Solutions for singlet molecular oxygen production
In an effort to improve social and environmental measures in developing countries, an on site assessment of an autonomous solar reactor system for drinking water purification has been created. The scientific and technological developments were based on photocatalytic generation of hydroxyl radicals and singlet oxygen species via the use of sunlight and without adding chemicals. Singlet molecular oxygen is a reactive oxygen type which can be used in applications such as organic synthesis, dye bleaching, disinfection processes and photodynamic therapy. Its advantage is that it can be expeditiously rendered by quenching of the excited state of a sensitiser by ground state molecular oxygen. Furthermore, it can be easily removed at the end of the process. Conducting a precise quantification of the singlet oxygen production is key in order to create the most suitable method for each application. This entails measuring the singlet oxygen production quantum yields (PHIdelta), a process that has not been fully established in heterogeneous systems. What has been proposed therefore is methylene blue (MB) dyed Nafion films as a means to quantify singlet oxygen production in solid samples. The production of singlet oxygen generated by MB photosensitisation in films of Nafion ionomer was characterised and results were compared. Following this it was found that Nafion films containing MB are homogeneous, reproducible and stable systems which make for appropriate references for PHIdelta determination in solid phase.
