Rice sand turns toxic waste into drinking water

[lestatdark]

Cirio said:

lestatdark said:

Cirio said:

mchaza said:
lol, when you first look you think Rice Sand? what is this, Mixing Rice with Sand?, but it has nothing to do with rice its called Rice sand because the university is called RICE and thats there sand lol.

Oh wow, really? I feel so stupid now haha. But in hindsight, I guess my questions earlier make sense now because I didn't understand how rice would make better filter paper than simply mixing copper oxide with the filter paper. If that's true, then this "discovery" isn't really all too impressive. I'm sure many people have already thought of this/attempted this. They probably just didn't publish their results.

 

Actually, this is different than normal filter paper. Sand-based filtrations are extremely dependent on the components of the sand itself. Regular sands filters act in three diferent ways: By gravity (rapid filtration), upflow and slow filters. 

Usually, the best grade sand filters can capture particles with concentrations below even 10 ppm and small sizes below 100 micrometers. This is made via different types of interactions between the sand filter, previously treated with different methods, such as adding small Ca2+ or Al3+ cations, adding polymer chains to create a thicker, bigger sand matrix or by simply charging the solution (putting the particles and the sand at different PH's) and the toxic particles. Unfortunately, most of the filtrated toxins are chemically reactive with those components, and in the long term the sand filter degrades and looses it's effectiveness.

What this sand does is that with the addition of graphite oxide, you create a nano-tube like structure within the sand, which isn't subject to long term degradation provoked by the toxins as grapgite oxide is chemically inert. Plus you can create a much larger nano-structure which can capture even lower concentration of particles (in the ppb order), which allows for a much more efficient filtration.

 

So what you're saying is that the addition of graphite oxide, you create a neutrally charged structure within the sand that isn't attracted to the toxins of those compounds. Plus adding graphite oxide creates a stiffer structure where there are smaller gaps that allow for much fewer particles to pass through the filter paper (kind of like creating interestial compounds by filling the gaps with carbon).

Indeed. Graphite oxide creates "corridors" of nano-tubes that fills the gaps of the sand-filter, creating a much wider area and much minuscule spaces in which the particles are allowed to pass (in the order of the nm scale). As graphite oxide is chemically inert, the toxins don't react to it, thus avoiding any long time degradation that normal sand filters suffer (such as PH issues, cations losing charge and so on).