Inside an OSRAM AirZing photocatalytic air purifier

[@BozhidarStefanov]

Yay :) I got quite excited about your video (since I am a fan of the channel and now you talk about the topic I'm researching for the past 15 years). TiO2 is a photocatalyst and is one of the most popular ones - it all started in 1970s with a failed experiment by two Japanese - Honda and Fujishima. The principle is that it TiO2 is a semiconductor (it is also called heterogeneous semiconductor photocatalysis) and when excited with light larger than its bandgap (3.2 eV or UV with lambda < 384 nm) it generates charge pairs (pretty much what happens in solar cells as well). If there is a molecule adsorbed on the surfaces, and these charge pairs (electrons and holes) reach it - you can oxidation and reduction reactions (and can break down organics). It works, quite well (even under modest UV illumination). There are some issues, however - in humid air you can water layers on the surface, which (in one hand help photocatalysis, because water can mediate the process forming hydroxyl or superoxide radicals and increase the efficiency since they have longer lifetimes, compared to the photogenerated charge pairs), but on the other hand it (water) can have detrimental effect on the overall process, blocking hydrophobic molecules from reaching the surface. There is also the entire issue of photocatalyst deactivation. My PhD thesis was all about photocatalytic air purification (using TiO2 coated windowpanes) and it is very effective against common contaminants in lab scale experiments (however in the real world there are other issues - but all in all it work - probably not as effectively as ozone, but with less maintenance and energy consumption). And regarding the filter mesh - not all TiO2 is photocatalytic, it needs to be in the anatase form and nanostructured (food-grade stuff is made of larger particles and usually is rutile). So - in this case they either probably coated the porous substrate with a thin layer of TiO2 sol (it is a liquid precursor of TiO2, which gets converted into the material after heat treatment - in this case it is important what the base material is, since titanates with lower activity may be formed // however the gimmick factor will be the same), alternatively - a better solution will be to start with Ti-metal foam and anodise it to form a TiO2 layer ontop (you need no more than 100 nm thickness to have photocatalytic effect).

[@falksweden]

KZbin post of the day! Thank you! :)

[@Biped]

Wow. I love getting this level of information firsthand. Clive really has the best community

[@bigclivedotcom]

I've since found titanium dioxide coated nickel foam on AliExpress.

[@mahlapropyzm9180]

Top answer - assuming you believe in atoms.

[@user255]

LEDs have approx. 85% efficiency. Not all of that light hits the TiO2. Part of the light that hits the TiO2 turns into heat directly or indirectly. The rest create chemical reactions and not all of them do anything useful. With that low power consumption, I'm very skeptical this device does any difference in practice.

[@gvii]

From exploding caps, random liquid distillations and carbonizations, to informative teardowns and circuit analyses. This channel has it all. And it's still one of my favorites, even after all these years.

[@aaronbrandenburg2441]

100000000000000% True

[@brianjohnson5789]

Don't forget the swim suits and flaming dolls

[@gvii]

@@brianjohnson5789 Or the Death Daleks. Lol.

[@I967]

Also a favourite - cooking with 230V.

[@Backroad_Junkie]

Clive's greatest achievement was "Mr Bun-bun's tragic easter." Still never fails to move me...

[@zeberto1986]

I remember seeing a company making windows using a titanium dioxide layer on the surface for self cleaning. Apparently the reaction from sun light helps break down the dirt on the glass then when it rains the dirt washes off with no streaks as the microcrystalline titanium dioxide is hydrophobic. The glass was supposed to work quite well.

[@K-Riz314]

Interesting!

[@xmanhoe]

Pilkington Activ self cleaning glass 😎

[@RobertSzasz]

Probably titanium dioxide on a nickel foam. Mostly because that's easy to make, has a large surface area, and lets tons of air past.

[@SeanBZA]

could also be regular household white PVA paint, which has Tio2 as an optical brightener, sprayed onto a thin carbon foam. Looks easy enough to make, I just have to go to the beach and collect some illmenite sand from the tide edge, and use a plate to density sort out the dark powder even more, giving pure very black titanium dioxide powder. Then can just coat a mesh with white PVA paint, and coat it with the powder while wet, giving a very similar finish, and very cheap. Works on the beach, where the black silt is exposed to direct sun, making it very reactive.

[@bigclivedotcom]

I did find (and order) some titanium dioxide on nickel foam afterwards. From Turkey via AliExpress.

[@DarkstarPyro]

My thoughts exactly - a metal mesh with a surface coating of Titaniun Dioxide. It may even be Titanium ‘foam’ (if such exists?) with the surface oxidised in the same way as Aluminium. The oxidised layer would only need to be atoms thick, so would appear metallic, not white.

[@cennethadameveson3715]

About to say the same. Ceramic figures with lace frills worth on same principles.

[@mustafayasiraydin]

@@bigclivedotcom There is a Turkish producer of such items here in Turkiye. I also worked on TiO2 nanoparticles decorated with much smaller gold nanoparticles in order to get better efficiencies under solar light. It looks like a nickel foam coated with TiO2 or it might be possible make It from titanium similar to nickel foam as noted above.

