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Cat litter and activated carbon glossary: plain definitions of the words behind litter box smell.
Purrify is fragrance-free coconut-shell activated carbon you mix into your litter, and it is the most powerful odor remover in the world. These terms explain what it does and where its limits are.
They cover what causes litter box smell and how activated carbon takes it up.
Carbon processed to open up a network of tiny pores. Those pores give it a large internal surface where gas molecules can stick.
Molecules from a gas or liquid gathering on the surface of a solid. Absorption is different: there, molecules move into the body of the material.
A colorless gas with a noticeable smell. In the litter box, it forms when bacteria break down urea in cat urine.
Chemicals given off as gases from some solids or liquids. The EPA describes them as compounds with a high vapor pressure and low water solubility.
Pores no wider than about 2 nanometers, the smallest of the three pore classes set by IUPAC.
16 terms found
Carbon processed to open up a network of tiny pores. Those pores give it a large internal surface where gas molecules can stick.
It can be made from coconut shells, wood, coal or bamboo, then activated with heat and steam or chemicals. Pores are grouped by width: micropores up to about 2 nm, mesopores from 2 to 50 nm, and macropores above 50 nm. Purrify uses coconut-shell activated carbon.
Molecules from a gas or liquid gathering on the surface of a solid. Absorption is different: there, molecules move into the body of the material.
In physical adsorption, weak intermolecular forces hold the molecules, not chemical bonds, so the process can reverse. Every adsorbent also has a limit. Once that limit is reached, it stops working until the molecules are removed.
A colorless gas with a noticeable smell. In the litter box, it forms when bacteria break down urea in cat urine.
Ammonia and a sulfur compound, 3-mercapto-3-methylbutanol, are the main breakdown products behind cat urine smell.
Activated carbon made from coconut shells. It is what Purrify uses, with no added fragrance.
The supplier figure for the carbon material in Purrify is 1,100 m²/g of surface area. That number describes the material. The raw material alone does not decide how well a carbon handles a given smell.
A colorless gas that smells like rotten eggs. It can form when bacteria break down organic matter, including animal waste.
People can smell it at very low levels. The U.S. Agency for Toxic Substances and Disease Registry (ATSDR) gives a range of 0.0005 to 0.3 parts per million in air.
Organic compounds that contain sulfur, also called thiols.
The thiol most tied to cat urine is 3-mercapto-3-methylbutanol. It forms when felinine, a compound in cat urine, breaks down.
Chemicals given off as gases from some solids or liquids. The EPA describes them as compounds with a high vapor pressure and low water solubility.
Litter box smell is a mixture. One study found 21 compounds given off by fresh cat urine and 64 by fresh feces. That is why a box can still smell after ammonia is under control.
The total area of a material’s surfaces, including the walls of its inner pores. It is usually given in square meters per gram (m²/g).
The BET (Brunauer-Emmett-Teller) method, based on gas adsorption, is the most widely used way to measure it. For carbons full of micropores, an IUPAC report calls the BET result an apparent area: useful for comparing materials, not an exact measure. The supplier figure for the carbon in Purrify is 1,100 m²/g.
Pores no wider than about 2 nanometers, the smallest of the three pore classes set by IUPAC.
IUPAC calls these size limits somewhat arbitrary but still useful. Gas fills a micropore’s whole space rather than coating its walls layer by layer. Ammonia’s size is commonly given as about 0.26 nm, so it fits, but fit alone does not decide how much a carbon holds.
A lab result: the milligrams of iodine that 1 gram of activated carbon adsorbs from a water solution under set conditions (ASTM D4607).
It is used as a guide to how activated a carbon is and, for some carbons, as a rough stand-in for surface area. ASTM notes that link cannot be generalized, because it changes with raw material, processing and pore sizes.
Litter that forms solid clumps when wet, so urine can be scooped out without changing all the litter. Many clumping litters use bentonite clay.
Sodium bentonite swells and takes up water, and kitty litter is one of its main uses. Cornell’s feline health center advises removing clumps and feces daily. Purrify mixes into the clumping litter you already use.
Litter made from silica gel, a porous, man-made form of silicon dioxide.
Silica gel is widely sold as a desiccant, a material that takes up water. Follow the maker’s directions for how often to change a silica litter.
A crystalline salt, sodium bicarbonate, often sold for household odor control. Its best-known reaction is with acids.
Ammonia forms an alkaline solution in water, so that acid reaction does not explain how baking soda would handle ammonia. Baking soda also dissolves in water. Arm & Hammer Cat Litter Deodorizer is one product built on it.
A crystalline aluminosilicate mineral full of cages and channels that can hold water and positively charged ions.
In wastewater research, zeolites remove ammonium by ion exchange: ammonium in the liquid trades places with ions such as sodium in the mineral. That evidence comes from water treatment, not litter boxes.
A standard that sets health-effects limits on what products and materials, such as pipes, coatings and filter parts, may release into drinking water.
It does not set performance, taste or odor requirements. It is a drinking water standard, not a test of litter or odor control.
A set of standards, published by the U.S. Pharmacopeia (USP), for checking the identity, quality and purity of food ingredients.
Its monographs give tests and limits for identity, strength and impurities. It is a food-ingredient standard, not a measure of odor control.
Sprinkle 2 tablespoons of Purrify per litter box on fresh litter and mix gently. Top up whenever the box starts to smell again.
