Brown "Mag-Sil"

Has anyone else seen this crap?

Magnesium Silicate of any decent grade is white…like extremely white. I’ve been seeing a lot of “Mag-Sil” going around that looks identical to bentonite. I hope this junk isn’t being sold for pesticide remediation.

Any magnesium silicate activated below 675C is just Talc powder.

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Is Florisil PR white as well?

Edit…should have just looked it up…yes its white as well. Dont know then!

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Absolutely. It is a pure white granular absorbent. @Killa12345


I think the giveaway is the low price too!
Just like cheap mol seives are garbage imposters.


I’ve seen grey talc powder. That’s my best guess too.

What is the brown Magsil used for outside of this industry?

It gets used for cleaning frying oil…talcum is just baby powder


So my Bonds medicated powder to reduce itching, odor, and provide soothing all day comfort is really just Magsil marketted for the groin area? Soothing menthol feel too. I would only want the white stuff too and not the brown. It must be activated if it is white, no?


Activation temp is everything for remediation with Mag-Sil.

Mag Sil A is activated at 650C, Mag Sil PR is activated at 675C. That 25C makes all the difference in surface chemistry when using this adsorbent… those are just the two highest grades of Mag Sil and both are BRIGHT white.

Mag Sil A is not appropriate for pesticide residue adsorption according to the EPA PR method 3620C.

Anything that came out of a cooler furnace is best reserved for drying baby bottoms, soothing itches, and cleaning fried breading from grease.


Bhogart was selling “Mag Sil PR” and I asked if we could compete against what he paid. Dude says a ridiculously low price for 10kg so I asked to see the invoice.

They had bought the wrong SKU at Spectrum Chem, it actually said ‘Talc’ when looking up the CAS#, because it was cheaper. When I looked up Spectrum’s Mag Sil PR pricing it was over $400/kg!

I shared that info with Bhogart and they seem to have backed out of the absorbent world for now.


How does restek sell the stuff at nearly half price as everyone else.

I’m sure they aren’t selling anything bootleg. I’m wondering how they are offering it as low as they do?

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Restek is charging $280/kg, our bulk price is better than half that, per kg.

Sigma Aldrich and US Silica sell single Kg’s for between $250-275.


Thanks for that. Appreciate it.

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Can you explain what the difference is between the words adsorbant and absorbant as used in this context? I read a brief description as it applies to activated carbon once but think I need to fill in gaps lol.


I mix the two terms up all the time but aDsorption is what we are all referring to, as far as I know. Here’s the diference in definition:

“ABSORPTION is the process in which a fluid is dissolved by a liquid or a solid (absorbent). ADSORPTION is the process in which atoms, ions or molecules from a substance (it could be gas, liquid or dissolved solid) adhere to a surface of the adsorbent.”

Or I suppose you could say water absorbs into a dessicant but pesticides and charged contaminants are adsorbed onto appropriate media. Help us @Photon_noir


Haha! really! What about all the brown talc the sold already?

Your definition is mostly correct. Both prefixes are from the Latin words:
Ab = “of, from” as in abuse = from use
Ad = “to, with” as in adhere = to stick (attach)

aBsorb is where molecules “of” one solution or state move “from” that form into the bulk of another material (e.g. solid dissolving into a liquid, or a liquid absorbing into a solid) Remember B is for “bulk”

aDsorb is where molecules “aDhere” to a surface. It is strictly a surface phenomenon.

The confusion enters when a porous solid adsorbs molecules on the interior pore surfaces! Activated carbon is hyper-porous and has reactive surfaces, so molecules adsorb to all those reactive sites, both to outside surfaces and inside the particle bulk! Mostly, this is aDsorption, but because it is porous, non-reactive species can also aBsorb into the pores… so porous or lamellar (layered flat particles, like clays) solid materials can do BOTH, depending on:

  1. The pretreatment (activation or functionalization) of the solid material
  2. The nature of the previously mobile species (reactive or inert).
  3. The temperature of the mobile phase (gas or liquid) in which the solid is immersed.

The best way to remember this is by the words Bulk and aDhere.
The best way to determine what is actually happening, is whether the solid material gets hotter or cooler (requires external heat) during the process.

  • aBsorption is endothermic, so it gets cooler and adding heat helps it happen!
  • aDsorption is exothermic, so it gets hot and cooling it helps it happen!

The B or the P in the middle of the word is simply an artifact of the word form, and does not change the meaning. For example, aBsorBent or aDsorBent perform aBsorPtion or aDsorPtion.

Here is a great summary:


Future4200 University in full form. Thank you sir.


So cooling the chromatography column makes it more efficient? Seems like the other variables, like the flow characteristics of cold distillate, would work against us

Good question! Now I can tell you how the effects in a chromatography column stationary phase (medium) are highly dependent on the mobile phase (solvent), and how they are NOT really aDsorptive in nature! Those interactions are superficial (surface) activity based, but they are completely overwhelmed by the aBsorptive effect of the column BULK porous material. Any true adsorption in a column is actually counterproductive to genuine chromatography, which is WHY most columns are heated; to DEsorb the dissolved species at a set temperature according to their rates of desorption and propagate their aBsorption through the medium by pressure and thermal force!

Did that just confuse everyone or clarify how chromatography works?