[@GiddeonFox]

It's probably just a titanium metal mesh. Titanium is one of those metals that forms a passivation layer in air, so that's where the titanium dioxide would come from.

[@wimwiddershins]

This would be my guess too. The mesh/sponge form maximizes surface area.

[@sumoddball]

Man I really enjoyed those sound effects of the transformation from dirty to clean air. Really helped me visualize the process happening.

[@aaronbrandenburg2441]

😆

[@michaelwilliams4086]

Loved the sound effects to describe how the UV light bombards the nasties entering the air purifier😁 I learned something about the use of Titanium Dioxide, I heard it was used in toothpaste and paint, but this utilisation was news to me 👍

[@3dlabs99]

I was disappointed the actual device didnt make those noises. Maybe the newer version has it.

[@Mike_Hughes]

@@3dlabs99 I agree, there should be a new model that makes those noises, especially when 'zapping' Farts.

[@KernArc]

When you look at the magnified picture of the filter at 4:23 just the right way: cross-eyed and and then defocus, you can see a man dancing and singing into the microphone. Well done, Clive!

[@fazerider9287]

As others have pointed out, titanium metal forms a passivation layer of Ti02 in air and a metal mesh is much more useful from a mechanical point of view. What puzzles me is that it’s illuminatied from the wrong side, i.e. the particles and virus’s etc that you wish to destroy are more likely to collide with poorly lit bits of the mesh. Not that I suppose it makes much difference, it’s such a small device that I doubt it’d have much effect on anything larger than a sandwich box.

[@wren_violet]

Maybe the surface builds up a charge that will attract particles?

[@dancoulson6579]

When the LEDs were shining through the mesh onto the neon yellow paper, it appears that quite a lot of light can pass through. So I wonder if using a reflective surface on the other side (inside of the bottom cover) would reflect enough back up to illuminate the other side of the mesh? If not, I dare say that a small square of foil tape would increase the efficiency of the unit (assuming that this really is a thing. I've never heard of using UVA light on titanium dioxide, so I have no information on the chemical side of things)

[@Dreoc]

I was researching how to make a DIY photocatalytic air purifier when I found your video. I had already discovered a source of TiO2 screen mesh available from either Europe or China, which was available in 3, 5, or 10 mm thick mesh. It had the same grey color that you questioned in this video. I thought the same thing but must assume that when it is sintered onto the mesh or somehow impregnated into it, it changes its color, but I'm not a chemist, so I may be wrong. This device is way easier to buy than to build one, so thank you!! Brilliant deconstruction of the tech too!

[@acole5975]

I would assume that it increases surface area for more reactivity. A small volume but large surface area due to the porous nature. This would increase the reaction rate. It is very good at reacting with organic chemicals but poor with inorganic. When UV radiation at energies larger than the band-gap energy of the TiO2 crystal (3.2 eV for anatase; 3.03 eV for rutile) is absorbed by the catalyst, an electron is promoted to the conduction band, creating a pair of a negatively-charged free electron and a positively-charged electron hole. The electron-hole pair migrating to the TiO2 surface has strong reducing and oxidizing activities. The hole in the valence band reacts with water to produce hydroxyl radicals (.OH). From "Application of ultraviolet light assisted titanium dioxide photocatalysis for food safety: A review". I imagine the filter should be removed and washed as the material from the above reaction would be somewhat attached or reacted with the mesh. By washing it you physically remove material This "recharges" the TiO2. The ROS can disrupt and damage cell functions and structures, and cause chemical modification or cleavage of the DNA and cell membrane. UV-A, UV-B, and UV-C light sources were used with TiO2 and it was shown that the combination led to structural changes in the super-coiled plasmid DNA and genomic DNA of E. coli. Photocatalysis is not limited to application of UV-C light. When combined with UV-A, and UV-B, TiO2 has proved to be less effective than UV-C for inactivation of pathogenic bacteria, E. coli. From "Application of ultraviolet light assisted titanium dioxide photocatalysis for food safety: A review".

[@SBCBears]

Pinnable!

[@RonJohn63]

ROS?

[@David.C.Velasquez]

Yes, but he asked why it wasn't white.

[@MadScientist267]

@@David.C.Velasquez Sputtered?

[@Piqus3]

And that's the answer, for which i didn't do nothing. Thanks, great explanation.

[@apexvoice1952]

Clive, I'd say your summary of the sound is the best extent of this *science* of light purification there is.

[@TheArchBodom]

If you’ve never used an air filter these are great. kzbin.infoUgkx_dppjvjF8BYEmPSDTcgCUdRsgWYLXNHN I ended up with three after starting out with one. The noise level depends on the 1-3 settings with how hard you want the machine to work. You can also upgrade the filters and get one better for pet hair and smells which is a must have in my home. I noticed the air seemed lighter and easier to breathe when running the machine for the first time. Works great every time. Highly recommended!

[@rbleth51]

All three of my heat pump interior heads units came with two of those to install. They were labeled for deodorizing. Looked like the exact same color material.

