A novel approach for arsenic adsorbents regeneration using MgO
| Autor: | Manassis Mitrakas, Maria Katsikini, Sofia Tresintsi, Konstantinos Simeonidis, G. Bantsis, E. C. Paloura |
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| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Environmental Engineering
Health Toxicology and Mutagenesis Inorganic chemistry chemistry.chemical_element Inner sphere electron transfer Ferric Compounds Arsenic Water Purification Adsorption Environmental Chemistry Sodium Hydroxide Recycling ddc:530 Waste Management and Disposal Extended X-ray absorption fine structure Chemistry Magnesium Pollution 6. Clean water X-ray absorption fine structure Leaching (metallurgy) Absorption (chemistry) Magnesium Oxide Water Pollutants Chemical |
| Zdroj: | Journal of hazardous materials 265, 217-225 (2014). doi:10.1016/j.jhazmat.2013.12.003 |
| DOI: | 10.1016/j.jhazmat.2013.12.003 |
| Popis: | An integrated procedure for the regeneration of iron oxy-hydroxide arsenic adsorbents by granulated MgO is proposed in this study. A continuous recirculation configuration, with a NaOH solution flowing sequentially through the saturated adsorbent (leaching step) and the MgO (adsorption step) column beds, was optimized by utilizing the high arsenic adsorption efficiency of MgO at strong alkaline environments. Experimental results indicated that the total amount of leached arsenic was captured by MgO whereas the regenerated iron oxy-hydroxide recovered around 80% of its removal capacity upon reuse. The improved adsorption capacity of MgO for As(V), which is maximized at pH 10, is explained by the intermediate hydration to Mg(OH)2 and the following As(V) oxy-anions adsorption on its surface through the formation of monodentate inner sphere complexes, as it is deduced from the Assingle bondK-edge X-ray absorption fine structure (EXAFS) analysis. In addition to the economical-benefits, corresponding tests proved that the solid wastes of this process, namely spent MgO/Mg(OH)2, can be environmentally safely disposed as stable additives in cement products, while the alkaline solution is completely detoxified and can be recycled to the regeneration task. |
| Databáze: | OpenAIRE |
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