Mixing of zeolite facilitates re-sequestration of heavy metals via generated Fe-(oxyhydr)oxides in sediments in the presence of NO3- compared to capping

IF 12.2 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Journal of Hazardous Materials Pub Date : 2025-05-28 DOI:10.1016/j.jhazmat.2025.138774

Gen Li, Tianshi Cheng, Xinpeng Wang, Zheng Zheng, Xionghan Feng

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Abstract

Under nitrate-rich conditions, microbially-driven nitrate reduction (as electron acceptor) mediates the transformation of oxidizable heavy metal (HM) species into acid-soluble and reducible fractions, concomitant with enhanced metal mobilization into overlying water. This study investigates the impact of zeolite application modes—capping and mixing—on controlling HM release with NO₃^- addition. Compared to capping, mixing provides a more sustained inhibition of upward HMs release from sediment. Furthermore, a significant decrease in HM concentrations in overlying water is observed when experiments ended, indicating that sediments transition from being a source to a sink of HMs. Additionally, the study reveals a two-stage Fe(II) oxidation process in sediment, characterized by an initial slow oxidation phase followed by a rapid reaction phase. The distribution of HM fractions suggests that Fe-(oxyhydr)oxides generation is the primary reason for HMs re-sequestration. Therefore, the two-stage Fe(II) oxidation process coupled with zeolite regulates HM mobilization behavior. During the sediment's transition to a pollution source phase (characterized by limited Fe-(oxyhydr)oxides formation), zeolites adsorb dissolved metals from interstitial water. Conversely, upon progression to the pollution sink phase (marked by extensive Fe-(oxyhydr)oxides generation), adsorbed metals by zeolite redistribute into newly-formed Fe-(oxyhydr)oxides, thereby regenerating zeolites' adsorption capacity for HMs.

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与封盖相比，沸石的混合有助于在NO3-存在的情况下通过沉积物中生成的铁（氧）氧化物对重金属的再封存

在富含硝酸盐的条件下，微生物驱动的硝酸盐还原（作为电子受体）介导可氧化重金属（HM）转化为酸溶性和可还原组分，同时增强金属在上覆水中的动员。研究了沸石应用方式——封顶和混合——对添加NO3控制HM释放的影响。与封盖相比，混合提供了更持久的抑制向上的HMs从沉积物释放。此外，当实验结束时，观察到上覆水体中HM浓度显著下降，表明沉积物从HM的来源转变为汇。此外，研究还揭示了沉积物中Fe（II）的两阶段氧化过程，其特征是最初的缓慢氧化阶段随后是快速反应阶段。HM组分的分布表明，铁（氧）氧化物的生成是HM再固存的主要原因。因此，两段Fe（II）氧化过程耦合沸石调控HM的活化行为。在沉积物过渡到污染源阶段（以有限的铁（氧）氧化物形成为特征）期间，沸石从间隙水中吸附溶解的金属。相反，在进入污染汇阶段（以大量生成铁（氧）氧化物为标志）后，沸石吸附的金属重新分布到新形成的铁（氧）氧化物中，从而再生沸石对HMs的吸附能力。

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

Journal of Hazardous Materials 工程技术-工程：环境

CiteScore

25.40

自引率

5.90%

发文量

3059

审稿时长

58 days

期刊介绍： The Journal of Hazardous Materials serves as a global platform for promoting cutting-edge research in the field of Environmental Science and Engineering. Our publication features a wide range of articles, including full-length research papers, review articles, and perspectives, with the aim of enhancing our understanding of the dangers and risks associated with various materials concerning public health and the environment. It is important to note that the term "environmental contaminants" refers specifically to substances that pose hazardous effects through contamination, while excluding those that do not have such impacts on the environment or human health. Moreover, we emphasize the distinction between wastes and hazardous materials in order to provide further clarity on the scope of the journal. We have a keen interest in exploring specific compounds and microbial agents that have adverse effects on the environment.