外源Mn(Ⅱ)对吸附于δ-MnO<sub>2</sub>表面的Cd迁移转化行为的影响

杜晓菲; 樊广萍; 黄琴; 张雨婷; 童非; 张明超; 邱一格; 陈金林; 高岩

文章摘要

外源Mn(Ⅱ)对吸附于δ-MnO₂表面的Cd迁移转化行为的影响

Effects of exogenous Mn(Ⅱ) on the migration and transformation behavior of Cd adsorbed on the surface of δ-MnO₂

Received:March 29, 2024

DOI：10.13254/j.jare.2024.0204

中文关键词: 土壤矿物，δ-MnO₂，镉，Mn（Ⅱ），吸附，解吸

英文关键词: soil mineral, δ-MnO₂, Cd, Mn(Ⅱ), adsorption, desorption

基金项目:江苏省农业科技自主创新资金项目[CX（21）3074]；2021年太仓市安全利用推进区（示范基地）核心区基地建设与示范项目（TCGGZY-2021G161）；江苏高校优势学科建设工程资助项目

Author Name	Affiliation	E-mail
DU Xiaofei	Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Agro-Environment in the Middle and Lower Reaches of the Yangtze Plain, Ministry of Agriculture and Rural Affairs/Liuhe Observation and Experimental Station of National Agro-Environment, Nanjing 210014, China
FAN Guangping	Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Agro-Environment in the Middle and Lower Reaches of the Yangtze Plain, Ministry of Agriculture and Rural Affairs/Liuhe Observation and Experimental Station of National Agro-Environment, Nanjing 210014, China School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China	fanguangping@jaas.ac.cn
HUANG Qin	Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Agro-Environment in the Middle and Lower Reaches of the Yangtze Plain, Ministry of Agriculture and Rural Affairs/Liuhe Observation and Experimental Station of National Agro-Environment, Nanjing 210014, China
ZHANG Yuting	School of Resources and Environment, Anhui Agricultural University, Hefei 230036, China
TONG Fei	Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Agro-Environment in the Middle and Lower Reaches of the Yangtze Plain, Ministry of Agriculture and Rural Affairs/Liuhe Observation and Experimental Station of National Agro-Environment, Nanjing 210014, China
ZHANG Mingchao	Jiangsu Cultivated Land Quality and Agricultural Environmental Protection Station, Nanjing 210036, China
QIU Yige	Jiangsu Province Ecological Environment Monitoring and Control Co., Ltd., Nanjing 210019, China
CHEN Jinlin	Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China	jlchen@njfu.edu.cn
GAO Yan	Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Agro-Environment in the Middle and Lower Reaches of the Yangtze Plain, Ministry of Agriculture and Rural Affairs/Liuhe Observation and Experimental Station of National Agro-Environment, Nanjing 210014, China School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China

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中文摘要:

为探究外源Mn（Ⅱ）对吸附于水钠锰矿（δ-MnO₂）表面的Cd（Ⅱ）迁移转化行为的影响，本研究采用土壤矿物培养试验，研究了厌氧-好氧条件下，添加不同浓度（2.5 mmol·L^-1和 10 mmol·L^-1）Mn（Ⅱ）以及不同的添加频率（一次性添加、分次添加）对 δ-MnO₂吸附固定Cd（Ⅱ）的影响。结果表明，添加Mn（Ⅱ）导致δ-MnO₂表面的Cd（Ⅱ）发生显著解吸，解吸率为20.5%~40.8%，高浓度Mn（Ⅱ）处理中 Cd（Ⅱ）解吸率比低浓度处理高 5.3~10.6 个百分点，分次添加 Mn（Ⅱ）处理中 Cd（Ⅱ）解吸率比一次性添加处理高0.3~4.1个百分点。在厌氧阶段，Mn（Ⅱ）通过与Cd（Ⅱ）竞争吸附位点，使吸附于δ-MnO₂表面的Cd（Ⅱ）的稳定性降低并释放到溶液中。XRD、FTIR和XPS结果表明，Mn（Ⅱ）与δ-MnO₂发生氧化还原反应并在活性氧（ROS）的催化作用下生成β-MnOOH，同时降低了体系 pH 值。进入有氧阶段后，固相中 Mn（Ⅲ）比例增加，β-MnOOH 特征峰增强，氧气催化氧化 Mn（Ⅱ）生成了更多的 β-MnOOH，β-MnOOH 对 Cd（Ⅱ）的吸附能力较弱，有氧阶段 Cd（Ⅱ）解吸率较厌氧阶段略有升高。电子顺磁的结果表明，分次添加Mn（Ⅱ）处理通过促进厌氧阶段超氧自由基（O₂^·-）的产生和延缓好氧阶段O₂^·-的衰减增加了 Mn（Ⅲ）的产生，降低了Cd（Ⅱ）在固相上的稳定性，进一步导致Cd（Ⅱ）的解吸。本研究发现外源Mn（Ⅱ）导致δ-MnO₂表面Cd（Ⅱ）的解吸，阐明了Mn（Ⅱ）与δ-MnO₂共存时Cd（Ⅱ）的固定与迁移机制。

英文摘要:

In order to explore the effect of exogenous Mn(Ⅱ) on the migration and transformation of Cd(Ⅱ) adsorbed on the surface of birnessite（δ-MnO₂）, the effects of different concentrations（2.5 mmol·L^-1, 10 mmol·L^-1）of Mn(Ⅱ) and different addition rates（one addition, fractional addition）on the adsorption and fixation of Cd(Ⅱ) by δ-MnO₂ under anaerobic-aerobic conditions were studied by soil mineral culture experiment. The results showed that the addition of Mn(Ⅱ) led to the desorption of Cd(Ⅱ) on the surface of δ-MnO₂. The desorption rate of Cd(Ⅱ) in high concentration Mn(Ⅱ) treatment was 5.3-10.6 percentage points higher than that in low concentration treatment, and the desorption rate of Cd(Ⅱ) in fractional addition Mn(Ⅱ) treatment was 0.6-4.1 percentage points higher than that in one addition treatment. Mn(Ⅱ) competes with Cd(Ⅱ) for adsorption sites, which led to the decrease of the stability of Cd(Ⅱ) adsorbed on the surface of δ-MnO₂ and the release of Cd(Ⅱ) into the solution. In the anaerobic stage, Mn(Ⅱ) react with δ-MnO₂ to generate β-MnOOH by redox reaction and reactive oxygen species（ROS）catalysis, while reducing the pH value of the system. After entering the aerobic stage, the proportion of Mn（Ⅲ）in the solid phase increases, the characteristic peak of β-MnOOH increased, and more β-MnOOH was generated by the catalytic oxidation of Mn(Ⅱ) by oxygen. The adsorption capacity of β-MnOOH for Cd(Ⅱ) was weak. The desorption rate of Cd(Ⅱ) in aerobic stage was higher than that in anaerobic stage. The results of electron paramagnetism showed that the addition of Mn(Ⅱ) increased the production of Mn（Ⅲ）by promoting the production of superoxide radicals（O₂^·-）in the anaerobic phase and delaying the decay of O₂^·- in the aerobic phase, which reduced the stability of Cd(Ⅱ) in the solid phase and further led to the desorption of Cd(Ⅱ). In this study, the mechanism of Cd(Ⅱ) immobilization and migration in the coexistence of Mn(Ⅱ) and δ- MnO₂ was described. This study found that exogenous Mn(Ⅱ) led to the desorption of Cd(Ⅱ) on the surface of δ-MnO₂, and clarified the mechanism of Cd(Ⅱ) immobilization and migration when Mn(Ⅱ) coexisted with δ-MnO₂.

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