Ghosh Jyoti P, Langford Cooper H, Achari Gopal
Department of Civil Engineering, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4.
J Phys Chem A. 2008 Oct 16;112(41):10310-4. doi: 10.1021/jp804356w. Epub 2008 Sep 18.
A detailed performance evaluation of a simple high intensity LED based photoreactor exploiting a narrow wavelength range of the LED to match the spectrum of a dye in a photocatalysis system is reported. A dye sensitized (coumarin-343, lambda max = 446 nm) TiO 2 photocatalyst was used for the degradation of 4-chlorophenol (4-CP) in an aqueous medium using the 436 nm LED based photoreactor. The LED reactor performed competitively with a conventional multilamp reactor and sunlight in the degradation of 4-CP. Light intensities entering the reaction vessel were measured by conventional ferrioxalate actinometry. The results can be fitted by approximate first order kinetic behavior in this system. Hydroxyl radicals were detected by spin trapping EPR, and effects of OH radical quenchers on kinetics suggest that the reaction is initiated by these radicals or their equivalents. LEDs operating at competitive intensities offer a number of advantages to the photochemist or the environmental engineer via long life, efficient current to light conversion, narrow bandwidth, forward directed output, and direct current power for remote operation. Matching light source spectrum to chromophore is a key.
报道了一种基于简单高强度发光二极管（LED）的光反应器的详细性能评估，该反应器利用LED的窄波长范围来匹配光催化系统中染料的光谱。使用染料敏化（香豆素-343，最大吸收波长λmax = 446 nm）的TiO₂光催化剂，在基于436 nm LED的光反应器中，于水介质中降解4-氯苯酚（4-CP）。在4-CP的降解过程中，该LED反应器与传统多灯反应器及阳光相比具有竞争力。通过传统的草酸铁化学 actinometry测量进入反应容器的光强度。该系统中的结果可用近似一级动力学行为拟合。通过自旋捕获电子顺磁共振（EPR）检测到了羟基自由基，并且羟基自由基猝灭剂对动力学的影响表明该反应是由这些自由基或其等效物引发的。以具有竞争力的强度运行的LED通过长寿命、高效的电流到光转换、窄带宽、前向定向输出以及用于远程操作的直流电源，为光化学家或环境工程师提供了许多优势。使光源光谱与发色团匹配是关键。
