Bentonite for the Dummy

Bentonite osmotic swelling

If it were not so downright insulting to those who know the facts, reading some of the rubbish pounded out by to self-appointed "wise" freelancers at WiseGEEK.com would be amusing. Unfortunately, however, their work is out there for all to see, masquerading as something "authoritative." We hope no one believes that the work of such hacks as Karize Uy is correct, but we suspect that some poor middle-schooler tried to use her "What Is Bentonite?" for a term-paper reference. That was a mistake...

It was a mistake because the j-school grad from Manila had absolutely no idea what she was talking about. Even someone with a basic knowledge of geology and/or chemistry would have figured it out from some of her misinformation, misinformation such as;

"Bentonite is a geological clay material that is mainly made up of a mineral group called montmorillonite."

That raises a question, Karize: is there another type of clay besides "geological"? And how about this ignorant claim:

"Other minerals included in bentonite clay are aluminum, calcium, potassium, and sodium. "

Karize, what you just listed there are some of the elements present as cations in montmorillonite – they are not "minerals." We also found this claim rather... curious:

"Geologists have estimated that the formation of bentonite can be traced as far back as 70 million years. This means that the clay has settled in the lower layers of the earth’s soil and usually requires mining and quarries to be obtained."

Sorry, but bentonites are known from the Paleozoic, as far back as 450 million years ago (and more). You must have been confused by the references to the thick bentonite layers in the Rocky Mountain basins. And then there's,

"Bentonites usually contain some impurities such as quartz and gypsum and may require filtering and purifying before use as a building material."

That's a rather strange claim: does Karize think that people use bentonite for building stone? What? The reality is that bentonite slurry is often used as a sealant to prevent groundwater from infiltrating excavations. And how about this rather bizarre chemistry discussion:

"...water then exchanges ions with the [clay] particles and the clay can expand and swell in size."

Ummm, ion exchange has little or nothing to do with swelling of montmorillonite clays. Instead, the clays swell through absorption of water and an unusual osmotic property. We understand that difference, but it's obvious that our Dumbass of the Day did not.

So why did she write this? easy: freelancing for dollars...

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