Development of titanium dioxide composites for the removal of pesticides from water using photocatalysis
O'Dwyer, Ross
(2014)
Development of titanium dioxide composites for the removal of pesticides from water using photocatalysis.
PhD thesis, Dublin City University.
The EU Water Framework Directive (WFD) specifies that measures must be adopted against contamination of water by pollutants presenting a significant risk to the aquatic environment. Annex VIII of the directive provides an indicative list of the main pollutant types in water systems, where specific reference is made to “biocides and plant protection products”. Pesticides are widely used and have the potential to enter surface waters and cause harmful effects to both humans and the environment. This project focuses on the removal of two such pesticides (4-Chloro-2-methylphenoxy acetic acid (MCPA) and 2,4-Dichlorophenoxy acetic acid (2,4-D) from water using three different titanium dioxide (TiO2) composites. The first composite is based on activated carbon and TiO2 illuminated with UV light. The second composite is based on the combination of dyes (porphryrin/methylene blue) and TiO2 to enhance the photocatalytic properties of TiO2 under visible light. The third composite is composed of dolomite and TiO2. Overall, while the pesticide removal rates using each of the three composites do not show any improvement over existing technologies, there have been a number of interesting findings that indicate scope for further work, particularly in TiO2 photocatalysis analysis.