[@morodochable]

I watched a video on the action lab channel recently where he explained that titanium dioxide is actually clear. The white colour is like the white colour of snow, from many small particles each of which is actually clear. He also explained why a layer of it produces the rainbow colours by interference between the light reflected from the metal surface and the oxide surface above it.

[@raymondo162]

link pls. thx

[@sofa-lofa4241]

@@raymondo162 kzbin.info/www/bejne/sKTLiX2vppKrma8 Not sure if the link will get deleted, check out his channel, it's great! I think its the most recent video he did, so it's easy to find

[@hetzz]

@@raymondo162 i would guess its this video pavp6dps6q0 named "Cold Welding Metals In a Vacuum"

[@morodochable]

@@raymondo162 kzbin.info/www/bejne/sKTLiX2vppKrma8

[@friedrichschwarz1547]

according to my art class teacher, to use titan dioxide as a white pigment, it needs to be at a specific particle size.

[@steubens7]

this would be fun to test, you could always put this thing, a voc and a voc sensor in a sealed box and watch it go. would be more complicated to sample the air for other compounds but still relatively simple. weigh the filter before and after

[@radiohirsch]

Its not acting as a filter (except for dust). Its supposed to break down organic molecules into smaller ones, essentially oxidising them

[@sarowie]

If I remember correctly, a voc sensor it self catalyzes voc in the air and measures the energy that takes to deduct the voc content. Meaning: in a small box leaving a voc sensor run long enough, the voc sensor would act as the air purifier.

[@graealex]

@@sarowie Correct. Most gas sensors act as catalyzed fuel cells. VOC are reducing gases, so at a catalyst, oxygen from the air reacts with the gas. Breathalyzers for example also. Notable exceptions are particle and CO2 sensors, which operate optically.

[@davidgrey943]

I have noticed that there are either through holes or some form of cooling for the LEDs near the UVA Leds.

[@MysticalDork]

Titanium dioxide is actually transparent in thin films (it's commonly used for optical coatings and such), so it's perfectly plausible that the metal mesh substrate is coated in titanium dioxide, or if the mesh is actually titanium itself, has had a thin oxide layer grown on it. Supported catalysts like that are pretty common, because it results in a cheap, durable, high surface area. I do want to mention that while the claims may seem a bit like marketing wank, photocatalytic activity of TiO2 thin films has been an area of study for quite a while now. Ben over at Applied Science has a video about TiO2-coated self-cleaning glass, which has potential applications in high-rise buildings where window washing is a bit of a pain.

[@rysacroft]

"which has potential applications in high-rise buildings where window washing is a bit of a pain." My Dad was an ambulance driver for 20 years in so over meals we'd get to hear the latest gruesome story. One day he arrived home with a Chamois leather, those things are expensive. A window cleaner had fallen off a tower block. My Dad just said, "he won't be needing that any more".

[@johndododoe1411]

@@rysacroft Disliked for stealing from patients.

[@goamarty]

@@johndododoe1411 I fear, the prior owner was no patient any more after this accident.

[@johndododoe1411]

@@goamarty Technically still a patient in terms of the privileged trust granted to ambulance crews.

[@rysacroft]

@@johndododoe1411 My Dad dealt with death and destruction on a daily basis. Picking up the pieces of someone who had jumped under a train. Could you do that? Being ex Royal Navy he'd come home and drink a nip of rum, I never saw him drunk.

[@KernelLeak]

1:30 It's a little known fact that the laser blasts during the trench run in Star Wars were actually UV blasts to freshen up the air in the trench...

[@aaronbrandenburg2441]

😆

[@Mike_Hughes]

and get rid of the Farts...

[@AndrewGillard]

6:18 (Someone else will point it out if I don't :)) since that diode is labelled "TVS1", I suspect it's intended to protect against voltage spikes rather than reverse polarity - though that likely doesn't invalidate what you said about it blowing the fuse if it did see reverse USB polarity! Are voltage spikes on USB supplies actually a concern in practice? Or is this just because it's for cars/etc? 🤔

[@benbaselet2026]

Well "USB" in this case is just a connector that's supposed to deliver a +5V and a return path to the device and it could come from absolutely anything. Like a very noisy broken switching supply or a melted regulator that lets say 12-15 volts straight out of it. Those LEDs would probably suffer from voltage spikes, the TVS can absorb them much better.

[@RandornCanis]

Good design practice to incorporate ESD protection on your USB power bus and data lines. Usually specified in the interface data sheets. May be required under USB specifications just as 10uF is the specified maximum capacitance on VBUS, but we've all seen that violated. Nonetheless, ESD protection good, and LEDs are ESD sensitive.

[@johndododoe1411]

@@RandornCanis 10μF straight across the bus draws the maximum inrush current tolerated by standard USB ports. If there's something limiting the inrush current in front of the capacitor, more capacitance may be safe.

[@Brian-L]

Big Clive upping his Hollywood production game, now with added sound effects!

