Microscopic images of E. coli before (left) and after disinfection. The bacteria died quickly after sunlight produced chemicals that caused serious damage to the bacterial cell membranes, as shown in the red circles. (Image credit: Tong Wu/Stanford University)

Generating Hydrogen Peroxide For Disinfecting Water Using A Solar-Driven Catalyst

Ensuring that water is safe to use and consume can be a real chore, especially for those who live in impoverished areas without access to safe drinking water. Here is where researchers at Stanford University hope that their recently developed low-cost catalyst can make a difference. This catalyst comes in the form of nano-sized particles (nanoflakes) consisting out aluminium oxide, molybdenum sulfide, copper and iron oxide. When exposed to sunlight,  the catalyst performs like a photon-sensitive semiconductor/metal junction (Cu-MoS2), with the dislodged electrons going on to react with the surrounding water, resulting in the formation of hydrogen peroxide (H2O2) and hydroxy radicals.

Disinfectant powder is stirred in bacteria-contaminated water (upper left). The mixture is exposed to sunlight, which rapidly kills all the bacteria (upper right). A magnet collects the metallic powder after disinfection (lower right). The powder is then reloaded into another beaker of contaminated water, and the disinfection process is repeated (lower left). (Image credit: Tong Wu/Stanford University)

Waterborne diseases are very common, with even the US reporting 7,000 deaths and 120,000 hospitalizations in 2021, according to the US CDC, and many more affected worldwide. Much of the harm is done by microbes, in particular bacteria such as E. coli, which are prolific in aquatic environments. By using this catalyst powder in contaminated water, the researchers reported that the Escherichia coli colonies in the tested samples were fully eradicated after a 60 second exposure to sunlight.

The reason for this is that hydrogen peroxide and similar reactive oxygen species are highly destructive to living cells, yet they are simultaneously very safe. Because of their high reactivity they are very unstable and thus short-lived. This is useful when the water with the now very dead microbes is consumed afterwards, with the catalyst itself being ferromagnetic and thus easily separated using a magnet.

With this proof of concept in hand, it’d be interesting to see what the product will look like, especially when it comes to the final separation step and making this as easy as possible. Since the catalyst is not consumed or presumably contaminated, it can last pretty much forever, making it an attractive alternative to water purification tablets and expensive filtration systems.

(Heading image: Microscopic images of E. coli before (left) and after disinfection. The bacteria died quickly after sunlight produced chemicals that caused serious damage to the bacterial cell membranes, as shown in the red circles. (Image credit: Tong Wu/Stanford University) )

A V2 Rocket Inspired Steam Turbine Skateboard Is Just Around The Corner

[Integza] never fails to amuse with his numerous (and sometimes really sketchy) attempts to create usable thrust, by pretty much all means possible and the latest video (embedded below) attempting to run a reaction turbine from decomposing hydrogen peroxide, doesn’t fail to disappoint. The inspiration came from the WWII V2 rocket, which used Sodium Permanganate to breakdown Hydrogen Peroxide. This produced high pressure steam, which spun a turbine, which in turn drove the turbopumps that delivered the needed huge quantity of alcohol and liquid oxygen into the combustion chamber.

After an initial test of this permanganate-peroxide reaction proved somewhat disappointing (and messy) he moved on to a more controllable approach — using a catalytic converter from a petrol scooter in place of the messy permanganate. This worked, so the next task was to build the turbine. Naturally, this was 3D printed, and the resulting design appeared to work pretty well with compressed air as the power source. After scaling up the design, and shifting to CNC-machined aluminium, it was starting to look a bit more serious. The final test shows the turbine being put through its paces, running from the new precious metal catalyst setup, but as can be seen from the video, there is work to be done.

There appears to be a fair amount of liquid peroxide passing through into the turbine, which is obviously not desirable. Perhaps the next changes should be the mount the catalyser vertically, to prevent the liquid from leaving so easily, as well as adding some baffling to control the flow of the liquid, in order to force it to recycle inside the reaction vessel? We can’t wait to see where this goes, hopefully the steam-turbine powered skateboard idea could actually be doable? Who knows? But we’re sure [Integza] will find a way!

With steam power, there’s more than one way to get usable rotational work, like using a reciprocating engine, which can be expanded to a whole machine shop, and whilst boiling water (or catalytically decomposing Hydrogen Peroxide)  provides high pressure gas, how about just using boiling liquid nitrogen? Possibly not.

Continue reading “A V2 Rocket Inspired Steam Turbine Skateboard Is Just Around The Corner”

Mask DIY sanitization device on the left, mask used as an example on the right. The device is a Tupperware-like plastic container, on top, a small motor plus battery device with an alligator clip attached to the motor. Mask is inserted into the container through the opening on top, hooked to the motor, and the motor then spins the mask inside the container where hydrogen peroxide vapor is being misted.

