ACS Earth and Space Chemistry最新文献_第9页

Chromium(III) Binding to Purified Fulvic and Humic Acids and Their Solid-Solution Partitioning and Speciation in Soil 铬（III）与纯化黄腐酸和腐植酸的结合及其在土壤中的固溶分配和形态

IF 2.9 3区化学

ACS Earth and Space Chemistry Pub Date : 2025-06-20 DOI: 10.1021/acsearthspacechem.5c00075

Frank van Raffe*, Rob N.J. Comans and Jan E. Groenenberg,

{"title":"Chromium(III) Binding to Purified Fulvic and Humic Acids and Their Solid-Solution Partitioning and Speciation in Soil","authors":"Frank van Raffe*, Rob N.J. Comans and Jan E. Groenenberg, ","doi":"10.1021/acsearthspacechem.5c00075","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.5c00075","url":null,"abstract":"Chromium (Cr) is a metal of high environmental concern, which exists as Cr(III) and Cr(VI) in the environment, with Cr(VI) considered the most toxic and mobile. Humic substances may reduce Cr(VI) to Cr(III) while simultaneously binding Cr(III), reducing its bioavailability and protecting it against (re)oxidation. Nevertheless, binding of Cr(III) to humic substances is insufficiently quantified, as binding constants in ion binding models are based on limited data and consequently uncertain. In this paper, Cr binding experiments to humic and fulvic acids were conducted in conjunction with the Donnan membrane technique to determine the free Cr3+ concentration. New NICA-Donnan binding parameters were derived using ORCHESTRA-PEST, exploring scenarios with solely Cr3+ binding and additionally considering Cr binding in the form of CrOH2+ or Cr2(OH)24+. Parameters for the scenario of combined Cr3+ and Cr2(OH)24+ binding were deemed most realistic, yet obtained binding affinities were unexpectedly low, potentially related to the previously suggested overestimated electrostatic contribution, particularly for trivalent ions in the NICA-Donnan model. Validating the new parameters showed a significant improvement compared to the generic NICA-Donnan parameters in predicting Cr-HA binding in a synthetic system and in predicting free Cr3+ concentrations in soil solution, the most relevant species concerning toxicity and (bio)availability. The new parameters underestimated binding to organic matter, however, resulting in inaccurate predictions of solid-solution partitioning in organic-poor deeper soil layers. The new parameters ultimately better reflect the spectroscopically identified mechanisms of Cr binding to humic substances, yet the found limitations highlight the incorrect description of electrostatic binding by the Donnan model.","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 7","pages":"1815–1824"},"PeriodicalIF":2.9,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/acsearthspacechem.5c00075","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144808370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Environmental Behavior of Coexisting Arsenite and Cadmium during Fe(II)-Induced Ferrihydrite Transformation under Anoxic and Circumneutral Conditions 缺氧和环中性条件下Fe（II）诱导水合铁转化过程中砷酸盐和镉共存的环境行为

IF 2.9 3区化学

ACS Earth and Space Chemistry Pub Date : 2025-06-20 DOI: 10.1021/acsearthspacechem.5c00060

Xu Ma, Mengyi Zi, Xiaoming Zhao*, Yuyin Ma, Dan Zhao*, Meiling Shi and Jinru Lin,

{"title":"Environmental Behavior of Coexisting Arsenite and Cadmium during Fe(II)-Induced Ferrihydrite Transformation under Anoxic and Circumneutral Conditions","authors":"Xu Ma, Mengyi Zi, Xiaoming Zhao*, Yuyin Ma, Dan Zhao*, Meiling Shi and Jinru Lin, ","doi":"10.1021/acsearthspacechem.5c00060","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.5c00060","url":null,"abstract":"Despite extensive studies on the environmental cycling of arsenite (As(III)) and cadmium (Cd(II)) in both engineered and natural settings, such as contaminated soils and sediments, the behavior of coexisting As(III) and Cd(II) during Fe(II)-induced ferrihydrite transformation remains unclear. Herein, we have investigated the mechanism controlling As(III) and Cd(II) mobilization during Fe(II)-induced ferrihydrite transformation at environmentally contaminated metal(loid) concentrations and pH values under anoxic conditions in both single and binary metal(loid) systems. Powder X-ray diffraction (XRD), Raman, and transmission electron microscopy (TEM) results demonstrate that goethite is the dominant secondary phase for the metal(loid)-free and single Cd(II) treatments, whereas goethite and lepidocrocite are the primary secondary phases for the single As(III) and binary metal(loid) treatments. The transformation of ferrihydrite decreases as the concentrations of As(III) and Cd(II) increase. The coexisting Cd(II) inhibits the oxidation of As(III) to As(V) during Fe(II)-induced ferrihydrite transformation. Chemical analysis reveals that surface adsorption and structural incorporation are the predominant mechanisms for As (III/V) and Cd(II) retention. Additionally, the presence of As(III) significantly enhances Cd(II) mobilization by restraining ferrihydrite transformation, whereas Cd(II) has negligible effects on the mobilization of As(III) due to the formation of As(III/V)–Cd(II)–Fe ternary complexes. This study can bridge the knowledge gap regarding the interaction between As(III) and Cd(II) in contaminated environments, thereby contributing to a deeper understanding of the fate of As(III) and Cd(II) under anoxic conditions.","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 7","pages":"1791–1800"},"PeriodicalIF":2.9,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144808404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

IF 2.9 3区化学