[@TATICMOOR]

What a breath of fresh air from our friend Clive. I would have thought the mesh is a metal of some sort, but with the blow-up photo from Clive, shows it has a more complicated pattern to it. Therefore, I recon it may be made of a natural and organic sponge. Whether it is a natural sponge or not, I would say it has been dipped with a Titanium Dioxide coating. This process in turn then causes a reaction and why it looks like a spongy off gray metal. The theory of how it works looks clear, but does it do what it says on the tin. With any of these devices to clean air or give out positive ions etc to help one's environmental space in a vehicle or room needs to be proven properly.

[@chrisa2735-h3z]

Your air purification sound effect made my day🤣 Your humor never gets old!

[@davidcoghill8612]

The mesh would start out as just regular plastic sponge, and then it's been coated in a layer of titanium dioxide. The reason it doesn't look very white is probably just that it's a very thin layer and some of the black sponge underneath is showing through. If you squeezed and smushed it a few times all the titanium dioxide would probably start flaking off. Alternatively, a more expensive process they might have done it to bake the sponge at a high temperature, the plastic vaporises into nothing and the the titanium dioxide + some binder sinters together and leaves a hard ceramic sponge, but probably not what they've done here.

[@awatt]

I'm thinking something along those lines.

[@getyerspn]

Titanium dioxide is used in self cleaning glass surface coating, Sutch as pilkington self cleaning glass.

[@carneeki]

I note the PCB reads "UVLED-EUMarket V1.0" in the bottom left. I wonder if a US and AUS/NZ version differs at all, and if so, how it may differ. In AU, our USB is as universal as anywhere else I imagine.

[@noop9k]

Maybe this means it has a fuse at least :)

[@keithking1985]

good to see real UV light's for a change.

[@pinkjaff]

I have a Mosquito trap that uses fan suction and UV bulb (it says 365 nm), it claims that the surface below the bulb is coated with titanium dioxide, which creates CO2 to attract the mosquitoes and then get sucked by the fan. It works, but I don't know how accurate the claim is.

[@adam5zki]

I am wondering, would this "photocatalyze" the VOC's produced when 3d printing with materials that release toxic stuff (e.g. ABS, ASA)...

[@johnsenchak1428]

"Pho-tonic" does it do induction ? I' AIN'T HAVING IT !

[@leosthrivwithautism]

Where’s my hammer? Smash therapy. Haha

[@WobblycogsUk]

You generally want a solid catalyst to be very small particles which gives a tremendous surface area. I suppose you could make something like a sintered frit of pure titanium dioxide but it probably wouldn't be any better than what they have done here which I would guess is capture particles on some sort of metal foam. I'm highly sceptical of any device like this though. I'm sure the UV is causing some reactions to take place on the catalytic surface but what is being produced? Changed is not necessarily better.

[@RolfHeckemann]

In a microorganism, a sufficient amount of random chemical alteration means certain death.

[@andersjjensen]

@@RolfHeckemann And in organic chemistry, a sufficient amount of random chemical alteration means (almost) certain production of carcinogenic by products and free radicals... so there is that :P

[@user255]

I think the problem is that it does nothing in practice. With that power consumption you cannot get much done, even when you assume efficiency of electrolysis. But here it is of course lower.

[@RolfHeckemann]

@@andersjjensen Sure, but your average Maillard reaction when you prepare a fried breakfast will likely produce more of those than this device will in its lifetime, even on a steady supply of microorganisms... :P

[@BrianHurry]

Titanium oxide is actually clear it just looks white when it's in a powder form the same way that snow looks white even though water is clear

[@mikec2111]

Spot on 😀 same as polar bear fur is semi-transparent. You can also draw a parallel to those bus window adverts where from outside you see the advert but inside you can see through the window. Microdots with space around. (If you see a bus at night you can see through the adverts). The Titanium is a thin layer so the nickel colour shows through. In addition the air spaces in the sponge let the light through. If you hold the sponge over a brighter coloured light source it will appear to change colour.

[@hempbear]

I love the "EUMarket" label on the PCB. Probably put there to distinguish between non-eumarket/eBay version with fake UV LEDs. The original design :)))

[@DUKE_of_RAMBLE]

Damn, I should've read the comments before I posted my own lol I came to the _very_ same conclusion! Hopefully we're just being overly pessimistic.......... 🤞😖

[@MrNoipe]

The amount of air flowing through the device is dwarfed by just opening up a window or turning on the air conditioner. Probably doesn't do much, but theoretically it should work (given a room thats 5 inch x 5 inch)

[@raymondo162]

boom. you nailed it mate. thx

[@AZOffRoadster]

Does it come with a snorkel mount?

[@underwoodblog]

air cleaner for ants

[@andrewmain3572]

Does the atmosphere processor on LV-426 not work in roughly the same way? (from the movie "Aliens" for the uninitiated)

[@Muonium1]

I think this actually.....kind of ....is... a plausible mechanism device??? There are in fact lots of papers all over on this and indeed most of them seem to be using ~370nm UV light to irradiate the TiO2 because this is in fact right around the bandgap for that material and maximum absorption should happen around there. And of course that's a reasonable wavelength for GaN LEDs to be producing a significant amount of light at (as opposed to UVB or C). I think this may actually work and not just be more quacky landfill fodder. You should test it by putting it into a totally sealed glass container with a small amount of alcohol or acetone and then run the device for a while inside. Open it and see if you still smell the VOCs. Repeat it with the LEDs shorted and see if there's a difference.

