Sciencemadness Discussion Board

Celite filter aid = diatomaceous earth (DE)

Sulaiman - 21-5-2017 at 04:32

I have just been looking at DE on eBay,

Apparently the darker marine DE has heavy metal content,
so I was looking at the 'purer' fresh water white DE;

Typical Chemical and Physical Analysis:
SiO2 94.2%,
Al2O3 2.5%,
Fe2O3 0.9%,
CaO 0.5%,
K2O 0.4%,
SO3 0.4%,
MgO 0.3%,
P2O5 0.3%,
Na2O 0.2%,
TiO2 0.2%,
Mn2O3 0.1%,
Specific Gravity 1.99,
Apparent Density 2.18,
Moisture 8.3%,
Water Absorption 90.9%,
Loss on Ignition 3.34%,
Porosity 64.5%,
Oil Absorption (30 mins) 58.0%,
Oil Absorption (72 hours) 66.3%,
Particle Size 400 mesh (<37 microns)

I have two questions;

1) does this look suitable ?

2) as it is DE rather than branded Celite, should I process this DE in any way before use ?

It seems odd to filter my reagents through such a chemical mix.

JJay - 21-5-2017 at 04:49

If you need something analytical grade, it's probably best to just buy some Celite.

That stated, you can improve the quality of that diatomaceous earth with acid washes and drying it at extremely high heat. Actually, I think that's how they make Celite:

[Edited on 21-5-2017 by JJay]

unionised - 21-5-2017 at 06:59

One approach is to wash the stuff, just before you use it, with whatever you are filtering.
So, if you are about to filter a solution of something in ethanol, you wash the celite with ethanol before use.
Similarly, you acid wash it before filtering an acid solution.
(I'd not recommend it for strongly alkaline materials)

Magpie - 21-5-2017 at 09:06

FYI I bought my Celite at a swimming pool supply store. Only problem is I had to buy a 25 lb bag. It's cheap though.

It's used with swimming pool filters for the same purpose it's used in the lab.

mr.crow - 21-5-2017 at 10:11

The kind you use for killing bugs is NOT suitable for filtering. It turns into goop and the water turns brown.

Sulaiman - 21-5-2017 at 10:17

Thanks for all the guidance,
I'll buy the lot that I pointed to and acid-wash it.
I'm guessing HCl then HNO3

JJay - 21-5-2017 at 11:09

I've used the bug killing kind before without incident, but I'm sure it does depend on exactly what kind you get.

violet sin - 21-5-2017 at 14:31

Wow is spendy 1kg for 6.71£ !! The swimming pool stuff is cheap like magpie says. 19$ for 25# last time around for me. Just got the pool filter all cleaned up and epoxy for some repairs. Spent little under a 100$ on chlorine and acid to boot( 25# trichloro, 2gal muriatic). Nice to have stuff around for experiments, as the beast always needs chlorine and I get to buy in bulk, but honestly I'd say <1% is ever used hobby wise.

Time to go epoxy some stuff and start cleaning, 18,000gal pool to filter free of sediment and dust. Getting warm here already, mid 80s and the 100+ will be here before you know it to steal 65 IQ pts. upon setting foot outside.