Study On The Photodegradation Of Benzophenone And Malachite Green Solution By 185nmUV Irradiation

In this dissertation, benzophenone and malachite green in water were degradated by using 185 nmUV irradiation.Comparing with the method of 254nmUV irradiation , we found that the concentration of benzophenone and malachite green in water and TOC(total organic carbon) level are much lower by using 185 nmUV irradiation, so it has better degradation effect. At the beginning of degradation process, the pH of the solution decreased, then became stable. During the degradation process of malachite green, Cl^-, NO₃^-, NH₄⁺ were engendered.By analysis of kinetic model, we speculated that this method conform with the law of (pseudo-) first order reaction and the experiment thereafter validated it. In the experiment, the influence of initial concentration Co, initial volume of solution V₀, velocity of flow Q, pH, H₂O₂, inorganic ions to degradation velocity constant k were studied. The result of the experiment show, the increase of Q and the addition of H₂O₂ are propitious to the degradation, and there is a optimum concentration of H₂O₂ (for example C_H2O2 =0.01mol/L). The increase of C₀ or V₀ and the existence of inorganicions are disincentive to the degradation.Using the method of GC-MS(gas chromatography-mass spectrometry) and ion chromatography, the intermediate products of degradation are studied and the possible path of the degradation is discussed. The study show, there are some poisonous phenols engendered during degradation, which has much higher reaction activity than benzophenone and malachite green. These phenols are easily oxidized by free radical of hydroxyl and become carboxylic acid, then finally be mineralized to be CO₂ and H₂O. Therefore, it is an effective and possible way to deal with the water polluted by benzophenone and malachite green by using 185nmUV irradiation.