Photo‐activated periodate in homogeneous degradation and mineralization of quinoline: Optimization, kinetic, and energy consumption

Abstract

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 mg L−1 of the substrate were [KPI] = 695.5 mg L−1, pH = 4.3 and T = 35.6 °C. 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 kWh m−3. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1621–1627, 2017