Ammonium () is an undesirable by-product of photocatalytic nitrate () reduction since it is harmful to aquatic life once it converts into ammonia (NH₃). This research investigated the removal efficiency of and for the first time quantified the relationships of initial nitrate concentrations ([]₀) and photocatalyst dosages on the remaining ammonium () 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 []₀ (10, 25, 50, 80, and 100 mg-N/L) and photocatalyst dosages (0.1, 0.5, 1.0, and 2.0 g). The removal efficiency of both photocatalysts was 98.96-99.98%, and the catalytic selectivity products were nitrogen gas (N₂), nitrite (), and . Of the two photocatalysts under comparable experimental conditions, 1.0%Ag-TiO₂ provided better removal efficiency. For both photocatalysts, the remaining was predominantly determined by []₀; higher []₀ led to higher . Multiple linear regression analysis confirmed the dominant role of []₀ in the remaining . The photocatalyst dosage could play an essential role in limiting in the treated wastewater, with large variation in []₀ from different sources.

中文翻译：

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初始硝酸盐浓度和光催化剂剂量对光催化还原处理合成废水中铵离子的影响

铵（）是光催化硝酸盐（）还原过程中不希望出现的副产物，因为一旦铵转化为氨（NH ₃）会对水生生物造成危害。这项研究调查了纳米颗粒二氧化钛（TiO ₂）或光催化还原工艺在合成废水中的初始硝酸盐浓度（[ ] ₀）和光催化剂剂量对合成废水中其余铵（）的去除效率，并首次进行了定量关系。在紫外线A（UVA）下为1.0％Ag-TiO ₂。实验是在[ ] _0的各种组合下系统地进行的（10、25、50、80和100 mg-N / L）和光催化剂剂量（0.1、0.5、1.0和2.0 g）。两种光催化剂的去除效率均为98.96-99.98％，催化选择性产物为氮气（N ₂），亚硝酸盐（）和。在可比较的实验条件下的两种光催化剂中，1.0％Ag-TiO ₂提供了更好的去除效率。对于这两种光催化剂，其余的主要由[ ] ₀确定。较高[ ] ₀导致较高。多元线性回归分析证实了[ ] ₀在其余的中的主导作用。光催化剂的用量在限制处理后的废水中起着至关重要的作用，不同来源的[ ] ₀变化很大。