[@aaronbrandenburg2441]

. not Shorted but disconnected. All so you woldent want. To do that on this device due to the fuse! Right next to that diode across the 5 volts input!! Strange that would be used on a usb powered device as wel. Thoughts on the use of revurse polarity protection on a usb powered device? Thoughts comments and more please! Just seems odd that work be a reversed polarity situation on USB power. I suppose that maybe prosperously in this wood may not have been designed to take USB power in perhaps just some other troubled source that could have been accidentally have had polarity reversed. Such as Barrel Jack initially perhaps circuit was designed for something like that but later I change or perhaps a different laptop power input. Those two will be where the polarity of a barrel jack is not always the same. AKA may not be for example center-positive!. Central negative is not common but is out there in the wild. Sometimes I think it's done on purpose but just a theory. One of the reasons Central pasta would be preferred. First help with Automotive applications. Is that if the outer contact on the barrel Jack contacted anything that would be additionally connect to the chassis ground of course being negative that would not be an issue. Not so much if the owner connection of the barrel Jack or positive. Could either be sparks flying or blown fuses. Or if things go wrong or poorly designed circuitry if it's not just a straight through 12-volt cable. Theoretically could in your damage or destroy components in some sort of power supply. Such as a Shuffle rag or a buck or boost circuit or other type of charging circuit or otherwise. Depending on a circuit for you it could do quite a bit of damage shorting the positive of an output negative chassis ground. Is it way since Kip Bradley yourself if this happens! I want some of this happened with 6 volt Center negative adapter running 4 volt cigarette lighter power port. Lots of smoke and a few sizzles and pops and that was it! If I remember correctly most of the smoke from just from resistors. Cool design very inefficient! Also produce a lot of heat even when it was working right initially before this happened! Also we are passing Casey Munoz ventilated person melted and deformed elsewhere! It was not a good day for that power adapter!

[@raymondo162]

i agree - lots more road testing is needed along with lab analysis of the mesh after a day / week / month

[@AZOffRoadster]

Is that a cheap brushed DC fan motor?

[@luvmechanix]

@@AZOffRoadster nah dude thats like a cpu fan

[@PaulMansfield]

Consider putting a piece of stale damp bread inside a sealed container with this device (powered up of course) and see if it can prevent mould?

[@Elminator666]

Titanium Dioxide is a pain. I work at a paint factory and we had a TiO2 contamination in a tank and it ruined like 3 batches of expensive automotive paint.

[@ferrumignis]

I imagine cleaning out a huge tank of paint is a difficult and potentially very messy job.

[@aaronbrandenburg2441]

@@ferrumignis to say the least!!!

[@McTroyd]

I initially read your thumbnail as "postapocalyptic." I really should take a sip of my coffee before starting in on KZbin.

[@KRiley129]

The PCB is labeled for the EU Market. Wonder what would change for other markets?

[@andyreact]

Does the air smell (ozone?) when it comes out?

[@bigclivedotcom]

No distinctive smell at all.

[@alexej01]

One thing I always wonder with all these air purifying technologies: what this does (if it works) is to oxidize things. Now of the myriads of diferent components that might be present in the air, couldn't some of them become smellier or more toxic when oxidized?

[@bigclivedotcom]

There's always a risk of a negative change.

[@proluxelectronics7419]

Is it really Osram, I would have at least expected a micro with PMW and led current supervision?

[@bigclivedotcom]

The resistors are OK for such a simple circuit with known 5V supply.

[@fabiosemino2214]

I recall that in Milan they did something like this on a larger scale, they painted a couple road tunnells ceiling and a multifloor parking/bus station with a TiO2 paint and scattered UV-A lamps along the standard place illumination. I'm curios about the results of the experiment, so far in the parking the just replaced everything with LED illumination

[@Miata822]

Years ago I examined some large photocatalytic air purifiers made by a company that no longer exists. They seemed well made and well documented and included a HEPA filter. These units were designed to be installed in medical offices and hospitals. Those units used UV-C tubes that had an aluminum grid with 1/2" openings before and after the array of 2 or 4 UV bulbs. The grid was similar to those sometimes found over office fluorescent light fixtures. The grid was painted with a titanium dioxide paint that had a coarse texture. The HEPA filter was mounted downstream of the lights and grids and was made to fit the inlet of an HVAC air handler. I assumed the UV-C did all the work and the catalysis was bunk. I have used an open pore polyester filter material that would look just like the filter you have if it had been sprayed with a light coating of white paint. As you mention, white paint is usually pigmented with titanium dioxide. I very much doubt that the UV-A does anything useful, but I've been wrong before. Once. In 1981.

