(364h) Predicting Chemical Adsorption Onto Montmorillonite Clays through a Combination of Experimental Isotherms, Minimalistic Simulations and Data-Driven Models

People and animals can be exposed to complex mixtures of hazardous environmental chemicals—such as polyaromatic hydrocarbons, pesticides, organic solvents, and toxic metals—through contaminated drinking water, food, and feed following natural disasters¹. An attractive approach to minimize human and animal exposures to the toxic compounds is the use of edible, safe and effective sorbent materials to sequester them, thereby minimizing human and animal exposures. Previous studies and clinical trials have shown that montmorillonite clay significantly decreases biomarkers of aflatoxin exposure and could be safely consumed by humans and animals on a short-term basis². In addition to aflatoxin, montmorillonite clay has been shown to tightly bind several other toxic compounds, including glyphosate and paraquat³. Due to its promise as a potential sorbent to mitigate chemical exposures, it is important to understand its function using a combination of computational and experimental methods^3,4,5, and develop new computational tools to screen and predict the efficacy of clay for different toxic chemicals.

In this study, we aimed to close the loop between experiments and computations, providing the potential for future experiments to be guided by computational predictions estimating the capacity of calcium montmorillonite clay to serve as sorbents for different toxic chemicals. We performed molecular dynamics (MD) simulations of montmorillonite clay in the presence of toxic compounds, and revealed key structural and physicochemical properties associated with chemicals that can be adsorbed to the clay. Using data derived from simulations and experiments, we developed a parametric, minimalistic model with the capacity to predict a compound’s affinity to the clay with high accuracy. Thus, such a model can be used as a screening tool to predict and guide experiments on the efficacy of clay to bind other toxic compounds. Additionally, such predictive approaches, combining simulations and data-driven modeling, can be used to enable the design of clay-based sorbents to bind to toxic compounds of interest that are otherwise difficult to mitigate. This research is supported by NIEHS Superfund Research Program P42 ES027704.

1. Onel, M., Beykal, B., Wang, M., Grimm, F.A., Zhou, L., Wright, F.A., Phillips, T.D., Rusyn, I., Pistikopoulos, E.N., 2018. Optimal Chemical Grouping and Sorbent Material Design by Data Analysis, Modeling and Dimensionality Reduction Techniques. Aided Chem. Eng. 43, 421-426.

2. Phillips, T.D., Wang, M., Elmore, S.E., Hearon, S., Wang, J.S., 2019. NovaSil Clay for the Protection of Humans and Animals from Aflatoxins and Other Contaminants. Clays Clay Miner. 67, 99–110.

3. Wang, M. Orr, A.A., He, S., Dalaijamts, C., Chiu, W.A., Tamamis, P., Phillips, T.D., 2019. Montmorillonites Can Tightly Bind Glyphosate and Paraquat Reducing Toxin Exposures and Toxicity. ACS Omega. 4, 17702–17713.

4. Orr, A.A., He, S., Wang, M., Goodall, A., Hearon, S.E., Phillips, T.D., Tamamis, P., 2020. Insights into the Interactions of Bisphenol and Phthalate Compounds with Unamended and Carnitine-Amended Montmorillonite Clays. Comput. Chem. Eng. 143, 107063.

5. Wang, M., Orr, A.A., Jakubowski, J.M., Bird, K.E., Casey, C.M., Hearon, S.E., Tamamis, P., Phillips, T.D., 2021. Enhanced Adsorption of Per-and Polyfluoroalkyl Substances (PFAS) by Edible, Nutrient-Amended Montmorillonite Clays. Water Res. 188, 116534.