Arsenic and iron removal in horizontal subsurface flow constructed wetlands with alternative supporting media: key mechanisms

IF 6.3 2区工程技术 Q1 ENGINEERING, CHEMICAL

Journal of water process engineering Pub Date : 2025-07-24 DOI:10.1016/j.jwpe.2025.108354

Katherine Lizama-Allende , José Ayala , Juan Morales

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Abstract

This work identifies the arsenic and iron removal mechanisms in a horizontal subsurface flow constructed wetlands system with zeolite and limestone as alternative supporting media. To do this, two sequential extraction procedures were performed in media samples obtained after the system treated highly acidic, metal and arsenic rich contaminated water. Advanced techniques were also employed to detect arsenic and metals in the media samples and discover possible changes in their composition. According to the arsenic fractioning revealed by the first procedure, which targets arsenic only, the main arsenic removal mechanisms depended on the media type. In limestone: coprecipitation with very amorphous iron oxyhydroxides and carbonates, since of the total extracted (982 mg As/kg), the fraction associated with these phases was 51.8 %; whereas in zeolite, of the total extracted (400 mg As/kg), the adsorbed fraction was 79.4 %. Conversely, the second procedure, which targets metals, indicated that the main mechanism was bonding to iron and manganese oxides in both media types, since this fraction was 78.8 % of the total extracted in zeolite (211 mg As/kg), and 68.9 % of the total extracted in limestone (272 mg As/kg) (average values). The iron fractioning indicated that iron was mainly removed by precipitation of very amorphous and amorphous iron oxyhydroxides in zeolite and limestone cells. Changes in the composition of both media were detected after being used as wetland media. To elucidate arsenic fractioning, sequential extraction procedures targeting arsenic instead of metals must be employed.

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不同载体水平潜流人工湿地对砷和铁的去除：关键机制

本研究确定了以沸石和石灰石作为替代支撑介质的水平潜流人工湿地系统中砷和铁的去除机制。为此，对系统处理过高酸性、富含金属和砷的污染水后获得的介质样品进行了两次连续提取程序。还采用先进技术检测介质样品中的砷和金属，并发现其成分可能发生的变化。根据第一种方法所揭示的仅针对砷的砷分馏，主要的砷去除机制取决于介质类型。在石灰石中：与非常无定形的铁氢氧化物和碳酸盐共沉淀，因为在总萃取物中（982 mg As/kg），与这些相相关的分数为51.8%；而在沸石中，总萃取物（400 mg As/kg）的吸附部分为79.4%。相反，针对金属的第二种方法表明，主要机制是在两种介质类型中与铁和锰氧化物结合，因为这一分数占沸石中提取总量的78.8% (211 mg As/kg)，占石灰石中提取总量的68.9% (272 mg As/kg)（平均值）。铁分馏表明，在沸石和石灰石细胞中，铁主要通过沉淀非定形和非定形铁氢氧化物去除。作为湿地介质使用后，检测了两种介质的组成变化。为了阐明砷分馏，必须采用针对砷而不是金属的顺序萃取程序。

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来源期刊

Journal of water process engineering Biochemistry, Genetics and Molecular Biology-Biotechnology

CiteScore

10.70

自引率

8.60%

发文量

846

审稿时长

24 days

期刊介绍： The Journal of Water Process Engineering aims to publish refereed, high-quality research papers with significant novelty and impact in all areas of the engineering of water and wastewater processing . Papers on advanced and novel treatment processes and technologies are particularly welcome. The Journal considers papers in areas such as nanotechnology and biotechnology applications in water, novel oxidation and separation processes, membrane processes (except those for desalination) , catalytic processes for the removal of water contaminants, sustainable processes, water reuse and recycling, water use and wastewater minimization, integrated/hybrid technology, process modeling of water treatment and novel treatment processes. Submissions on the subject of adsorbents, including standard measurements of adsorption kinetics and equilibrium will only be considered if there is a genuine case for novelty and contribution, for example highly novel, sustainable adsorbents and their use: papers on activated carbon-type materials derived from natural matter, or surfactant-modified clays and related minerals, would not fulfil this criterion. The Journal particularly welcomes contributions involving environmentally, economically and socially sustainable technology for water treatment, including those which are energy-efficient, with minimal or no chemical consumption, and capable of water recycling and reuse that minimizes the direct disposal of wastewater to the aquatic environment. Papers that describe novel ideas for solving issues related to water quality and availability are also welcome, as are those that show the transfer of techniques from other disciplines. The Journal will consider papers dealing with processes for various water matrices including drinking water (except desalination), domestic, urban and industrial wastewaters, in addition to their residues. It is expected that the journal will be of particular relevance to chemical and process engineers working in the field. The Journal welcomes Full Text papers, Short Communications, State-of-the-Art Reviews and Letters to Editors and Case Studies