guangxi and immobilized on biochar to make an immobilized bacterial agent. The effects of biochar type， addition amount， solution pH and initial concentration of Cd²⁺ on the adsorption performance of the immobilized bacterial agent were investigated； the process and mechanism of Cd²⁺ adsorption by the immobilized bacterial agent were studied by combining adsorption kinetics， adsorption isotherm， 16S rDNA， SEM， FTIR， XPS and other analytical tests. The results showed that immobilized bacterial agent prepared from bamboo biochar （ZBCM） prepared from bamboo biochar had the best Cd²⁺ adsorption performance. At a Cd²⁺ concentration of 20 mg·L^-1， pH of 6 and biochar dosing of 3 g·L^-1， Cd²⁺ adsorption by ZBCM reached 89.49%， which was 54.6% and 53.51% higher than that by biochar and bacterial flora. At the genus level， the flora consisted mainly of Clostridium_sensu_stricto， Lachnoclostridium_5 and Caproiciproducens， and the dominant bacteria became Paraclostridium， Lachnoclostridium_5 and Cupriavidus after the adsorption of Cd²⁺ by ZBCM， and the increase of Cupriavidus abundance enhanced the complexation and bioaccumulation of Cd²⁺ by ZBCM. The adsorption process of Cd²⁺ by ZBCM conforms to the pseudo-secondary kinetics and Langmuir model， indicating that the adsorption process was dominated by chemisorption within the single molecular layer. The FTIR and XPS results show that the mechanisms of action of ZBCM on Cd²⁺ include ion exchange， ligand complexation and cation-π bonding， and bioaccumulation.

• Key words：biochar  cadmium-tolerant bacterial flora  Cd²⁺  adsorption mechanism

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