Silica-Based Porous Adsorbents for Efficient 17α-Ethinylestradiol Removal: Role of Organic Functionalization and Water Matrices

abstract

Three silica-based porous adsorbents, MCM-41 (pure silica), vinyl-MCM-41 (hybrid silica), and Ph-PMO (periodic mesoporous phenylene-silica), were tested to evaluate the effect of organic functionalities on removing the hormone disruptor 17α-ethinylestradiol (EE2) from water. Different adsorbent dosages were tested in ultrapure water spiked with 200 μg L–1 EE2, and the results revealed that adsorbent concentrations higher than 500 mg L–1 did not significantly enhance the EE2 removal efficiency. Both materials containing organic functionalities (using a dose of 500 mg L–1) were tested in ultrapure water, phosphate buffer at pH 5, 7, and 9, and wastewater effluent to evaluate the pH impact and the effect of different water matrices on their adsorption performance. An increase in pH significantly improved the EE2 adsorption capacity of Ph-PMO, reaching 94 ± 2% at pH 9, while it decreased the adsorption efficiency of vinyl-MCM-41 to 14 ± 7% at the same pH. Following a comprehensive characterization of the materials, including assessments of chemical stability across varying pH conditions, point of zero charge, hydrophobicity, and textural properties such as specific surface area, pore volume, and pore diameter, the findings suggest that the homogeneous distribution of organic functionalities in Ph-PMO enhances surface interactions, such as π–π stacking and hydrophobic interactions, with the EE2 hormone. Ph-PMO demonstrated superior performance in wastewater effluents, and kinetic studies showed rapid EE2 adsorption across all matrices, reaching equilibrium within 5 min. This study highlights the potential of Ph-PMO for the advanced-stage removal of EE2 from water effluents.

authors

Tiago Morais, Diogo Pereira, Geraldine Sequera, Ana C. Moreira, Marina Ilkaeva, Luís Mafra, Mariana Sardo, Vânia Calisto, Mirtha A. O. Lourenço

Groups

G1 - Porous Materials and Nanosystems

Projects

CICECO-Aveiro Institute of Materials R&D Unit Pluriannual Funding (CICECO-Aveiro Institute of Materials)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

Rede Nacional de Ressonância Magnética Nuclear (PTNMR)

Unveiling CO2 chemisorption mechanisms in solid adsorbents via surface-enhanced ex(in)-situ NMR (NMR4CO2)

Rationale design of sustainable porous organosilicas for optimal CO2 uptake from biogas (GRACE)

acknowledgements

This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UID/50011/2025 (DOI 10.54499/UID/50011/2025) & LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020), financed by national funds through the FCT/MEC (PIDDAC). This work was also funded by national funds through FCT – Fundação para a Ciência e a Tecnologia I.P., under the project CESAM-Centro de Estudos do Ambiente e do Mar, references UID/50017/2025 (doi.org/10.54499/UID/50017/2025) and LA/P/0094/2020 (doi.org/10.54499/LA/P/0094/2020). The NMR spectrometers are part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project 022161 (cofinanced by FEDER through COMPETE 2020, POCI, and PORL and FCT through PIDDAC). This work has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement 865974). FCT is also acknowledged by T.M for a Ph.D Studentship (2024.03066.BD), D.P. for a Ph.D. Studentship (2020.05389. BD), M.I., M.A.O.L., and M.S. for Researcher positions (CEECIND/00546/2018, CEECIND/01158/2021, and CEECIND/00056/2020, respectively). M.A.O.L further acknowledges the funding from the European Union’s Horizon Europe research and innovation programme (ERA-PF grant agreement No 101090287). MI also acknowledges the Spanish Ministry of Science, Innovation, and Universities for the “Beatriz Galindo” Scholarship (MU-23-BG22/00145).