Design And Performance Of A Tube Photocatalytic Reactor For The Photocatalytic Degradation Of Tetracycline Wastewater

Antibiotics is a kind of drug for infectious disease control and the treatment of animal and plant diseases and insect pests, due to the irrational use of antibiotics has caused the ecological environment and human health of the larger negative impact. Photocatalysis as one of advanced oxidation technologies can decompose refractory organic pollutants into CO₂, H₂ O and inorganic ions, which has a wide application prospect in the treatment of antibiotic wastewater because of its strong oxidation ability and clean process. However, the utilization of photocatalytic technology still faced some problems that restrict its potential development and application space. For example, it is difficult to separate powdered photocatalyst and wastewater, and photocatalytic reactor has many disadvantages such as low catalytic efficiency, high operating costs, equipment complexity. The purpose of this study is to prepare a new supported catalyst which can be effectively recovered and to develop a new photocatalytic reactor which has simple structure and high photocatalytic efficiency, so as to realize the industrialization application of photocatalytic reactor. And researches were carried out in three aspects:1. Bi₂WO₆ loaded scoria（BWO@S） was synthesized via a facile one-step hydrothermal route. The prepared samples were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）. The results indicate that the flower-like Bi₂WO₆ was loaded evenly on the surface of the scoria and exhibited highly responsive to visible light. In addition, the effects of granule size of scoria, loading times and reusing times on the performance of BWO@S were investigated by the photo-degradation of tetracycline hydrochloride（TCH）. The results indicated that the photocatalyst supported on 2 mm sized scoria and loading 3 times exhibit the greatest photocatalytic activity after repeated 4 times, which prove that the photocatalyst has good stability.2. With the integrated advisement about design element of photo-reactor,we designed a new tube photocatalytic reactor that can be all-weather operation. The reactor adopted compound parabolic concentrator as solar collecting component in order to improve the solar energy utilization ratio, and supported photocatalyst was filled in quartz tube so as to tackle the problem of separation, and high luminous efficiency and long life LED lamps were used as the auxiliary light source and gained power supply from the solar energy photovoltaic power generation system, which improves the efficiency of process and reduces the operation cost of the reactor.3. The photo-degradation of tetracycline hydrochloride were carried out in the tube photocatalytic reactor in order to investigate the effects of catalyst amount, light intensity, contaminant concentration, hydraulic retention time and oxidant amount on the performance of reactor. The results of the degradation of TCH（50 mg/L） showed that the photodegradation rate was 98.7% under the optimal condition of the catalyst dosage was 40 g/L, the light intensity was 6.55⁹.95×104 Lux, the H₂O₂ concentration was 180 mg/L, and the hydraulic retention time was 70 min. Hence, it determined that the photocatalytic reactor showed great photodegradation for tetracycline hydrochloride.