Engineered dual-template SBA-15/Fe₃O₄ nanocomposites: Mesoporous structure and magnetically recoverable adsorbents for Pb(II) and synthetic dye removal

Synthetic dyes and heavy metal ions are commonly found in industrial waste, which are classified as organic and inorganic pollutants. Therefore, to reduce the content of industrial pollutants, high-performance adsorbents are necessary. Two types of surfactant templating were used in the formation and arrangement of the silica mesostructured, SBA-15 Y sample (Pluronic template) and SBA-15 Z (Pluronic–PVA dual template). The dual-template approach provides more precise control of the pore structure, thereby enhancing the integration of Fe₃O₄ nanoparticles. Wet impregnation method to synthesize nanocomposite SBA-15/Fe₃O₄ based on silica SBA-15 as a supporting cell material and Fe₃O₄ nanoparticles. Nitrogen physisorption studies, FTIR spectra, XRD, SEM-EDX, and element mapping confirmed the final stage of Fe₃O₄ deposition within the SBA-15 framework to characterize the meso-structured SBA-15/ Fe₃O₄. Through qualitative methodologies, SBA-15/Fe₃O₄ shows a strong magnetic response to neodymium magnets. Nitrogen physisorption demonstrates that SBA-15 Y and SBA-15 Z possess outstanding mesoporous structures, featuring BET surface areas reaching 1191 m²/g and pore volumes of 1.7 cm³ /g. Enhancing the silica composition to 60–90 % can improve the textural properties of SBA-15 Y, while the SBA-15 Z series samples demonstrate stability in high surface area and pore volume. The SBA-15/Fe₃O₄ effectively adsorbs rhodamine, methylene blue, and Pb(II) (80–98 %) due to its ordered meso-structure, strong Si–O–Si band intensity, and large surface area. Based on the new insights, a suitable foundation can be established for the advancement of mesoporous adsorbents intended for wastewater treatment. • The (Pluronik-PVA) surfactant template-engineered SBA-15/Fe₃O₄ exhibits favorable adsorption and magnetic recovery. • SBA-15 Z demonstrates significant MB and RhB adsorption, as evidenced by a Langmuir separation factor (Rₗ = 0.013). • The Freundlich model provides a more effective basis for Pb(II) adsorption on 60-SBA-Z, implying a heterogeneous surface. • The mesoporous structure and high surface area of SBA-15 enhance its adsorption capacity and affinity.