Evaluation of commercial zerovalent iron sources in combination with solar energy to remove microcontaminants from natural water at circumneutral pH.
Chemosphere
; 286(Pt 1): 131557, 2022 Jan.
Article
em En
| MEDLINE
| ID: mdl-34293562
ABSTRACT
Solar zerovalent iron (ZVI) was studied at circumneutral pH in combination with hydrogen peroxide and persulfate for removal of imidacloprid as a model contaminant in natural water. Three commercial ZVI sources, steel wool (ZVI-SW) and two iron micro-powders (ZVI-MS and ZVI-S) were independently evaluated. First, different ZVI corrosion conditions were tested in contact with air, exposed to natural solar radiation and with addition of oxidants, such as H2O2 and S2O82-, demonstrating the importance of released iron. Then, the technical feasibilities of solar/H2O2/ZVI and solar/S2O82-/ZVI were assessed for the elimination of 1 mg/L of imidacloprid. In general, H2O2 concentrations and treatment times were high. Only ZVI-MS (1 mM) reached 80% imidacloprid degradation after 157 min and 3 mM (102 mg/L) of H2O2. Solar/S2O82-/ZVI performance was better, reaching >80% imidacloprid degradation in <60 min with 1 mM (192 mg/L) S2O82- for all ZVI sources. Efficiency was highest with ZVI-MS, which was therefore selected for feasibility testing of a microcontaminant (MC) mixture containing 100 µg/L each of atrazine, carbendazim, imidacloprid and thiamethoxam with both solar/oxidizing agents/ZVI. H2O2 took 180 min to achieve 76% degradation of the sum of MCs, while 80% total degradation was reached after 69 min by adding S2O82-, confirming its higher efficiency. Finally, this study showed that ZVI in combination with solar radiation does not enhance significantly the photocatalytic cycle.
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01-internacional
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MEDLINE
Assunto principal:
Energia Solar
/
Poluentes Químicos da Água
Idioma:
En
Revista:
Chemosphere
Ano de publicação:
2022
Tipo de documento:
Article