Centro de Química - Vila Real, Escola de Ciências da Vida e do Ambiente, Universidade de Trás-os-Montes e Alto Douro, 5000-801, Vila Real, Portugal.
Centro de Química - Vila Real, Escola de Ciências e Tecnologia, Universidade de Trás-os-Montes e Alto Douro, 5000-801, Vila Real, Portugal.
J Environ Manage. 2020 Sep 1;269:110740. doi: 10.1016/j.jenvman.2020.110740. Epub 2020 May 16.
An ultraviolet light emitting diode (UV-A LED) system was built to test the capability of performing heterogeneous photocatalysis using TiO P25. The LEDs maximum wavelength is 365 nm with an irradiance power of 85 W m. The device was tested in batch and continuous (CSTR) mode in a laboratorial scale reactor. The degradation of an agro-industrial wastewater model compound (p-hydroxybenzoic acid, pHBA) was investigated, assessing the effect of different experimental conditions such as pH, pHBA and TiO concentration keeping constant the UV-A LEDs power and temperature. The photodegradation of different concentrations of pHBA with [TiO] = 500 mg L, I = 85 W m and a T = 21 °C were analysed by pseudo-first order kinetics. The results were applied to the Langmuir-Hinshelwood model yielding k = 0.885 mg L min and k = 0.217 L mg. In a comparative experiment the UV-A LEDs system showed faster kinetics (k = 0.0134 min) than solar radiation (I = 23 W m; k = 0.0077 min), with [pHBA] = 75 mg L and [TiO] = 500 mg L. The values of the Electric Energy per Order (E) = 115 kWh m order and the Specific Applied Energy (E) = 318 kWh mol order were obtained with [TiO] = 1000 mg L and [pHBA] = 50 mg L. Analogous results were obtained ([TiO] = 500 mg L) in a CSTR with a slight decrease in the first order kinetic constant due to the "non-ideal" reactor: from 0.0284 to 0.0158 min and from 0.0143 to 0.00825 min with [pHBA] = 50 mg L and 75 mg L, respectively. This work shows that photocatalytic reactors with UV-A LEDs can advantageously replace conventional UV mercury lamps based reactors in the photodegradation of phenolic compounds.
构建了一个紫外发光二极管（UV-A LED）系统，以测试使用 TiO P25 进行非均相光催化的能力。LED 的最大波长为 365nm，辐照度功率为 85W m。该设备在实验室规模的反应器中以批处理和连续（CSTR）模式进行了测试。研究了一种农业工业废水模型化合物（对羟基苯甲酸，pHBA）的降解，评估了不同实验条件的影响，例如保持 UV-A LED 功率和温度恒定的 pH、pHBA 和 TiO 浓度。在 [TiO] = 500mg L、I = 85W m 和 T = 21°C 的条件下，用假一级动力学分析了不同浓度的 pHBA 的光降解。结果应用于 Langmuir-Hinshelwood 模型，得到 k = 0.885mg L min 和 k = 0.217L mg。在对比实验中，UV-A LED 系统显示出比太阳辐射（I = 23W m；k = 0.0077 min）更快的动力学（k = 0.0134 min），[pHBA] = 75mg L 和 [TiO] = 500mg L。在 [TiO] = 1000mg L 和 [pHBA] = 50mg L 时，获得了每阶电量（E）= 115kWh m 阶和每摩尔阶特定应用电量（E）= 318kWh mol 阶的值。在 CSTR 中获得了类似的结果（[TiO] = 500mg L），由于“非理想”反应器，一级动力学常数略有下降：[pHBA]分别为 50mg L 和 75mg L 时，从 0.0284 降至 0.0158 min，从 0.0143 降至 0.00825 min。这项工作表明，在酚类化合物的光降解中，UV-A LED 光催化反应器可以有利地替代传统的基于汞灯的 UV 反应器。