[@Miata822]

Aaaand doing a quick little search immediately turns up credible sounding information that 350nm +/- (UV-A) works best with Titanium Dioxide when used in catalysis. Hmm.

[@SeanBZA]

Your filter would probably have been more effective if they simply painted the inside of the air handler, in the areas the UV would reach, with PVA paint with high quantities of TiO2, which would have made the entire surface a converter, plus improved the diffusion of the light as well.

[@thebrowns5337]

@@SeanBZA maybe thats why they went bust

[@oscarwylder]

I would like to know if the mesh is conductive.

[@UpLateGeek]

Interesting that you mention they're experimenting with putting titanium dioxide on roof tiles to help "clean the air". I imagine if it makes them lighter coloured then it might help reduce the absorption of heat and reduce the cost of cooling in summer. At least that's the reason why they're looking at banning dark coloured roofs on new houses in my state. Which is probably a good idea considering how hot an Australian summer gets (although surprisingly not so much for the last week).

[@brianm6337]

It occurs that they should make roof tiles that turn a white color when it's hot and sunny out, but black in cold weather.

[@theginganinjaofficial]

So you are bouncing all that thermal energy back into the atmosphere to heat it up.... nice!

[@UpLateGeek]

@@brianm6337 That's a great idea. I know they could make this work with thermochromic paint or coating, but my understanding is that these are pretty expensive and delicate, so they might not necessarily stand up to environmental exposure. Hopefully someone's working on those problems, since I think it definitely could make a noticeable difference in energy use.

[@UpLateGeek]

@@theginganinjaofficial I mean that's kinda how the polar ice caps work and them going away is apparently a big problem, sooooo....

[@theginganinjaofficial]

@@UpLateGeek so cover Australia in glaciers...? Or are we covering the glaciers with shingles?

[@herauthon]

Howmuch volume can it process in howmuch time - and - can it thus keep-up . . the appearance ?

[@andreiu4ce]

Please think of a way to add an ozone inside, maybe to replace the fan? I wil love to see that ! Great content great knowledge share Clive thanks!

[@aBoogivogi]

Titanium dioxide can also be used an additive in concrete if you want a whiter finish without bothering with paint. My guess is that's how they make the roofing tiles as well given that concrete is a pretty common material for those. Also fun fact. The most expensive color additive to concrete would be blue which is achieved by adding cobalt if I remember correctly.

[@BobMuir100]

Clive my friend, very interesting as usual. My questions are simple: will a single unit clean the air in a family car and should I buy one? Thanks Clive Bob England

[@bigclivedotcom]

They're available from, Lidl from time to time. I couldn't say if they are effective or not.

[@markscheutzow3446]

Possibly the foam is either titanium or plated with titanium, abd forms it's own thin layer of oxide in use?

[@mtreis86]

I enjoyed the sound effects

[@aurthorthing7403]

WhiteOut is titanium dioxide. I'm curious if you could make one by painting a pot scrubber?

[@wolfierarar9652]

I think your bag of titanium dioxide is 2 years past its its expiry date lol... great video as always Clive

[@bigclivedotcom]

Yeah, I don't plan on eating it though. It's purely as a pigment or possibly for photocatalysis experiments.

[@noop9k]

What can happen to a simple inorganic substance in 2 extra years?

[@DUKE_of_RAMBLE]

@@noop9k I know this is a _bad_ comparison, given TiO2 is stable, BUT, there are quite a few that decay into something else entirely. (I'd read on Wiki last year about some exotic, man-manipulated, variants I'd Mercury and Platinum, which are unstable but decay into stable Gold -- granted, the one from Mercury occurs in just 2.5 *days*, well sorry if 2yrs... Although, one/some will result in a _radioactive_ gold, which isn't great lol)

[@noop9k]

@@DUKE_of_RAMBLE Sorry, this is totally irrelevant. And an isotope with such a short half life would emit life-threatening amount of radiation

[@DUKE_of_RAMBLE]

@@noop9k my point still remains, though. Things can undergo a stark change in as short a time as 2yr. Don't get me wrong, I'm only playing devils advocate. I'm with you on this, not knowing what could "expire" in this case. Most things like this would oxidize, which would end up generally tasting different; however, this already IS, sooo... Indeed, what's left for it to do? lol Though a thought, if it absorbs to much moisture, it could become like some powdered products, and become slightly acidic? **shrug**

[@phonotical]

Oh cack, I bought one the other day and I thought it might be interesting then I saw the metal sponge being used as a filter and thought, that's really familiar... I doubt this is photocatalyctic, I thought I could replace the leds with actual uv leds, but the fan is so weak, how's it ever going to suck anything in...

[@beehard44]

A local paint manufacturer here markets a special paint loaded with TiO2 and CaCO3 that kicks out NOx from the air by catalyzing it with water to form nitric acid, which then reacts with the CaCO3 to form CO2 and Ca(NO3)2 which gets washed away with rain or at least that's what their marketing blurb says lol

[@DesignedbyWill2084]

There was some research done on using titanium dioxide paint on pools so sunlight would keep algae from growing.

