TPPS(4)—Sensitized Photooxidation of Micropollutants—Singlet Molecular Oxygen Kinetic Study

Visible light-sensitized oxidation of micropollutants (MPs) in the presence of meso-tetrakis(4-sulfonatophenyl)porphyrin photosensitizers was studied. In order to explore the role of type I (ROS generation) or type II (singlet oxygen) photooxidation, radical scavengers were used to obtain insight into the mechanism of photodegradation. It was revealed that singlet oxygen is the main ROS taking part in TPPS(4)- sensitized photooxidation of micropollutants. The interaction of MPs with (1)O(2) in deuterium oxide (D(2)O) was investigated by measuring the phosphorescence lifetime of (1)O(2). The rate constant (kq) for the total (physical and chemical) quenching of (1)O(2) by MPs was determined in a D(2)O buffer (pD 7, 9 and 10.8). The rate constants of singlet oxygen quenching and reaction with MPs were determined, and the rate constant of excited TPPS(4) quenching by MPs was also estimated.