• 关键词：Pb（II）  好氧颗粒污泥  生物效应  迁移转化  吸附机制

• 基金项目：国家自然科学基金项目（No.51408551）；浙江省自然科学基金项目（No.LY21E080028）；宁波市重点研发计划暨“揭榜挂帅”项目（No.2022Z059）；浙江省一流学科课题（No.CX2021046）；浙江万里学院科研创新团队资助项目

• 王显海
• 浙江万里学院生物与环境学院，宁波 315100;浙江仁欣环科院有限责任公司，宁波 315100

• 谢周云
• 浙江万里学院生物与环境学院，宁波 315100

• 王宇
• 浙江万里学院生物与环境学院，宁波 315100

• 张妮
• 浙江万里学院生物与环境学院，宁波 315100

• 谢晴帆
• 浙江万里学院生物与环境学院，宁波 315100

• 徐佳杰
• 浙江万里学院生物与环境学院，宁波 315100

• 杨国靖
• 浙江万里学院生物与环境学院，宁波 315100

• 摘要：Pb（II）会随工业的应用而残留在各类水体中，对人类和水生态构成潜在风险.以好氧颗粒污泥（Aerobic Granular Sludge， AGS）为接种污泥，在序批式反应器中研究Pb（II）对AGS的生物毒性及其迁移转化特性，同时探讨AGS对Pb（II）的吸附行为与机制.结果表明，Pb（II）会破坏AGS的三维结构，致使污泥生物量下降和沉降性能恶化.同时促进微生物分泌胞外聚合物（Extracellular Polymeric Substances， EPS），但由于污泥内部孔道堵塞使得微生物以EPS为碳源，且Pb（II）的持续毒性超过EPS保护阈值，最终导致EPS含量由对照组的（295.90±6.22） mg·g^-1 最低降至（217.23±7.35） mg·g^-1.在20 mg·L^-1 Pb（II）的长期暴露下，AGS同步硝化反硝化作用明显削弱，导致TN去除率由对照组的97.15%大幅下降至70.04%.高通量结果表明，Exiguobacterium和Candidatus_Competibacter菌属在高浓度Pb（II）的胁迫下成为优势菌属，而与脱氮相关的Pseudomonas菌群相对丰度锐减至6.87%.此外，当Pb（II）进水浓度为1 mg·L^-1时，AGS可对其实现99.15%的高效去除.整个过程的吸附动力学可以用准二级模型充分解释，且由多种扩散机制调控.使用Freundlich等温线模型可以较好地描述Pb（II）的吸附，Temkin模型也进一步证实化学吸附可在去除过程中起主导作用.结合扫描电子显微镜、X射线能谱仪和红外光谱表征结果，确定AGS对Pb（II）的吸附机制是以表面络合和沉淀反应为关键途径，并伴有离子交换和静电吸附.

• Abstract：Industrial activities promote the release of Pb（II） into the various water bodies posing a potential threat to the human and water ecology. In the present study， batch experiments were carried out in sequencing batch reactors with aerobic granular sludge （AGS） as inoculated sludge to investigate the biotoxicity， migration， and transformation of Pb（II） in AGS. The subsequent adsorption behavior of Pb（II） in AGS was also explored along with analyses of the mechanism. Experimental results showed that Pb（II） disrupted the three-dimensional structure of AGS which led to the reduction of sludge biomass and deterioration of settling performance. Meanwhile， Pb（II） could promote the secretion of extracellular polymeric substances （EPS） by microorganisms. However， the channel blockage inside the sludge led to the consumption of EPS by microorganisms as a carbon source， and the persistent toxicity of Pb（II） exceeded the EPS protection threshold. The above two reasons ultimately resulted in distinct decreases of the EPS were observed from （295.90±6.22） mg·g^-1 to （217.23±7.35） mg·g^-1. The simultaneous nitrification and denitrification of AGS was significantly weakened by the long-term exposure of 20 mg·L^-1 Pb（II）. Thus， the TN removal rate decreased significantly from 97.15% in the control group to 70.04%. The high-throughput results showed that Exiguobacterium and Candidatus_Competibacter became the dominant genus under the stress of high concentration Pb（II）. Nevertheless， the relative abundance of Pseudomonas related to denitrification decreased sharply to 6.87%. In addition， AGS can achieve 99.15% efficient removal of Pb（II） when the influent concentrations is 1 mg·L^-1. The pseudo-second-order model can be better adapted to the adsorption process and regulated by multiple diffusion mechanisms. Pb（II） adsorption can be better described using the Freundlich isotherm model， and the Temkin model further confirms that chemisorptions can play a dominant role in the removal process. Combined with scanning electron microscope， energy dispersive spectrometer and fourier transform infrared spectrometer characterization results， it can be determined that the mechanism of Pb（II） adsorption by AGS is dominated by surface complexation and precipitation reactions， accompanied by ion exchange and electrostatic attraction.

• Key words：Pb（II）  aerobic granular sludge  bio-effects  migration and transformation  adsorption mechanism

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