Uv sterilization

[Cory]

Half time of hydrogen peroxide in seawater is 12-120 h, according to Millero, who also says it ranges from 10 -200 nM and generally correlates with organic matter (more organics yields more hydrogen peroxide). Some is made by UV reacting with organics, and some by metals reacting with UV.

From another thread you said that. I was wondering do uv sterilizers also produce hydrogen peroxide?

 

[Snoopdog]

For living organisms, it basically destroys there ability to reproduce.

Like a vasectomy but without all tedious consults, anesthesia and laying on your a$s for three days.

 

[Randy Holmes-Farley]

So would damaged dna be able to repair in an hour?

Too hard to answer. It is an ongoing repair process. Whether organisms can recover, and how long that takes, will depend on exactly how badly they were damaged to begin with.

 

[Randy Holmes-Farley]

From another thread you said that. I was wondering do uv sterilizers also produce hydrogen peroxide?

They can, yes. Whether that is an important part of the process, i do not know.

 

[Cory]

Is a uv sterilizer destroying hydrogen peroxide I dose? It seems to be significantly less effective when i dose it with the uv on.

 

[Randy Holmes-Farley]

Is a uv sterilizer destroying hydrogen peroxide I dose? It seems to be significantly less effective when i dose it with the uv on.

It may, yes:

http://newfrontchem.iqstorm.ro/upload/10-NFC-23-2_Cataldo.pdf

" An alternative way to decompose diluted H2O2 involves the use of a UV light source [16]. The process of H2O2 decomposition can be generally described by the simple reaction scheme H2O2  2 •OH, but in reality is much more complex and characterized by a quantum yields approximately ≈ 1.0-1.5 in a wide range of wavelengths used for irradiation spanning from 193 nm to the canonical 254 nm to the UV-A represented by 308 and 354 nm [16-27] "

 

[Cory]

Ive read multiple posts about people mentioning that adding hydrogen peroxide does something good with uv sterilizers. I know @Lasse mentioned it. Whats it doing?

 

[Randy Holmes-Farley]

I don’t know if it is “good” but that paper suggests it breaks the hydrogen peroxide into hydroxyl radicals that are very reactive.

 

[Lasse]

Ive read multiple posts about people mentioning that adding hydrogen peroxide does something good with uv sterilizers. I know @Lasse mentioned it. Whats it doing?

I don’t know if it is “good” but that paper suggests it breaks the hydrogen peroxide into hydroxyl radicals that are very reactive.

IMO - That´s true - at least with some type of UVC technique (low pressure and mercury/amalgam tubes) However is unclear if it is the real UVC (254 nm ) wavelength that catalyst the H2O2. - These tubes also emit some ozon ( 185 nm ) and ozone have a known affect in the catalyst of H2O2. I worked together with one of Sweden's leading experts in this combined method and I could never have him to confirm this. However - he never denied it either. However - they only worked with low pressure mercury/amalgam technique.

Sincerely Lasse

 

[Cory]

I don’t know if it is “good” but that paper suggests it breaks the hydrogen peroxide into hydroxyl radicals that are very reactive.

What do hydroxyl radicals do in our tanks? Ive noticed when i put peroxide directly into tbe uv bubbles come out.

 

[Cory]

IMO - That´s true - at least with some type of UVC technique (low pressure and mercury/amalgam tubes) However is unclear if it is the real UVC (254 nm ) wavelength that catalyst the H2O2. - These tubes also emit some ozon ( 185 nm ) and ozone have a known affect in the catalyst of H2O2. I worked together with one of Sweden's leading experts in this combined method and I could never have him to confirm this. However - he never denied it either. However - they only worked with low pressure mercury/amalgam technique.

Sincerely Lasse

What was the purpose of this job? What were you trying to do?

 

[Lasse]

UVP-system - Raydar AB

UV-light and hydrogen peroxide produce clean, clear, odourless water. The UVP-system is a combination of adding hydrogen peroxide to bath […]

www.raydar.se

Sincerely Lasse

 

[Cory]

UVP-system - Raydar AB

UV-light and hydrogen peroxide produce clean, clear, odourless water. The UVP-system is a combination of adding hydrogen peroxide to bath […]

www.raydar.se

Sincerely Lasse

Nice, thank you for the link. Now thats a uv sterilizer lol! Uvp sounds interesting
If im dosing it directly to the uv, im not harming the tank with h202 but decomposing it instantly with uv radiation. Possibly creating hydroxyl radicals as Randy pointed out. But what are they? Good or bad? Sounds like ozone almost.

I thought this was interesting

 

[Cory]

Application of UV and UV/H2O2 to seawater: Disinfection and natural organic matter removal



Abstract
Application of new disinfection technologies for marine waters has been investigated recently, mainly ozone and UV. This study proposes to compare UV performances to an AOP, UV/H 2 O 2 , for seawater disinfection and natural organic matter removal. Those processes present the interest in avoiding the formation of disinfection by-products such as bromate and trihalomethanes. For the doses applied, UV and UV/H 2 O 2 achieved full disinfection. Organic matter degradation was greatly improved by H 2 O 2 addition achieving absorbance reduction and biodegradability increase. Mineralization was very poor (less than 10%). Oxidant efficiency decreases with the increase of hydrogen peroxide consumption. Bromide oxidation by-products were not observed. No residual oxidant, no bromate and no disinfection by-products were formed. Those observations are consistent with the theory and suggest a real interest of UV/H 2 O 2 for seawater treatment in specific areas where organic matter degradation has to deal with the control of toxic by-products generation (marine aquaculture, aquarium).

 

[Cory]

Do hydroxyl radicals destroy plastic like ozone does?