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Young Scientist Journal

Young Scientist Journal

Clumping Properties of Cat Litter made from Diatomaceous Earth, Bentonite and Wheat Flour Blends

ABSTRACT

Cat litter is a useful commodity item in the US household and is used in large quantities. In this work, I hypothesize that cheap and sustainable materials such as diatomaceous earth and wheat flour, with or without the clumping clay, can be used to produce sustainable clumping cat litter. Typically, sodium bentonite is an expensive material that is generally used to prepare clumping cat litter.

INTRODUCTION.

It is estimated that there is a population of 74.1 million cats [1] in the United States alone, which means that lots of resources are required for these pets [2]. One specific resource is cat litter. Cat litter is a type of clay mixed with minerals and other ingredients. It is put in litter boxes to mask the odor of cat urine and feces. Cat litter plays an important role when it comes to feline health and hygiene. With the creation of cat litter starting with Ed Lowe’s brand of ‘Kitty Litter’, there has been an introduction of multiple different brands of cat litter [2]. Not only that, but the introduction of different types of cat litter as well. There are different types of cat litter; however, the most common ones include clumping clay litter, silica gel litter, plant-based litter, and paper litter. It has been reported that the most recommended litter was clumping clay litter [3]. This cat litter is made from a natural mineral, clay, and its sodium form that can form clumps. It is reported that cat litter boxes should be cleaned at a minimum once per day. This suggests that litter must be refilled and can be used up rather quickly. Consumers are also looking for a good quality source of cat litter, creating demand for that type of litter. This creates a problem for people who own cats to purchase more litter frequently, and as demand rises for cat litter, the price also rises.  The cat litter market itself is roughly around $6.2 billion and the raw resources to create the cat litter are becoming scarce [4]. Clumping cat litter tends to be expensive as expensive clumping minerals such as sodium bentonite, are used in its preparation, which are in demand these days due to their application in the fracking oil industry, sparking the need to research the possibility of creating cat litter material at reduced cost.

Therefore, in this study, I attempted to prepare a blend of clay and non-clay materials with a glueing agent such as starch could produce clumping cat litter. Diatomaceous earth (DE) is a naturally occurring sedimentary rock and is the fossilized remains of aquatic creatures known as diatoms [5]. It is known for odor-neutralizing and has low-density characteristics. Currently, it is not much used in cat litter but finds application as an additive in agricultural soils. As such, cat litter prototypes were prepared by combining DE with bentonite clay with the hypothesis that wheat flour will function as a glue to facilitate clumping. Physico-chemical properties and clumping properties of the mixtures were studied using conventional methods.

MATERIALS AND METHODS.

Bentonite clay and diatomaceous earth products were obtained from an online store (Amazon.com); wheat flour was obtained from a local store.

A weighing balance (Oxhaus) with the accuracy of four digits was used for all measurements. All the glassware used was thoroughly washed and dried in an oven at 100 °C before use. The comparative cat litter used in this study was ‘Purina Clumping Multi-Cat Clay Cat Litter’. The pH of the produced material was measured by dispersing 10 g of cat litter in 150 g of water and measuring the pH using a pH meter (Thermo Fischer). The pH meter was calibrated using buffer solutions of pH 4 and 10.

To 100g of the cat litter produced, 10 g of water was added. The clump formed was lifted and dropped 1 foot from the ground. The score of 10 was given to the clump produced by pure Na-bentonite, in which the solid mass was round and maintained its structure even after dropping onto the ground. If the clump broke into two pieces, a score of 5, and so on depending on the damage was assigned, which indicated the quality of the clump.

RESULTS.

A simple schematic structure of bentonite clay is shown in Figure 1. As shown in this figure, the clay has alternating layers that are made from silica and alumina. This is an example of layered materials (6). The space between the layers is filled with cations, which neutralize the framework charge. These cations (mostly Na+) are hydrated when they encounter water molecules, which impart a clumping property to the clay structure. However, as stated earlier, such clumping clays are expensive, heavy and difficult to mine. Diatomaceous silica, on the other hand, occurs on the surface of the earth.

Figure 1. A simple schematic structure of clumping Na-bentonite clay.

The materials used in this study, with their tap density, are shown in Table 1. 500 milliliters (mL) of the material were used for this test following the tapping method. The amount was tapped into a measuring cylinder and the corresponding weight for that material was measured using a precision balance. The density was calculated using the formula (d = m/v). The density of cat litter is important, as although it is sold by weight, it is used in volume when placed in a litter box.

It can be noted from the data in Table 1 that DE is very lightweight with a very low density of only 0.124 g/mL compared to the other materials. Bentonite has a higher density of 1.156 g/mL and will form a heavy material with high density. Utilizing it as the sole component in cat litter formulations is also cost-prohibitive, as pure clay is very expensive.  Table 1 also shows the pH of the three materials, which were close, between 6 and 7. The pH was measured by dispersing 10 g of the material into 150 mL of water, stirring the suspension for 30 minutes on a magnetic plate and measuring the pH of the suspension using a pH meter as described above. It is expected that the pH of the cat litter is maintained close to neutral for the consideration of the health of the animal and the handler.

Table 1. Some properties of the materials used in this study.
Material Mass, g Volume, mL Density, g/mL pH
DE 62 500 0.124 6
Bentonite 578 500 1.156 7
Cat Litter 543 500 1.086 6

To test the hypothesis on forming cat litter with sustainable additives, we prepared different blends using DE and bentonite, as shown in Table 2. The pH of the mixture was measured, and its clumping ability was evaluated by adding 100 g of water.

