2025 Spring Meeting and 21st Global Congress on Process Safety
(133a) Removal of Monomeric Siloxanes from Water Using Hydrophobic Zeolites
Authors
Dariana Vega-Santander - Presenter, University of Puerto Rico at Mayaguez
Rodinson Arrieta-Perez, University of Puerto Rico at Mayaguez
Daniela Rivera Mirabal, University of Puerto Rico at Mayagüez
Gabriela Del Valle-Perez, University of Puerto Rico at Mayaguez
Miguel Sepulveda-Pagan, University of Puerto Rico at Mayagüez
Juan Munoz-Senmache, University of Puerto Rico – Mayaguez
Carolina Colon-Colon, University of Puerto Rico at Mayaguez
Yomaira Pagan Torres, University of Puerto Rico at Mayaguez
Siloxanes represent an important category of compounds utilized in various industries and consumer goods. Recently, their demand has increased notably, with global production reaching 8–10 million metric tons, and this trend is anticipated to persist. As a result, the concentration of siloxane compounds released into the environment is likely to rise, potentially impacting water sources. Monomeric siloxanes, including monomethylsilanetriol (MMST), dimethylsilanediol (DMSD), and trimethylsilanol (TMS), may pose toxicity risks to humans if ingested over extended durations, as they can penetrate biological membranes and skin, affecting the central nervous system. In closed-loop water reclamation systems like those found in the US International Space Station (ISS), MMST, DMSD, and TMS concentrations tend to be higher due to the closed infrastructure. While adsorption presents an efficient and cost-effective method for removing siloxanes, commercial adsorbents often lack the necessary capacity and selectivity for monomeric siloxanes, particularly in water, owing to their highly hydrophilic nature. This research aims to assess the siloxane adsorption capacity of porous hydrophobic zeolitic materials in single-component and multi-component systems while examining the siloxane adsorption mechanisms. The materials under consideration include UTD-1, ZSM-12, SSZ-74, de-aluminated Beta zeolite, and a hierarchical carbon-faujasite composite. These materials were selected for their hydrophobic characteristics and thermal and chemical stability, making them promising candidates for removing MMST, DMSD, and TMS from water. Preliminary results suggest that framework defects in pure silica zeolites exhibit the highest siloxane adsorption capacity and selectivity for siloxanes in single-component systems and multi-component matrices. For example, UTD-1 demonstrated a TMS adsorption capacity of at least 18.0 mg g−1 at a 10 mg L−1 aqueous concentration, outperforming previously reported commercial materials (maximum 3.3 mg g−1).