Effect of precursor type on the reduction of concentrated nitrate using zero-valent copper and sodium borohydride
In this study, we demonstrated that the choice of precursor has a strong effect on the reduction of nitrate (NO3-) using zero-valent copper (Cu0) synthesized by sodium borohydride (NaBH4). Different precursors: CuSO4, CuO, Cu2O, Cu powder, and Cu mesh were used to reduce NO3- at 677 mg-N/L under the...
| Publié dans: | Water science and technology : a journal of the International Association on Water Pollution Research. - 1986. - 77(2018), 1-2 vom: 23. Jan., Seite 114-122 |
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| Auteur principal: | |
| Autres auteurs: | , , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2018
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| Accès à la collection: | Water science and technology : a journal of the International Association on Water Pollution Research |
| Sujets: | Journal Article Borohydrides Nitrates Nitrites Nitrogen Oxides Water Pollutants, Chemical Copper 789U1901C5 sodium borohydride 87L0B9CPPA |
| Résumé: | In this study, we demonstrated that the choice of precursor has a strong effect on the reduction of nitrate (NO3-) using zero-valent copper (Cu0) synthesized by sodium borohydride (NaBH4). Different precursors: CuSO4, CuO, Cu2O, Cu powder, and Cu mesh were used to reduce NO3- at 677 mg-N/L under the reducing conditions of NaBH4. Compared with the prehydrolyzed samples, those prepared without prehydrolysis exhibited lower reduction rates, longer times and higher concentrations of nitrite (NO2-) intermediate. It was found that one-time addition of NaBH4 resulted in higher reduction rate and less NO2- intermediate than two-step addition. Results showed that Cu0 from CuSO4 possessed the smallest particle size (890.9 nm), highest surface area (26.0 m2/g), and highest reaction rate (0.166 min-1). Values of pseudo-first-order constant (kobs) were in the order: CuSO4 > CuO > Cu2O > Cu powder >Cu mesh. However, values of surface area-normalized reaction rate (kSA) were approximately equal. It was proposed that NO3- was reduced to NO2- on Cu0, and then converted to NH4+ and N2, respectively; H2 generated from both NaBH4 hydration and Cu (II) reduction contributed to NO3- reduction as well |
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| Description: | Date Completed 26.04.2018 Date Revised 02.12.2018 published: Print Citation Status MEDLINE |
| ISSN: | 0273-1223 |
| DOI: | 10.2166/wst.2017.525 |