Removal of arsenite by reductive precipitation in dithionite solution activated by UV light
| Autor: | Bill Batchelor, Vishakha Kaushik, Yuhang Duan, Aya Safan, Ahmed Abdel-Wahab, Bahngmi Jung |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Environmental Engineering
Arsenites Ultraviolet Rays chemistry.chemical_element 02 engineering and technology 010501 environmental sciences Dithionite 01 natural sciences Sodium dithionite chemistry.chemical_compound Chemical Precipitation Environmental Chemistry Arsenic 0105 earth and related environmental sciences General Environmental Science Arsenite Photolysis Precipitation (chemistry) Photodissociation General Medicine 021001 nanoscience & nanotechnology Solutions Light intensity chemistry Arsenic sulfide 0210 nano-technology Oxidation-Reduction Water Pollutants Chemical Nuclear chemistry |
| Zdroj: | Journal of Environmental Sciences. 74:168-176 |
| ISSN: | 1001-0742 |
| Popis: | This study investigates the removal of arsenite (As(III)) from water using dithionite activated by UV light. This work evaluated the removal kinetics of As(III) under UV light irradiation as affected by dithionite dose and light intensity, and characterized the nature of the precipitated solids using XPS and SEM-EDS. Photolysis of dithionite was observed by measuring dithionite concentration using UV absorbance at 315nm. This study also investigated the effect of UV light path length on soluble As concentrations to understand resolubilization mechanisms. Total soluble As concentrations were observed to decrease with reaction time due to reduction of arsenite to form solids having a yellow-orange color. The removal mechanism was found to be reductive precipitation that formed solids of elemental arsenic or arsenic sulfide. However, these solids were observed to resolubilize at later times after dithionite had been consumed. Resolubilization of As was prevented and additional As removal was obtained by frequent dosing of dithionite throughout the experiment. As(III) removal is attributed to photolysis of dithionite by UV light and production of reactive radicals that reduce As(III) and convert it to solid forms. |
| Databáze: | OpenAIRE |
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