Mask Sanitization That Anyone Can Build

We’ve seen a wide variety of mask sanitization solutions, and now, [spiritplumber] from [Robots Everywhere] brings us a frugal and ingenious design – one that you barely even need tools for. This project might look rough around the edges but looks were never a prerequisite, and as a hacker worth their salt will recognize – this is an answer to “how to design a mask disinfector that anyone can build”.

Local shortages of masks have been threatening communities here and there, doubly so if you need a specific kind of mask that might be out of stock. This design could apply to a whole lot of other things where sterilization is desired, too – improving upon concepts, after all, is our favourite pastime.

The design is simple – a battery-powered motor rotating a mask inside a vat of concentrated H2O2, turned into mist by a cheap ultrasonic misting gadget. As the “turntable” rotates a your PPE of choice, making sure that every crevice is graced with cleaning touch of peroxide, it also causes the H2O2 mist to circulate. Fulfilling most important requirements for a proper sanitization system that more complex devices have been struggling with, this approach has certainly earned its place under the sun.

[Robots Everywhere] have shared a small library of their DIY PPE resources with all of us, and that’s not all they work on – recently, we’ve seen their aeroponics project rejuvenating garlic.

Using hydrogen peroxide vapour for PPE sanitization is a well-tested approach by now, as we’ve seen it deployed back in 2020 on a larger scale as part of an FDA-approved design. And if you only have 3% peroxide at hand, might as well try concentrating it further!

Continue reading “Mask Sanitization That Anyone Can Build”

Building A Devil’s Toothpaste Rocket Motor

When it comes to weird and wacky homebrew rocket experiments, [Integza] keeps himself fairly busy. He’s now attempted a design repurposing Devil’s Toothpaste for propulsion.

Devil’s Toothpaste is really the same as the famous Elephant Toothpaste experiment, just executed with higher concentration hydrogen peroxide. In this case, [Integza] is using 50% hydrogen peroxide combined with potassium permanganate as a catalyst. When the two are combined, the hydrogen peroxide breaks down into oxygen and water, which [Integza] uses here to propel a skateboard.

The potassium permanganate catalyst is impregnated into 3D printed porous ceramic parts. The peroxide is then  injected into this matrix via a compressed air mechanism, where it decomposes, creating a jet of water and oxygen that then blasts out of a 3D printed rocket nozzle to generate thrust.

It works surprisingly well, even if it’s a messy and unconventional way to build a rocket. It’s also a lot less fiery than most of [Integza]’s previous projects. Video after the break.

Continue reading “Building A Devil’s Toothpaste Rocket Motor”

FDA Says PPE Can Be Reused After Trip Through Shipping Container Decontamination System

We are hearing so much in the news about shortages of personal protective equipment, or PPE, for healthcare workers. Factories are being asked to perform the impossible when it comes to production be the need is so real, so immediate, and so widespread.

The problem with rapid consumption of PPE is that once it has been exposed to infection, it’s contaminated and can’t be used again. Physically it may be fine, but it retains the capability to infect other people. If there were some way it could be effectively cleaned and decontaminated for re-use, it would reduce the strain on the supply chain and result in a greater availability of PPE for all those who require it.

This is the promise of Battelle’s Critical Care Decontamination System, a shipping-container-sized unit which has received approval from the FDA at break-neck speed.

Continue reading “FDA Says PPE Can Be Reused After Trip Through Shipping Container Decontamination System”

Yellowing: The Plastic Equivalent Of A Sunburn

Your fancy white electronic brick of consumer electronics started off white, but after some time it yellowed and became brittle. This shouldn’t have happened; plastic is supposed to last forever. It turns out that plastic enclosures are vulnerable to the same things as skin, and the effects are similar. When they are stared at by the sun, the damage is done even though it might not be visible to you for quite some time.

Continue reading “Yellowing: The Plastic Equivalent Of A Sunburn”

Octobot soft body robot

Soft Robot With Microfluidic Logic Circuit

Perhaps our future overlords won’t be made up of electrical circuits after all but will instead be soft-bodied like ourselves. However, their design will have its origins in electrical analogues, as with the Octobot.

The Octobot is the brainchild a team of Harvard University researchers who recently published an article about it in Nature. Its body is modeled on the octopus and is composed of all soft body parts that were made using a combination of 3D printing, molding and soft lithography. Two sets of arms on either side of the Octobot move, taking turns under the control of a soft oscillator circuit. You can see it in action in the video below.

Continue reading “Soft Robot With Microfluidic Logic Circuit”