Reactive transport and retention of Cd, Pb, and Zn under coexisting multimetal-xanthate conditions in porous media

IF 12.4 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Water Research Pub Date : 2025-10-01 DOI:10.1016/j.watres.2025.124713

Bowen Luo , Kouping Chen , Xianwu Zheng , Jichun Wu , Ping Li , Huali Chen

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Abstract

The geochemical fate of heavy metals in mining regions is significantly complicated by the coupled effects of residual flotation reagents and the co-existence of multiple metals. Combining column transport experiments and spectroscopic characterization, this study developed a Multisurface Speciation Model (MSM) to describe the reaction processes between cadmium (Cd), lead (Pb), and zinc (Zn) and key retention components including iron oxides, organic matter, clay minerals, and ethyl xanthate (EX), to quantitatively elucidate the impact of system complexity and EX-loaded concentration on their transport and retention behaviors in actual porous media. First, increasing the EX-loaded concentration from 0 to 1 mmol/L enhanced overall retention and inhibited the transport of all the three metals. Conversely, increasing system complexity from single-metal to multimetal systems diminished overall retention and enhanced transport. EX loading established EX as a dominant component for metal retention and concurrently suppressed the retention contribution of other soil components. However, the transition from single metal systems to ternary metal systems led to the intensified competition between metals and EX, thereby reducing the adsorption of EX onto the porous media and consequently weakening its overall capacity to retain the heavy metals, with the EX-retained concentrations of Cd, Pb, and Zn decreasing by 78.62 %, 52.44 %, and 80.46 %, respectively. The characterization results demonstrated that while the introduction of EX enhanced heavy metal retention through introducing new sulfur-containing functional groups, increasing the net negative surface charge, and promoting metal-immobilizing sulfidation reactions, the enhancement was significantly offset in multimetal systems by the intensified inter-metal competition and by a concurrent weakening of electrostatic attraction. This study successfully deconvolved the dual effects of EX loading and multimetal competition on the transport and retention of Cd, Pb, and Zn, offering a new perspective on the fate of heavy metals in xanthate-affected systems.

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多孔介质中多金属-黄药共存条件下Cd、Pb和Zn的反应传递和保留

由于浮选药剂残留和多种金属共存的耦合作用，矿区重金属的地球化学命运十分复杂。本研究结合柱输运实验和光谱表征，建立了多表面形态模型（MSM）来描述镉（Cd）、铅（Pb）和锌（Zn）与氧化铁、有机物、粘土矿物和乙基黄药（EX）等关键保留组分之间的反应过程，以定量阐明系统复杂性和EX负载浓度对其在实际多孔介质中输运和保留行为的影响。首先，将ex负载浓度从0增加到1 mmol/L，增强了总体保留并抑制了所有三种金属的运输。相反，从单金属到多金属系统的复杂性增加会降低总体保留率，增强运输能力。EX加载确定了EX作为金属滞留的主导组分，同时抑制了其他土壤组分的滞留贡献。然而，从单一金属体系到三元金属体系的转变导致金属与EX之间的竞争加剧，从而减少了EX在多孔介质上的吸附，从而削弱了其对重金属的总体保留能力，EX的Cd、Pb和Zn的保留浓度分别下降了78.62%、52.44%和80.46%。表征结果表明，虽然引入EX通过引入新的含硫官能团、增加净负表面电荷和促进金属固定化硫化反应来增强重金属的保留，但在多金属体系中，这种增强被金属间竞争的加剧和静电吸引力的减弱所显著抵消。该研究成功地解决了EX加载和多金属竞争对Cd、Pb和Zn的运输和保留的双重影响，为研究黄原药影响体系中重金属的命运提供了新的视角。

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来源期刊

Water Research 环境科学-工程：环境

CiteScore

20.80

自引率

9.40%

发文量

1307

审稿时长

38 days

期刊介绍： Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include: •Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management; •Urban hydrology including sewer systems, stormwater management, and green infrastructure; •Drinking water treatment and distribution; •Potable and non-potable water reuse; •Sanitation, public health, and risk assessment; •Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions; •Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment; •Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution; •Environmental restoration, linked to surface water, groundwater and groundwater remediation; •Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts; •Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle; •Socio-economic, policy, and regulations studies.