Vol.:(0123456789) 1 3 Journal of Porous Materials https://doi.org/10.1007/s10934-019-00821-y Mesoporous magnetic nanocomposites: a promising adsorbent for the removal of dyes from aqueous solutions Roxana Nicola 1  · Otilia Costişor 1  · Simona‑Gabriela Muntean 1  · Maria‑Andreea Nistor 1  · Ana‑Maria Putz 1  · Cătălin Ianăşi 1  · Radu Lazău 2  · László Almásy 3,4  · Liviu Săcărescu 5 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract Water pollution by synthetic organic dyes is mainly regarded as environmental and ecological issues worldwide and requires feasible solutions in face of the short-term risk to human health and stability of eco-systems. Therefore, in this paper, the magnetic mesoporous composites (MMC) were synthesized by surfactant template sol–gel method, using cetyl-trimethyl- ammonium bromide (CTAB) as mesoporous structure generator and investigated for anionic and cationic dyes removal from aqueous solutions. The magnetic iron oxide nanoparticles were obtained by reverse co-precipitation, followed by mesoporous silica coating through modifed sol–gel method. The obtained materials were characterized by FT-IR spectroscopy, X-ray difraction, transmission electron microscopy, Mössbauer spectroscopy, nitrogen adsorption, small-angle X-ray scatter- ing and magnetization measurements. The infuence of CTAB amount on the morpho-textural and structural properties of nanocomposites was studied. XRD and Mössbauer spectroscopy showed that the obtained nanocomposites were composed of pure maghemite nanoparticles, and TEM images revealed particles size around 10 nm, embedded in silica matrix. The combination of magnetic properties and high surface area values, up to 695 m 2 /g, made suitable the obtained nanocomposites to be used as adsorbents. The dye removal efciency was higher than 90% after the frst adsorption and remained above 65% after four adsorption–desorption cycles, indicating that the as-prepared magnetic mesoporous nanocomposites can be con- sidered excellent adsorbent materials for the removal of both anionic and cationic dyes from wastewaters, and the recycling performance revealed the stability of MMC. Keywords Adsorption · Dyes · Sol–gel · Iron oxide silica nanocomposites 1 Introduction During last years, there has been a growing interest in nano- materials due to special properties ofered by their specifc dimensions, which are signifcantly diferent from those of bulk materials. These unique properties arise from large fraction of surface atoms, high surface energy, spatial con- fnement, reduced imperfections [1, 2]. Nanocomposites represent an important class of nanoma- terials with many applications in diferent felds. Iron oxides with mesoporous silica are a class of nanocomposites that have attracted increased attention due to their unique func- tionality and separability [3]. The combined functionalities of the cores and shells have brought core/shell structured nanoparticles to the attention of researchers, because they exhibit magnetic response, low cytotoxicity, and chemically modifable surface [4]. This kind of material have potential applications in biomedicine, biotechnology, MRI, catalysis, * Simona-Gabriela Muntean sgmuntean@yahoo.com * Ana-Maria Putz lacramaanamaria@yahoo.com 1 “Coriolan Drăgulescu” Institute of Chemistry, Romanian Academy, Bv. Mihai Viteazu, No. 24, 300223 Timisoara, Romania 2 Faculty of Industrial Chemistry and Environmental Engineering, “Politehnica” University of Timişoara, Vasile Pârvan Bd., No. 6, 300223 Timisoara, Romania 3 Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, POB 49, Budapest 1525, Hungary 4 State Key Laboratory of Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, Sichuan, China 5 Institute of Macromolecular Chemistry “Petru Poni”, Aleea Grigore Ghica Voda, nr. 41A, 700487 Iasi, Romania