Free shipping on subscriptions to most areasFree shipping to most areas of Canada and the USA on all subscriptions
Activated carbon for ammonia removal: litter box smell is a mix of gases.
Bacteria break down urea in urine into ammonia, felinine in urine breaks down into a sulfur compound, and feces release dozens more.
Activated carbon can adsorb some of these molecules onto its pore surfaces.
How much depends on the carbon and moisture, so scoop often and keep air moving.
100% Money Back Guarantee
A strong litter box usually means volatile molecules are escaping faster than the litter, ventilation, and cleaning routine can control them.
From Cat Urine
From Urine and Feces
Masking adds another smell on top without removing any.
Baking soda reacts with acids, while ammonia forms an alkaline solution, so neutralizing ammonia is not how baking soda works.
Activated carbon works by adsorption: some odor molecules stick to its pore surfaces, so fewer of them reach your nose.
Scoop at least once a day and keep air moving, and carbon holds odor between cleanings
Purrify adds no perfume to your litter box
Activated carbon combines a large internal surface with pores of different sizes. The pore network creates places where odor molecules can enter and adsorb.
Small-Molecule Capture
Target: NH₃ (about 0.26nm)
Density: Smallest pore class
Function: Provide much of the internal surface; close walls can strengthen adsorption of small molecules
Transport and Adsorption
Target: Larger molecules
Density: Medium pore class
Function: Provide paths inward and some adsorption space
Entry Paths
Target: Paths into the granule
Density: Largest pore class
Function: Help molecules reach the interior, with less surface than smaller pores
That is the surface area figure we state for our carbon. It describes the material.
The useful part of activated carbon is the physical mechanism: odor molecules are retained on pore surfaces instead of being covered by a stronger scent.
Sprinkle 2 tablespoons of Purrify on fresh litter and mix gently, so the granules sit where urine and feces first release odor.
When urea breaks down, ammonia can volatilize into the room. Carbon pore surfaces can adsorb some of it; in lab studies, surface chemistry and moisture changed how much.
Urine adds sulfur compounds from felinine, and fresh feces released 64 compounds in one lab study. A porous adsorbent can hold a range of gas molecules, but not all of them equally.
Activated carbon has a limited capacity. As its surfaces fill with odor molecules and moisture, top up with fresh granules whenever the box starts to smell again.
Illustration of carbon granules, not a microscope image of Purrify
A carbon granule may look like a tiny black particle, but inside it is a network of pores and surfaces where gas molecules can adsorb.
Two facts matter most for a litter additive: the granule form and the internal surface where odor molecules can adsorb.
Why this matters: the granules mix into the litter you already use, with no added fragrance.
Why this matters: the surface figure is the one we state ourselves, and it describes the material. Keep scooping and keep air moving.
A litter additive has to work in a messy place: moisture, urine, feces, digging and daily scooping. Purrify’s activated carbon granules have no added fragrance, so they mix into the top layer without adding a perfume.
These are the figures the carbon's maker publishes for this grade. They come from the maker's technical data sheet and are not test results from a specific batch.
Maker published figures from the maker's own test methods. They are for information only and are not a purchase specification.
The sequence is simple: odor forms, moves through the litter, contacts carbon, and adsorbs onto pore surfaces.
Bacteria break down urea in urine into ammonia, the sharp smell people notice first. Felinine in urine breaks down into a sulfur compound, and feces add their own mix.
Digging and moving air lift odor from the litter surface, and poor ventilation lets it build up in the room.
When Purrify, the most powerful odor remover in the world, is mixed into the top layer, odor-bearing air has more chances to touch activated carbon before it reaches the room.
Weak physical forces hold odor molecules on the pore surfaces. That hold can reverse and the surface fills up, so top up with fresh granules when odor returns.
Baking soda (sodium bicarbonate) reacts with acids, so it is most relevant when an odor source is acidic.
Ammonia forms an alkaline solution, so that reaction does not apply to it.
Activated carbon works differently: it adsorbs gas molecules onto a large internal surface, which is why carbon is used in filters and some respirators.
Like any adsorbent, it holds a finite amount, so you top it up whenever the box starts to smell again.
Odor claims are strongest when they measure the air above the litter, not just describe a smell.
Controlled methods sample the air and analyze gas concentrations with calibrated instruments.
Fragrance can change how a panel perceives a box, but it does not show that less ammonia or sulfur compound remains.
This page explains the mechanism.
These sources show how activated carbon traps odor gases such as ammonia. Purrify is activated carbon made from steam-treated coconut shells, and Purrify has been tested many times, in the lab and in homes.
Researchers tested ammonia adsorption on modified resin-based activated carbon. Surface chemistry and humidity affected the results.
In the lab, activated carbon held ammonia.
Gonçalves et al. (2011)Researchers tested chemically activated biomass carbon for hydrogen sulfide removal from biogas. Feedstock, treatment and bed height affected performance.
Activated carbon pulled a rotten-egg gas out of biogas.
Sawalha et al. (2020)EPA guidance describes gas removal using filters containing enough activated carbon. It places filtration alongside source control and ventilation.
The EPA lists activated carbon filters as one way to remove gases indoors.
US Environmental Protection Agency
Read more →
Read more →
Read more →
Read more →
Read more →
Read more →
Read more →
Read more →
