Advanced carbon dioxide hydrate-based treatment of high-alkaline wastewater from zinc-air batteries: A molecular simulation study

IF 6.3 2区工程技术 Q1 ENGINEERING, CHEMICAL

Journal of water process engineering Pub Date : 2025-07-15 DOI:10.1016/j.jwpe.2025.108322

Kai Guo , Yonghuan Zang , Wenxiang Zhang , Xiao Jiang , Sizhe Zhou , Ziyi Qu , Qing Xiao , Haojie Gao , Jun Chen

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Abstract

Zinc-air batteries produce electrolytic wastewater with metal ions, posing environmental challenges. Recycling these ions is crucial for sustainable chemical management. Hydrate-based wastewater treatment has emerged as a promising green chemistry method. This study uses molecular dynamics simulations (GROMACS) to examine CO₂ hydrate formation in strongly alkaline wastewater (pH 14) containing Zn(CH₃COO)₂ and KOH, aiming for sustainable metal ion recovery. Over 5000 ns, the study analyzes hydrate growth kinetics, ion migration paths, structural evolution, and key metrics like four-body structural order (F₄), energy trends, cage structure evolution, radial distribution functions (RDF), mean square displacement (MSD), and ion concentration changes. Results show CO₂ molecules form sI-type hydrate structures effectively, with hydrate numbers peaking at 640 ns and ion concentration increasing from 6.99 mol/L to 8.26 mol/L, an 18.2 % enrichment, indicating metal enrichment efficiency. Ion migration analysis reveals K⁺ and OH⁻ form blocking zones, inhibiting hydrate growth, while CH₃COO⁻ promotes it by attaching to hydrate surfaces. Zn²⁺ exhibited the strongest interaction with water molecules, playing a key role in hydrate nucleation. Transient irregular cages act as nucleation sites for stable hydrates. This study offers insights into using CO₂ hydrates for wastewater treatment and metal recovery in green chemistry.

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高级二氧化碳水合物处理锌空气电池高碱性废水：分子模拟研究

锌空气电池产生的电解废水中含有金属离子，对环境构成挑战。回收这些离子对可持续化学品管理至关重要。水合基废水处理已成为一种很有前途的绿色化学方法。本研究利用分子动力学模拟（GROMACS）研究了含Zn(CH3COO)2和KOH的强碱性废水（pH 14）中CO2水合物的形成，旨在实现金属离子的可持续回收。在5000 ns的时间内，研究分析了水合物的生长动力学、离子迁移路径、结构演变以及四体结构顺序（F4）、能量趋势、笼状结构演变、径向分布函数（RDF）、均方位移（MSD）和离子浓度变化等关键指标。结果表明，CO2分子能有效形成si型水合物结构，水合物数在640 ns处达到峰值，离子浓度从6.99 mol/L增加到8.26 mol/L，富集幅度为18.2%，表明了金属的富集效率。离子迁移分析表明，K+和OH−形成阻塞区，抑制水合物生长，而CH3COO−通过附着在水合物表面促进水合物生长。Zn2+与水分子的相互作用最强，在水合物成核过程中起关键作用。瞬态不规则笼作为稳定水合物的成核点。该研究为利用二氧化碳水合物进行废水处理和绿色化学中的金属回收提供了见解。

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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