Effects of Initial Nitrate Concentrations and Photocatalyst Dosages on Ammonium Ion in Synthetic Wastewater Treated by Photocatalytic Reduction
Ammonium (NH4+) is an undesirable by-product of photocatalytic nitrate (NO3−) reduction since it is harmful to aquatic life once it converts into ammonia (NH3). This research investigated the removal efficiency of NO3− and for the first time quantified the relationships of initial nitrate concentrat...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2020-01-01
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| Series: | International Journal of Photoenergy |
| Online Access: | http://dx.doi.org/10.1155/2020/8893816 |
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| Summary: | Ammonium (NH4+) is an undesirable by-product of photocatalytic nitrate (NO3−) reduction since it is harmful to aquatic life once it converts into ammonia (NH3). This research investigated the removal efficiency of NO3− and for the first time quantified the relationships of initial nitrate concentrations ([NO3−]0) and photocatalyst dosages on the remaining ammonium (NH4+) in synthetic wastewater using photocatalytic reduction process with either nanoparticle titanium dioxide (TiO2) or 1.0%Ag-TiO2 under Ultraviolet A (UVA). The experiments were systematically carried out under various combinations of [NO3−]0 (10, 25, 50, 80, and 100 mg-N/L) and photocatalyst dosages (0.1, 0.5, 1.0, and 2.0 g). The NO3− removal efficiency of both photocatalysts was 98.96-99.98%, and the catalytic selectivity products were nitrogen gas (N2), nitrite (NO2−), and NH4+. Of the two photocatalysts under comparable experimental conditions, 1.0%Ag-TiO2 provided better NO3− removal efficiency. For both photocatalysts, the remaining NH4+ was predominantly determined by [NO3−]0; higher [NO3−]0 led to higher NH4+. Multiple linear regression analysis confirmed the dominant role of [NO3−]0 in the remaining NH4+. The photocatalyst dosage could play an essential role in limiting NH4+ in the treated wastewater, with large variation in [NO3−]0 from different sources. |
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| ISSN: | 1110-662X 1687-529X |