There are several processes for generating .OH radicals but their fundamentals can have significant differences. Those based on the combination of TiO2 and UV radiation take theirs from the excitement of electrons in the layer of valence of the catalyser thanks to the aforementioned radiation. This movement of electrons to a higher band is the origin of the catalysing reaction.
Like all radicals, the hidroxyl radical (.OH) is a molecule with an unpaired electron. Its urgency to recombine is the basis of its 3 intrinsic characteristics.
Firstly, a redox potential (2.8 EV*) which allows it to break down covalent organic links eliminating all undesirable water borne organic material breaking it down into simple CO2 and water (the process known as mineralisation).
Secondly, an extremely high reaction speed (109 to 1012 times that of ozone)
Thirdly, a life measured in nanoseconds, after which the radical returns to a water molecule.
*Source : Handbook of environmental engineering vol.4 (Lawrence K.,Norman C; Hung,2005)
In recent years, laboratory research has shown many positive results many of which have been published. However, it seemed impossible to develop a single technology with a sufficiently viable cost/efficiency ratio to be feasible in such a competitive market.
In 2005 the solution emerged from technological development which resulted in reactors known today as “h2otitanium” – Mono-bloc units which act as a TiO2 heterogeneous catalyser, able to generate enormous amounts of hydroxyl radicals, more simply and with a far higher reliability than any other method of producing them.
The elimination of organic material usually also results in clarification, odour removal , etc.. This, in turn, brings tertiary effects such as the possibility of reducing concentrations of necessary chemicals such as de-flocculants, flocculants, biocides etc.. Our generation of hydroxyl radicals (.OH) also allows us to oxidise ammonia and control concentrations of nitrates and nitrites in aquariums. Thus the mineralisation of all organic material in the water gives an indirect boost to its disinfection.