[@willusher3297]

Anyone know what the PCB perforations next to the LEDs are for? Heatsinking?

[@bigclivedotcom]

They're plated through holes, and will help with heat dissipation from the LEDs.

[@Slikx666]

How long will it take to clean the air in a car? Probably longer than it takes to create new smells?

[@agw5425]

Would not uv c give a better/stronger reaction against bacteria, or would the ozone smell be a problem at this low power level?

[@bigclivedotcom]

UVA appears to be optimal for the TiO2 reaction.

[@richardgreen8694]

Different subject. But how do stop DC switch sparking on a 36v li ion battery ( e bike ) .

[@bigclivedotcom]

If the switch is arcing because it's breaking high current then it may have to have a wider breaking capability (DC sustains a continuous arc like a welder.) A snubber network - a resistor in series with a filter capacitor - will potentially shunt the arc noise and help quench it.

[@davidgunther8428]

The photocatalytic activity of TiO2 depends on the crystal structure. The powder used for paint usually has low amounts of the higher activity forms because it will break down the paint. Nano-size particles of TiO2 are clear, not white. Like the newer not-white zinc oxide and titanium oxide sun screens. Washing the mesh probably gets dust out of it. The catalyst only works on things directly in contact with it, so large particles can't effectively be broken down. The range is only as far as an OH radical can get before reacting with something, so a few nm, I think.

[@fenman1954]

Love the sound effects

[@davidcoghill8612]

Ikea sells a range of air purifiers now, might be a bit too big and pricey for you but might be good to look at and see if they're worth the price.

[@thebrowns5337]

Yes they look interesting. Basically a fan in a box with a hepa type filter and an additional charcol filter for smells if you want. The whole lot seems good value vs competitors but I do wonder if Ikea will change the filter size one day and make it all obselete. It's what they seem to do when they design something brilliant.

[@Backroad_Junkie]

Would something like this remove the cigarette/cigar smoke smell from a car? I've used ozium and scented dryer sheets (which actually worked), but if I ever encounter it again, this might be more useful...

[@bigclivedotcom]

An ozone generator in an empty vehicle for a while might help.

[@simonstergaard]

You need Anatase Titanium dioxide...Rutile form is not very photocatalytic. I work with photocatalysts as a professional. Ask any question you like.

[@carlbrenninkmeijer8925]

So interesting. Can you measures the electrical resistance of the porous metal filter? Often catalysts are metals on a ceramic carrier. This one looks like metal perhaps titanium slightly oxidised. For instance aluminium always has a thin oxide layer. Even shiny chromium has an oxide layer. When I measure the resistance I'd aluminium I musst puncture the inside layer.

[@BedsitBob]

I've got one, and it does light up at the top.

[@MrBobWareham]

Hi Clive a good video and very interesting to see I wonder if they make a room version? and how long before you review the Chinese copy with blue leds and a peace of sponge

[@bigclivedotcom]

The Chinese throw it into the mix by claiming photocatalytic action for white plastic insect catchers with blue LEDs.

[@Equiluxe1]

Is the mesh sintered titanium, the surface would them be titanium oxide.

[@awatt]

I was thinking that. Maybe pressed with something else that is flushed out before sintering? Just a thought.

[@TechGorilla1987]

Why would the circuit board be labeled at EU Market I wonder?

[@bigclivedotcom]

Not sure. I can't think of what changes might be required for other markets.

[@KernelLeak]

3:48 Actually, titanium dioxide is on the way out as a food additive, at least in the EU: en.wikipedia.org/wiki/Titanium_dioxide#Possible_carcinogenicity_by_ingestion

[@awatt]

The EU tried to ban vitamin supplements some time ago.

[@thebrowns5337]

@@awatt oh lord, we're off! As you typed that, under your framed picture of our straw haired Glorious Leader, did you look mournfully over at your ridiculously straight bananas and crave a bar of prohibited Dairy Milk? Did you rue having to buy a left hand drive car with your Euros? Seriously. These EU bashes are old. And none of them happen. Put the Daily Mail down - they got what they wanted, we left, if only they could stop banging on about the EU now! Plus compare Frances response to energy price rises vs our pathetic government. Sure, EDF won't thank the French government for the 20% tumble in their share value but at least French families can afford to heat their homes AND eat, safe in the knowledge no tax money will be used as a 'fix' either. Double win.

[@awatt]

@@thebrowns5337 You lost the vote and you are still salty after all these years. Get over it.

[@thebrowns5337]

@@awatt i have no problem with accepting the result of the vote. I honestly appreciate democracy and I look for positives. Plus I'm thankfully well ofv enough to cope with the downsides. I don't like liars so the way we got to the result troubled me. The thing that makes me salty (and hence my original comment) is people, including you and our pathetic PM along with the trashy rag tops STILL banging on about the EU. We left - so stop talking about how we are better off or what perceived issues the EU has. Move forward and deal with the issues Brexit created. And pay the NHS that £360m a week or whatever was on the side of that bus!

[@Tone260]

Is that derogatory? One moment please...

