Modeling UV photocatalysis of organic contaminants on titanium dioxide

摘要

Photocatalytic degradation using UV activated titanium dioxide (TiO_2) is one of the key technologies for the cleanup of hazardous wastes. The photocatalytic process has several advantages including: (1) capable of degrading a wide variety of contaminants; (2) destruct contaminants to innocuous end products; (3) immune to contaminants toxicity; (4) fast reaction rate; (5) ease of process. The principle of photocatalytic degradation is based on the activation of TiO_2 surface using near ultraviolet (UV) light (1 < 365 nm). When TiO_2 particles are illuminated by UV, electron and hole pairs are generated. In aqueous soltion, the holes can be scavenged by hydroxide ions (OH~-) to form hydroxyl free radical (OH). The free radicals are strong oxidizing agent capable of triggering the degradation the degradation of organic and inorganic contaminants~1. Previous studies have shown that many hazardous organic compounds including halogenated organic compounds (HOCs) can be mineralized to innocuous end products.~(2, 3)