Photoelectrocatalytic degradation of quinoline with a novel three-dimensional electrode-packed bed photocatalytic reactor

Photoelectrocatalytic degradation performance of quinoline in saline water was assessed with a newly designed continuous flow three-dimensional electrode-packed bed photocatalytic reactor. The efficiency of the three-dimensional electrode electrochemically assisted photocatalytic process was measured in terms of degradation and mineralization of quinoline. It was found that quinoline could be degraded more efficiently by photoelectrochemical process than by photocatalytic or electrochemical oxidation in saline water. The experimental results showed that oxidation of quinoline by photoelectrochemical process were well described with a pseudo first-order kinetics. The dependence of the rate constants on various parameters in the photoelectrocatalytic reactor, such as initial concentration of chloride ion, applied cell voltage, airflow and pH value were investigated in detail. Photoelectrocatalytic degradation of quinoline was more favorable in alkali solution than in acidic solution. It is also interesting to note that chloride ion had an obvious enhancement effect rather than a scavenging effect on the photoelectrocatalytic degradation of quinoline in saline water. A kinetic synergetic effect was observed with an enhancement of the rate constant by a factor of 3.7 compared to photoelectrocatalytic degradation of quinoline without addition of Cl- ion. (C) 2004 Elsevier B.V. All rights reserved.