·OH Radicals
It is not a biocide. It is not UV radiation. They’re ·OH radicals.
Titanium Dioxide – Why?
In a process known as advanced oxidative photocatalysis (AOP), h2o.TITANIUM reactors are the simplest, cheapest and most reliable way to produce OH radicals.
OH radicals are extremely unstable and reactive. They are the molecule with the highest redox power among the oxidising agents on the water treatment market. They are distinguished by:
- Highest oxidising power (2.8 eV)
- Highest oxidation rate: up to one billion times faster than ozone.
- Very short estimated lifetime: milli or nanoseconds (depending on authors).
Titanium Dioxide – Scientific Basis?
To remove organic matter contained in water by oxidising agents obeys a process depending on the capacity of the oxidising agent to subtract electrons from the bonds making up the molecules to be destroyed.
If they have it, they can break each and every one of the bonds of the polluting molecules, which, oxidised, will have been transformed into CO2 and H2O. This is called mineralisation.
The redox potential of the agent defines its oxidative capacity. If it is not sufficient, the amount of oxidising agent does not matter, as the redox potential does not increase with their concentration.
Since its redox potential is the maximum, what cannot be oxidised (removed) by the OH radicals cannot be oxidised by any other oxidising agent.
The extremely short OH radical lifetime means two things. One, no residual effect is possible. Two, everything happens inside, and only inside, the reactor. And at such a rate that it is impossible to quantify.
Titanium dioxide is what is known as a broadband semiconductor. When irradiated, at the right wavelength, it is activated (electron excitation – electronic bandgap shift). This triggers the generation of the OH radical. See the scientific article in the image below for more details.
However, there has been a wealth of scientific info on this subject for many years (Lawrence K., Norman C., Hung, 2005, for example).
Titanium Dioxide – what makes us different?
- A single block of titanium dioxide – not just a coating. No possibility of titanium dioxide release.
- Unlimited life – The reactor acts as a heterogeneous catalyst; it is unalterable.
- Sustainability – No need to use chemicals. Does not produce by-products.
- Simplicity of design, installation, use and control.
- Reliability of the result.
- Minimal OPEX costs.
- Low energy consumption – 15-20 W/m3 treated water.
- WRAS certificated.
Alternative Technology Table
| FACTORS / CONSIDERATIONS | OH* RADICAL | TRADITIONAL UV | OZONE |
|---|---|---|---|
| Changes in pH | Does not affect | Does not affect | Little effect |
| High turbidity or TSS | Does not affect | Makes it ineffective | More demand for O3 |
| Temperature decrease | Does not affect | Does not affect | Reduces efficiency |
| Ammonia and organic products | Reduce / Eliminate | Makes it ineffective | More demand for O3 |
| Health effects | None | None | None <limit |
| Effects on taste and odor | Gets better | None | Gets better |
| Undesirable by-products | None | None | Bromates and aldehydes |
| PH requirements | 4<pH<11 | None | 6<pH<9.5 |
| Turbidity requirements | None | <1 UTN | <1 UTN |
| Temperature requirements | 0 C – 60 C | 0 C – 60 C | Better at high T |
| Introduced substances | None | None | 03. oxygen or air |
| Effect on microorganisms | Death | Possible reactivation | Death |
| Instalation and maintenance | Simple | Simple | Complex |
| Civil work | No | High flow rates | Sometimes |
| Space required | Reduced | Moderate | High |
Technical and economic research on wastewater disinfection by oxidation. Higher Technical School of Civil Engineering. Gerardo Enrique Gordillo de Coss.
“The processes for the generation of -OH radicals are not few and their basis can be remarkably different. Those based on the combination of TiO2 and UV radiation are based on the excitation of electrons in the valence layer of the catalyst by the aforementioned radiation. This shift of electrons to a higher band is the origin of the catalytic action”.
Titanium Dioxide Technology
Innovation award in the food industry for its breakthrough in water reuse. Our h2o.TITANIUM technology received the Innovation Award from the Agrupación de Cooperativas del Valle del Jerte of Agroalimentary Cooperatives of Spain.