A perfect hard clump received 10 points, while other clumps were visually inspected and rated accordingly.  The clumping scale with scores of 10, 8, 5 and 1 can be gauged from the data shown in Table 2.

Table 2. Cat litter formulations tried in this work.
Bentonite, g DE, g water, g pH Clumping Scale
10 0 100 7 10
8 2 100 7 8
6 4 100 7 5
4 6 100 7 3
2 8 100 6 2
0 10 100 6 1

At the next stage, to improve the clumping property of the litter prototype and test our hypothesis of wheat flour acting as a glue, I added a constant amount of wheat flour to each of the formulations from Table 2 to form new formulations that are shown in Table 3.

Table 3. Cat litter formulations with wheat flour prepared in this work.
Bentonite, g DE, g water, g Wheat flour, g pH Clumping Scale
10 0 100 1 7 9
8 2 100 1 7 7
6 4 100 1 7 7
4 6 100 1 7 7
2 8 100 1 6 6
0 10 100 1 6 6

This experiment was also performed to explore the possibility of minimizing the expensive bentonite from formulation. The data is shown in Table 3. As can be seen, the clumping scores were improved markedly, consistent with the hypothesis of wheat flour functioning as a glue to hold the clumps together. In fact, a decent clump number was also obtained without any bentonite in the formulation, indicating that a functioning and sustainable cat litter can be prepared in the absence of expensive bentonite.

DISCUSSION.

It is important to explore new methods of producing cat litter, as most current methods involve production methods through mining minerals or chemical manufacturing. Also, sodium bentonite, which is a clumping clay, is a limited resource and is not widely distributed in the US.  Therefore, its use in clumping cat litter should be minimized as much as possible. I tested the hypothesis of making a clumping material using a sustainable clumping additive in the form of wheat flour.

My hypothesis of adding wheat flour clearly impacted on the clumping behavior of the mixture, as flour imparted a gluing or clumping property to the mixture. However, remarkably, the formulations containing higher DE, which had shown lower clumping quality in the absence of flour, improved the clumping quality and behaved remarkably upon addition to a small amount of wheat flour.  Thus, making the cheaper formulation to clump better.

Clumping is an important consideration for the commercial success of clumping litter, as it helps in containing the bio-odors in the litter box. Moreover, efficient clumping was brought about by a cheaper material, DE [6], which helps in producing cat litter in a sustainable way, as bentonite is a useful resource [7].

It is important to realize that DE is a low-density material; therefore, it can pack more volume in a given space. Cat litter is used by volume and not by weight by consumers. Creating lighter cat litter with the same effectiveness as heavier types of cat litter benefits consumers by reducing costs and eliminating the need to carry bulky materials.  Additionally, limiting the use of costly bentonite clay will help encourage sustainability.  Other low-cost and biodegradable materials, such as paper, sawdust, wood pellets, etc. [8] may also be tried in lieu of diatomaceous earth.

Furthermore, the pH of the formulation was not impacted by the addition of wheat flour. Overall, I present a method to eliminate expensive mineral resource bentonite from cat litter material. Some other cheap materials with various types of flour as sustainable clumping additives may also be tried. My hypothesis that wheat flour, a relatively cheap resource, could function as a clumping substitute for sodium bentonite was successfully tested and proven in this study.

CONCLUSION.

In this work, I tested the hypothesis for using sustainable materials to prepare quality, workable and sustainable clumping cat litter. The prototype cat litter was produced using diatomaceous earth (DE), which is a lightweight material, bentonite clay and wheat flour. The wheat flour acted as a glue to bind the water to form a clump just the way bentonite clay does. Because bentonite also has limited resources in the US, experiments were performed to check if blends of bentonite clay and diatomaceous earth with the mixing of bread flour could produce cheaper but efficacious cat litter, which appears to be possible through such blending approaches.

ACKNOWLEDGMENTS.

I thank Dr. Sajo Naik for supervision and guidance.

REFERENCES

  1. https://worldpopulationreview.com/country-rankings/cat-population-by-country
  2. Grigg E., Pick, L., Nibblett, B. “Litter box preference in domestic cats: covered versus uncovered.” J. of Feline Med. and Surg. 15(4), 280–284 (2012).
  3. LeAnn S, Natalie L. Sarah T, Ragen T. “Enhancing cat care: Un-veiling the technology of intelligent litter box monitoring.” Appl. Anim. Behav. Sci. 292, 106811, (2025).
  4. Cat Litter Market Size, Demand & Trends 2025-2035. (2025), https://www.futuremarketinsights.com/reports/global-cat-litter-market
  5. Diatomaceous Earth Fact Sheet. (n.d.). https://npic.orst.edu/factsheets/degen.html
  6. Di L, Chao N, Yongchun G, Ke W, Yao M, Z Zhang , Fei C. “Structure-activity relationship of modified montmorillonite for treating polluted water.” Mater. Chem. Phys. 353 ,132155 (2026).
  7. Department of Energy, Environment and Climate Action. (2023). https://resources.vic.gov.au/geology-exploration/minerals/industrial-minerals/Bentonite
  8. Steven V, Sean L, Mark B, Jill W, Steven P , Gordon S, William H, Michael J, Christopher S. “Production of an odor-reducing, low-dust, clumping cat litter from soybean hulls and soybean hull biochar” Bioresour. Technol. Rep. 21, 101317(2023).

Posted by on Friday, May 15, 2026 in May 2026.

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