Photocatalytic Titanium Dioxide - is it for real?

[Raygun99]

@Shamozzle

Isn’t titanium dioxide also used as a food ingredient? I recall seeing it listed in some sour gumballs I used to eat when I was a kid.

It’s a common ingredient in coffee whitener.

[Necros]

This would be an example of what I am talking about:

SteriPEN Adventurer Water Purifier | REI Co-op

It does not appear to be substantially different that what beowulff is talking about.
I have no idea how it would work on surfaces, but it definitely works in water.
Sorry, we appeared to have hijacked. :o

[Raygun99]

@beowulff

No, I’m not sure.
Here’s what I’m skeptical about: Portable Solar Power - Solar Products - Solar Lights - Earthtech Products
(Actually, I’m skeptical about any UV sanitizer wand, LED or not)

I might question its necessity for a kitchen counter, but there’s no reason to wonder whether it would work. A number of water treatment plants are moving to UV treatment of water as an alternative to or addition to chlorine.

[Illuminatiprimus]

@beowulff

No, I’m not sure.
Here’s what I’m skeptical about: Portable Solar Power - Solar Products - Solar Lights - Earthtech Products
(Actually, I’m skeptical about any UV sanitizer wand, LED or not)

I see - yes that product description is a tad confusing. I don’t know if it works, to be honest (although like you I’m pretty sceptical).

[beowulff]

@Raygun99

I might question its necessity for a kitchen counter, but there’s no reason to wonder whether it would work. A number of water treatment plants are moving to UV treatment of water as an alternative to or addition to chlorine.

Once again, I know that UV treatment CAN work (in an industrial setting). I just doubt that the units sold for home use actually do anything. You can read some information here: http://www.iuva.org/iuva/faqs
You are welcome to calculate whether a small UV “sterilizer” actually puts out enough energy to work.

[Necros]

Here are some tests results, at least for water purification, for the pen I linked to:
http://www.steripen.com/testing.html

Here is one such relevant test performed by the University of Maine regarding sterilization of a 32 ounce Nalgene bottle, and the resulting 99.9%+ kill percentage (PDF-O-Rama!):
http://www.steripen.com/PDF/Report_Nalgene_UMaine.pdf

[beowulff]

@Necros

Here are some tests results, at least for water purification, for the pen I linked to:
http://www.steripen.com/testing.html

Here is one such relevant test performed by the University of Maine regarding sterilization of a 32 ounce Nalgene bottle, and the resulting 99.9%+ kill percentage (PDF-O-Rama!):
http://www.steripen.com/PDF/Report_Nalgene_UMaine.pdf

Not bad. But, it’s a 254 nm light source. I wouldn’t expect UV LEDs to do as well.

[AllWalker]

Back to the original topic,

@Shark

But if they aren’t talking about nanoparticles, which I doubt they are, since they are talking about using it as an industrial coating, it’s just white paint. Most paints use TiO2 as the white pigment.

A lot of paints use TiO2 nanoparticles now. The particles are in suspension. And since the thread title mentions photocatalytic TiO2, I would assume nanoparticles.

My take on this is that someone has found a way to play up the characteristics of TiO2 in a completely different environment, and claim that it conferrs magical properties to standard old white paint. In other words, snake oil.

You do have to be skeptical. There is a lot of nano-snake oil out there. Still, there is a lot of cool stuff it can do.

I do agree with AllWalker that nanoparticles can be cool in the right applications. I also think they might present a host of biological dangers due to the small size of the particles. It’s fascinating to me, that the properties of a solid can be changed so significantly by a reduction in size

And that’s why I study it.

@mindfield

Is this the stuff I’d read and seen a video about a year or two ago that, when coating buildings and the like, can filter and neutralize CO2 emissions?

One of the big promises of the immediate future is photovoltaic stuff. They have developed photovoltaic glass, but I don’t think it’s commercially available (or even viable) IIRC. One of the original ideas was paint that was photosynthetic in the traditional sense, taking light and CO2 to make electricity and oxygen. Last I heard, it didn’t work very well, though it did work. TiO2 would have been one of the components, probably.