C02 Generation methods/Titanium Dioxide Catalyst fact/fiction 1

[salukikev]

thread804-78534

I just came across moltenmetal's very helpful post regarding use of Titanium Dioxide in the course of water treatment efforts. Honestly, I'm not a chemical engineer so much of the discussion was outside of my experience- I wasn't able to derive a clear answer about the effectiveness of using Titanium Dioxide as a catalyst to generate CO2, especially in the context of ultraviolet light. Basically, a claim illustrated by this product is what I wanted to validate or invalidate. My takeaway at the moment is that actual C02 production would be negligible if it occurs at all in a non-water treatment application like this. I'd like for someone more experienced to confirm that my understanding is clear on that.

Secondly, in lieu of Titanium Dioxide, I'd like to find a compact method to produce C02 without need of a retail consumable (eg. Propane cartridge). Any suggestions there?
Thanks for any help!
-kevin

 

[moltenmetal]

Anatase TiO2 irradiated with UV light produces oxidannt radicals which oxidize organic matter. The ULTIMATE products are CO2, water and oxidized species such as CO2 (usually as HCO3- in water though), Cl-, NO3-, SO4-2 etc. So this insect attractant device with its UV lamps and TiO2 coating- what is the source of CARBON that it is oxidizing? If it is just what drifts by in the air, the thing will generate negligible amounts of CO2. In my opinion, unless I'm missing something huge here, it's snake oil for attracting bugs- as a means to separate fools from their money. TiO2 has some legit uses such as coatings for self-cleaning surfaces and in producing ultrapure water, but its use for manufacturing snake oil has been far more valuable over the past thirty years or so than these legit uses have ever been.

As to a device to make CO2 without a "retail consumable", what you mean is that you want to use a utility to generate the CO2. Terribly wasteful and energy inefficient relative to buying CO2 cylinders I'd think, since 100% of the combustion energy would be wasted in that process. But your only choice, aside from absorbing CO2 directly from the atmosphere itself (fighting a huge entropic gradient in the process) would be to burn natural gas. That would be your ONLY choice, as it's the only utility source of carbon that enters a normal home or business. It would be a matter of deodorizing the natural gas, then burning it and absorbing the CO2. If such a device exists using propane as the fuel (again, why on earth you'd want to waste that precious fuel in that way is beyond me!), then converting it to run off natural gas would likely be comparatively simple.

The other option: anaerobically digest sewage, then burn the CO2/methane mixture you get to make more CO2. Don't think I'd want to drink the bubbly effluent of that process, though.

 

[salukikev]

Hey, thanks for the reply, and confirmation. I'd assumed as much, but I always like to confirm with an expert.

As to the "retail consumable"- yes, you could define that as a utility at the end of the day. The nearest example I could imagine would be a coronal ozone generator (see example). Efficiency wouldn't be a huge concern, as we would have AC power or ample batteries- I understand the ozone generator example isn't particularly efficient. I actually don't get why propane bug attractors are a thing- if the goal is C02 generation (whether thats effective or not notwithstanding), and you need a cartridge, why not just spec. a CO2 cartridge?

Anyway, that's neither here no there- I have my answer, and you have my gratitude.
Thanks again!
-k