Adsorption and desorption effect of modified bentonite on soil heavy metal Pb/Cd and the feasibility assessment of reducing the ecotoxicity

IF 6 3区环境科学与生态学 Q1 ENVIRONMENTAL SCIENCES

Environmental Sciences Europe Pub Date : 2025-06-21 DOI:10.1186/s12302-025-01144-3

Xue Yang, Yuancheng Li, Maoxi Gan, Yuling Chen, Hailong Meng, Lun Li, Jianhong Xu, Meihong Zhao, Dongpeng Lv

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引用次数: 0

Abstract

Background

Lead and cadmium (Pb/Cd) are pervasive in soils, and their detrimental effects on ecosystems are increasingly evident. Therefore, taking measures to mitigate the toxicity of Pb/Cd is urgently necessary. In this study, bentonite was used as a raw material for modification, and the influence of modified bentonite on the soil adsorption and desorption of Pb/Cd was investigated. The potential application of modified bentonite in mitigating the phytotoxicity of Pb/Cd was evaluated by conducting pot experiments, and the environmental risk was evaluated by acid rain leaching test.

Results

Results indicate that the removal rates of Pb/Cd of BTS obtained by 450℃ calcination and 20% citric acid activation reached 88.03% and 80.04%, respectively. Pb/Cd was primarily adsorbed by BTS through coordination between the groups (e.g., siloxane, hydroxyl, and carboxyl) and Pb/Cd. BTS amendment at an appropriate concentration (1%, 3%, and 5%, w/w) to soils contaminated with Pb/Cd resulted in a significant increase in ryegrass yield and chlorophyll (P < 0.05), and it enhanced root activity and antioxidant enzyme activity. Furthermore, under the effect of acid rain at pH 5.0, the release concentrations of Pb/Cd were the lowest when BTS-5% was added, and the cumulative release concentrations were 2.079 and 1.506 mg·L⁻¹, respectively. The extractable acid state increased before and after leaching, whereas the residual state decreased.

Conclusion

BTS (3% and 5%) can reduce the environmental risk level from a strong risk to a slight risk. Furthermore, the results of this study can provide theoretical basis for the promotion and application of bentonite in pollution control.

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改性膨润土对土壤重金属Pb/Cd的吸附和解吸效果及降低生态毒性的可行性评价

背景：铅和镉（Pb/Cd）在土壤中普遍存在，其对生态系统的有害影响日益明显。因此，采取措施减轻铅/镉的毒性是迫切需要的。本研究以膨润土为原料进行改性，考察改性后的膨润土对土壤中Pb/Cd吸附和解吸的影响。通过盆栽试验评价改性膨润土在减轻Pb/Cd植物毒性方面的应用潜力，通过酸雨淋滤试验评价改性膨润土的环境风险。结果450℃煅烧和20%柠檬酸活化制备的BTS对Pb/Cd的去除率分别达到88.03%和80.04%。铅/镉主要通过基团（硅氧烷、羟基和羧基）和Pb/Cd之间的配位被BTS吸附。适当浓度的BTS（1%、3%和5%，w/w）对Pb/Cd污染土壤的处理显著提高了黑麦草产量和叶绿素含量（P < 0.05），提高了根系活性和抗氧化酶活性。在pH为5.0的酸雨条件下，添加BTS-5%时Pb/Cd的释放浓度最低，累积释放浓度分别为2.079和1.506 mg·L−1。浸出前后可萃取酸态增加，剩余酸态减少。结论bts（3%和5%）可将环境风险等级由高风险降至低风险。研究结果可为膨润土在污染治理中的推广应用提供理论依据。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Environmental Sciences Europe Environmental Science-Pollution

CiteScore

11.20

自引率

1.70%

发文量

110

审稿时长

13 weeks

期刊介绍： ESEU is an international journal, focusing primarily on Europe, with a broad scope covering all aspects of environmental sciences, including the main topic regulation. ESEU will discuss the entanglement between environmental sciences and regulation because, in recent years, there have been misunderstandings and even disagreement between stakeholders in these two areas. ESEU will help to improve the comprehension of issues between environmental sciences and regulation. ESEU will be an outlet from the German-speaking (DACH) countries to Europe and an inlet from Europe to the DACH countries regarding environmental sciences and regulation. Moreover, ESEU will facilitate the exchange of ideas and interaction between Europe and the DACH countries regarding environmental regulatory issues. Although Europe is at the center of ESEU, the journal will not exclude the rest of the world, because regulatory issues pertaining to environmental sciences can be fully seen only from a global perspective.