Ochuma Idoko J, Fishwick Robert P, Wood Joseph, Winterbottom J Mike
School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
J Hazard Mater. 2007 Jun 18;144(3):627-33. doi: 10.1016/j.jhazmat.2007.01.086. Epub 2007 Jan 30.
The heterogeneous photocatalytic oxidation of aqueous solutions of 2,4,6-trichlorophenol (2,4,6-TCP) as a model pollutant in industrial wastewater has been carried out in a pilot scale cocurrent downflow contactor reactor (CDCR). The reactions were carried out in the presence of Ultra-Violet radiation, O(2) and TiO(2) photocatalyst (VP Aeroperl P25/20). The TiO(2) was characterized by Dynamic Vapour Sorption (DVS) technique giving specific surface area and surface energy of 46.06 m(2)g(-1) and 80.12 mJ m(-2), respectively. The CDC reactor was fitted with an internally and vertically mounted 1.0 kW or 2.0 kW UV lamp. The reactions were carried out at 50 degrees C and 1 bar, with the reactor being operated in closed loop recycle mode and suspended photocatalyst being re-circulated. The CDC reactor, a device of very high mass transfer efficiency giving unusually large gas hold-up of approximately 50%, was operated with oxygen mass transfer and dissolution in the zone above the UV lamp (high mass transfer zone) and along and around the UV lamp housing (reaction zone). Under optimized reaction conditions, 100% conversion of 2,4,6-TCP was achieved in 180 min using 15 dm(3) solutions with initial concentration of 120 mg dm(-3). A combination of TiO(2) photocatalyst, UV irradiation and oxidant was observed to give the most rapid photodegradation and photomineralization of the 2,4,6-TCP in comparison with irradiation only. Using the 1 kW or 2 kW UV lamps, conversion of 100 mg dm(-3) of 2,4,6-TCP after 30 min was 62.51% and 90.71%, respectively, with initial reaction rates of 1.33 x 10(-5) and 4.22 x 10(-5) mol min(-1), respectively, and rate constants 0.0046 and 0.29 min(-1), respectively.
在中试规模的并流向下流动接触器反应器（CDCR）中，对作为工业废水中典型污染物的2,4,6 - 三氯苯酚（2,4,6 - TCP）水溶液进行了多相光催化氧化。反应在紫外线辐射、氧气和二氧化钛光催化剂（VP Aeroperl P25/20）存在的条件下进行。通过动态蒸汽吸附（DVS）技术对二氧化钛进行表征，其比表面积和表面能分别为46.06 m²g⁻¹和80.12 mJ m⁻²。CDCR反应器内部垂直安装了1.0千瓦或2.0千瓦的紫外线灯。反应在50℃和1巴的条件下进行，反应器以闭环循环模式运行，悬浮的光催化剂进行再循环。CDCR反应器是一种传质效率非常高的装置，气体滞留率异常大，约为50%，在紫外线灯上方区域（高传质区）以及紫外线灯外壳周围（反应区）进行氧气的传质和溶解。在优化的反应条件下，使用初始浓度为120 mg dm⁻³的15 dm³溶液，180分钟内2,4,6 - TCP的转化率达到100%。与仅辐照相比，观察到二氧化钛光催化剂、紫外线照射和氧化剂的组合能使2,4,6 - TCP实现最快的光降解和光矿化。使用1千瓦或2千瓦的紫外线灯时，30分钟后100 mg dm⁻³的2,4,6 - TCP转化率分别为62.51%和90.71%，初始反应速率分别为1.33×10⁻⁵和4.22×10⁻⁵ mol min⁻¹，速率常数分别为0.0046和0.29 min⁻¹。