[@SusanAmberBruce]

Great video thanks Didn't you have a UVA test card, maybe that was another video, anyway fluorescing is not sure test of UVA but the current draw tends to support that they are.

[@der.Schtefan]

Cool. Does that mean you can use it as a tanning booth with the filter so you can get a freckled face? I am sure that'd sell!

[@davidkennedy8]

4:46, i got mine from ALDI, my instructions tell me to blow the dust off with a hairdryer set to low every 6 months

[@joeboatwrench9315]

As an auto body repair tech I am in a lot of cars and trucks. Few have the time to clean up before they drop their car off. Most vehicles are quite smelly! Smokers. Fast food eaters. Dairy farmers. Mini vans full of children. Dope smokers. Beer drinkers. Dog lovers. ( thats me) If that unit works, It isn't nearly big enough to do any good!

[@jaylang11]

i have an air purifier that uses a "cold catalyst" prefilter. not sure if its the same thing, same claims about what it does. no UV tho. its a hathaspace filter i found on amazon, is it all mumbo jumbo? i got it for the good hepa.

[@danielegger6460]

Hm, I'm curious whether the LEDs do their job. We have a UV box with the same LEDs from Ledvance (formerly OSRAM) which supposedly kills a variety of bacteria and viruses on objects put into and activating it for many minutes...

[@bigclivedotcom]

Could those be the little gold coloured UVC LEDs?

[@danielegger6460]

@@bigclivedotcom Whoops, upon closer inspection: you're absolutely right, they're gold coloured.

[@magnumopus9631]

our high end leds grow light use samsung 301b,and osram reds,so this should be interesting they use osram,only thing were finding uv b leds are killing the L90 too fast,and uva isnt in the right range for plant stressors for resin increase,so hope they get a handle and make uvb leds cooler in time

[@V3racious3]

1:19 THIS is why I am subscribed. Highly technical details explained in layman's terms.

[@Big_Computer]

Since this is an appropriate video to ask, about UVC. I have found almost nothing on the internet about that, as we know UVC tubes are very "dangerous" and do work as space and surface disinfection. But UVC LEDs do actually exist, they are expensive, and are covered in gold (at least looks like gold) but I dont know about how effective/dangerous they are compared to regular UVC tubes. Can a few real UVC leds each about 30mA to 350mA (at around 275nm) do anything? (LEDs the size of a standard 5050 smd package)

[@Spiralem]

My guess that the reason that it is off white is because there is only a thin film coated on it and it may have other impurity added for the photocatalytic effect.

[@ranger175a2w]

Thanks from Texas Clive

[@aceventura999]

3:16 Thank's for the warning,but didn't work out for me.

[@MikeOrkid]

The "gadoow gadoow gadoow" sound really made me smile.

[@JoeKingAudits]

Don't light bulbs clean the air?

[@voiceoftheclan8087]

Is the ultraviolet LEDs strong enough to do any good Clive, or could the powder material you have been bleeched whiter and the natural process they put theirs through change it to grey, would love to know more so going to explore this, thank you for activating my brain, another good video.

[@Cadissio]

Hi Cleave, it is very common solution: porous carrier coated with functional material. In humane words: it is titanium or titanated nickel sponge coated with tiandioxide. Metal sponge is mechanical stable and cheap, TiO2 supports the photochemical oxidation of the negative air components on its surface. Looks cool, cleverly grounded, but functionality remains questionable.

[@davidkennedy8]

7:11, me again, mine lights up blue, used a bit of insulation tape on the top as it was distracting, as a side note my box for this was orange

[@hmax1591]

All that and i still don't know if it really works. Should have done a test were you enclosed it in a big jar, put smoke inside, turn it on and see if it removed the smoke and the tobacco smell, then take it apart.

[@777anarchist]

For the photocatalytics to work the TiO2 has to be in nanoparticle form. And usually the smaller the particle size is the darker the substance looks. Platinum black is a good example.

[@RomanoPRODUCTION]

I am sure BigClive will make a giant version of the cleaner for all of his city. He will be known as the BigBreather and introduced in the hall of Fame of the City ❤️

[@seanmangan2769]

I thought it was UV-C that killed? Do I have it wrong?

[@bigclivedotcom]

UVC destroys stuff directly, but in this case it appears UVA is a better wavelength for TiO2 stimulation.

[@thedarkknight1971]

05:23 - "AAAAAGH FOCUS YOU FAKKK"!!! hahaha, good old AvE 🤣🤣 👍😎🇬🇧

[@pressurechangerecord]

The data sheet says it’s nickel with nano coated TiO2

[@yosmith1]

The 4th magic bean?

[@ceeboneee5632]

Is it a 12v fan, quietly running at 5v, or is it a descent 5v fan?

[@bigclivedotcom]

I think it's 5V. But deliberately restricted to reduce air flow.

[@Howtoeatrocks]

I don't know about titanium for tiles but I know a lot of people use zinc tiles and coating to help with rainwater tanks

[@just_noXi]

I guess the mesh absorbs light like sound insulating foam absorbs sound. It looks white in the magnified image.