Elimination at source of biocidal agents from fresh water environments by TiO2 photocatalysis

Project Description

Herbicides and pesticides (i.e. biocides) are widely used world-wide. Many biocidal agents are persistent in the freshwater environment and are on the EU watchlist for priority and priority hazardous substances, as well as the Scottish Environmental Protection Agencies risk matrix for contaminants in surface waters. Several biocidal agents have been shown to have adverse health effects in humans including carcinogenic properties, birth defects, and disruption of the endocrine system. Therefore, the development of a system for the source management of these compounds is timely and pressing. Photocatalytic degradation of biocidal agents is well established in the scientific literature, mostly by the application of titanium dioxide (TiO2) photocatalysis. TiO2 is a non-toxic, abundant chemical that has many applications including in the food and cosmetics industries. Photocatalytic activity results in the creation of short-lived high energy hydroxyl radicals upon the input of UV irradiation resulting in the subsequent oxidation of pollutants. To date, TiO2 photocatalytic treatment has not been not widely employed due to limitations such as catalyst removal and energy costs. The requirement of energy input in the form of near UV light has been a barrier to deployment until the recent advent of water submersible UV-light emitting diodes (UV-LEDs ; 367 nm).