The advantages of silver peroxide:
- Long term effectiveness.
- Effective even in low concentrations (disinfection will require a long time) .
- Effective in a wide range of temperatures up to the boiling point.
- Gentle to the skin.
- Biodegradable with the exception of silver-nitrate.
- No build-up of resistance by micro-organism.
- Colourless, odourless and tasteless.
The disadvantages of silver peroxide:
- Silver in the form of silver-nitrate (most toxic form of silver). Silver-nitrate is one of the most toxic forms of a heavy metal, surpassed only by mercury and thus has been assigned to the highest toxicity class, together with cadmium, chromium (VI), copper, and mercury
- Silver precipitates out in contact with chlorites (salts/minerals) – generally speaking cannot therefore be used with ground water.
- Restriction on use of silver in drinking water – in UK no longer allowed for continual dosage.
- Poor disinfection at temperatures of 10oC and lower.
- Slow disinfection at low dosage.
- Silver remains in system and/or environment.
- Cannot be used in contact with copper
SILVER PEROXIDE fulfils many of the requirements which are placed on disinfectants and is often superior to conventional products in its ability to eliminate bacteria, viruses, mould, fungi, amoeba, and spores as well as control biofilm.
SILVER PEROXIDE disinfects reliably all areas where reduction of germs and sterility are a prime necessity.
Composition and activity of Silver PeroxydeSilver-peroxide is a disinfectant based mainly on hydrogen peroxide. Silver-peroxides are a combination of silver-nitrate, hydrogen peroxide and numerous other components all of which are kept highly secret by the various manufacturers. The reason for this is that there is no patent on silver-peroxide so that they have to kept the formula secret or else everybody would be making it…. So although most manufacturers claim their products to be a combination of silver-nitrate and hydrogen peroxide, there may be 5, 10 or even 20 other substances present.
The other substances are necessary to keep the formulation stable. A combination of only silver-nitrate plus hydrogen peroxide is not stable for any length of time nor does it have the disinfecting ability nor the stability associated with the major silver-peroxides available on the market.
Depending on the manufacturer the silver content varies between 36 g/l to twice that amount or more. It is a colourless and odourless liquid that – in contrast with most traditional disinfectants – doesn’t contain halogens or quaternary ammonium compounds.
What’s so special about Silver peroxide?The main difference between silver- peroxide and ordinary hydrogen peroxide lies in the presence of the silver-nitrate which has a bactericidal action of its own.
Silver-nitrate as ‘activator’:The silver-nitrate also performs as an activator. The singularity of this silver activator is that it only activates the hydrogen peroxide when it is exposed to pollution (organic material…). Under the influence of the silver the hydrogen peroxide becomes strongly activated in contact with organic material. In contact with organic material the silver starts to activate the hydrogen peroxide (kinetic energy). The capacity of the silver to activate the hydrogen peroxide is preserved until the hydrogen peroxide comes into contact with the organic material/micro-organism, following this any un-used hydrogen peroxide deactivates and returns to a stabilised situation
In this respect this activator differs from all the others (metals, UV-radiation, alkali…) which activate hydrogen peroxide but do not return it to a stable situation as does silver-peroxide. Eventually all present hydrogen peroxide will react or lose their stability, so that only water, oxygen and silver-nitrate remains after the reaction.
Microbial activity of Silver peroxideJust as with normally activated hydrogen peroxide all sorts of active oxygen compounds are formed (radicals, anions, ...). But because of the interaction forces between the silver activator and the hydrogen peroxide molecules the formed radicals and anions possess a high kinetic energy. This enables them to penetrate the cell wall easier, so that the internal oxidation of the microbial cell can occur much more efficiently.
Therefore silver peroxide disinfects much better then ordinary hydrogen peroxide. Compared with ordinary hydrogen peroxide one needs less silver peroxide to obtain the same result!
Oxidation of microbial cell by silver peroxide
What remains after the reaction?
The activation of the hydrogen peroxide stops when all the organic
material is oxidised. At the end of the oxidative reaction the non-reacted hydrogen peroxide remains stabilised (H2O2). On the other hand the reacted hydrogen peroxide which is converted in active oxygen decomposes in water (H2O) and oxygen (O2) after the oxidation of the organic material. Silver-nitrate does not break down and therefore remains in the environment.
In contrast with normally activated hydrogen peroxide the reaction isn’t irreversible so that only the hydrogen peroxide, required for the complete oxidation of the present organic material, is broken down. The residual non-reacted hydrogen peroxide remains stabilised and preserved in association with the silver-nitrate.
Because of the depot action an excellent disinfection can be assured during a long period, if dosed correctly.
Overview of the reaction of Silver peroxide with organic material
H2O2: non reacted, stabilised hydrogen peroxide
H2O2: hydrogen peroxide that has reacted with organic material
After the reaction has taken place, the residuals are: O2, H2O and silver-nitrate.