Study On The Degradation Of Triclocarban Via UV And UV/H₂O₂

In recent years, pharmaceutical and personal care products are used more and more widely in our daily life. As they cannot be removed effectively by traditional wastewater treatment process, their concentrations in the environment are increasing. PPCPs have been detected in the underground water and interface water. Some researches show that PPCPs can be harmful to the water environment. So it is important to investigate the degradations of this pollutant in water. UV irradiation is one of the most important degradation ways for organic compounds in natural water. As one of the PPCPs, triclocarban(TCC) are widely used in antibacterial soaps and toothbrushes. This work aims to investigate the degradation of TCC under direct UV irradiation and UV-H2O2 processes. We also detected the effects of many factors on the degradation. And we predicted the possible ways of TCC photolysis.The degradation of TCC is more efficient under UV irradiation than that of simulated sunlight. And the reaction of TCC under UV fits the pseudo-first order kinetics. The initial concentration of TCC is important for the degradation and the rate constant increase at first and then decrease along with the initial concentration increase. The reaction rate constant increase with the initial p H values increase. Ti O2 additions promote the rate constant at low concentration and inhibit it at high concentration. We also find that the exists of Cl-、SO42- and NO3- inhibit the photolysis.We investigate the mechanism of TCC photolysis. The byproducts were detected by using UPLC-MS. We find that they are diverse under acidic condition and neutral and alkaline conditions. And we predict the possible mechanisms under different conditions. Cl- concentration and p H values of the reaction are detected and it can be seen that the Cl- concentration increased while the p H values decreased along with the reaction. The toxicity of the solution increase at first and decrease at last.The degradation of TCC under UV/H2O2 process was also investigated. It shows that moderate H2O2 addition can promote the degradation. And the reaction rate constant increase and then decrease along with the increase of initial p H values at first, and then decreased. The optimal initial p H value is p H=7. Exist of anions, such as Cl-, NO3-, SO42-, CO32- and HCO3-, and kations, namely Cu2+, Mg2+, Ca2+ and Fe3+, inhabit the degradation at a whole. HA additions promote the degradation at low concentration and inhibit it at high concentration.