Complexing characteristics between Cu(Ⅱ) ions and dissolved organic matter in combined sewer overflows: Implications for the removal of heavy metals by enhanced coagulation
| Autor: | Hao Chen, Dai-zong Meng, Zhi-chao Zhao, Zhenliang Liao, Jing-cheng Zhu |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Environmental Engineering
Health Toxicology and Mutagenesis Metal ions in aqueous solution 0208 environmental biotechnology Inorganic chemistry 02 engineering and technology 010501 environmental sciences 01 natural sciences Fluorescence spectroscopy Ion Metals Heavy Dissolved organic carbon Environmental Chemistry Humic Substances 0105 earth and related environmental sciences Ions Chemistry Public Health Environmental and Occupational Health Heavy metals General Medicine General Chemistry Pollution 020801 environmental engineering Spectrometry Fluorescence Combined sewer Titration Factor Analysis Statistical |
| Zdroj: | Chemosphere. 265 |
| ISSN: | 1879-1298 |
| Popis: | Enhanced coagulation has been widely used in storm tanks to remove heavy metal ions (HMs) from combined sewer overflows (CSOs), but faces challenges on removing the HMs bound to dissolved organic matter (DOM) with small molecular weight (MW). DOM ubiquitously existing in CSOs generally contains a large distribution range of MW, which can significantly impact the MW distribution of HMs by complexing reaction, thereby adding uncertainties for the removal efficiency of coagulation. Therefore, realizing the potential MW distribution of the HMs bound to CSO-DOM is greatly important for cost-effectively removing HMs from CSOs in the coagulation process. This paper presents a comprehensive approach of ultrafiltration, fluorescence quenching titration, excitation-emission matrix parallel factor analysis, complexation model, and two-dimensional correlation fluorescence spectroscopy for exploring the MW-based complexing characteristics between Cu(II) ions and CSO-DOM components. Results show that: (1) Cu(II) ions that bound to the CSO-DOM were mainly distributed in the MW range of5 kDa, which makes them very difficult to be removed from CSOs by coagulation technique. (2) Concentration effect and molecular composition exerted great impacts on the MW distribution of the Cu(II) ions bound to CSO-DOM. (3) The humic-like component of terrestrial origin with the MW range of 100 kDa∼0.45 μm possessed high binding stability, capacity, and priority with Cu(II) ions, and they could be used at a high concentration to promote the removal efficiency of coagulation for Cu(Ⅱ) ions of CSOs by competitive complexation and inter-molecular bridging. |
| Databáze: | OpenAIRE |
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