Phenylene‐Bridged Magnetic Mesoporous Silica for Dual‐Target Elimination of Arsenic(III) and Doxycycline from Real Water

Magnetic mesoporous silica with amino, thiol, or bifunctional surfaces are synthesized via sol–gel coating of magnetite using a phenylene-bridged polysilsesquioxane precursor. These eco-friendly materials (237–980 m² g⁻¹, up to 2.5 mmol g⁻¹ functional groups) show balanced hydrophilicity/hydrophobicity and excellent adsorption of As(III) and doxycycline, even in complex natural water.

The issues of adsorption and adsorbents remain highly relevant, particularly in light of their application for real adsorption from dam water, where competitive adsorption occurs on surfaces from multicomponent solutions containing contaminants in nano- or micro-quantities. In this study, magnetic mesoporous mono- and bifunctional samples (featuring amino and/or thiol groups for dual simultaneous adsorption) are developed. It is established that the obtained samples exhibit a well-developed specific surface area owing to the use of a precursor with a phenylene bridge in the synthesis (237–980 m² g⁻¹), with a total content of functional groups of up to 2.5 mmol g⁻¹. A comparison of water and benzene vapor adsorption revealed their rapid kinetics and equal hydrophilic/hydrophobic balance for all the samples. The thiol-functionalized sample proved to be the best in arsenic ions adsorption, while the bifunctional amino/thiol sample demonstrated the highest performance during doxycycline adsorption.  In real water containing trace amounts of other metals, the bifunctional sample Fe₃O₄/≡OSi–C₆H₄–SiO≡/≡Si(CH₂)₃NH₂/≡Si(CH₂)₃SH showed its advantages, as the different types of active centers on its surface additionally bound nontarget contaminants.

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