Photo-activated Periodate in Homogeneous Degradation and Mineralization of Quinoline: Optimization, Kinetic, and Energy Consumption

摘要

Aqueous solutions of quinoline (Qu) were treated with photo-activated potassium periodate (UV/KPI) process. A low consumption, cylindrical photo-reactor was employed for this purpose. Either KPI oxidant or UV irradiation alone had little effect in Qu degradation; however, the combined UV/KPI process leads to significant degradation and mineralization. Experiments were conducted based on central composite design (CCD) methodology. The established optimized conditions for treatment of 40 mgL~(-1) of the substrate were [KPI]= 695.5 mgL~(-1), pH= 4.3 and T = 35.6 ℃. Under these conditions, 96.5% degradation and 71.5% mineralization were obtained after 70 min operations. A quadratic equation predicts the variation of degradation efficiency as a function of the influencing parameters. To investigate about the involved species, tert-butyl alcohol was used as radical scavenger and it was found that the contribution of hydroxyl radical was about 73.1%. Kinetic study revealed that Qu degradation was a pseudo first-order reaction and the corresponding activation energy was determined. Meanwhile, the required irradiation energy for one order of magnitude degradation was estimated as 3-13 kWbm~(-3).