Vol.:(0123456789) 1 3 Journal of Porous Materials https://doi.org/10.1007/s10934-019-00803-0 Iron oxide impregnated mesoporous MCM‑41: synthesis, characterization and adsorption studies Jyoti Prakash Dhal 1,2  · Tapan Dash 3  · Garudadhwaj Hota 2 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract Mesoporous MCM-41 and MCM-41 impregnated with structural iron (Fe–MCM-41) were prepared by a facile surfactant based wet chemical method using tetraethyl orthosilicate, cetyl trimethyl ammonium bromide in the presence of ammonium hydroxide and FeSO 4 ·7H 2 O as impregnated reagent. The prepared mesoporous materials were characterized by small and wide angle X-ray difraction (XRD), XPS, FESEM, HRTEM, FTIR and N 2 gas adsorption/desorption isotherm techniques. The results indicate the formation of high surface area (1266 m 2 /g) porous structure with particle size in the range of 200–400 nm for MCM-41. In case of Fe–MCM-41 the surface area decreases (880 m 2 /g) substantially with formation of iron oxide nanoparticles in the frame work of MCM-41. The obtained mesoporous materials were used as adsorbents for the removal of methylene blue from aqueous media. The percentage removal of the dye was found to be 99.9% for Fe–MCM- 41 and 94.5% for MCM-41, respectively, by using 20 mL of dye solution with initial concentration of 100 mg/L and 0.05 g of each adsorbent. The maximum adsorption capacity of Fe–MCM-41 was found to be 194 mg/g and for MCM-41, it was 149.5 mg/g. This result suggests that the prepared Fe–MCM-41 is an efective adsorbent for decontamination of Methylene blue from aqueous media. Keywords Mesoporous materials · MCM-41 · Fe–MCM-41 · Adsorption · Methylene blue 1 Introduction Mesoporous materials such as MCM-41, MCM-48, and SBAs have been the subject of intensive research in the feld of adsorption and heterogeneous catalysis because of their high surface area, high pore volume, favorable and control- lable pore uniformity, high hydrophobicity and relatively high thermal stability [1–3]. MCM-41 (Mobil composite material number 41, frst discovered in 1992) consists of hexagonal array of uniformly sized one-dimensional pore geometry with a pore diameter of 2 to 10 nm [4]. Due to its excellent removal capacity, mesoporous MCM-41 has been used for adsorption of various contaminants from aqueous media. For the improvement of the adsorption capacity and selectivity of adsorption, modifcation of MCM-41 is very helpful [5]. Particularly, incorporation of heteroatoms such as Fe, Al, Cr and so on into the primarily inert frameworks make the structure more potential for the application in the feld of catalysis and adsorption [6, 7]. Due to its high surface area of around 1000 m 2 /g, porosity and amorphous structure, there is a possibility of impregnation of transition metal ion inside the mesoporous framework by substitution of Si atoms in regular tetrahedral positions [8, 9]. Amongst the various heteroatoms, iron atom incorporated into the silica framework results the generation of strong acid sites; as a result Fe-containing mesoporous silicates have shown improved performance towards catalytic activ- ity and adsorption. Very recently several attempts have been made in which iron-containing mesoporous materials MCM-41(Fe 3+ ) have been extensively studied because of its considerable interest for various applications, especially * Jyoti Prakash Dhal jyoti84.chem@gmail.com * Garudadhwaj Hota garud@nitrkl.ac.in 1 Department of Chemistry, College of Engineering and Technology (A Constituent and Autonomous College of Biju Patnaik University of Technology, Orissa), Bhubaneswar, India 2 Department of Chemistry, National Institute of Technology, Rourkela, Odisha 769008, India 3 Centurion University of Technology and Management, Odisha, India