The main objective of this work is to present a novel approach to evaluate quantitatively the action spectra and energy efficiency for chemical oxidation and bacterial inactivation of photocatalytic processes using monochromatic LED sources. Two different catalysts with different absorption spectra (TiO₂ and iron citrate complex) were used. In all cases, it was confirmed a direct relationship between the absorption spectrum of the catalyst and the spectral dependence of the photonic efficiency. The best alternative for TiO₂ processes in terms of energy consumption when using artificial lighting is the use of 365 nm. In contrast, for iron complexes it seems more economically feasible the use of longer wavelengths close to the visible range, because the lower absorption of the complex is counterbalanced by the higher energy efficiency of the LED devices. This can be obviously extrapolated to the use of sunlight, where the use of iron-based photocatalytic processes can harvest a higher fraction of the available light. Predictions of the process efficiency under solar irradiation based on the action spectra determined with LED at laboratory scale have been successfully validated by experimental data. The methodology proposed in this work could be easily extrapolated to other wavelength ranges required by novel catalysts or efficient short wavelength monochromatic LED sources available in the future.

中文翻译：

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光催化水处理效率的波长依赖性

这项工作的主要目的是提出一种新颖的方法，以定量评估使用单色LED光源进行光催化过程的化学氧化和细菌灭活的作用谱和能量效率。使用了两种具有不同吸收光谱的催化剂（TiO ₂和柠檬酸铁络合物）。在所有情况下，都证实了催化剂的吸收光谱与光子效率的光谱依赖性之间存在直接关系。TiO ₂的最佳替代品在使用人造照明时，在能耗方面的过程是使用365 nm。相反，对于铁配合物，使用更接近可见范围的更长波长在经济上似乎是可行的，因为配合物的较低吸收被LED装置的更高能量效率所抵消。显然，这可以推断为使用太阳光，在这种情况下，使用铁基光催化工艺可以收获更多的可用光。实验数据已成功验证了基于LED在实验室规模下确定的作用谱对太阳辐照下工艺效率的预测。