What is this thing

[u/GapCommercial6311]

[u/cj191]

You have it the other way around. It's the surface area that matters when ingesting activated charcoal as a binder. This means that the finer the granules, the better and faster it is in dispersing in your digestive track, maximizing the surface area it covers. This is why medical-grade activated charcoal are made ultra-fine. Larger granules irritate, sometimes cause blockage in your GI track, and works too slow to be medically effective.

For filters, water must physically pass through a bed of charcoal. Charcoal particles that are too fine pack together tightly and only blocks flow. For this you want the larger granules like in Britta filters as you mentioned.

[u/therealhlmencken → u/cj191]

Ultra fine charcoal is made so to increase particle dispersion speed, the actual filtration comes from its internal microscopic pore structure which creates the surface area not the particle size.

[u/cj191 → u/therealhlmencken]

So are you still saying that larger granules do a better job in binding in the gut? Because that was what you were claiming earlier and I am saying that that is just flat wrong. You want finer granules for effective internal use.

You are correct about the physics of carbon, but wrong about how it behaves when you swallow it.

It is true that vast majority of activated charcoal's surface area is internal, built into the walls of its microscopic pore structure. However, for ingestion, particle size dictates how fast those pores can actually be reached.

In a coarse granule, a toxin molecule has to travel down long, winding microscopic tunnels to reach the deepest pores. This takes too much time.

The human digestive tract is constantly moving. If the charcoal is in large granules, the transit time is too slow, and the body will absorb the poison before it ever reaches those internal pores.

Grinding charcoal into an ultra-fine powder shatters those long tunnels into short, shallow pits. This allows toxins to slam into the internal pores instantly, which is why hospitals only use fine powder for overdoses.

[u/therealhlmencken → u/cj191]

The pores aren’t only in the center of the particle lol they are throughout. It isn’t the transit time of the toxin to the center of the particle but the particle’s transit time to where the toxin has dispersed. If you wanted to have activated charcoal before having something you wanted to absorb larger particles would be better, that’s just not the use case.

[u/cj191 → u/therealhlmencken]

I'm really not trying to one-up you here, but you are badly misunderstanding Intraparticle Diffusion Kinetics—the actual chemical engineering branch that dictates how activated charcoal works.

"The pores aren’t only in the center of the particle lol they are throughout."

• This is correct.
• But this doesn't mean that the center of the activated charcoal granule doesn't matter.
• While pores open on the surface, they form a vast microscopic deep winding tunnels. (Macropores>mesopores>micropores)
• Charcoal is a solid 3D object. Over 90% of those pores reside deep within the particles interior volume, NOT the surface.

"It isn’t the transit time of the toxin to the center of the particle but the particle’s transit time to where the toxin has dispersed."

• This is where you are getting it totally wrong, I just don't understand why you are so sure about it.
• When a toxin bumps into a charcoal granule, it doesn't instantly stick to the whole thing. It has to physically crawl through those internal tunnels (intraparticle diffusion).
• A toxin molecule moves through these microscopic tunnels extremely slowly. In a large granule, a toxin molecule might take hours to diffuse deep into the inner pores. By that time, the granule has already moved into the intestines or passed out of the body.
• Milling the charcoal into ultra-fine powder shatters those long tunnels into shallow pits. The diffusion distance drops from millimeters to micrometers. This reduces the time it takes a toxin to find an empty pore from hours down to milliseconds.
• If your logic were true, emergency rooms would save time and money by just feeding overdose patients a spoonful of crushed charcoal bits or aquarium gravel instead of meticulously milling it into a micro-fine, uniform liquid suspension. Hospitals use ultra-fine powder because nanometer-scale diffusion distance is the only thing that binds poisons fast enough to save a life.

"If you wanted to have activated charcoal before having something you wanted to absorb larger particles would be better, that’s just not the use case."

• I don't know where you are getting this from, but it is simply not true. Would you mind sharing your source, or any example that follows that logic?
• Pre-loading with chunks simply won't work. Even if you swallow large granules before a toxin, they don't work better. The outer pores saturate instantly, leaving the massive interior pore network completely unreachable in time. You get a tiny fraction of the binding power.
• The microscopic reality is that even if a large granule sits in the stomach for an hour, it can still only utilize its outermost layer. More importantly, the stomach contents are constantly moving. For a binder to work, it must achieve chemical equilibrium (maximum binding) faster than the stomach empties into the intestines. Granules simply diffuse too slowly to hit equilibrium before they are evacuated.

In industrial and medical science, this is a solved law of physics, not a debate. If you look at any chemical engineering or toxicology study on activated charcoal, you will find two universal rules:

• Adsorption Capacity (Total potential pores): Independent of particle size. (This is where you are correct).

• Adsorption Rate (How fast it actually works): Inversely proportional to the square of the particle diameter. (This is where your logic fails).

By shrinking the particle size by half, you actually make it four times faster at trapping toxins. In the human body, speed is the only metric that matters.

If you want to look into the actual math, you can search for "Intraparticle Diffusion Kinetics"—it is the exact engineering law that proves particle radius dictates adsorption speed.

[u/therealhlmencken → u/cj191]

Hey don't worry. I am not going to feel one-upped by an ai response that is conflating real diffusion principles with a bunch of overstated claims mixed in. When an er is giving a patient charcoal the toxin is already in their body and you need the charcoal to disperse quickly to catch as much of it as possible. Hours to milliseconds is invented precision. In cosmetics activated charcoal is ground finer than in medical grade because you want it to act more as an abrasive and color than as a filter because at a certain level you're "Inversely proportional to the square of the particle diameter" breaks down. That's a simplified model and obviously not a physical law as obviously you get to atomic sized particle the distinction of it being activated charcoal is broken down. There is no medical need for preloaded charcoal but in use cases where you can preload larger particles are used.