Contradictory tendency of As(V) releasing from Fe–As complexes: Influence of organic and inorganic anions
| Autor: | Yang Zhang, Shiming Su, Benhua Sun, Xibai Zeng, Yanan Wang, Nan Zhang, Zhonglan Yang, Cuixia Wu |
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| Rok vydání: | 2022 |
| Předmět: |
Environmental Engineering
Health Toxicology and Mutagenesis Inorganic chemistry Infrared spectroscopy Ferric Compounds Oxalate Phosphates chemistry.chemical_compound Ferrihydrite X-Ray Diffraction Environmental Chemistry Sulfate Minerals biology Silicates Public Health Environmental and Occupational Health Arsenate General Medicine General Chemistry Phosphate Pollution Silicate chemistry biology.protein Adsorption Organic anion |
| Zdroj: | Chemosphere. 286:131469 |
| ISSN: | 0045-6535 |
| DOI: | 10.1016/j.chemosphere.2021.131469 |
| Popis: | The strong ability of ferrihydrite and its aged minerals for fixing arsenate is a key factor in remediating arsenate-polluted environments. It is therefore crucial to clarify the stability of Fe–As complexes and the release conditions for As(V). The As(V) release amount was evaluated and compared in the presence of six representative anions, namely, phosphate, silicate, sulfate, inositol hexaphosphate, citrate, and oxalate. It was found that the As(V) release amount changed with the aging time of ferrihydrite and that this tendency generally followed two rules. These are, longer aging time leads to lower As(V) release (Rule 1), and longer aging time leads to higher As(V) release (Rule 2). Whether Rule 1 or Rule 2 dominated As release depended on the number of surface groups, size of competing anions, and contribution of As(V) re-adsorption. Characterization results using X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) provided evidence for the predicted mechanisms of As(V) release under various circumstances. In this work, it was demonstrated that when inorganic anions such as sulfate and silicate are present, ferrihydrite with longer aging time led to decreased As(V) release. When organic anions are present, ferrihydrite with less aging time results in reduced As(V) leaching. For anions such as phosphate, the As(V) release amount in relation to the ferrihydrite aging time depends on the concentration of phosphate ions. Nevertheless, the ligand concentration and As(V) loading rate on ferrihydrite should be simultaneously considered for the rule governing As(V) releasing. |
| Databáze: | OpenAIRE |
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